title: android auto active click event
body: <p>I have a function about accelemeter sensor.
  I want when I shake the device, the onclick event on a button could be actived.
  for example:</p>
  
  <pre><code>btn1 = (btn1)findviewbyid(R.id.btn1);
  btn1.setonclickListener(new View.onclick(){
  //something happend
  });
  
  public void onSensorChanged(SensorEvent event) {
  //when I shake, auto active onlick listener
  }
  </code></pre>
  
  <p>How can I trigger the button onclick event?
  cheers!</p>