title: Android custom alert dialog with rounded corners and transparent background
body: <p>I have created a custom AlertDialog with rounded corners using <code>onDraw</code> of <code>LinearLayout</code> as below,</p>
  
  <pre><code>public class RoundedLinearLayout extends LinearLayout {
  
  private Paint drawPaint;
  private Paint roundPaint;
  
  private int mCornerRadius = 100;
  
  private RectF bounds;
  
  @TargetApi(Build.VERSION_CODES.HONEYCOMB)
  public RoundedLinearLayout(Context context, AttributeSet attrs, int defStyle) {
      super(context, attrs, defStyle);
      onInit();
  }
  
  public RoundedLinearLayout(Context context, AttributeSet attrs) {
      super(context, attrs);
      onInit();
  }
  
  public RoundedLinearLayout(Context context) {
      super(context);
      onInit();
  }
  
  protected void onInit() {
      drawPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
      drawPaint.setColor(0xffffffff);
      drawPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
  
      roundPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
      roundPaint.setColor(0xffffffff);
  
      setWillNotDraw(false);
  }
  
  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
      super.onSizeChanged(w, h, oldw, oldh);
      if (w != oldw &amp;&amp; h != oldh) {
          bounds = new RectF(0, 0, w, h);
      }
  }
  
  @Override
  protected void dispatchDraw(Canvas canvas) {
      Bitmap bitmap = Bitmap.createBitmap((int) bounds.width(), (int) bounds.height(), Bitmap.Config.ARGB_8888);
      Canvas c = new Canvas(bitmap);
      super.dispatchDraw(c);
  
      BitmapShader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
  
      Paint paint = new Paint();
      paint.setAntiAlias(true);
      paint.setShader(shader);
  
      canvas.drawRoundRect(bounds, mCornerRadius, mCornerRadius, paint);
  }
  }
  </code></pre>
  
  <p>And then I added transparency by <code>getWindow()</code> and setting <code>window.alpha = 0.5f</code> .
  The resulting dialog is,</p>
  
  <p><img src="https://i.stack.imgur.com/ubGEP.png" alt="Custom alert with transparency"></p>
  
  <p>I want to remove those corner white background. I have searched 100s of questions here and no answer could get me the perfect rounded corner alert dialog. Any help would be appreciated!</p>