title: How to fill rectangle with opacity in android
body: <p>I can fill rectangle with canvas draw rect:</p>
  
  <pre><code>Rect rt = new Rect(0, 0, getWidth(), getHeight());
  myPaint.setColor(myColor);
  myPaint.setStyle(Style.FILL);
  canvas.drawRect(rt, myPaint);
  </code></pre>
  
  <p>But I need the method to fill rectangle with the opacity (in percent, with 0% is TRANSPARENT).
  <br>How can I do that?</p>