android中保存Bitmap图片到指定文件夹中的方法

public void saveBitmapToFile(String path, Bitmap bm, String picName) {

File f = new File(path, picName);
FileOutputStream out = null;

try {
out = new FileOutputStream(f);
bm.compress(Bitmap.CompressFormat.PNG, 90, out);
out.flush();

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}

}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>