NullPointerException異常時啓動PreferenceActivity

SOLUTION
在我arrays.xml文件時，該項陣列是<string-array/>和值數組是<integer-array/>。我的解決方案是使整數數組字符串數組。NullPointerException異常時啓動PreferenceActivity

我想爲我的應用程序創建一個設置活動，並且遇到了很多問題。開始活動時，我一直收到NullReferenceException。這裏是我的代碼：
CalculatorActivity.onOptionsItemSelected(MenuItem item)：

int id = item.getItemId(); 
if (id == R.id.action_settings) { 
    startActivity(new Intent(CalculatorActivity.this, SettingsActivity.class)); 
    return true; 
}

SettingsActivity.onCreate(Bundle savedInstanceState)：

setTheme(R.style.SettingsTheme); 
super.onCreate(savedInstanceState); 
getFragmentManager().beginTransaction().replace(android.R.id.content, new PreferenceFragment() { 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     addPreferencesFromResource(R.xml.preferences); 
    } 
}).commit();

preferences.xml：

<?xml version="1.0" encoding="utf-8"?> 
<PreferenceScreen 
    xmlns:android="http://schemas.android.com/apk/res/android" > 
    <PreferenceCategory 
     android:title="@string/pref_1"> 
     <ListPreference 
      android:entries="@array/tempUnitsEntries" 
      android:title="@string/temp_title" 
      android:dialogTitle="@string/temp_title" 
      android:key="@string/temp_key" 
      android:entryValues="@array/tempUnitsValues" 
      android:defaultValue="0"/> 
     <ListPreference 
      android:title="@string/dist_title" 
      android:dialogTitle="@string/dist_title" 
      android:key="@string/dist_key" 
      android:entryValues="@array/distUnitsValues" 
      android:entries="@array/distUnitsEntries" 
      android:defaultValue="0"/> 
     <ListPreference 
      android:entryValues="@array/speedUnitsValues" 
      android:entries="@array/speedUnitsEntries" 
      android:title="@string/speed_title" 
      android:dialogTitle="@string/speed_title" 
      android:key="@string/speed_key" 
      android:defaultValue="0"/> 
     <ListPreference 
      android:entryValues="@array/psrUnitsValues" 
      android:entries="@array/psrUnitsEntries" 
      android:title="@string/psr_title" 
      android:dialogTitle="@string/psr_title" 
      android:key="@string/psr_key" 
      android:defaultValue="0"/> 
    </PreferenceCategory> 
    <PreferenceCategory 
     android:title="@string/pref_2"> 
     <CheckBoxPreference 
      android:key="@string/autoGet_key" 
      android:defaultValue="true" 
      android:title="@string/autoGet_title"/> 
    </PreferenceCategory> 
    <PreferenceCategory 
     android:title="@string/pref_3"> 
     <SwitchPreference 
      android:key="@string/vbMain_key" 
      android:defaultValue="false"/> 
     <!-- THIS BLOCK WAS CAUSING ANOTHER ERROR --> 
     <!-- <MultiSelectListPreference 
      android:entryValues="@array/verboseModeDataValues" 
      android:dialogTitle="@string/vbData_title" 
      android:title="@string/vbData_title" 
      android:entries="@array/verboseModeDataEntries" 
      android:key="@string/vbData_key"/> --> 
    </PreferenceCategory> 
</PreferenceScreen>

這是堆棧跟蹤（注意，沒有任何條目屬於我的app）：

05-25 10:25:50.342: E/AndroidRuntime(3744): FATAL EXCEPTION: main 
05-25 10:25:50.342: E/AndroidRuntime(3744): Process: com.example.myapp PID: 3744 
05-25 10:25:50.342: E/AndroidRuntime(3744): java.lang.NullPointerException 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.ListPreference.findIndexOfValue(ListPreference.java:223) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.ListPreference.getValueIndex(ListPreference.java:232) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.ListPreference.getEntry(ListPreference.java:210) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.ListPreference.getSummary(ListPreference.java:156) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.Preference.onBindView(Preference.java:524) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.Preference.getView(Preference.java:462) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.preference.PreferenceGroupAdapter.getView(PreferenceGroupAdapter.java:221) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.AbsListView.obtainView(AbsListView.java:2263) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.ListView.makeAndAddView(ListView.java:1790) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.ListView.fillDown(ListView.java:691) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.ListView.fillFromTop(ListView.java:752) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.ListView.layoutChildren(ListView.java:1630) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.AbsListView.onLayout(AbsListView.java:2091) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.View.layout(View.java:14817) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewGroup.layout(ViewGroup.java:4631) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.View.layout(View.java:14817) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewGroup.layout(ViewGroup.java:4631) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.FrameLayout.onLayout(FrameLayout.java:388) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.View.layout(View.java:14817) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewGroup.layout(ViewGroup.java:4631) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.View.layout(View.java:14817) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewGroup.layout(ViewGroup.java:4631) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.widget.FrameLayout.onLayout(FrameLayout.java:388) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.View.layout(View.java:14817) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewGroup.layout(ViewGroup.java:4631) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1987) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1744) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.Choreographer.doCallbacks(Choreographer.java:574) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.Choreographer.doFrame(Choreographer.java:544) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.os.Handler.handleCallback(Handler.java:733) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.os.Handler.dispatchMessage(Handler.java:95) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.os.Looper.loop(Looper.java:136) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at android.app.ActivityThread.main(ActivityThread.java:5017) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at java.lang.reflect.Method.invokeNative(Native Method) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at java.lang.reflect.Method.invoke(Method.java:515) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
05-25 10:25:50.342: E/AndroidRuntime(3744):  at dalvik.system.NativeStart.main(Native Method)

另外，我要指出的是，這些線路只是異常之前出現在logcat中：

05-25 10:25:42.941: W/EGL_emulation(3744): eglSurfaceAttrib not implemented 
05-25 10:25:47.851: W/Resources(3744): Converting to string: TypedValue{t=0x10/d=0x0 a=-1} 
05-25 10:25:47.991: W/Resources(3744): Converting to string: TypedValue{t=0x10/d=0x0 a=-1} 
05-25 10:25:47.991: W/Resources(3744): Converting to string: TypedValue{t=0x10/d=0x0 a=-1} 
05-25 10:25:47.991: W/Resources(3744): Converting to string: TypedValue{t=0x10/d=0x0 a=-1} 
05-25 10:25:49.131: W/EGL_emulation(3744): eglSurfaceAttrib not implemented 
05-25 10:25:50.252: D/AndroidRuntime(3744): Shutting down VM 
05-25 10:25:50.252: W/dalvikvm(3744): threadid=1: thread exiting with uncaught exception (group=0xb0d09b20)

來源

2015-05-25 Greg Whatley

'ListPreference.findIndexOfValue'應該告訴你其中一個ListPreferences有問題。可能與其價值觀有關。可能是拼寫錯誤的名字？ –

@DerGolem，導致我找到解決方案。看我的編輯。謝謝！ –

您應該將解決方案作爲答案發布。所以你可以接受它，爲了從未答覆的問題隊列中刪除這篇文章。 –

在我arrays.xml文件時，該項陣列是<string-array/>和值數組是<integer-array/>。我的解決方案是使整數數組字符串數組。這似乎解決了這個問題。

來源

2015-05-25 18:49:56

NullPointerException異常時啓動PreferenceActivity

回答

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