从android中的图像获取元数据

我正在尝试使用ExiFinInterface获取jpg图像的元数据。 我能够获得数据，但我对flash数据感到困惑。 我如何从元数据中知道flash处于打开/关闭状态？ 这是我的密码

public class MainActivity extends Activity {

TextView myTextView;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    myTextView = (TextView) findViewById(R.id.textview);

    // change with the filename & location of your photo file
    String filename = "/sdcard/DCIM/Camera/b.jpg";
    try {
        ExifInterface exif = new ExifInterface(filename);
        ShowExif(exif);
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        Toast.makeText(this, "Error!", Toast.LENGTH_LONG).show();
    }
}

private void ShowExif(ExifInterface exif) {
    String myAttribute = "Exif information ---\n";
    myAttribute += getTagString(ExifInterface.TAG_DATETIME, exif);
    myAttribute += getTagString(ExifInterface.TAG_FLASH, exif);
    myAttribute += getTagString(ExifInterface.TAG_GPS_LATITUDE, exif);
    myAttribute += getTagString(ExifInterface.TAG_GPS_LATITUDE_REF, exif);
    myAttribute += getTagString(ExifInterface.TAG_GPS_LONGITUDE, exif);
    myAttribute += getTagString(ExifInterface.TAG_GPS_LONGITUDE_REF, exif);
    myAttribute += getTagString(ExifInterface.TAG_IMAGE_LENGTH, exif);
    myAttribute += getTagString(ExifInterface.TAG_IMAGE_WIDTH, exif);
    myAttribute += getTagString(ExifInterface.TAG_MAKE, exif);
    myAttribute += getTagString(ExifInterface.TAG_MODEL, exif);
    myAttribute += getTagString(ExifInterface.TAG_ORIENTATION, exif);
    myAttribute += getTagString(ExifInterface.TAG_WHITE_BALANCE, exif);
    myTextView.setText(myAttribute);
}

private String getTagString(String tag, ExifInterface exif) {
    return (tag + " : " + exif.getAttribute(tag) + "\n");
}

}

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谢谢

flash tag的值是多少？我会根据不同的设备得到不同的值，比如HTC one ON:9、OFF:16、auto:24，其中nexus 4中的任何flash的开启或关闭都是空的。