Android Stop handler.postDelayed()
我通过new Handler()调用多个处理程序。postDelayed(new Runnable()。。。。。 单击“上一步”时如何停止Android Stop handler.postDelayed(),android,handler,android-handler,postdelayed,Android,Handler,Android Handler,Postdelayed,我通过new Handler()调用多个处理程序。postDelayed(new Runnable()。。。。。 单击“上一步”时如何停止 public class MyActivity extends AppCompatActivity implements OnClickListener { private Button btn; private Handler handler; private Runnable myRunnable; @Override
public class MyActivity extends AppCompatActivity implements OnClickListener {
private Button btn;
private Handler handler;
private Runnable myRunnable;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
btn = (Button) findViewById(R.id.trainingsstart);
btn.setOnClickListener(this);
}
@Override
public void onClick(View v) {
Handler handler = new Handler();
Runnable myRunnable = new Runnable() {
public void run() {
// Things to be done
}
};
handler.postDelayed(myRunnable, 3000);
}
@Override
public void onBackPressed() {
super.onBackPressed();
handler.removeCallbacks(myRunnable);
}
}
我有一个问题,我的处理程序没有像“myHandler”这样的名称。我如何处理它
谢谢你的帮助
现在我得到了这些错误:
03-28 17:47:03.662: E/AndroidRuntime(1961): FATAL EXCEPTION: main
03-28 17:47:03.662: E/AndroidRuntime(1961): java.lang.NullPointerException
03-28 17:47:03.662: E/AndroidRuntime(1961): at de.basti12354.tage.uebungen.Tag1.onBackPressed(Tag1.java:120)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.app.Activity.onKeyUp(Activity.java:2159)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.KeyEvent.dispatch(KeyEvent.java:2647)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.app.Activity.dispatchKeyEvent(Activity.java:2389)
03-28 17:47:03.662: E/AndroidRuntime(1961): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1860)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:3791)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3774)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3483)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3406)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3540)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3406)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3516)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3666)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:1982)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1698)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1689)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:1959)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.os.MessageQueue.nativePollOnce(Native Method)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.os.MessageQueue.next(MessageQueue.java:132)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.os.Looper.loop(Looper.java:124)
03-28 17:47:03.662: E/AndroidRuntime(1961): at android.app.ActivityThread.main(ActivityThread.java:5103)
03-28 17:47:03.662: E/AndroidRuntime(1961): at java.lang.reflect.Method.invokeNative(Native Method)
03-28 17:47:03.662: E/AndroidRuntime(1961): at java.lang.reflect.Method.invoke(Method.java:525)
03-28 17:47:03.662: E/AndroidRuntime(1961): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
03-28 17:47:03.662: E/AndroidRuntime(1961): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-28 17:47:03.662: E/AndroidRuntime(1961): at dalvik.system.NativeStart.main(Native Method)
您可以使用:
Handler handler = new Handler()
handler.postDelayed(new Runnable())
handler.removeCallbacksAndMessages(null);
或者您可以使用:
Handler handler = new Handler()
handler.postDelayed(new Runnable())
handler.removeCallbacksAndMessages(null);
文档
public final void removeCallbacksAndMessages(对象令牌)
在API级别1中添加删除任何挂起的回调和发送的帖子
obj为令牌的消息。如果令牌为null,则所有回调和
邮件将被删除
或者,您也可以执行以下操作:
Handler handler = new Handler()
Runnable myRunnable = new Runnable() {
public void run() {
// do something
}
};
handler.postDelayed(myRunnable,zeit_dauer2);
然后:
文档
公共最终作废移除回调(可运行r)
添加到API级别1中,删除所有挂起的Runnable r帖子
在消息队列中
公共最终void removeCallbacks(可运行r,对象令牌)
编辑:
更改此项:
@Override
public void onClick(View v) {
Handler handler = new Handler();
Runnable myRunnable = new Runnable() {
致:
因为您在onCreate
之前声明了下面的.Declared,但是您在onClick
中重新声明并初始化了它,从而生成了一个NPE
Handler handler; // declared before onCreate
Runnable myRunnable;
这可能是旧的,但对于那些寻找答案的人,你可以使用这个
public void stopHandler() {
handler.removeMessages(0);
}
干杯当您想要停止处理程序时,您可以定义一个布尔值并将其更改为false。如下
boolean stop = false;
handler.postDelayed(new Runnable() {
@Override
public void run() {
//do your work here..
if (!stop) {
handler.postDelayed(this, delay);
}
}
}, delay);
已将handler.removeCallbacks(myRunnable);添加到我的onBackPressed()中是吗?@user3433232使用它你想停止运行吗?请看我的代码,我试图使用你的帮助,但现在我得到了错误,你可以在我的帖子中看到。@user3433232检查编辑。你的处理程序为空。你在onClick中重新声明它,导致NPEI正在处理API 16和处理程序。removeCallbacks(runnable)不起作用。但是handler.removeCallbacksAndMessages(null);工作感谢请解释为什么这段代码回答了这个问题。假设您在XML start和Stop中有2个按钮。这段代码演示了如何通过单击start按钮启动处理程序,以及如何通过Stop按钮停止处理程序。它可以工作,但runnable仍在后台运行。
Boolean condition=false; //Instance variable declaration.
//-----------------Inside oncreate---------------------------------------------------
start =(Button)findViewById(R.id.id_start);
start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
starthandler();
if(condition=true)
{
condition=false;
}
}
});
stop=(Button) findViewById(R.id.id_stoplocatingsmartplug);
stop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
stophandler();
}
});
}
//-----------------Inside oncreate---------------------------------------------------
public void starthandler()
{
handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
if(!condition)
{
//Do something after 100ms
}
}
}, 5000);
}
public void stophandler()
{
condition=true;
}