停止处理程序（）。postDelay
我通过new Handler（）调用多个Handler（）。postDelayed（new Runnable（）…..如果我点击返回button，怎样才能阻止它？
public class Tag1 extends Oberklasse implements OnClickListener { public Button btn; //private Handler myHandler = new Handler(); Handler handler; Runnable myRunnable; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.tt1); //Bildschirm soll anbleiben!!! getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); //Lautstärke BUttons enable setVolumeControlStream(AudioManager.STREAM_MUSIC); getActionBar().setTitle("Tag 1"); getActionBar().setDisplayHomeAsUpEnabled(true); //tt1.xml beschriften TextView textView = (TextView)findViewById(R.id.uebung1); textView.setText("Übung 1:"); TextView textView2 = (TextView)findViewById(R.id.uebung2); textView2.setText("Übung 2:"); TextView textView3 = (TextView)findViewById(R.id.uebung3); textView3.setText("Übung 3:"); TextView textView4 = (TextView)findViewById(R.id.uebung4); textView4.setText("Übung 4:"); TextView textView5 = (TextView)findViewById(R.id.uebung5); textView5.setText("Übung 5:"); TextView textView6 = (TextView)findViewById(R.id.uebung6); textView6.setText("Übung 6:"); TextView textView7 = (TextView)findViewById(R.id.uebung7); textView7.setText("Übung 7:"); //Button finden und Initialisieren! btn = (Button) findViewById(R.id.trainingsstart); btn.setOnClickListener(this); } @Override public void onClick(View v) { Crunch(); Handler handler= new Handler(); Runnable myRunnable = new Runnable() { public void run() { UnterarmLiegestütz1(); } }; handler.postDelayed(myRunnable,3000); } @Override public void onBackPressed() { super.onBackPressed(); uebung.stop(); handler.removeCallbacks(myRunnable); } } 我有我的处理程序没有像“myHandler”这样的名称的问题。 我该如何处理？ 感谢帮助！
现在我得到这些错误：
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()
您可以使用
handler.removeCallbacksAndMessages(null);
文件
public final void removeCallbacksAndMessages (Object token) Added in API level 1 Remove any pending posts of callbacks and sent messages whose obj is token. If token is null, all callbacks and messages will be removed.
要么
Handler handler= new Handler() Runnable myRunnable = new Runnable() { public void run() { // do something } }; handler.postDelayed(myRunnable,zeit_dauer2);
然后
handler.removeCallbacks(myRunnable);
文件
public final void removeCallbacks (Runnable r) Added in API level 1 Remove any pending posts of Runnable r that are in the message queue. public final void removeCallbacks (Runnable r, Object token)
编辑：
改变这一点
@Override public void onClick(View v) { Crunch(); Handler handler= new Handler(); Runnable myRunnable = new Runnable() {
至
@Override public void onClick(View v) { Crunch(); handler= new Handler(); myRunnable = new Runnable() {
因为你有以下。 在onCreate之前声明，但您重新声明，然后在onClick导致NPE初始化它。
Handler handler; // declared before onCreate Runnable myRunnable;
这可能是旧的，但对于那些寻找答案，你可以使用这个…
public void Stop() { handler.removeMessages(0); }
干杯
你可以定义一个布尔值，并当你想停止处理程序时将其更改为false。 喜欢这个..
boolean stop = false; handler.postDelayed(new Runnable() { @Override public void run() { //do your work here.. if (!stop) { handler.postDelayed(this, delay); } } }, delay);
