Question

//this is the resource which i want to access by setContentView method.

我正在使用平板电脑的横向模式，此资源文件位于lyaout-sw720dp-land文件夹

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //for landscape screen 
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

    setContentView(R.layout.prof_res_recycler_view_tab);

...

    02-22 18:47:43.129: E/AndroidRuntime(5167): FATAL EXCEPTION: main
        02-22 18:47:43.129: E/AndroidRuntime(5167): Process: com.pg.dentistpartnerapp.mt, PID: 5167
        02-22 18:47:43.129: E/AndroidRuntime(5167): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pg.dentistpartnerapp.mt/com.pg.dentistpartnerapp.mt.activities.SearchagainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.ImageButton.getVisibility()' on a null object reference
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread.access$800(ActivityThread.java:144)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.os.Handler.dispatchMessage(Handler.java:102)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.os.Looper.loop(Looper.java:135)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread.main(ActivityThread.java:5221)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at java.lang.reflect.Method.invoke(Native Method)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at java.lang.reflect.Method.invoke(Method.java:372)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
        02-22 18:47:43.129: E/AndroidRuntime(5167): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.ImageButton.getVisibility()' on a null object reference
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at com.pg.dentistpartnerapp.mt.activities.SearchagainActivity.openSearchBox(SearchagainActivity.java:279)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at com.pg.dentistpartnerapp.mt.activities.SearchagainActivity.onCreate(SearchagainActivity.java:239)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.Activity.performCreate(Activity.java:5933)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
        02-22 18:47:43.129: E/AndroidRuntime(5167):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
       02-22 18:47:43.129: E/AndroidRuntime(5167):  ... 10 more

Answer 1

您的错误在第279行（在方法openSearchBox(...)中），而不在您显示的代码中。看起来您正在尝试调用getVisibility()和ImageButton引用尚未设置为任何内容（null）。

Caused by: java.lang.NullPointerException: 
    Attempt to invoke virtual method 'int android.widget.ImageButton.getVisibility()' on a null object reference
          at com.pg.dentistpartnerapp.mt.activities.SearchagainActivity.openSearchBox(SearchagainActivity.java:279)

获取android.content.res.Resources $ NotFoundException：异常

1 个答案: