MediaStore找不到保存的图像

Question

我已将ScrollView转换为Bitmap图像并将其保存到外部存储中。一个Toast会弹出，或者说图像已经成功保存，或者它没有。

    Bitmap bmp = screenShot();
    Bitmap b = bmp.copy(Bitmap.Config.ARGB_8888, true);

    Context context = getApplicationContext();
    int duration = Toast.LENGTH_SHORT;

    String fileName = "story.png";
    // create a File object for the parent directory
    File wallpaperDirectory = new File(Environment.getExternalStorageDirectory().getPath() + "/Stories/");
    // have the object build the directory structure, if needed.
    wallpaperDirectory.mkdirs();
    // create a File object for the output file
    File outputFile = new File(wallpaperDirectory, fileName);
    //now attach OutputStream to the file object, instead of a String representation
    FileOutputStream fos = null;
    try 
    {
        fos = new FileOutputStream(outputFile);
        b.compress(Bitmap.CompressFormat.PNG, 100, fos);
        fos.flush();
        fos.close();
        MediaStore.Images.Media.insertImage(this.getContentResolver(), b, "Screen", "screen");

        CharSequence text = "Story saved in file Stories";
        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    }
    catch (FileNotFoundException e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
        CharSequence text = "Could not save story";
        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    } 
    catch (Exception e) 
    {
        // TODO Auto-generated catch block
        e.printStackTrace();
        CharSequence text = "Could not save story";
        Toast toast = Toast.makeText(context, text, duration);
        toast.show();
    }

Toast弹出，表示PNG图像已成功保存。但是，当我在Gallery中查看它时，我会收到以下错误。

07-08 02:22:02.597: E/MediaStore(6833): Failed to insert image
07-08 02:22:02.597: E/MediaStore(6833): java.io.FileNotFoundException: No such file or directory
07-08 02:22:02.597: E/MediaStore(6833):     at android.database.DatabaseUtils.readExceptionWithFileNotFoundExceptionFromParcel(DatabaseUtils.java:146)
07-08 02:22:02.597: E/MediaStore(6833):     at android.content.ContentProviderProxy.openAssetFile(ContentProviderNative.java:611)
07-08 02:22:02.597: E/MediaStore(6833):     at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:922)
07-08 02:22:02.597: E/MediaStore(6833):     at android.content.ContentResolver.openOutputStream(ContentResolver.java:669)
07-08 02:22:02.597: E/MediaStore(6833):     at android.content.ContentResolver.openOutputStream(ContentResolver.java:645)
07-08 02:22:02.597: E/MediaStore(6833):     at android.provider.MediaStore$Images$Media.insertImage(MediaStore.java:902)
07-08 02:22:02.597: E/MediaStore(6833):     at com.example.letswrite.EndScreen.saveToDevice(EndScreen.java:128)
07-08 02:22:02.597: E/MediaStore(6833):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 02:22:02.597: E/MediaStore(6833):     at java.lang.reflect.Method.invoke(Method.java:515)
07-08 02:22:02.597: E/MediaStore(6833):     at android.view.View$1.onClick(View.java:3818)
07-08 02:22:02.597: E/MediaStore(6833):     at android.view.View.performClick(View.java:4438)
07-08 02:22:02.597: E/MediaStore(6833):     at android.view.View$PerformClick.run(View.java:18422)
07-08 02:22:02.597: E/MediaStore(6833):     at android.os.Handler.handleCallback(Handler.java:733)
07-08 02:22:02.597: E/MediaStore(6833):     at android.os.Handler.dispatchMessage(Handler.java:95)
07-08 02:22:02.597: E/MediaStore(6833):     at android.os.Looper.loop(Looper.java:136)
07-08 02:22:02.597: E/MediaStore(6833):     at android.app.ActivityThread.main(ActivityThread.java:5017)
07-08 02:22:02.597: E/MediaStore(6833):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 02:22:02.597: E/MediaStore(6833):     at java.lang.reflect.Method.invoke(Method.java:515)
07-08 02:22:02.597: E/MediaStore(6833):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-08 02:22:02.597: E/MediaStore(6833):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-08 02:22:02.597: E/MediaStore(6833):     at dalvik.system.NativeStart.main(Native Method)

我能做些什么吗？我是否可能因为使用Android模拟器而收到这些错误？