ANDROID 屏幕方向变化

Question

如何在 Android 中正确处理屏幕方向更改？

谁能帮我解决这个问题吗？

我总是收到此错误：

05-12 07:20:38.223: ERROR/AndroidRuntime(410): FATAL EXCEPTION: main
05-12 07:20:38.223: ERROR/AndroidRuntime(410): java.lang.RuntimeException: Unable to destroy activity {com.loginpage/com.loginpage.MainActivity}: java.lang.NullPointerException
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3655)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3673)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3789)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.access$2400(ActivityThread.java:125)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2037)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.os.Looper.loop(Looper.java:123)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at java.lang.reflect.Method.invokeNative(Native Method)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at java.lang.reflect.Method.invoke(Method.java:521)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at dalvik.system.NativeStart.main(Native Method)
05-12 07:20:38.223: ERROR/AndroidRuntime(410): Caused by: java.lang.NullPointerException
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at com.loginpage.MainActivity.storePreferences(MainActivity.java:80)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at com.loginpage.MainActivity.onDestroy(MainActivity.java:29)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3642)
05-12 07:20:38.223: ERROR/AndroidRuntime(410):     ... 12 more

Answer 1

在 com.loginpage.MainActivity.storePreferences(MainActivity.java:80)

崩溃发生在 MainActivity 的第 80 行。

为了避免重新创建您的活动，请将其添加到您的清单文件中，

android:configChanges="keyboardHidden|orientation"

并将其添加到活动中

@Override
public void onConfigurationChanged(Configuration newConfig) {
  super.onConfigurationChanged(newConfig);
  setContentView(R.layout.myLayout);
}

Answer 2

将其放在

 android:screenOrientation="sensor"
 android:configChanges="keyboardHidden|orientation"

AndroidManifest.xml 中的活动声明中，如下所示：

 <activity android:name=".activity.activityname"
                  android:label="@string/app_name"
                  android:theme="@android:style/Theme.Light"
                  android:windowSoftInputMode="adjustPan"
                  android:screenOrientation="sensor"
                  android:configChanges="keyboardHidden|orientation">
         </activity>

Answer 3

您应该发布代码，无论如何，堆栈跟踪会告诉您很多信息：

MainActivity.storePreferences(MainActivity.java:80) 处的 Java 空指针异常

调试/检查您的代码..