java.io.FileNotFoundException: /storage/emulated/0/ ……: open failed: EACCES (Permissi

已经在manifests添加了权限：

<!--往sdcard中写入数据的权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!--在sdcard中创建/删除文件的权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

但是 还是  failed: EACCES (Permission denied)  拒绝访问

需要动态获取权限

//动态获取内存存储权限
public static void verifyStoragePermissions(Activity activity) {
    // Check if we have write permission
    int permission = ActivityCompat.checkSelfPermission(activity,
            Manifest.permission.WRITE_EXTERNAL_STORAGE);

    if (permission != PackageManager.PERMISSION_GRANTED) {
        // We don't have permission so prompt the user
        ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,
                REQUEST_EXTERNAL_STORAGE);
    }
}