Loading Android Resource in GridView

Refer to Android document R.drawable, there are a number of System Resources from 17301504 to 17301655.

This exercise modify the last GridView exercise to load the System Resources, instead of loading from /res/drawable.



mThumbIds[] is used to hold the resources id, to be passed to ImageAdapter. It is initialized in initResourceID()in ImageAdapter's constructor.

Each object is passed to to imageView using imageView.setImageResource(mThumbIds[position]) inside getView().

The main.xml is same as that in GridView exercise.

AndroidGridView2.java

package com.exercise.AndroidGridView2;

import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

public class AndroidGridView2 extends Activity {
 
  final int resourceStart = 17301504;
  final int resourceEnd = 17301655;
  final int ResourceLength = resourceEnd - resourceStart + 1; 
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);

      GridView gridview = (GridView) findViewById(R.id.gridview);
      gridview.setAdapter(new ImageAdapter(this));
    
      gridview.setOnItemClickListener(gridviewOnItemClickListener);
  }

  private GridView.OnItemClickListener gridviewOnItemClickListener =
   new GridView.OnItemClickListener(){

   @Override
   public void onItemClick(AdapterView arg0, View arg1, int arg2,
     long arg3) {
    // TODO Auto-generated method stub
    String strResource =
     arg0.getAdapter().getItem(arg2).toString() +
     " " +
     Resources.getSystem().getResourceName(arg2+resourceStart);
    Toast.makeText(AndroidGridView2.this,
      strResource,
      Toast.LENGTH_LONG).show();
   }
  };


  public class ImageAdapter extends BaseAdapter {
      private Context mContext;

      public ImageAdapter(Context c) {
          mContext = c;
          initResourceID();
      }

      public int getCount() {
          return mThumbIds.length;
      }

      public Object getItem(int position) {
          return mThumbIds[position];
      }

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

      // create a new ImageView for each item referenced by the Adapter
      public View getView(int position, View convertView, ViewGroup parent) {
          ImageView imageView;
          if (convertView == null) {
           // if it's not recycled, initialize some attributes
              imageView = new ImageView(mContext);
              imageView.setLayoutParams(new GridView.LayoutParams(50, 50));
              imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
              imageView.setPadding(8, 8, 8, 8);
          } else {
              imageView = (ImageView) convertView;
          }

          imageView.setImageResource(mThumbIds[position]);
          return imageView;
      }

      private int[] mThumbIds = new int[ResourceLength];
      private void initResourceID(){
       for ( int i = 0; i < ResourceLength; i++)
       {
        mThumbIds[i] = i + resourceStart;
       }
      }
  }
}

Download the files.