Question

我是Android的新手...我开发了一个应用程序，通过单击按钮来转换图像，我添加了一个Handler Runnable以自动转换图像（当没有按下按钮时），延迟时间为5000毫秒。但是我必须在按下按钮的时候停止Handler这个延迟，因为某些原因我不能这样做。

public class MainActivity extends AppCompatActivity {

    private Integer images[]={R.drawable.pic1, R.drawable.pic21, ....
    public int currImage=0;
    public int ThreadCnt = 0;
    public boolean backInt=true,forwardInc=false, ThreadInc=true;
...
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
...
    initializeImageSwitcher();
    setInitialImage();
    setImageRotateListener();  

   final Handler handler = new Handler();

            final Runnable run = new Runnable() {
                @Override
            public void run() {

    //forwardInc is a Boolean indicating that click button occurred
                if(forwardInc){
    //and in this case (of forwardInc=true) I want to stop runnable for 5sec
                    handler.removeCallbacks(this);
                    handler.postDelayed(this, 5000);
                    forwardInc=false;
                    setInitialImage();
                    setImageRotateListener();
                    currImage++;
                    ThreadCnt++;
}
            handler.postDelayed(this, 5000);

  }
    };
    handler.post(run);

这是按钮点击的代码

public void setImageRotateListener() {
        final Button rotatebutton=(Button) findViewById(R.id.btnRotateImage);
      rotatebutton.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              currImage++;
 //forwardInc indicating that click button occurred
              forwardInc=true;
                ...
              setCurrentImage();
     ...

Answer 1

目前还不清楚你要做什么。但据我所知，请尝试以下方法：

首先，在班级中设置Runnable和Handler全局。

public class MainActivity extends AppCompatActivity{
    private Handler handler = new Handler();
    private Runnable runnable = new Runnable(){
        public void run(){/**/}
    }
    //other declarations.
    //methods
}

runnable的内部运行方法：

public void run(){
    setInitialImage(); //probably set next image
    currImage++;
    ThreadCnt++;
    handler.postDelayed( this, 5000 )
}

现在在onClick中：

public void onClick(View view){
    handler.removeCallbacks(this);
    handler.postDelayed(this, 5000);
    //no idea why you are using other code here.
}

在onCreate里面：

//other lines
setImageRotateListener();
handler.post(runnable);

如何在postDelay中停止Runnable Handler

1 个答案: