title: Weird behaviour in drawing a ring using Path.arcTo() in Android
body: <p>I have implemented an animated drawing ring by start sweeping at angle 0 to 360 successfully.
  However when the tail of the ring meets its head at 360 angle, all drawing is disappear.</p>
  
  <p>This is my code for the ring in <code>onDraw()</code></p>
  
  <pre><code>        float startAngle = 270;
          float sweepAngle = -359;
  
          paint.setColor(Color.DKGRAY);
          paint.setShadowLayer(4, 2, 2, 0x80000000);
  
          rectF.set(cenX - outerRadius, cenY - outerRadius, cenX + outerRadius,
                  cenY + outerRadius);
          path.arcTo(rectF, startAngle, sweepAngle);
          //canvas.drawArc(rectF, 0, 360, false, paint);
          rectF.set(cenX - innerRadius, cenY - innerRadius, cenX + innerRadius,
                  cenY + innerRadius);
          /*paint.reset();
          paint.setAntiAlias(true);
          paint.setColor(Color.WHITE);
          canvas.drawArc(rectF, 0, 360, false, paint);*/
          path.arcTo(rectF, startAngle + sweepAngle, -(sweepAngle));
  
          canvas.drawPath(path, paint);
  </code></pre>
  
  <p>and this is the result,</p>
  
  <p><img src="https://i.stack.imgur.com/S51jt.jpg" alt="enter image description here"></p>
  
  <p>notice here that i set sweepAngle to -359 just before it becomes circle.
  However if I change sweepAngle to -360. It produces this result.</p>
  
  <p><img src="https://i.stack.imgur.com/8flWK.jpg" alt="enter image description here"></p>
  
  <p>It disappears!!
  Anyone know how to solve this please help me?</p>
  
  <p>Thanks.</p>
  
  <p>PS. I don't want to use <code>drawArc()</code> because I want to make a hole inside the ring. With <code>drawArc()</code>, my button will be gone.</p>