啓動活動導致了java.lang.RuntimeException

我在清單活動：啓動活動導致了java.lang.RuntimeException

<activity android:name="RingdroidSelectActivity" 
      android:label="@string/main_activity_label"> 

    <intent-filter> 
     <action android:name="android.intent.action.GET_CONTENT" /> 
     <category android:name="android.intent.category.DEFAULT" /> 
     <category android:name="android.intent.category.OPENABLE" /> 
     <data android:mimeType="audio/*" /> 
    </intent-filter> 

</activity>

當使用如下代碼打開它：

startActivity (new Intent(getApplicationContext(), com.ringdroid.RingdroidSelectActivity.class));

我得到：

06-03 09:49:32.744: ERROR/AndroidRuntime(11360): FATAL EXCEPTION: main 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ringdroid/com.ringdroid.RingdroidSelectActivity}: java.lang.NullPointerException 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.os.Handler.dispatchMessage(Handler.java:99) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.os.Looper.loop(Looper.java:130) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread.main(ActivityThread.java:3683) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at java.lang.reflect.Method.invokeNative(Native Method) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at java.lang.reflect.Method.invoke(Method.java:507) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at dalvik.system.NativeStart.main(Native Method) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360): Caused by: java.lang.NullPointerException 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at com.ringdroid.RingdroidSelectActivity.onCreate(RingdroidSelectActivity.java:108) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
06-03 09:49:32.744: ERROR/AndroidRuntime(11360):  ... 11 more

有什麼想法？

來源

2011-06-03 OkyDokyman

問題似乎出現在您的活動代碼中，而不是啓動本身。由com.ringdroid.RingdroidSelectActivity.onCreate（RingdroidSelectActivity.java:108）引發java.lang.NullPointerException。發佈'RingdroidSelectActivity.java' – dmon 2011-06-03 13:59:42

什麼是RingdroidSelectActivity.java:108？ – Egor 2011-06-03 14:00:19

它的代碼會導致錯誤： Intent intent = getIntent（）; mWasGetContentIntent = intent.getAction（）。equals（ Intent.ACTION_GET_CONTENT）; – OkyDokyman 2011-06-03 14:03:44

顯然你有intent.getAction（）== null。

修復您的代碼行：

mWasGetContentIntent = Intent.ACTION_GET_CONTENT.equals(intent.getAction());

來源

2011-06-03 14:12:13

如果您指定要啓動的活動的類，則不必指定操作 – fleetway76 2011-06-03 14:17:54

對此代碼：

Intent intent = getIntent(); 
mWasGetContentIntent = intent.getAction().equals(Intent.ACTION_GET_CONTENT);

這是最好的做法（常識）使用.equals()時把你知道不在左側爲空，所以你避免這些NullPointerException s。因此，將其重寫爲：

mWasGetContentIntent = Intent.ACTION_GET_CONTENT.equals(intent.getAction());

來源

2011-06-03 14:27:49 dmon

啓動活動導致了java.lang.RuntimeException

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