SD卡动态权限

private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
        "android.permission.READ_EXTERNAL_STORAGE",
        "android.permission.WRITE_EXTERNAL_STORAGE"};

在oncreate中调用下面方法

public static void verifyStoragePermissions(Activity activity) {

    try {
        //检测是否有写的权限
        int permission = ActivityCompat.checkSelfPermission(activity,
                "android.permission.WRITE_EXTERNAL_STORAGE");
        if (permission != PackageManager.PERMISSION_GRANTED) {
            // 没有写的权限，去申请写的权限，会弹出对话框
            ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}