媒体文件读取

如何解决媒体文件读取

| 我正在尝试读取手机中图像的缩略图。下面的代码在Emulator中工作正常，但在Phone中失败。 gives0ѭ（我的手机中有很多照片）：

String[] img = { MediaStore.Images.Thumbnails._ID };
cursor imagecursor = managedQuery(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,img,null,MediaStore.Images.Thumbnails.IMAGE_ID + \"\");
int image_column_index =  imagecursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);
count = imagecursor.getCount();
System.err.println(\"image_column_index= \" + image_column_index);
System.err.println(\"count= \" + count);

您好，感谢您提供信息。.请在下面找到日志...实际上，这里的计数根本不应该为零。

    06-16 15:17:28.360 W/System.err(10250): image_column_index= 0
    06-16 15:17:28.360 W/System.err(10250): count= 0
    06-16 15:17:28.370 W/dalvikvm(10250): threadid=1: thread exiting with uncaught exception (group=0x40020ac0)
    06-16 15:17:28.370 E/AndroidRuntime(10250): FATAL EXCEPTION: main
    06-16 15:17:28.370 E/AndroidRuntime(10250): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.imagegallery/com.test.imagegallery.LocalThumbnailActivity}: java.lang.Arrayindexoutofboundsexception
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread.performlaunchActivity(ActivityThread.java:2663)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.os.Handler.dispatchMessage(Handler.java:99)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.os.Looper.loop(Looper.java:123)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread.main(ActivityThread.java:4627)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at java.lang.reflect.Method.invokeNative(Native Method)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at java.lang.reflect.Method.invoke(Method.java:521)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at dalvik.system.NativeStart.main(Native Method)
    06-16 15:17:28.370 E/AndroidRuntime(10250): Caused by: java.lang.Arrayindexoutofboundsexception
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at com.test.imagegallery.LocalThumbnailActivity.init_phone_image_grid(LocalThumbnailActivity.java:48)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at com.test.imagegallery.LocalThumbnailActivity.onCreate(LocalThumbnailActivity.java:29)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     at android.app.ActivityThread.performlaunchActivity(ActivityThread.java:2627)
    06-16 15:17:28.370 E/AndroidRuntime(10250):     ... 11 more
    06-16 15:17:28.380 W/ActivityManager( 1366):   Force finishing activity com.test.imagegallery/.LocalThumbnailActivity
    06-16 15:17:28.380 W/ActivityManager( 1366):   Force finishing activity com.test.imagegallery/.Imagegallery

    

解决方法

        

cursor imagecursor = managedQuery(...);

您要在此处实例化的类称为

Cursor

（大写）。 另外，您还应该提供LogCat输出以及所获得的任何异常或错误消息。