Android请求读取、写入权限

//如果仅读取自己app内目录，无需调用下面的方法动态申请权限
public void requestPermission() {
        String[] permissions = new String[]{
                Manifest.permission.READ_EXTERNAL_STORAGE,
                Manifest.permission.WRITE_EXTERNAL_STORAGE
        };
        for (String permission : permissions) {
            if (ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, permissions, 100);
            }
        }
    }

<!--无论读写什么文件都要将下面的信息填到AndroidManifest.xml中-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>