的Android得managedQuery光标数据路径

Question

我试图表明我的设备上的我的mp3和wav文件列表。点击播放音乐时，我尝试将所有铃声保存到mAudioPath[]。我得到ListView资源字符串数组与此：

private String[] getMusic() { 
     mCursor = managedQuery(
       MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, 
       new String[] { MediaStore.Audio.Media.DISPLAY_NAME}, 
       Audio.Media.DATA + " like ? OR " + Audio.Media.DATA + " like ? ", 
       new String[] {"%mp3","%wav"}, 
       "LOWER(" + MediaStore.Audio.Media.TITLE + ") ASC"); 

     int count = mCursor.getCount(); 

     String[] songs = new String[count]; 
     int i = 0; 
     if (mCursor.moveToFirst()) { 
      do { 
       songs[i] = mCursor.getString(0); 
       mAudioPath[i] = mCursor.getString(mCursor 
         .getColumnIndexOrThrow(MediaStore.Audio.Media.DATA)); 
       //--EXCEPTION-- 
       i++; 
      } while (mCursor.moveToNext()); 
     } 

     mCursor.close(); 

     return songs; 
    } 

但行mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA)抛出follewed异常：

W/dalvikvm(14188): threadid=1: thread exiting with uncaught exception (group=0x4001d560) 
E/AndroidRuntime(14188): FATAL EXCEPTION: main 
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapp/com.example.myapp.Ringtones}: java.lang.IllegalArgumentException: column '_data' does not exist 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667) 
    at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:130) 
    at android.app.ActivityThread.main(ActivityThread.java:3687) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:507) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 
    at dalvik.system.NativeStart.main(Native Method) 
    Caused by: java.lang.IllegalArgumentException: column '_data' does not exist 
    at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314) 
    at android.database.CursorWrapper.getColumnIndexOrThrow(CursorWrapper.java:99) 
    at com.example.myapp.Ringtones.getMusic(Ringtones.java:115) 
    at com.example.myapp.Ringtones.onCreate(Ringtones.java:73) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615) 
    ... 11 more 

请告诉我如何解决它

Answer 1

改变投影得到MediaStore.Audio查询中的.Media.DATA列。

mCursor = managedQuery(
        MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, 
        new String[] { MediaStore.Audio.Media.DISPLAY_NAME, 
MediaStore.Audio.Media.DATA}, 
        Audio.Media.DATA + " like ? OR " + Audio.Media.DATA + " like ? ", 
        new String[] {"%mp3","%wav"}, 
        "LOWER(" + MediaStore.Audio.Media.TITLE + ") ASC");