Android-er: set SpanSizeLookup to GridLayoutManager of RecyclerView

Monday, July 20, 2015

set SpanSizeLookup to GridLayoutManager of RecyclerView

GridLayoutManager.SpanSizeLookup help to provide the number of spans each item of RecyclerView to occupies. Call setSpanSizeLookup(GridLayoutManager.SpanSizeLookup) method of GridLayoutManager to apply it.

This example modify from last exercise of "LinearLayoutManager and GridLayoutManager for RecyclerView". Create own custom GridLayoutManager.SpanSizeLookup, com.example.androidrecyclerview.MySpanSizeLookup.java

package com.example.androidrecyclerview;

import android.support.v7.widget.GridLayoutManager;

public class MySpanSizeLookup extends GridLayoutManager.SpanSizeLookup {

    int spanPos, spanCnt1, spanCnt2;

    public MySpanSizeLookup(int spanPos, int spanCnt1, int spanCnt2) {
        super();
        this.spanPos = spanPos;
        this.spanCnt1 = spanCnt1;
        this.spanCnt2 = spanCnt2;
    }

    @Override
    public int getSpanSize(int position) {
        return (position % spanPos ==0 ? spanCnt2 : spanCnt1);
    }
}

Modify com.example.androidrecyclerview.MainActivity.java, in onCreate() to implement and set MySpanSizeLookup().

package com.example.androidrecyclerview;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity implements RecyclerViewAdapter.OnItemClickListener{

    private RecyclerView myRecyclerView;
    private RecyclerViewAdapter myRecyclerViewAdapter;

    EditText nameField;
    Button btnAdd;

    RadioGroup optGroupLayout;
    RadioButton optLinearLayoutHorizontal;
    RadioButton optLinearLayoutVertical;
    RadioButton optGridLayoutHorizontal;
    RadioButton optGridLayoutVertical;

    private LinearLayoutManager linearLayoutManagerVertical;
    private LinearLayoutManager linearLayoutManagerHorizontal;
    private GridLayoutManager gridLayoutManagerVertical;
    private GridLayoutManager gridLayoutManagerHorizontal;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myRecyclerView = (RecyclerView)findViewById(R.id.myrecyclerview);

        linearLayoutManagerVertical =
                new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        linearLayoutManagerHorizontal =
                new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
        gridLayoutManagerVertical =
                new GridLayoutManager(this,
                        2, //The number of Columns in the grid
                        LinearLayoutManager.VERTICAL,
                        false);
        gridLayoutManagerHorizontal =
                new GridLayoutManager(this,
                        3, //The number of rows in the grid
                        LinearLayoutManager.HORIZONTAL,
                        false);

        //set SpanSizeLookup()
        gridLayoutManagerVertical.setSpanSizeLookup(new MySpanSizeLookup(5, 1, 2));
        gridLayoutManagerHorizontal.setSpanSizeLookup(new MySpanSizeLookup(4, 1, 3));

        myRecyclerViewAdapter = new RecyclerViewAdapter(this);
        myRecyclerViewAdapter.setOnItemClickListener(this);
        myRecyclerView.setAdapter(myRecyclerViewAdapter);
        myRecyclerView.setLayoutManager(linearLayoutManagerVertical);

        //Add MyItemDecoration
        myRecyclerView.addItemDecoration(new MyItemDecoration());

        nameField = (EditText)findViewById(R.id.namefield);
        btnAdd = (Button)findViewById(R.id.addbutton);
        btnAdd.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                String newName = nameField.getText().toString();

                if(!newName.equals("")){
                    if(myRecyclerViewAdapter.getItemCount()>1){
                        myRecyclerViewAdapter.add(1, newName);
                    }else{
                        myRecyclerViewAdapter.add(0, newName);
                    }
                }
            }
        });

        optGroupLayout = (RadioGroup)findViewById(R.id.optGroupLayout);
        optLinearLayoutHorizontal = (RadioButton)findViewById(R.id.optLinearLayoutHorizontal);
        optLinearLayoutVertical = (RadioButton)findViewById(R.id.optLinearLayoutVertical);
        optGridLayoutHorizontal = (RadioButton)findViewById(R.id.optGridLayoutHorizontal);
        optGridLayoutVertical = (RadioButton)findViewById(R.id.optGridLayoutVertical);
        optGroupLayout.setOnCheckedChangeListener(optLayoutCheckedChangeListener);

        //pre-load dummy items
        myRecyclerViewAdapter.add(0, "SpanSizeLookup");
        myRecyclerViewAdapter.add(0, "ItemDecoration");
        myRecyclerViewAdapter.add(0, "GridLayoutManager");
        myRecyclerViewAdapter.add(0, "LinearLayoutManager");
        myRecyclerViewAdapter.add(0, "RecyclerViewAdapter");
        myRecyclerViewAdapter.add(0, "RecyclerView example");
        myRecyclerViewAdapter.add(0, "RecyclerView");
        myRecyclerViewAdapter.add(0, "android-er.blogspot.com");
        myRecyclerViewAdapter.add(0, "android-er");
        myRecyclerViewAdapter.add(0, "android");

    }

    private RadioGroup.OnCheckedChangeListener optLayoutCheckedChangeListener =
            new RadioGroup.OnCheckedChangeListener(){
                @Override
                public void onCheckedChanged(RadioGroup group, int checkedId) {
                    if(optLinearLayoutVertical.isChecked()){
                        myRecyclerView.setLayoutManager(linearLayoutManagerVertical);
                    }else if(optLinearLayoutHorizontal.isChecked()){
                        myRecyclerView.setLayoutManager(linearLayoutManagerHorizontal);
                    }else if(optGridLayoutHorizontal.isChecked()){
                        myRecyclerView.setLayoutManager(gridLayoutManagerHorizontal);
                    }else if(optGridLayoutVertical.isChecked()){
                        myRecyclerView.setLayoutManager(gridLayoutManagerVertical);
                    }
                }
            };


    @Override
    public void onItemClick(RecyclerViewAdapter.ItemHolder item, int position) {
        Toast.makeText(this,
                "Remove " + position + " : " + item.getItemName(),
                Toast.LENGTH_SHORT).show();
        myRecyclerViewAdapter.remove(position);
    }
}