Showing posts with label Drag and Drop. Show all posts
Showing posts with label Drag and Drop. Show all posts

Monday, January 19, 2015

Drag and Drop between ListView and GridView

Previous example show how to implement Drag-and-Drop between ListViews. As both ListView and Gridiew subclasses of AbsListView, it's easy to implement Drag-and-Drop between ListView and GridView.


Refactory LinearLayoutListView.java to LinearLayoutAbsListView.java, to implement our custom LinearLayout associate with AbsListView, for ListView or GridView.
package com.example.androidimageviewlist;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.AbsListView;
import android.widget.LinearLayout;

public class LinearLayoutAbsListView extends LinearLayout {
 
 AbsListView absListView;

 public LinearLayoutAbsListView(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
 }

 public LinearLayoutAbsListView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
 }

 public LinearLayoutAbsListView(Context context, AttributeSet attrs,
   int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  // TODO Auto-generated constructor stub
 }

 public void setAbsListView(AbsListView alv){
  absListView = alv;
 }

}

Create /res/layout/gridrow.xml to define row layout for GridView.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <ImageView
        android:id="@+id/gridrowImageView"
        android:layout_gravity="center"
        android:layout_width="48dp"
        android:layout_height="48dp" />

</LinearLayout>

Modify /res/layout/activity_main.xml to include three <com.example.androidimageviewlist.LinearLayoutAbsListView>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="4dp"
    tools:context="com.example.androidimageviewlist.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="2"
        android:background="@android:color/background_dark"
        android:orientation="horizontal" >

        <com.example.androidimageviewlist.LinearLayoutAbsListView
            android:id="@+id/pane1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.example.androidimageviewlist.LinearLayoutAbsListView>

        <com.example.androidimageviewlist.LinearLayoutAbsListView
            android:id="@+id/pane2"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.example.androidimageviewlist.LinearLayoutAbsListView>
        
        <com.example.androidimageviewlist.LinearLayoutAbsListView
            android:id="@+id/pane3"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <GridView
                android:id="@+id/gridview3"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:numColumns="auto_fit"
                android:verticalSpacing="10dp"
                android:horizontalSpacing="10dp"
                android:columnWidth="60dp"
                android:stretchMode="columnWidth"
                android:gravity="center" />
        </com.example.androidimageviewlist.LinearLayoutAbsListView>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal" >

        <TextView
            android:id="@+id/prompt"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@android:color/black"
            android:gravity="bottom"
            android:textColor="@android:color/white" />
    </LinearLayout>

</LinearLayout>

MainActivity.java
package com.example.androidimageviewlist;

import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

 //items stored in ListView
 public class Item {
  Drawable ItemDrawable;
  String ItemString;
  Item(Drawable drawable, String t){
   ItemDrawable = drawable;
   ItemString = t;
  }
 }
 
 //objects passed in Drag and Drop operation
 class PassObject{
  View view;
  Item item;
  List<Item> srcList;
  
  PassObject(View v, Item i, List<Item> s){
   view = v;
   item = i;
   srcList = s;
  }
 }
 
 static class ViewHolder {
  ImageView icon;
  TextView text; 
 }
 
 static class GridViewHolder {
  ImageView icon; 
 }
 
 public class ItemBaseAdapter extends BaseAdapter {

  Context context;
  List<Item> list;

  ItemBaseAdapter(Context c, List<Item> l){
   context = c;
   list = l;
  }

  @Override
  public int getCount() {
   return list.size();
  }

  @Override
  public Object getItem(int position) {
   return list.get(position);
  }

  @Override
  public long getItemId(int position) {
   return position;
  }
  
  public List<Item> getList(){
   return list;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   // TODO Auto-generated method stub
   return null;
  }
  
 }
 

 public class ItemListAdapter extends ItemBaseAdapter {
  
  ItemListAdapter(Context c, List<Item> l) {
   super(c, l);
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   View rowView = convertView;
   
      // reuse views
      if (rowView == null) {
       LayoutInflater inflater = ((Activity) context).getLayoutInflater();
       rowView = inflater.inflate(R.layout.row, null);

       ViewHolder viewHolder = new ViewHolder();
       viewHolder.icon = (ImageView) rowView.findViewById(R.id.rowImageView);
       viewHolder.text = (TextView) rowView.findViewById(R.id.rowTextView);
       rowView.setTag(viewHolder); 
      }

      ViewHolder holder = (ViewHolder) rowView.getTag();
      holder.icon.setImageDrawable(list.get(position).ItemDrawable);
      holder.text.setText(list.get(position).ItemString);
      
      rowView.setOnDragListener(new ItemOnDragListener(list.get(position)));

      return rowView;
  }

 }
 
 public class ItemGridAdapter extends ItemBaseAdapter {

  ItemGridAdapter(Context c, List<Item> l) {
   super(c, l);
  }
  
  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   View gridrowView = convertView;
   
      // reuse views
      if (gridrowView == null) {
       LayoutInflater inflater = ((Activity) context).getLayoutInflater();
       gridrowView = inflater.inflate(R.layout.gridrow, null);

       GridViewHolder gridviewHolder = new GridViewHolder();
       gridviewHolder.icon = (ImageView) gridrowView.findViewById(R.id.gridrowImageView);
       gridrowView.setTag(gridviewHolder); 
      }

      GridViewHolder holder = (GridViewHolder) gridrowView.getTag();
      holder.icon.setImageDrawable(list.get(position).ItemDrawable);

      gridrowView.setOnDragListener(new ItemOnDragListener(list.get(position)));

      return gridrowView;
  }
  
 }

 List<Item> items1, items2, items3;
 ListView listView1, listView2;
 GridView gridView3;
 ItemListAdapter myItemListAdapter1, myItemListAdapter2;
 ItemGridAdapter myItemGridAdapter3;
 LinearLayoutAbsListView area1, area2, area3;
 TextView prompt;
 
 //Used to resume original color in drop ended/exited
 int resumeColor;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  listView1 = (ListView)findViewById(R.id.listview1);
  listView2 = (ListView)findViewById(R.id.listview2);
  gridView3 = (GridView)findViewById(R.id.gridview3);
  
  area1 = (LinearLayoutAbsListView)findViewById(R.id.pane1);
  area2 = (LinearLayoutAbsListView)findViewById(R.id.pane2);
  area3 = (LinearLayoutAbsListView)findViewById(R.id.pane3);
  area1.setOnDragListener(myOnDragListener);
  area2.setOnDragListener(myOnDragListener);
  area3.setOnDragListener(myOnDragListener);
  area1.setAbsListView(listView1);
  area2.setAbsListView(listView2);
  area3.setAbsListView(gridView3);
  
  initItems();
  myItemListAdapter1 = new ItemListAdapter(this, items1);
  myItemListAdapter2 = new ItemListAdapter(this, items2);
  myItemGridAdapter3 = new ItemGridAdapter(this, items3);
  listView1.setAdapter(myItemListAdapter1);
  listView2.setAdapter(myItemListAdapter2);
  gridView3.setAdapter(myItemGridAdapter3);
  
  listView1.setOnItemClickListener(listOnItemClickListener);
  listView2.setOnItemClickListener(listOnItemClickListener);
  gridView3.setOnItemClickListener(listOnItemClickListener);
  
  listView1.setOnItemLongClickListener(myOnItemLongClickListener);
  listView2.setOnItemLongClickListener(myOnItemLongClickListener);
  gridView3.setOnItemLongClickListener(myOnItemLongClickListener);
  
  prompt = (TextView) findViewById(R.id.prompt);
  // make TextView scrollable
  prompt.setMovementMethod(new ScrollingMovementMethod());
  //clear prompt area if LongClick
  prompt.setOnLongClickListener(new OnLongClickListener(){
   
   @Override
   public boolean onLongClick(View v) {
    prompt.setText("");
    return true; 
   }});
  
  resumeColor  = getResources().getColor(android.R.color.background_light);

 }
 
 OnItemLongClickListener myOnItemLongClickListener = new OnItemLongClickListener(){

  @Override
  public boolean onItemLongClick(AdapterView<?> parent, View view,
    int position, long id) {
   Item selectedItem = (Item)(parent.getItemAtPosition(position));
   
   ItemBaseAdapter associatedAdapter = (ItemBaseAdapter)(parent.getAdapter());
      List<Item> associatedList = associatedAdapter.getList();
   
   PassObject passObj = new PassObject(view, selectedItem, associatedList);

   ClipData data = ClipData.newPlainText("", "");
   DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
   view.startDrag(data, shadowBuilder, passObj, 0);
   
   return true;
  }
  
 };
 
 OnDragListener myOnDragListener = new OnDragListener() {

  @Override
  public boolean onDrag(View v, DragEvent event) {
   String area;
   if(v == area1){
    area = "area1"; 
   }else if(v == area2){
    area = "area2"; 
   }else if(v == area3){
    area = "area3"; 
   }else{
    area = "unknown"; 
   }
   
   switch (event.getAction()) {
    case DragEvent.ACTION_DRAG_STARTED:
     prompt.append("ACTION_DRAG_STARTED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_ENTERED:
     prompt.append("ACTION_DRAG_ENTERED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_EXITED:
     prompt.append("ACTION_DRAG_EXITED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DROP:
     prompt.append("ACTION_DROP: " + area  + "\n");

     PassObject passObj = (PassObject)event.getLocalState();
     View view = passObj.view;
     Item passedItem = passObj.item;
     List<Item> srcList = passObj.srcList;
     AbsListView oldParent = (AbsListView)view.getParent();
     ItemBaseAdapter srcAdapter = (ItemBaseAdapter)(oldParent.getAdapter());
     
     LinearLayoutAbsListView newParent = (LinearLayoutAbsListView)v;
     ItemBaseAdapter destAdapter = (ItemBaseAdapter)(newParent.absListView.getAdapter());
        List<Item> destList = destAdapter.getList();
     
     if(removeItemToList(srcList, passedItem)){
      addItemToList(destList, passedItem);
     }
     
     srcAdapter.notifyDataSetChanged();
     destAdapter.notifyDataSetChanged();
     
     //smooth scroll to bottom
     newParent.absListView.smoothScrollToPosition(destAdapter.getCount()-1);
     
     break;
      case DragEvent.ACTION_DRAG_ENDED:
       prompt.append("ACTION_DRAG_ENDED: " + area  + "\n");  
      default:
       break;    
   }
      
   return true;
  }
  
 };
 
 class ItemOnDragListener implements OnDragListener{
  
  Item  me;
  
  ItemOnDragListener(Item i){
   me = i;
  }

  @Override
  public boolean onDrag(View v, DragEvent event) {
   switch (event.getAction()) {
   case DragEvent.ACTION_DRAG_STARTED:
    prompt.append("Item ACTION_DRAG_STARTED: " + "\n");
    break; 
   case DragEvent.ACTION_DRAG_ENTERED:
    prompt.append("Item ACTION_DRAG_ENTERED: " + "\n");
    v.setBackgroundColor(0x30000000);
    break; 
   case DragEvent.ACTION_DRAG_EXITED:
    prompt.append("Item ACTION_DRAG_EXITED: " + "\n");
    v.setBackgroundColor(resumeColor);
    break; 
   case DragEvent.ACTION_DROP:
    prompt.append("Item ACTION_DROP: " + "\n");

    PassObject passObj = (PassObject)event.getLocalState();
    View view = passObj.view;
    Item passedItem = passObj.item;
    List<Item> srcList = passObj.srcList;
    AbsListView oldParent = (AbsListView)view.getParent();
    ItemBaseAdapter srcAdapter = (ItemBaseAdapter)(oldParent.getAdapter());
    
    AbsListView newParent = (AbsListView)v.getParent();
    ItemBaseAdapter destAdapter = (ItemBaseAdapter)(newParent.getAdapter());
    List<Item> destList = destAdapter.getList();
    
    int removeLocation = srcList.indexOf(passedItem);
    int insertLocation = destList.indexOf(me);
    /*
     * If drag and drop on the same list, same position,
     * ignore
     */
    if(srcList != destList || removeLocation != insertLocation){
     if(removeItemToList(srcList, passedItem)){
      destList.add(insertLocation, passedItem);
     }
     
     srcAdapter.notifyDataSetChanged();
     destAdapter.notifyDataSetChanged();
    }

    v.setBackgroundColor(resumeColor);
    
    break;
     case DragEvent.ACTION_DRAG_ENDED:
      prompt.append("Item ACTION_DRAG_ENDED: "  + "\n");
      v.setBackgroundColor(resumeColor);
     default:
      break;    
  }
     
  return true;
  }
  
 }
 
 OnItemClickListener listOnItemClickListener = new OnItemClickListener(){

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position,
    long id) {
   Toast.makeText(MainActivity.this, 
     ((Item)(parent.getItemAtPosition(position))).ItemString, 
     Toast.LENGTH_SHORT).show();
  }
  
 };

 private void initItems(){
  items1 = new ArrayList<Item>();
  items2 = new ArrayList<Item>();
  items3 = new ArrayList<Item>();
  
  TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
  TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
  
  for(int i=0; i<arrayDrawable.length(); i++){
   Drawable d = arrayDrawable.getDrawable(i);
   String s = arrayText.getString(i);
   Item item = new Item(d, s);
   items1.add(item);
  }
  
  arrayDrawable.recycle();
  arrayText.recycle();
 }
 
 private boolean removeItemToList(List<Item> l, Item it){
  boolean result = l.remove(it);
  return result;
 }
 
 private boolean addItemToList(List<Item> l, Item it){
  boolean result = l.add(it);
  return result;
 }

}

download filesDownload the files.

Tuesday, January 13, 2015

Drag and Drop items between ListView, with OnDragListener on ListView cells

In last two post "Drag and Drop items between ListView" and "Improved Drag and Drop items between ListView", it drag a ListView item, drop on a LinearLayout, then add the item to the associated ListView, always on bottom. Not drop on ListView actually.

In this exercise, another OnDragListener (ItemOnDragListener) implemented for rowView of ListView items, such that we can actually drop on ListView items, and insert in the previous position.


MainActivity.java
package com.example.androidimageviewlist;

import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

 //items stored in ListView
 public class Item {
  Drawable ItemDrawable;
  String ItemString;
  Item(Drawable drawable, String t){
   ItemDrawable = drawable;
   ItemString = t;
  }
 }
 
 //objects passed in Drag and Drop operation
 class PassObject{
  View view;
  Item item;
  List<Item> srcList;
  
  PassObject(View v, Item i, List<Item> s){
   view = v;
   item = i;
   srcList = s;
  }
 }
 
 static class ViewHolder {
  ImageView icon;
  TextView text; 
 }

 public class ItemsListAdapter extends BaseAdapter {
  
  private Context context;
  private List<Item> list;

  ItemsListAdapter(Context c, List<Item> l){
   context = c;
   list = l;
  }

  @Override
  public int getCount() {
   return list.size();
  }

  @Override
  public Object getItem(int position) {
   return list.get(position);
  }

  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   View rowView = convertView;
   
      // reuse views
      if (rowView == null) {
       LayoutInflater inflater = ((Activity) context).getLayoutInflater();
       rowView = inflater.inflate(R.layout.row, null);

       ViewHolder viewHolder = new ViewHolder();
       viewHolder.icon = (ImageView) rowView.findViewById(R.id.rowImageView);
       viewHolder.text = (TextView) rowView.findViewById(R.id.rowTextView);
       rowView.setTag(viewHolder); 
      }

      ViewHolder holder = (ViewHolder) rowView.getTag();
      holder.icon.setImageDrawable(list.get(position).ItemDrawable);
      holder.text.setText(list.get(position).ItemString);
      
      rowView.setOnDragListener(new ItemOnDragListener(list.get(position)));

      return rowView;
  }
  
  public List<Item> getList(){
   return list;
  }
 }

 List<Item> items1, items2, items3;
 ListView listView1, listView2, listView3;
 ItemsListAdapter myItemsListAdapter1, myItemsListAdapter2, myItemsListAdapter3;
 LinearLayoutListView area1, area2, area3;
 TextView prompt;
 
 //Used to resume original color in drop ended/exited
 int resumeColor;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  listView1 = (ListView)findViewById(R.id.listview1);
  listView2 = (ListView)findViewById(R.id.listview2);
  listView3 = (ListView)findViewById(R.id.listview3);
  
  area1 = (LinearLayoutListView)findViewById(R.id.pane1);
  area2 = (LinearLayoutListView)findViewById(R.id.pane2);
  area3 = (LinearLayoutListView)findViewById(R.id.pane3);
  area1.setOnDragListener(myOnDragListener);
  area2.setOnDragListener(myOnDragListener);
  area3.setOnDragListener(myOnDragListener);
  area1.setListView(listView1);
  area2.setListView(listView2);
  area3.setListView(listView3);
  
  initItems();
  myItemsListAdapter1 = new ItemsListAdapter(this, items1);
  myItemsListAdapter2 = new ItemsListAdapter(this, items2);
  myItemsListAdapter3 = new ItemsListAdapter(this, items3);
  listView1.setAdapter(myItemsListAdapter1);
  listView2.setAdapter(myItemsListAdapter2);
  listView3.setAdapter(myItemsListAdapter3);
  
  /*
  //Auto scroll to end of ListView
  listView1.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  listView2.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  listView3.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  */
  
  listView1.setOnItemClickListener(listOnItemClickListener);
  listView2.setOnItemClickListener(listOnItemClickListener);
  listView3.setOnItemClickListener(listOnItemClickListener);
  
  listView1.setOnItemLongClickListener(myOnItemLongClickListener);
  listView2.setOnItemLongClickListener(myOnItemLongClickListener);
  listView3.setOnItemLongClickListener(myOnItemLongClickListener);
  
  prompt = (TextView) findViewById(R.id.prompt);
  // make TextView scrollable
  prompt.setMovementMethod(new ScrollingMovementMethod());
  //clear prompt area if LongClick
  prompt.setOnLongClickListener(new OnLongClickListener(){
   
   @Override
   public boolean onLongClick(View v) {
    prompt.setText("");
    return true; 
   }});
  
  resumeColor  = getResources().getColor(android.R.color.background_light);

 }
 
 OnItemLongClickListener myOnItemLongClickListener = new OnItemLongClickListener(){

  @Override
  public boolean onItemLongClick(AdapterView<?> parent, View view,
    int position, long id) {
   Item selectedItem = (Item)(parent.getItemAtPosition(position));
   
   ItemsListAdapter associatedAdapter = (ItemsListAdapter)(parent.getAdapter());
      List<Item> associatedList = associatedAdapter.getList();
   
   PassObject passObj = new PassObject(view, selectedItem, associatedList);

   ClipData data = ClipData.newPlainText("", "");
   DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
   view.startDrag(data, shadowBuilder, passObj, 0);
   
   return true;
  }
  
 };
 
 OnDragListener myOnDragListener = new OnDragListener() {

  @Override
  public boolean onDrag(View v, DragEvent event) {
   String area;
   if(v == area1){
    area = "area1"; 
   }else if(v == area2){
    area = "area2"; 
   }else if(v == area3){
    area = "area3"; 
   }else{
    area = "unknown"; 
   }
   
   switch (event.getAction()) {
    case DragEvent.ACTION_DRAG_STARTED:
     prompt.append("ACTION_DRAG_STARTED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_ENTERED:
     prompt.append("ACTION_DRAG_ENTERED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_EXITED:
     prompt.append("ACTION_DRAG_EXITED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DROP:
     prompt.append("ACTION_DROP: " + area  + "\n");

     PassObject passObj = (PassObject)event.getLocalState();
     View view = passObj.view;
     Item passedItem = passObj.item;
     List<Item> srcList = passObj.srcList;
     ListView oldParent = (ListView)view.getParent();
     ItemsListAdapter srcAdapter = (ItemsListAdapter)(oldParent.getAdapter());
     
     LinearLayoutListView newParent = (LinearLayoutListView)v;
     ItemsListAdapter destAdapter = (ItemsListAdapter)(newParent.listView.getAdapter());
        List<Item> destList = destAdapter.getList();
     
     if(removeItemToList(srcList, passedItem)){
      addItemToList(destList, passedItem);
     }
     
     srcAdapter.notifyDataSetChanged();
     destAdapter.notifyDataSetChanged();
     
     //smooth scroll to bottom
     newParent.listView.smoothScrollToPosition(destAdapter.getCount()-1);
     
     break;
      case DragEvent.ACTION_DRAG_ENDED:
       prompt.append("ACTION_DRAG_ENDED: " + area  + "\n");  
      default:
       break;    
   }
      
   return true;
  }
  
 };
 
 class ItemOnDragListener implements OnDragListener{
  
  Item  me;
  
  ItemOnDragListener(Item i){
   me = i;
  }

  @Override
  public boolean onDrag(View v, DragEvent event) {
   switch (event.getAction()) {
   case DragEvent.ACTION_DRAG_STARTED:
    prompt.append("Item ACTION_DRAG_STARTED: " + "\n");
    break; 
   case DragEvent.ACTION_DRAG_ENTERED:
    prompt.append("Item ACTION_DRAG_ENTERED: " + "\n");
    v.setBackgroundColor(0x30000000);
    break; 
   case DragEvent.ACTION_DRAG_EXITED:
    prompt.append("Item ACTION_DRAG_EXITED: " + "\n");
    v.setBackgroundColor(resumeColor);
    break; 
   case DragEvent.ACTION_DROP:
    prompt.append("Item ACTION_DROP: " + "\n");

    PassObject passObj = (PassObject)event.getLocalState();
    View view = passObj.view;
    Item passedItem = passObj.item;
    List<Item> srcList = passObj.srcList;
    ListView oldParent = (ListView)view.getParent();
    ItemsListAdapter srcAdapter = (ItemsListAdapter)(oldParent.getAdapter());
    
    ListView newParent = (ListView)v.getParent();
    ItemsListAdapter destAdapter = (ItemsListAdapter)(newParent.getAdapter());
    List<Item> destList = destAdapter.getList();
    
    int removeLocation = srcList.indexOf(passedItem);
    int insertLocation = destList.indexOf(me);
    /*
     * If drag and drop on the same list, same position,
     * ignore
     */
    if(srcList != destList || removeLocation != insertLocation){
     if(removeItemToList(srcList, passedItem)){
      destList.add(insertLocation, passedItem);
     }
     
     srcAdapter.notifyDataSetChanged();
     destAdapter.notifyDataSetChanged();
    }

    v.setBackgroundColor(resumeColor);
    
    break;
     case DragEvent.ACTION_DRAG_ENDED:
      prompt.append("Item ACTION_DRAG_ENDED: "  + "\n");
      v.setBackgroundColor(resumeColor);
     default:
      break;    
  }
     
  return true;
  }
  
 }
 
 OnItemClickListener listOnItemClickListener = new OnItemClickListener(){

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position,
    long id) {
   Toast.makeText(MainActivity.this, 
     ((Item)(parent.getItemAtPosition(position))).ItemString, 
     Toast.LENGTH_SHORT).show();
  }
  
 };

 private void initItems(){
  items1 = new ArrayList<Item>();
  items2 = new ArrayList<Item>();
  items3 = new ArrayList<Item>();
  
  TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
  TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
  
  for(int i=0; i<arrayDrawable.length(); i++){
   Drawable d = arrayDrawable.getDrawable(i);
   String s = arrayText.getString(i);
   Item item = new Item(d, s);
   items1.add(item);
  }
  
  arrayDrawable.recycle();
  arrayText.recycle();
 }
 
 private boolean removeItemToList(List<Item> l, Item it){
  boolean result = l.remove(it);
  return result;
 }
 
 private boolean addItemToList(List<Item> l, Item it){
  boolean result = l.add(it);
  return result;
 }

}

LinearLayoutListView.java and the layout file, /res/layout/activity_main.xml, refer to last post.

/res/layout/row.xml and /res/values/arrays.xml, refer to previous post of "Custom ListView with ImageView".

To use Drag and Drop on your app, you have to modify AndroidManifest.xml to set android:minSdkVersion="11".



download filesDownload the files.

Next:
Drag and Drop between ListView and GridView

Sunday, January 11, 2015

Improved Drag and Drop items between ListView

Last post show my first try "Drag and Drop items between ListView". The source and destination of the Drag and Drop operation is hard coded and fixed. It's too un-flexible! It is improved here to provide more flexible approach.


In order to get the associated ListView from any LinearLayout to be drop, I create a new class LinearLayoutListView extends LinearLayout, associated with a ListView.

LinearLayoutListView.java
package com.example.androidimageviewlist;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.LinearLayout;
import android.widget.ListView;

public class LinearLayoutListView extends LinearLayout {
 
 ListView listView;

 public LinearLayoutListView(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
 }

 public LinearLayoutListView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
 }

 public LinearLayoutListView(Context context, AttributeSet attrs,
   int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  // TODO Auto-generated constructor stub
 }

 public void setListView(ListView lv){
  listView = lv;
 }

}

Modify /res/layout/activity_main.xml, to use <com.example.androidimageviewlist.LinearLayoutListView>. And also display three to show the flexibility of the new approach.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="4dp"
    tools:context="com.example.androidimageviewlist.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="2"
        android:background="@android:color/background_dark"
        android:orientation="horizontal" >

        <com.example.androidimageviewlist.LinearLayoutListView
            android:id="@+id/pane1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.example.androidimageviewlist.LinearLayoutListView>

        <com.example.androidimageviewlist.LinearLayoutListView
            android:id="@+id/pane2"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.example.androidimageviewlist.LinearLayoutListView>
        
        <com.example.androidimageviewlist.LinearLayoutListView
            android:id="@+id/pane3"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview3"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </com.example.androidimageviewlist.LinearLayoutListView>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal" >

        <TextView
            android:id="@+id/prompt"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@android:color/black"
            android:gravity="bottom"
            android:textColor="@android:color/white" />
    </LinearLayout>

</LinearLayout>

MainActivity.java
package com.example.androidimageviewlist;

import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

 //items stored in ListView
 public class Item {
  Drawable ItemDrawable;
  String ItemString;
  Item(Drawable drawable, String t){
   ItemDrawable = drawable;
   ItemString = t;
  }
 }
 
 //objects passed in Drag and Drop operation
 class PassObject{
  View view;
  Item item;
  List<Item> srcList;
  
  PassObject(View v, Item i, List<Item> s){
   view = v;
   item = i;
   srcList = s;
  }
 }
 
 static class ViewHolder {
  ImageView icon;
  TextView text; 
 }

 public class ItemsListAdapter extends BaseAdapter {
  
  private Context context;
  private List<Item> list;

  ItemsListAdapter(Context c, List<Item> l){
   context = c;
   list = l;
  }

  @Override
  public int getCount() {
   return list.size();
  }

  @Override
  public Object getItem(int position) {
   return list.get(position);
  }

  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   View rowView = convertView;
   
      // reuse views
      if (rowView == null) {
       LayoutInflater inflater = ((Activity) context).getLayoutInflater();
       rowView = inflater.inflate(R.layout.row, null);

       ViewHolder viewHolder = new ViewHolder();
       viewHolder.icon = (ImageView) rowView.findViewById(R.id.rowImageView);
       viewHolder.text = (TextView) rowView.findViewById(R.id.rowTextView);
       rowView.setTag(viewHolder); 
      }

      ViewHolder holder = (ViewHolder) rowView.getTag();
      holder.icon.setImageDrawable(list.get(position).ItemDrawable);
      holder.text.setText(list.get(position).ItemString);

      return rowView;
  }
  
  public List<Item> getList(){
   return list;
  }
 }

 List<Item> items1, items2, items3;
 ListView listView1, listView2, listView3;
 ItemsListAdapter myItemsListAdapter1, myItemsListAdapter2, myItemsListAdapter3;
 LinearLayoutListView area1, area2, area3;
 TextView prompt;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  listView1 = (ListView)findViewById(R.id.listview1);
  listView2 = (ListView)findViewById(R.id.listview2);
  listView3 = (ListView)findViewById(R.id.listview3);
  
  area1 = (LinearLayoutListView)findViewById(R.id.pane1);
  area2 = (LinearLayoutListView)findViewById(R.id.pane2);
  area3 = (LinearLayoutListView)findViewById(R.id.pane3);
  area1.setOnDragListener(myOnDragListener);
  area2.setOnDragListener(myOnDragListener);
  area3.setOnDragListener(myOnDragListener);
  area1.setListView(listView1);
  area2.setListView(listView2);
  area3.setListView(listView3);
  
  initItems();
  myItemsListAdapter1 = new ItemsListAdapter(this, items1);
  myItemsListAdapter2 = new ItemsListAdapter(this, items2);
  myItemsListAdapter3 = new ItemsListAdapter(this, items3);
  listView1.setAdapter(myItemsListAdapter1);
  listView2.setAdapter(myItemsListAdapter2);
  listView3.setAdapter(myItemsListAdapter3);
  
  //Auto scroll to end of ListView
  listView1.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  listView2.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  listView3.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);

  listView1.setOnItemClickListener(listOnItemClickListener);
  listView2.setOnItemClickListener(listOnItemClickListener);
  listView3.setOnItemClickListener(listOnItemClickListener);
  
  listView1.setOnItemLongClickListener(myOnItemLongClickListener);
  listView2.setOnItemLongClickListener(myOnItemLongClickListener);
  listView3.setOnItemLongClickListener(myOnItemLongClickListener);
  
  prompt = (TextView) findViewById(R.id.prompt);
  // make TextView scrollable
  prompt.setMovementMethod(new ScrollingMovementMethod());
  //clear prompt area if LongClick
  prompt.setOnLongClickListener(new OnLongClickListener(){
   
   @Override
   public boolean onLongClick(View v) {
    prompt.setText("");
    return true; 
   }});

 }
 
 OnItemLongClickListener myOnItemLongClickListener = new OnItemLongClickListener(){

  @Override
  public boolean onItemLongClick(AdapterView<?> parent, View view,
    int position, long id) {
   Item selectedItem = (Item)(parent.getItemAtPosition(position));
   
   ItemsListAdapter associatedAdapter = (ItemsListAdapter)(parent.getAdapter());
      List<Item> associatedList = associatedAdapter.getList();
   
   PassObject passObj = new PassObject(view, selectedItem, associatedList);
   
   
   ClipData data = ClipData.newPlainText("", "");
   DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
   view.startDrag(data, shadowBuilder, passObj, 0);
   
   return true;
  }
  
 };
 
 OnDragListener myOnDragListener = new OnDragListener() {

  @Override
  public boolean onDrag(View v, DragEvent event) {
   String area;
   if(v == area1){
    area = "area1"; 
   }else if(v == area2){
    area = "area2"; 
   }else if(v == area3){
    area = "area3"; 
   }else{
    area = "unknown"; 
   }
   
   switch (event.getAction()) {
    case DragEvent.ACTION_DRAG_STARTED:
     prompt.append("ACTION_DRAG_STARTED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_ENTERED:
     prompt.append("ACTION_DRAG_ENTERED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_EXITED:
     prompt.append("ACTION_DRAG_EXITED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DROP:
     prompt.append("ACTION_DROP: " + area  + "\n");

     PassObject passObj = (PassObject)event.getLocalState();
     View view = passObj.view;
     Item passedItem = passObj.item;
     List<Item> srcList = passObj.srcList;
     ListView oldParent = (ListView)view.getParent();
     ItemsListAdapter srcAdapter = (ItemsListAdapter)(oldParent.getAdapter());
     
     LinearLayoutListView newParent = (LinearLayoutListView)v;
     ItemsListAdapter destAdapter = (ItemsListAdapter)(newParent.listView.getAdapter());
        List<Item> destList = destAdapter.getList();
     
     if(removeItemToList(srcList, passedItem)){
      addItemToList(destList, passedItem);
     }
     
     srcAdapter.notifyDataSetChanged();
     destAdapter.notifyDataSetChanged();
     
     break;
      case DragEvent.ACTION_DRAG_ENDED:
       prompt.append("ACTION_DRAG_ENDED: " + area  + "\n");   
      default:
       break;    
   }
      
   return true;
  }
  
 };
 
 OnItemClickListener listOnItemClickListener = new OnItemClickListener(){

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position,
    long id) {
   Toast.makeText(MainActivity.this, 
     ((Item)(parent.getItemAtPosition(position))).ItemString, 
     Toast.LENGTH_SHORT).show();
  }
  
 };

 private void initItems(){
  items1 = new ArrayList<Item>();
  items2 = new ArrayList<Item>();
  items3 = new ArrayList<Item>();
  
  TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
  TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
  
  for(int i=0; i<arrayDrawable.length(); i++){
   Drawable d = arrayDrawable.getDrawable(i);
   String s = arrayText.getString(i);
   Item item = new Item(d, s);
   items1.add(item);
  }
  
  arrayDrawable.recycle();
  arrayText.recycle();
 }
 
 private boolean removeItemToList(List<Item> l, Item it){
  boolean result = l.remove(it);
  return result;
 }
 
 private boolean addItemToList(List<Item> l, Item it){
  boolean result = l.add(it);
  return result;
 }

}

/res/layout/row.xml and /res/values/arrays.xml, refer to previous post of "Custom ListView with ImageView".

To use Drag and Drop on your app, you have to modify AndroidManifest.xml to set android:minSdkVersion="11".

download filesDownload the files.


In this exercise, it drag a ListView item, drop on a LinearLayout, then add the item to the associated ListView, always on bottom. Not drop on ListView actually.

In this exercise, "Drag and Drop items between ListView, with OnDragListener on ListView cells", another OnDragListener (ItemOnDragListener) implemented for rowView of ListView items, such that we can actually drop on ListView items, and insert in the previous position.

Drag and Drop items between ListView

This example show how to move items between ListView by Drag and Drop. (I don't know any standard method to achieve this, it's my own implementation)


MainActivity.java
package com.example.androidimageviewlist;

import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {
 
 //items stored in ListView
 public class Item {
  Drawable ItemDrawable;
  String ItemString;
  Item(Drawable drawable, String t){
   ItemDrawable = drawable;
   ItemString = t;
  }
 }
 
 //objects passed in Drag and Drop operation
 class PassObject{
  View view;
  Item item;
  
  PassObject(View v, Item i){
   view = v;
   item = i;
  }
 }
 
 static class ViewHolder {
  ImageView icon;
  TextView text; 
 }

 public class ItemsListAdapter extends BaseAdapter {
  
  private Context context;
  private List<Item> list;

  ItemsListAdapter(Context c, List<Item> l){
   context = c;
   list = l;
  }

  @Override
  public int getCount() {
   return list.size();
  }

  @Override
  public Object getItem(int position) {
   return list.get(position);
  }

  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   View rowView = convertView;
   
      // reuse views
      if (rowView == null) {
       LayoutInflater inflater = ((Activity) context).getLayoutInflater();
       rowView = inflater.inflate(R.layout.row, null);

       ViewHolder viewHolder = new ViewHolder();
       viewHolder.icon = (ImageView) rowView.findViewById(R.id.rowImageView);
       viewHolder.text = (TextView) rowView.findViewById(R.id.rowTextView);
       rowView.setTag(viewHolder); 
      }

      ViewHolder holder = (ViewHolder) rowView.getTag();
      holder.icon.setImageDrawable(list.get(position).ItemDrawable);
      holder.text.setText(list.get(position).ItemString);

      return rowView;
  }
  
  public List<Item> getList(){
   return list;
  }
 }

 List<Item> items1, items2;
 ListView listView1, listView2;
 ItemsListAdapter myItemsListAdapter1, myItemsListAdapter2;
 LinearLayout area1, area2;
 TextView prompt;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  listView1 = (ListView)findViewById(R.id.listview1);
  listView2 = (ListView)findViewById(R.id.listview2);
  
  area1 = (LinearLayout)findViewById(R.id.pane1);
  area2 = (LinearLayout)findViewById(R.id.pane2);
  area1.setOnDragListener(myOnDragListener);
  area2.setOnDragListener(myOnDragListener);
  
  initItems();
  myItemsListAdapter1 = new ItemsListAdapter(this, items1);
  myItemsListAdapter2 = new ItemsListAdapter(this, items2);
  listView1.setAdapter(myItemsListAdapter1);
  listView2.setAdapter(myItemsListAdapter2);
  
  //Auto scroll to end of ListView
  listView1.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
  listView2.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);

  listView1.setOnItemClickListener(listOnItemClickListener);
  listView2.setOnItemClickListener(listOnItemClickListener);
  
  listView1.setOnItemLongClickListener(myOnItemLongClickListener);
  listView2.setOnItemLongClickListener(myOnItemLongClickListener);
  
  prompt = (TextView) findViewById(R.id.prompt);
  // make TextView scrollable
  prompt.setMovementMethod(new ScrollingMovementMethod());
  //clear prompt area if LongClick
  prompt.setOnLongClickListener(new OnLongClickListener(){
   
   @Override
   public boolean onLongClick(View v) {
    prompt.setText("");
    return true; 
   }});

 }
 OnItemLongClickListener myOnItemLongClickListener = new OnItemLongClickListener(){

  @Override
  public boolean onItemLongClick(AdapterView<?> parent, View view,
    int position, long id) {
   Item selectedItem = (Item)(parent.getItemAtPosition(position));
   PassObject passObj = new PassObject(view, selectedItem);
   
   
   ClipData data = ClipData.newPlainText("", "");
   DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
   view.startDrag(data, shadowBuilder, passObj, 0);
   
   return true;
  }
  
 };
 
 OnDragListener myOnDragListener = new OnDragListener() {

  @Override
  public boolean onDrag(View v, DragEvent event) {
   String area;
   if(v == area1){
    area = "area1"; 
   }else if(v == area2){
    area = "area2"; 
   }else{
    area = "unknown"; 
   }
   
   switch (event.getAction()) {
    case DragEvent.ACTION_DRAG_STARTED:
     prompt.append("ACTION_DRAG_STARTED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_ENTERED:
     prompt.append("ACTION_DRAG_ENTERED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DRAG_EXITED:
     prompt.append("ACTION_DRAG_EXITED: " + area  + "\n");
     break; 
    case DragEvent.ACTION_DROP:
     prompt.append("ACTION_DROP: " + area  + "\n");

     PassObject passObj = (PassObject)event.getLocalState();
     View view = passObj.view;
     Item passedItem = passObj.item;
     ListView oldParent = (ListView)view.getParent();
     LinearLayout newParent = (LinearLayout)v;
     
     if(oldParent.equals(listView1)){
      prompt.append("Drag source: listView1" + "\n");
      
      if(newParent.equals(area2)){
       prompt.append("Drop target: area2" + "\n");
       
       if(removeItemToList(items1, passedItem)){
        addItemToList(items2, passedItem); 
       }
       myItemsListAdapter1.notifyDataSetChanged();
       myItemsListAdapter2.notifyDataSetChanged();
       
      }else{
       prompt.append("Invalid Drop target" + "\n");
      }
      
     }else if(oldParent.equals(listView2)){
      prompt.append("Drag source: listView2" + "\n");
      
      if(newParent.equals(area1)){
       prompt.append("Drop target: area1" + "\n");
       
       if(removeItemToList(items2, passedItem)){
        addItemToList(items1, passedItem); 
       }
       myItemsListAdapter1.notifyDataSetChanged();
       myItemsListAdapter2.notifyDataSetChanged();
      }else{
       prompt.append("Invalid Drop target" + "\n");
      }
      
     }else{
      prompt.append("Invalid Drag source: unknown" + "\n");
     }
     break;
      case DragEvent.ACTION_DRAG_ENDED:
       prompt.append("ACTION_DRAG_ENDED: " + area  + "\n");   
      default:
       break;    
   }
      
   return true;
  }
  
 };
 
 OnItemClickListener listOnItemClickListener = new OnItemClickListener(){

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position,
    long id) {
   Toast.makeText(MainActivity.this, 
     ((Item)(parent.getItemAtPosition(position))).ItemString, 
     Toast.LENGTH_SHORT).show();
  }
  
 };

 private void initItems(){
  items1 = new ArrayList<Item>();
  items2 = new ArrayList<Item>();
  
  TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
  TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
  
  for(int i=0; i<arrayDrawable.length(); i++){
   Drawable d = arrayDrawable.getDrawable(i);
   String s = arrayText.getString(i);
   Item item = new Item(d, s);
   items1.add(item);
  }
  
  arrayDrawable.recycle();
  arrayText.recycle();
 }
 
 private boolean removeItemToList(List<Item> l, Item it){
  boolean result = l.remove(it);
  return result;
 }
 
 private boolean addItemToList(List<Item> l, Item it){
  boolean result = l.add(it);
  return result;
 }

}

/res/layout/activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="4dp"
    tools:context="com.example.androidimageviewlist.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="2"
        android:background="@android:color/background_dark"
        android:orientation="horizontal" >

        <LinearLayout
            android:id="@+id/pane1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </LinearLayout>

        <LinearLayout
            android:id="@+id/pane2"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_weight="1"
            android:background="@android:color/background_light"
            android:orientation="vertical" >

            <ListView
                android:id="@+id/listview2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal" >

        <TextView
            android:id="@+id/prompt"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@android:color/black"
            android:gravity="bottom"
            android:textColor="@android:color/white" />
    </LinearLayout>

</LinearLayout>

/res/layout/row.xml and /res/values/arrays.xml, refer to previous post of "Custom ListView with ImageView".

To use Drag and Drop on your app, you have to modify AndroidManifest.xml to set android:minSdkVersion="11".

download filesDownload the files.


Next:
- It's a too un-flexible approach, The source and destination of the Drag and Drop operation is hard coded and fixed. Next is a "Improved Drag and Drop items between ListView".

- In the exercise "Drag and Drop items between ListView, with OnDragListener on ListView cells", another OnDragListener (ItemOnDragListener) implemented for rowView of ListView items, such that we can actually drop on ListView items, and insert in the previous position.

Tuesday, January 6, 2015

Android Drag and Drop example

This example show how to implement Drag and Drop on Android, to move ImageView between two LinearLayout.


To use Drag and Drop on Android, minSdkVersion in AndroidManifest.xml have to be 11 or higher.

Create /res/values/arrays.xml to define drawables in our ImageViews.
<?xml version="1.0" encoding="utf-8"?>
<resources>

    <array name="resicon">
        <item>@android:drawable/ic_dialog_alert</item>
        <item>@android:drawable/ic_dialog_dialer</item>
        <item>@android:drawable/ic_dialog_email</item>
        <item>@android:drawable/ic_dialog_info</item>
        <item>@android:drawable/ic_dialog_map</item>
    </array>

</resources>

/res/layout/activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="4dp"
    tools:context="com.example.androiddraganddrop.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="2"
            android:background="#202020"
            android:orientation="horizontal" >

            <LinearLayout
                android:id="@+id/area1"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:layout_margin="4dp"
                android:background="#404040"
                android:orientation="vertical" >
            </LinearLayout>

            <LinearLayout
                android:id="@+id/area2"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:layout_margin="4dp"
                android:background="#606060"
                android:orientation="vertical" >
            </LinearLayout>
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/prompt"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@android:color/black"
                android:textColor="@android:color/white"
                android:gravity="bottom" />
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

MainActivity.java
package com.example.androiddraganddrop;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.content.ClipData;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 LinearLayout area1, area2;
 TextView prompt;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  area1 = (LinearLayout) findViewById(R.id.area1);
  area2 = (LinearLayout) findViewById(R.id.area2);

  prompt = (TextView) findViewById(R.id.prompt);
  // make TextView scrollable
  prompt.setMovementMethod(new ScrollingMovementMethod());
  //clear prompt area if LongClick
  prompt.setOnLongClickListener(new OnLongClickListener(){

   @Override
   public boolean onLongClick(View v) {
    prompt.setText("");
    return true;
   }});

  TypedArray arrayResources = getResources().obtainTypedArray(
    R.array.resicon);

  for (int i = 0; i < arrayResources.length(); i++) {
   ImageView imageView = new ImageView(this);
   imageView.setImageDrawable(arrayResources.getDrawable(i));
   imageView.setOnLongClickListener(myOnLongClickListener);
   area1.addView(imageView);
  }

  arrayResources.recycle();
  
  area1.setOnDragListener(myOnDragListener);
  area2.setOnDragListener(myOnDragListener);
 }

 OnLongClickListener myOnLongClickListener = new OnLongClickListener() {

  @Override
  public boolean onLongClick(View v) {
   ClipData data = ClipData.newPlainText("", "");
   DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(v);
   v.startDrag(data, shadowBuilder, v, 0);
   //v.setVisibility(View.INVISIBLE);
   return true;
  }

 };

 OnDragListener myOnDragListener = new OnDragListener() {
  
  @Override
  public boolean onDrag(View v, DragEvent event) {
   
   String area;
   if(v == area1){
    area = "area1";
   }else if(v == area2){
    area = "area2";
   }else{
    area = "unknown";
   }
   
   switch (event.getAction()) {
   case DragEvent.ACTION_DRAG_STARTED:
    prompt.append("ACTION_DRAG_STARTED: " + area  + "\n");
    break;
   case DragEvent.ACTION_DRAG_ENTERED:
    prompt.append("ACTION_DRAG_ENTERED: " + area  + "\n");
    break;
   case DragEvent.ACTION_DRAG_EXITED:
    prompt.append("ACTION_DRAG_EXITED: " + area  + "\n");
    break;
   case DragEvent.ACTION_DROP:
    prompt.append("ACTION_DROP: " + area  + "\n");
    View view = (View)event.getLocalState();
    LinearLayout oldParent = (LinearLayout)view.getParent();
    oldParent.removeView(view);
    LinearLayout newParent = (LinearLayout)v;
    newParent.addView(view);
    break;
   case DragEvent.ACTION_DRAG_ENDED:
    prompt.append("ACTION_DRAG_ENDED: " + area  + "\n");
   default:
    break;
   }
   return true;
  }

 };
}



download filesDownload the files.

More example of Drag and Drop
Drag and Drop items between ListView
- Improved Drag and Drop items between ListView
Drag and Drop items between ListView, with OnDragListener on ListView cells
Drag and Drop between ListView and GridView