How do I set wallpaper as lock screen in this coding?

button.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               setBackgroundImage();

           }
       });
   }

   private void setBackgroundImage() {
       Bitmap bitmap = ((BitmapDrawable)imageView.getDrawable()).getBitmap();
       WallpaperManager manager =  WallpaperManager.getInstance(getApplicationContext());

       try {
           manager.setBitmap(bitmap);
           Toast.makeText(getApplicationContext(), "Set Wallpaper Successfully ", Toast.LENGTH_SHORT).show();
       }
       catch (IOException e)
       {
           Toast.makeText(this, "Wallpaper not load yet!", Toast.LENGTH_SHORT).show();
       }

button.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               setBackgroundImage();

           }
       });
   }

   private void setBackgroundImage() {
       Bitmap bitmap = ((BitmapDrawable)imageView.getDrawable()).getBitmap();
       WallpaperManager manager =  WallpaperManager.getInstance(getApplicationContext());

       try {
           manager.setBitmap(bitmap);
           Toast.makeText(getApplicationContext(), "Set Wallpaper Successfully ", Toast.LENGTH_SHORT).show();
       }
       catch (IOException e)
       {
           Toast.makeText(this, "Wallpaper not load yet!", Toast.LENGTH_SHORT).show();
       }