sendEmptyMessage And sendMessage

/**
* Sends a Message containing only the what value.
*/
public final boolean sendEmptyMessage(int what)
{
　　return sendEmptyMessageDelayed(what, 0);
}

/**
* Pushes a message onto the end of the message queue after all pending messages
* before the current time. It will be received in {@link #handleMessage},
* in the thread attached to this handler.
*/
public final boolean sendMessage(Message msg)
{
　　return sendMessageDelayed(msg, 0);
}