android请求权限

   /**
     * 请求读写权限
     */
    private void checkReadPermission() {
        if (ContextCompat.checkSelfPermission(mContext,
                Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            //TODO 此处写第一次检查权限且已经拥有权限后的业务
        } else {
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE){
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                        REQUEST_STORAGE_PERMISSION);
            } else {
                Log.e(TAG, "requestPermissions");
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                        REQUEST_STORAGE_PERMISSION);
            }
        }
    }

以上是请求读写权限的代码，请求权限后会有回调处理，如下

 /**
     * 检查权限后的回调
     *
     * @param requestCode
     * @param permissions
     * @param grantResults
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case REQUEST_STORAGE_PERMISSION:
                if (permissions.length != 0 && grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(this, "打开相册失败，请允许存储权限后再试", Toast.LENGTH_SHORT).show();
                } else {
                    //TODO 请求权限弹窗 允许后回调返回的成功回调 在此写业务逻辑
                }
                break;
        }
    }