HelloGallery, read picture files from SD, display in ImageView, and set as Wallpaper

Modify the exercise "HelloGallery, read picture files from SD, display in ImageView". When user click on the displayedImageView, it will be set as Wallpaper, using using WallpaperManager.

package com.exercise.HelloGallery;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.WallpaperManager;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class HelloGallery extends Activity {
 
 Bitmap bitmap;
 
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  final ImageView imageView = (ImageView)findViewById(R.id.imageview);

  Gallery g = (Gallery) findViewById(R.id.gallery);
  final List<String> SD = ReadSDCard();
  g.setAdapter(new ImageAdapter(this, SD));

  g.setOnItemClickListener(new OnItemClickListener() {
      public void onItemClick(AdapterView<?> parent,
        View v, int position, long id) {
       
       String imageInSD = SD.get(position);
       
       Toast.makeText(HelloGallery.this,
         imageInSD,
            Toast.LENGTH_LONG).show();
       
       bitmap = BitmapFactory.decodeFile(imageInSD);
          imageView.setImageBitmap(bitmap);
       
      }
  });

  imageView.setOnClickListener(new OnClickListener(){

  @Override
  public void onClick(View view) {
   // TODO Auto-generated method stub
   WallpaperManager myWallpaperManager
    = WallpaperManager.getInstance(getApplicationContext());
      try {
       myWallpaperManager.setBitmap(bitmap);
      } catch (IOException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }
  }});
}

private List<String> ReadSDCard()
{
List<String> tFileList = new ArrayList<String>();

//It have to be matched with the directory in SDCard
File f = new File("/sdcard/pictures/");

File[] files=f.listFiles();

for(int i=0; i<files.length; i++)
{
File file = files[i];
//add the selected file type only
String curFile=file.getPath();
String ext=curFile.substring(curFile.lastIndexOf(".")+1,
  curFile.length()).toLowerCase();
if(ext.equals("jpg")||ext.equals("gif")||ext.equals("png"))
tFileList.add(file.getPath());
}

return tFileList;
}

public class ImageAdapter extends BaseAdapter {
  int mGalleryItemBackground;
  private Context mContext;
  private List<String> FileList;

  public ImageAdapter(Context c, List<String> fList) {
      mContext = c;
      FileList = fList;
      TypedArray a = obtainStyledAttributes(R.styleable.Theme);
      mGalleryItemBackground = a.getResourceId(
        R.styleable.Theme_android_galleryItemBackground,
        0);
      a.recycle();
  }

  public int getCount() {
      return FileList.size();
  }

  public Object getItem(int position) {
      return position;
  }

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

  public View getView(int position, View convertView,
    ViewGroup parent) {
      ImageView i = new ImageView(mContext);

      Bitmap bm = BitmapFactory.decodeFile(
        FileList.get(position).toString());
      i.setImageBitmap(bm);

      i.setLayoutParams(new Gallery.LayoutParams(150, 100));
      i.setScaleType(ImageView.ScaleType.FIT_XY);
      i.setBackgroundResource(mGalleryItemBackground);

      return i;
  }
}
}

* Please note that in order to use WallpaperManager, minimum API level have to be set to 5.
* In order to access system wallpaper, AndroidManifest.xml have t be modified to grant permission of "android.permission.SET_WALLPAPER".

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.exercise.HelloGallery"
    android:versionCode="1"
    android:versionName="1.0">
  <uses-sdk android:minSdkVersion="7" />
  <uses-permission android:name="android.permission.SET_WALLPAPER"></uses-permission>

  <application android:icon="@drawable/icon" android:label="@string/app_name">
      <activity android:name=".HelloGallery"
                android:label="@string/app_name">
          <intent-filter>
              <action android:name="android.intent.action.MAIN" />
              <category android:name="android.intent.category.LAUNCHER" />
          </intent-filter>
      </activity>

  </application>
</manifest>

Download the files.