Two ways to refresh the interface in Android

Android provides Invalidate methods for interface refreshes, but Invalidate cannot be called directly from within a thread because it violates the single-threaded model: Android UI operations are not thread-safe and must be called within UI threads.

There are two methods of Android interface refresh: Handler and postInvalidate().

Use Handler to refresh the interface

Instantiate 1 Handler object and override handleMessage method to call invalidate() to realize interface refresh; In the thread, the interface update message is sent through sendMessage.

//  in onCreate() Open thread in 

new Thread(new GameThread()).start();
//  instantiation 1 a handler

Handler myHandler = new Handler() {

 // Processing after receiving the message 

 public void handleMessage(Message msg) {

  switch (msg.what) {

  case Activity01.REFRESH:

   mGameView.invalidate();// Refresh the interface 

   break;

  }

  super.handleMessage(msg);

 }                  

};
class GameThread implements Runnable {

 public void run() {

     while (!Thread.currentThread().isInterrupted()) {

         Message message = new Message();

            message.what = Activity01.REFRESH;

            // Send a message 

            Activity01.this.myHandler.sendMessage(message);

            try {

             Thread.sleep(100);

            }

            catch (InterruptedException e) {

             Thread.currentThread().interrupt();

            }

  }

 }

}

Use postInvalidate() to refresh the interface

Using postInvalidate is relatively simple. handler is not required, just call postInvalidate directly from the thread.

class GameThread implements Runnable {

 public void run() {

  while (!Thread.currentThread().isInterrupted()) {

   try {

    Thread.sleep(100);

   }

            catch (InterruptedException e) {

    Thread.currentThread().interrupt();

   }
   //  use postInvalidate You can update the interface directly in a thread 

   mGameView.postInvalidate();

  }

 }

}