android – 应用程序在锁定/睡眠屏幕崩溃 – NullPointerException

使用设备进行测试 – 每当我锁定屏幕(或闲置1分钟后休眠),应用程序崩溃,logcat会在onResume()方法的imageView.setOnClickListener上显示NullPointerException.

这是我获得异常的代码的一小部分：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.critical_items_list);

    // instantiate member variables

    mExtras = getIntent().getExtras();
    mItems_P1 = mExtras.getParcelableArrayList(EXTRA_ITEMS_P1);
    mItems_P2 = mExtras.getParcelableArrayList(EXTRA_ITEMS_P2);
    mItems_Engine = mExtras.getParcelableArrayList(EXTRA_ITEMS_ENGINE); 
}

protected void onResume() {
    super.onResume();

    ImageView imageAddToMultiple = (ImageView) findViewById(R.id.image_add_to_multiple);

    //This is where the I get the NullPointer
    imageAddToMultiple.setOnClickListener(listenerAddToMultipleItems); 

    refreshLists();
    ListView listP1 = (ListView) findViewById(R.id.list_p1);
    ListView listP2 = (ListView) findViewById(R.id.list_p2);
    ListView listEngine = (ListView) findViewById(R.id.list_engine);

    listP1.setAdapter(new MyAdapter(mList_P1));
    listP2.setAdapter(new MyAdapter(mList_P2));
    listEngine.setAdapter(new MyAdapter(mList_Engine));
}

imageView本身位于RelativeLayout：


我不知道为什么我会得到这个NullPointer.


FATAL EXCEPTION: main

          java.lang.RuntimeException: Unable to resume activity {nmw.nss/nmw.nss.CriticalList}: java.lang.NullPointerException  at

  android.app.ActivityThread.performResumeActivity(ActivityThread.java:2820)

    at

  android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2859)

    at

  android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2242)

    at android.app.ActivityThread.access$600(ActivityThread.java:139)   at

  android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)

    at android.os.Handler.dispatchMessage(Handler.java:99)  at

  android.os.Looper.loop(Looper.java:154)   at

  android.app.ActivityThread.main(ActivityThread.java:4974)     at

  java.lang.reflect.Method.invokeNative(Native Method)  at

  java.lang.reflect.Method.invoke(Method.java:511)  at

  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)

    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)     at

  dalvik.system.NativeStart.main(Native Method)     Caused by:

  java.lang.NullPointerException    at

  nmw.nss.CriticalList.onResume(CriticalList.java:93)
at

  android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1236)

    at android.app.Activity.performResume(Activity.java:4620)   at

  android.app.ActivityThread.performResumeActivity(ActivityThread.java:2804)

    … 12 more

谢谢.
编辑：我添加了完整的活动(类型),xml和logcat.
我是否需要覆盖任何Activity方法,可能是onStop或onPause以使其工作？


最佳答案
终于找到了！
我的应用程序基本上是在横向模式下运行,而在清单中我添加了——-
机器人：screenOrientation = “风景”.
好吧,这就是问题：在你锁定设备的模式下,findViewById()总是在纵向模式下搜索XML并且在我的情况下,根本没有ImageView.因此NullPointerException.
 原文链接：https://www.f2er.com/android/430627.html

android – 应用程序在锁定/睡眠屏幕崩溃 – NullPointerException

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