解决方案
在我的arrays.xml
文件中,条目数组是<string-array/>
,值数组是<integer-array/>
. 我的解决方案是制作整数数组字符串数组。
我正在尝试为我的应用创建设置活动,但遇到了很多问题。NullReferenceException
开始活动时我一直收到一个。这是我的代码
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>
这是堆栈跟踪(请注意,没有任何条目与我的应用程序有关):
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,我想指出,这些行出现在 LogCat 中就在异常之前:
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)