Xamarin中的权限设置

两种类型的权限设置

1. AndroidManifest.xml中添加权限
2. 动态添加权限（有些权限 Android6.0之后需要动态添加权限），在使用到权限时，监测是否授权，没有授权的申请授权。

AndroidManifest.xml中添加权限

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.companyname.weatherstation.app" android:installLocation="auto">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28" />
    <application android:label="气象生态环境监测系统" android:usesCleartextTraffic="true" android:icon="@drawable/icon"></application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <!-- 访问网络，网络定位需要上网-->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>

动态添加权限（AndroidManifest.xml中也要加入该权限）

Android中的权限申请

class PermisionUtils
    {
        private static int REQUEST_EXTERNAL_STORAGE = 1;
        private static String[] PERMISSIONS_STORAGE = {
           Manifest.Permission.ReadExternalStorage,
           Manifest.Permission.WriteExternalStorage};

        public static bool VerifyStoragePermissions(Activity activity)
        {
            var permission = ActivityCompat.CheckSelfPermission(activity,
              Manifest.Permission.WriteExternalStorage);

            if (permission == Permission.Denied)
            {
                ActivityCompat.RequestPermissions(activity, PERMISSIONS_STORAGE,
                  REQUEST_EXTERNAL_STORAGE);
                return false;
            }
            return true;
        }
    }

MainActivity.cs中返回

public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }

【推荐】可以在Nuget添加Plugin.Permissions
这个可以对各个Android IOS UWP统一申请权限

protected override void OnAppearing()        {
            base.OnAppearing();
            SetPermission();
        }

        private async void SetPermission()
        {
            // Granted storage permission
            var storageStatus = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Storage);

            if (storageStatus != PermissionStatus.Granted)
            {
                var results = await CrossPermissions.Current.RequestPermissionsAsync(new[] { Permission.Storage });
                storageStatus = results[Permission.Storage];
            }

        }