android 保存图片，及将图片更新到图库

public static File saveImage(Bitmap bmp) {
    File appDir = new File(Environment.getExternalStorageDirectory(), "文件夹名字");
    if (!appDir.exists()) {
        appDir.mkdir();
    }
    String fileName = System.currentTimeMillis() + ".jpg";
    File file = new File(appDir, fileName);
    try {
        FileOutputStream fos = new FileOutputStream(file);
        bmp.compress(CompressFormat.JPEG, 100, fos);
        fos.flush();
        fos.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

try {
    MediaStore.Images.Media.insertImage(context.getMyContext().getContentResolver(), file.getAbsolutePath(), fileName, null);
} catch (FileNotFoundException e) {
    e.printStackTrace();
}

                context.getMyContext().sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + file.getPath())));