API level22下SD卡写入读取权限

SDK min 18 , compile with 25,运行在22的 AVD下,虽然在manifest文件下写了权限

但是实际运行中仍然被拒绝:提示

open failed: EACCES (Permission denied)

需要在使用权限之前询问:

 // Storage Permissions
    private static final int REQUEST_EXTERNAL_STORAGE = 1;
    private static String[] PERMISSIONS_STORAGE = {
            Manifest.permission.READ_EXTERNAL_STORAGE,
            Manifest.permission.WRITE_EXTERNAL_STORAGE
    };

    /**
     * Checks if the app has permission to write to device storage
     *
     * If the app does not has permission then the user will be prompted to grant permissions
     *
     * @param activity
     */
    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
            );
        }
    }

在使用前调用verifyStoragePermission方法,暂时解决了. (在stackoverflow看到的解决方法之一,使用有效)

2017 .1.11

实际上就这三行代码

 int code = checkSelfPermission("android.permission.READ_CONTACTS");
        if(code!= PackageManager.PERMISSION_GRANTED)
            requestPermissions(new String[]{"android.permission.READ_CONTACTS"},1);