android - wait()函数在android studio中的线程中不起作用

Question

在问这个问题之前，让我告诉你我是 android 开发的新手。 我的问题是关于 Threads 和 wait();功能。现在我正在尝试实现每 3 秒更改一次文本颜色的线程，但程序一启动它就崩溃了。这是代码。

package care.client_application;

public class MainActivity extends AppCompatActivity {
   Thread Thread3=null; //Coloring thread
   public TextView Warning;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      Warning= (TextView) findViewById(R.id.warning);
      UIHandler = new Handler();  //Initialization of handler

      this.Thread3= new Thread(new Thread3());
      this.Thread3.start();
   }

   class Thread3 implements Runnable{
      @Override
      public void run() {
         Warning.setTextColor(Color.rgb(200,200,0));
         wait(3000);
         Warning.setTextColor(Color.rgb(200,0,0));
      }
   }
}

Answer 1

I want to change the color of text every 3 seconds

为什么不使用 Handler 而不是 Thread

private Runnable task = new Runnable () {
    public void run() {
            //update textview color 
            Warning.setTextColor(Color.rgb(200,200,0));
            mHandler.postDelayed(task, 3000);  //repeat task
    }
};

调用它使用:

 private Handler mHandler = new Handler();
// call updateTask after 3 seconds
mHandler.postDelayed(task, 3000);

停止任务:

    @Override
protected void onPause() {
     mHandler.removeCallbacks(task);
     super.onPause();
}