我在这一行得到一个空指针异常:
public void hideKeyboard(){
InputMethodManager inputManager = (InputMethodManager)
this.getSystemService(Context.INPUT_METHOD_SERVICE);
inputManager.hideSoftInputFromWindow(this.getCurrentFocus().getWindowToken(),
InputMethodManager.HIDE_NOT_ALWAYS);
}
这是从以下方法调用的:
@Override
public void onBackPressed() {
super.onBackPressed();
hideKeyboard();
}
这是唯一的活动。后退按钮是从片段中按下的。
堆栈:
09-28 19:14:40.301: E/InputEventSender(30324): Exception dispatching finished signal.
09-28 19:14:40.301: E/MessageQueue-JNI(30324): Exception in MessageQueue callback: handleReceiveCallback
09-28 19:14:40.325: E/MessageQueue-JNI(30324): java.lang.NullPointerException
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at com.example.ecohelp.MainActivity.hideKeyboard(MainActivity.java:75)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at com.example.ecohelp.MainActivity.onBackPressed(MainActivity.java:31)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.app.Activity.onKeyUp(Activity.java:2159)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.KeyEvent.dispatch(KeyEvent.java:2647)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.app.Activity.dispatchKeyEvent(Activity.java:2389)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1860)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:3791)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3774)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3483)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3406)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3540)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3406)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3379)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3429)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3398)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3516)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3666)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:1982)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1698)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1689)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:1959)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.os.MessageQueue.nativePollOnce(Native Method)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.os.MessageQueue.next(MessageQueue.java:132)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.os.Looper.loop(Looper.java:124)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at android.app.ActivityThread.main(ActivityThread.java:5103)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at java.lang.reflect.Method.invokeNative(Native Method)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at java.lang.reflect.Method.invoke(Method.java:525)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-28 19:14:40.325: E/MessageQueue-JNI(30324): at dalvik.system.NativeStart.main(Native Method)
发布于 2014-09-18 17:23:34
在隐藏键盘之前,我只需要检查是否有焦点视图。
例如,如果您的活动或片段中有一个EditText
,那么它可能是焦点视图。当EditText
不再被关注时,getCurrentFocus()
可能会返回null (除非有其他视图被关注)。
void hideKeyboard() {
InputMethodManager inputManager = (InputMethodManager) getActivity().getSystemService(
Context.INPUT_METHOD_SERVICE);
View focusedView = getActivity().getCurrentFocus();
/*
* If no view is focused, an NPE will be thrown
*
* Maxim Dmitriev
*/
if (focusedView != null) {
inputManager.hideSoftInputFromWindow(focusedView.getWindowToken(),
InputMethodManager.HIDE_NOT_ALWAYS);
}
}
发布于 2013-09-30 05:06:58
正如CommonsWare提到的,getCurrentFocus()是空的,因为在当前的View中没有持有焦点的Activity组件。
如果您的活动中已有视图,请使用它来获取窗口令牌。例如,如果我有一个Button组件:
inputManager.hideSoftInputFromWindow(myButton.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
或者更糟的是,如果我的活动中没有任何视图,我可以这样做:
inputManager.hideSoftInputFromWindow(new View(this).getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
这将解决你的NPE问题,但我希望你能找到有用的描述。
关于键盘的另一件事是,当用户在键盘可见的情况下按下后退按钮时,键盘接收并消耗后退按键来隐藏其自身。或者至少大多数键盘都是这样的。
发布于 2014-03-10 21:50:12
上面的每个人都正确地指出getWindowToken()
返回的是null。
当我遇到同样的问题时,我正在使用默认的代码getCurrentFocus().getWindowToken()
来隐藏键盘。
然后我意识到,因为没有获得焦点的视图,所以我得到了NullPointerException
。
我们可以将上述内容更改为:
anyView.getWindowToken()
其中anyView
只是布局中的任何视图。
https://stackoverflow.com/questions/19069448
复制相似问题