Set Wallpaper Android

Define Object 

File    myFolder;
    File file;
    WallpaperManager wallpaperManager ;

In Oncreat

boolean success = false;
        myFolder = new File("/sdcard/Diwali/");
        if( myFolder.exists() ){
            Log.d("", "FOLDER EXISTS");
        }else{

            success = myFolder.mkdir();

            if( success ){
                // Do something on success

            } else {
                // Do something else on failure
                throw new RuntimeException("File Error in writing new folder");
            }
        }

On Click Set Wallpaper


                SetWallpaper();
               
                DisplayMetrics displaymetrics = new DisplayMetrics();
                getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
                int height = displaymetrics.heightPixels;
                int width = displaymetrics.widthPixels;
                img.setDrawingCacheEnabled(true);
                Bitmap bmScreen = img.getDrawingCache();
                Bitmap scaled = Bitmap.createScaledBitmap(bmScreen, width, height, true);
               
               
                File myDir = new File(""+myFolder);   
                myDir.mkdirs();
                Random generator = new Random();
                int n = 10000;
                n = generator.nextInt(n);
                String fname = "Image-"+ n +".jpg";
                 file = new File (myDir, fname);
                if (file.exists ()) file.delete ();
                try {
                    FileOutputStream out = new FileOutputStream(file);
                    scaled.compress(Bitmap.CompressFormat.JPEG, 90, out);
                    out.flush();
                    out.close();

                    wallpaperManager = WallpaperManager.getInstance(GalleryActivity.this.getApplicationContext());

                } catch (Exception e) {
                    e.printStackTrace();
                }


Methods


private void SetWallpaper() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setTitle("Confirm");
        builder.setMessage("Set as Wallpaper ?");

        builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {
                // Do nothing but close the dialog
                applyWallpaperFromFile(file);
                dialog.dismiss();
            }

        });

        builder.setNegativeButton("NO", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                // Do nothing
                dialog.dismiss();
            }
        });

        AlertDialog alert = builder.create();
        alert.show();
       
    }


    public static Bitmap decodeFile(File file, int reqWidth, int reqHeight){
        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(file.getPath(), options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeFile(file.getPath(), options);    
    }
       
    private static int calculateInSampleSize(
        BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            // Calculate ratios of height and width to requested height and width
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);

            // Choose the smallest ratio as inSampleSize value, this will guarantee
            // a final image with both dimensions larger than or equal to the
            // requested height and width.
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }

        return inSampleSize;
    }  
   
    private void applyWallpaperFromFile(final File file)
    {
        Bitmap wallpaperImage = BitmapFactory.decodeFile(file.getPath());
        try {
            if((wallpaperManager.getDesiredMinimumWidth()>0)&&(wallpaperManager.getDesiredMinimumHeight()>0))
            {
                Bitmap blank = BitmapHelper.createNewBitmap(wallpaperManager.getDesiredMinimumWidth(), wallpaperManager.getDesiredMinimumHeight());
                Bitmap overlay = BitmapHelper.overlayIntoCentre(blank, wallpaperImage);

                wallpaperManager.setBitmap(overlay);

            }
            else
            {
                wallpaperManager.setBitmap(wallpaperImage);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        this.runOnUiThread(new Runnable() {

            @Override
            public void run() {
                //Toast.makeText(FullSMSView.this,"Wallpaper set to:"+file.getName(), Toast.LENGTH_SHORT).show();
                Toast.makeText(GalleryActivity.this,"Set as a Wallpaper", Toast.LENGTH_SHORT).show();

            }
        });

    }
   
    public static class BitmapHelper {

        public static Bitmap overlayIntoCentre(Bitmap bmp1, Bitmap bmp2) {
            Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(), bmp1.getConfig());
            Canvas canvas = new Canvas(bmOverlay);
            canvas.drawBitmap(bmp1, new Matrix(), null);//draw background bitmap

            //overlay the second in the centre of the first
            //(may experience issues if the first bitmap is smaller than the second, but then why would you want to overlay a bigger one over a smaller one?!)
            canvas.drawBitmap(bmp2, (bmp1.getWidth()/2)-(bmp2.getWidth()/2), 0, null);

            return bmOverlay;
        }

        public static Bitmap createNewBitmap(int width, int height)
        {
                    //create a blanks bitmap of the desired width/height
            return Bitmap.createBitmap(width, height, Config.ARGB_8888);
        }
        }


Njoy the Code!!