[Xamarin][原创]Android SD卡读写 动态权限添加

先 要在AndroidManifest.xml文件中添加权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

然后Activity中设置两个私有静态变量

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

然后在Activity中的onCreate引用方法

protected override void OnCreate(Bundle savedInstanceState)
         {
             base.OnCreate(savedInstanceState);
             Xamarin.Essentials.Platform.Init(this, savedInstanceState);
             // Set our view from the "main" layout resource
             SetContentView(Resource.Layout.activity_main);
             verifyStoragePermissions(this);
         } public void verifyStoragePermissions(Activity activity)
         {
             try
             {
                 //检测是否有写的权限
                 var permission = ActivityCompat.CheckSelfPermission(activity,"android.permission.WRITE_EXTERNAL_STORAGE");
                 if (permission != Android.Content.PM.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 ex)
             {
                 Toast.MakeText(activity, ex.Message, ToastLength.Short).Show();
             }
         }