具有非默认语言环境的 ActionBar NullPointerException 的 Android 应用程序

Question

我创建了带有 ActionBar 和 2 个选项卡的非常基本的 Android 应用程序。它工作正常。然后我添加了语言环境资源目录 res/values-de 并在其中 strings.xml 将字符串翻译成德语。我将 Nexus7 上的语言更改为德语，应用程序在部署后无法启动。我在模拟器上遇到了同样的问题。

你能帮我让这个应用程序在我的移动设备上运行一些非默认语言环境吗？就我而言，德语...

报以下错误。

02-07 15:32:41.314: W/dalvikvm(16682): threadid=1: thread exiting with uncaught exception (group=0x40d82930)
02-07 15:32:41.324: E/AndroidRuntime(16682): FATAL EXCEPTION: main
02-07 15:32:41.324: E/AndroidRuntime(16682): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tabactionbar/com.example.tabactionbar.MainActivity}: java.lang.NullPointerException
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.os.Looper.loop(Looper.java:137)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread.main(ActivityThread.java:5039)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at java.lang.reflect.Method.invokeNative(Native Method)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at java.lang.reflect.Method.invoke(Method.java:511)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at dalvik.system.NativeStart.main(Native Method)
02-07 15:32:41.324: E/AndroidRuntime(16682): **Caused by: java.lang.NullPointerException
02-07 15:32:41.324: E/AndroidRuntime(16682):    at com.example.tabactionbar.MainActivity.onCreate(MainActivity.java:20)**
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.Activity.performCreate(Activity.java:5104)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
02-07 15:32:41.324: E/AndroidRuntime(16682):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
02-07 15:32:41.324: E/AndroidRuntime(16682):    ... 11 more
02-07 15:32:41.334: W/ActivityManager(492):   Force finishing activity com.example.tabactionbar/.MainActivity
02-07 15:32:41.434: D/dalvikvm(492): GC_FOR_ALLOC freed 546K, 19% free 15994K/19568K, paused 64ms, total 64ms
02-07 15:32:41.574: D/libgps(492): proxy_gps_nmea_cb()

没有 TabListener 的 MainActivity 代码:

public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ActionBar actionBar = getActionBar();

    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    String label1 = getResources().getString(R.string.label1);
    Tab tab = actionBar.newTab();
    tab.setText(label1);
    TabListener<Tab1Fragment> tl = new TabListener<Tab1Fragment>(this,
            label1, Tab1Fragment.class);
    tab.setTabListener(tl);
    actionBar.addTab(tab);

    String label2 = getResources().getString(R.string.label2);
    tab = actionBar.newTab();
    tab.setText(label2);
    TabListener<Tab2Fragment> tl2 = new TabListener<Tab2Fragment>(this,
            label2, Tab2Fragment.class);
    tab.setTabListener(tl2);
    actionBar.addTab(tab);          
} 

报错的第20行是 actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

strings.xml with German 文本是

<string name="app_name">TabActionBar</string>
<string name="hello_world">Hello world!</string>
<string name="menu_settings">Settings</string>
<string name="title_activity_main">MainActivity</string>
<string name="label1">Eins</string>
<string name="label2">Zwei</string>
<string name="body1">Erste</string>
<string name="body2">Zweite</string>

你能帮我让这个应用程序在我的移动设备上运行一些非默认语言环境吗？就我而言，德语...

Answer 1

查看此讨论: Action Bar - Menu Button - Missing

顺便问一下，values-de 文件夹中是否也有 styles.xml 文件？这可能会导致 ActionBar 变为 NULL 的问题。