停止运行处理程序

Question

我实现了一个处理程序，允许用户使用任务栏菜单启动一个每 5 秒重复一次的事件。允许用户从任务栏菜单停止事件的最佳使用方法是什么？

public class MainActivity extends Activity{ 
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
        case R.id.menuitem_tracklogOn:
            final Handler handler = new Handler();
            Timer t = new Timer();
            t.schedule(new TimerTask() {
                public void run() {
                    handler.post(new Runnable() {
                        public void run() {
                            //DO SOME ACTIONS HERE , THIS ACTIONS WILL WILL EXECUTE AFTER 5 SECONDS...
                            handler.postDelayed(this, 5000);//repeat every n-milliseconds
                        }
                    });
                }
            }, 0);//start after n-milliseconds
            return true;

       case R.id.menuitem_tracklogOff:
       //stops running event from R.id.menuitem_tracklogOn
       return true;

解决方案：

final Handler handler = new Handler();
Timer t = new Timer();
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
        case R.id.menuitem_tracklogOn:
            t.schedule(new TimerTask() {
                public void run() {
                    handler.post(new Runnable() {
                        public void run() {
                            //DO SOME ACTIONS HERE , THIS ACTIONS WILL WILL EXECUTE AFTER 5 SECONDS...
                            handler.postDelayed(this, 5000);//repeat every n-milliseconds
                        }
                    });
                }
            }, 2000);//start after n-milliseconds
            return true;
        case R.id.menuitem_tracklogOff:
            t.cancel();
            handler.removeCallbacksAndMessages(null);
            return true;

Answer 1

您需要致电 timer.cancel() 取消定时器。

public void cancel () // Added in API level 1

Cancels the Timer and all scheduled tasks. If there is a currently running task it is not affected. No more tasks may be scheduled on this Timer. Subsequent calls do nothing.

Answer 2

What is the best method to use that would also allow the user to stop the event from the taskbar menu?

要在 menuitem_tracklogOff 上停止 Handler，请单击：

1. 通过调用 timer.cancel()

取消 Timer

2.调用removeCallbacksAndMessages删除所有回调和消息：

handler.removeCallbacksAndMessages(null);

首先要访问 Timer 和 Handler 对象的外部 case 声明其他外部 onOptionsItemSelected 方法或在 switch-case 块之前。

停止运行处理程序

Stopping a running handler

android

timer

android-handler

停止 运行 处理程序

Stopping a running handler

android

timer

android-handler

停止运行处理程序