Insert view to GridLayout dynamically, with even width and height

This example insert our custom view to a GridLayout (Added in API level 14) dynamically in Java code, and set the width of height evenly.


Modify layout, activity_main.xml, to have a GridLayout without child.

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidtouchview.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" />

    <GridLayout
        android:id="@+id/mygrid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:columnCount="8"
        android:rowCount="5"
        android:background="@android:color/background_light" >
    </GridLayout>

</LinearLayout>

MyView.java

package com.example.androidtouchview;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class MyView extends View {
 
 public interface OnToggledListener {
  void OnToggled(MyView v, boolean touchOn);
 }

 boolean touchOn;
 boolean mDownTouch = false;
 private OnToggledListener toggledListener;
 int idX = 0; //default
 int idY = 0; //default

 public MyView(Context context, int x, int y) {
  super(context);
  idX = x;
  idY = y;
  init();
 }
 
 public MyView(Context context) {
  super(context);
  init();
 }

 public MyView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }

 public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
 }

 private void init() {
  touchOn = false;
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
    MeasureSpec.getSize(heightMeasureSpec));
 }

 @Override
 protected void onDraw(Canvas canvas) {
  if (touchOn) {
   canvas.drawColor(Color.RED);
  } else {
   canvas.drawColor(Color.GRAY);
  }
 }

 @Override
 public boolean onTouchEvent(MotionEvent event) {
  super.onTouchEvent(event);

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
             
             touchOn = !touchOn;
       invalidate();
       
       if(toggledListener != null){
        toggledListener.OnToggled(this, touchOn);
       }
             
                mDownTouch = true;
                return true;

            case MotionEvent.ACTION_UP:
                if (mDownTouch) {
                    mDownTouch = false;
                    performClick();
                    return true;
                }
        }
        return false;
 }

 @Override
 public boolean performClick() {
        super.performClick();
        return true;
 }
 
 public void setOnToggledListener(OnToggledListener listener){
  toggledListener = listener;
 }
 
 public int getIdX(){
  return idX;
 }
 
 public int getIdY(){
  return idY;
 }

}

MainActivity.java
Our custom views, MyView, are created dynamically and add to the GridLayout in onCreate(). Then re-align their LayoutParams in OnGlobalLayoutListener(), will be called when the global layout state or the visibility of views within the view tree changes.

package com.example.androidtouchview;

import com.example.androidtouchview.MyView.OnToggledListener;

import android.support.v7.app.ActionBarActivity;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.GridLayout;
import android.widget.Toast;
import android.os.Bundle;

public class MainActivity extends ActionBarActivity 
 implements OnToggledListener{
 
 MyView[] myViews;
 
 GridLayout myGridLayout;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  myGridLayout = (GridLayout)findViewById(R.id.mygrid);
  
  int numOfCol = myGridLayout.getColumnCount();
  int numOfRow = myGridLayout.getRowCount();
  myViews = new MyView[numOfCol*numOfRow];
  for(int yPos=0; yPos<numOfRow; yPos++){
   for(int xPos=0; xPos<numOfCol; xPos++){
    MyView tView = new MyView(this, xPos, yPos);
    tView.setOnToggledListener(this);
    myViews[yPos*numOfCol + xPos] = tView;
    myGridLayout.addView(tView);
   }
  }
  
  myGridLayout.getViewTreeObserver().addOnGlobalLayoutListener(
   new OnGlobalLayoutListener(){

   @Override
   public void onGlobalLayout() {
    
    final int MARGIN = 5;
    
    int pWidth = myGridLayout.getWidth();
    int pHeight = myGridLayout.getHeight();
    int numOfCol = myGridLayout.getColumnCount();
    int numOfRow = myGridLayout.getRowCount();
    int w = pWidth/numOfCol;
    int h = pHeight/numOfRow;
    
    for(int yPos=0; yPos<numOfRow; yPos++){
     for(int xPos=0; xPos<numOfCol; xPos++){
      GridLayout.LayoutParams params = 
       (GridLayout.LayoutParams)myViews[yPos*numOfCol + xPos].getLayoutParams();
      params.width = w - 2*MARGIN;
      params.height = h - 2*MARGIN;
      params.setMargins(MARGIN, MARGIN, MARGIN, MARGIN);
      myViews[yPos*numOfCol + xPos].setLayoutParams(params);
     }
    }

   }});
 }

 @Override
 public void OnToggled(MyView v, boolean touchOn) {

  //get the id string
  String idString = v.getIdX() + ":" + v.getIdY();

  Toast.makeText(MainActivity.this, 
   "Toogled:\n" +
   idString + "\n" +
   touchOn, 
   Toast.LENGTH_SHORT).show();
 }

}

Download the files.

Notice:
- OnGlobalLayoutListener will be called repeatly this way. To remove it, call removeGlobalOnLayoutListener() or removeOnGlobalLayoutListener(), read next post.