正在启动活动结果java.lang.RuntimeException

Question

我在清单中有一个活动：

<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>

当使用以下代码打开它时：

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

我得到了：

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

有什么想法吗？

Answer 1

你的==()显然是空的。

将您的代码行修改为：

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

Answer 2

关于这段代码：

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

在使用.equals()将您知道不为空的内容放在左侧时，这是最佳实践(也是常识)，因此您可以避免使用这些NullPointerException。因此，请重写为：

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