java - 暂停和恢复可运行线程

Question

我有一个 Activity (不是我的主要 Activity )，可以在可运行的线程中播放一些声音并绘制一些图形。有一个图像按钮，我应该用它来暂停和恢复线程。但无论我尝试什么，线程都会继续运行。我完全被困住了!请帮忙。

public class PlayInterval extends Activity {
   private Handler customHandler;
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_playinterval);
      final ImageButton playPauseButton = (ImageButton) findViewById(R.id.playPauseButton);//Play/Pause
      playPauseButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
           onPlayPauseClicked(playPauseButton,(String)playPauseButton.getTag());
        }
     });
     customHandler = new Handler();
     new Thread(new Task()).start();
  }
  @Override
  public void onBackPressed() {
     customHandler.removeCallbacksAndMessages(null);
     finish();
  }
  class Task implements Runnable {
     @Override
     public void run() {
        // Do really cool stuff
        // and even cooler stuff
        customHandler.postDelayed(this, 100);
     }
  }
  private void onPlayPauseClicked(ImageButton playPauseButton, String status) {
     if (status == "playing") {
        playPauseButton.setTag("paused");
        customHandler.removeCallbacksAndMessages(null); //TODO suspend here not working!
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
           playPauseButton.setImageResource(getResources().getIdentifier("pause_image", "drawable", getPackageName()));
        } else {
            playPauseButton.setImageDrawable(getDrawable(getResources().getIdentifier("pause_image", "drawable", getPackageName())));
        }
    } else {
        playPauseButton.setTag("playing");
        customHandler.postDelayed(this, 100); //TODO resume here not working!
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            playPauseButton.setImageResource(getResources().getIdentifier("play_image", "drawable", getPackageName()));
        } else {
            playPauseButton.setImageDrawable(getDrawable(getResources().getIdentifier("play_image", "drawable", getPackageName())));
        }
    }
  }
}

Answer 1

我从未得到答案，所以经过反复试验，我想出了这个。我在 StackOverflow 上红了很多次，据我了解，这不是应该的方式。但它工作得很好，所以如果有人能解释为什么不应该使用这样的同步方法并提供更好的答案，我将不胜感激。干杯

public class PlayInterval extends Activity {
   private Handler customHandler;
   Boolean isRunning;
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_playinterval);
      final ImageButton playPauseButton = (ImageButton)findViewById(R.id.playPauseButton);//Play/Pause
      playPauseButton.setOnClickListener(new View.OnClickListener() {
         public void onClick(View v) {
            onPlayPauseClicked(playPauseButton);
         }
      });
      customHandler = new Handler();
      isRunning=true;
      new Thread(new Task()).start();
   }

   @Override
   public void onBackPressed() {
      customHandler.removeCallbacksAndMessages(null);
      finish();
   }

   class Task implements Runnable {
      @Override
      public void run() {
      if (isRunning == true){
         // Do really cool stuff
         // and even cooler stuff
      } else {
         // it is paused
      }
      customHandler.postDelayed(this, 100);
   }


   private syncronized void onPlayPauseClicked(ImageButton playPauseButton) {
     if (isRunning==true) {
        isRunning=false;
        playPauseButton.setImageResource(getResources().getIdentifier("play_image", "drawable", getPackageName()));
     } else {
        isRunning=true;
        playPauseButton.setImageResource(getResources().getIdentifier("pause_image", "drawable", getPackageName()));
      }
  }
}