Android for ever: 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);
    }
}