所以我试图让用户获得在我试图创建的应用程序上使用Location的权限。我在Android Manifest中包含了该权限
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
在Splash屏幕所在的SplashActivity页面以及我希望向用户显示权限的位置我已将以下代码放入：
namespace Cabiee.Droid
{
[Activity(Theme = "@style/Theme.Splash",
MainLauncher = true,
NoHistory = true,
Icon = "@drawable/CabieBackground")]
public class SplashActivity : Activity
{
protected async override void OnCreate(Bundle savedInstanceState)
{
await TryToGetPermissions();
base.OnCreate(savedInstanceState);
System.Threading.Thread.Sleep(500);
StartActivity(typeof(Login));
// Create your application here
}
#region RuntimePermissions
async Task TryToGetPermissions()
{
if ((int)Build.VERSION.SdkInt >= 23)
{
await GetPermissionsAsync();
return;
}
}
const int RequestLocationId = 0;
readonly string[] PermissionsGroupLocation =
{
//TODO add more permissions
Manifest.Permission.AccessCoarseLocation,
Manifest.Permission.AccessFineLocation,
};
async Task GetPermissionsAsync()
{
const string permission = Manifest.Permission.AccessFineLocation;
if (CheckSelfPermission(permission) == (int)Android.Content.PM.Permission.Granted)
{
//TODO change the message to show the permissions name
Toast.MakeText(this, "Special permissions granted", ToastLength.Short).Show();
return;
}
if (ShouldShowRequestPermissionRationale(permission))
{
//set alert for executing the task
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.SetTitle("Permissions Needed");
alert.SetMessage("The application need special permissions to continue");
alert.SetPositiveButton("Request Permissions", (senderAlert, args) =>
{
RequestPermissions(PermissionsGroupLocation, RequestLocationId);
});
alert.SetNegativeButton("Cancel", (senderAlert, args) =>
{
Toast.MakeText(this, "Cancelled!", ToastLength.Short).Show();
});
Dialog dialog = alert.Create();
dialog.Show();
return;
}
RequestPermissions(PermissionsGroupLocation, RequestLocationId);
}
public override async void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
{
switch (requestCode)
{
case RequestLocationId:
{
if (grantResults[0] == (int)Android.Content.PM.Permission.Granted)
{
Toast.MakeText(this, "Special permissions granted", ToastLength.Short).Show();
}
else
{
//Permission Denied :(
Toast.MakeText(this, "Special permissions denied", ToastLength.Short).Show();
}
}
break;
}
//base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}
#endregion
}
但是，不会要求用户提供权限。我认为它可能与await TryToGetPermissions（）有关;朝向代码的开头，它实际上没有调用TryToGetPermissions，因此它不起作用。
任何帮助将不胜感激。
谢谢！
我有一个完全相同的工作解决方案，如下所示：
在OnCreate方法中检查现有权限：
if (!(CheckPermissionGranted(Manifest.Permission.AccessCoarseLocation) &&
CheckPermissionGranted(Manifest.Permission.AccessFineLocation)))
{
RequestLocationPermission();
}
else
{
InitializeLocationManager();
}
InitPageWidgets();
检查权限Granted是一种类似这样的方法：
[Export]
public bool CheckPermissionGranted(string Permissions)
{
// Check if the permission is already available.
if (ActivityCompat.CheckSelfPermission(this, Permissions) != Permission.Granted)
{
return false;
}
else
{
return true;
}
}
请求权限代码如下所示：
private void RequestLocationPermission()
{
if (ActivityCompat.ShouldShowRequestPermissionRationale(this, Manifest.Permission.AccessFineLocation))
{
// Provide an additional rationale to the user if the permission was not granted
// and the user would benefit from additional context for the use of the permission.
// For example if the user has previously denied the permission.
ActivityCompat.RequestPermissions(this, PermissionsLocation, REQUEST_LOCATION);
}
else
{
// Camera permission has not been granted yet. Request it directly.
ActivityCompat.RequestPermissions(this, PermissionsLocation, REQUEST_LOCATION);
}
}
如果你不需要async / await，下面是我在我的应用程序中所做的，我需要Camera权限。它非常适合我的需求，也许它也适合你。
您的实现将更简单，因为您不需要在OnRequestPermissionsResult（）中迭代多个结果。我不得不这样做，因为我的应用程序需要保存图片，因此在我加载相机界面/活动之前需要Camera和WriteExternalStorage权限。
[Activity(Label = "@string/app_name", Theme = "@style/AppTheme.NoActionBar", MainLauncher = true, ScreenOrientation = ScreenOrientation.Landscape)]
public class MainLoaderActivity : AppCompatActivity {
private const string LOG_TAG = "CAMERA2_LOG";
private const int PERMISSION_REQUEST_CODE_CAMERA_USAGE = 4500; // Arbitrary number to identify our permissions required for camera app usage
private Button btnLoadCameraActivity;
protected override void OnCreate(Bundle savedInstanceState) {
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.main_loader);
btnLoadCameraActivity = FindViewById<Button>(Resource.Id.btnLoadCameraActivity);
btnLoadCameraActivity.Click += btnLoadCameraActivity_Click;
}
private void btnLoadCameraActivity_Click(object sender, EventArgs e) {
// Using the camera on Android 6.0 and later requires a run-time permissions granting by the user.
// So, check to see if user manually enabled in Settings, or previously was prompted in this app and was granted access. If not, we'll prompt them...
if (CheckSelfPermission(Android.Manifest.Permission.Camera) == Permission.Granted &&
CheckSelfPermission(Android.Manifest.Permission.WriteExternalStorage) == Permission.Granted) {
// We have both permissions necessary to run the Camera interface...
StartActivity(typeof(CameraActivity));
return;
}
// If we get here, at least one of the required permissions hasn't been approved, so find out which one and request accordingly...
var listPermissions = new System.Collections.Generic.List<string>();
// Build array of permissions needed for Camera usage
if (CheckSelfPermission(Android.Manifest.Permission.Camera) != Permission.Granted) {
Log.Warn(LOG_TAG, "CheckSelfPermission(Camera) not yet granted - will prompt user for permission");
listPermissions.Add(Android.Manifest.Permission.Camera);
}
if (CheckSelfPermission(Android.Manifest.Permission.WriteExternalStorage) != Permission.Granted) {
Log.Warn(LOG_TAG, "CheckSelfPermission(WriteExternalStorage) not yet granted - will prompt user for permission");
listPermissions.Add(Android.Manifest.Permission.WriteExternalStorage);
}
// Make the request with the permissions needed...and then check OnRequestPermissionsResult() for the results
RequestPermissions(listPermissions.ToArray(), PERMISSION_REQUEST_CODE_CAMERA_USAGE);
}
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Android.Content.PM.Permission[] grantResults) {
Log.Info(LOG_TAG, $"OnRequestPermissionsResult(requestCode={requestCode} - Permissions Count={permissions.Length} - GrantResults Count={grantResults.Length})");
switch (requestCode) {
// To use the camera, the user must grant privs to the Camera as well as writing to external storage, so this case checks both
case PERMISSION_REQUEST_CODE_CAMERA_USAGE: {
for (var i = 0; i < permissions.Length; i++) {
Log.Info(LOG_TAG, $"Checking permission for {permissions[i]}...");
if (grantResults[i] != Permission.Granted) {
Log.Info(LOG_TAG, $"Permission Denied for {permissions[i]}!");
Toast.MakeText(this, "You must approve all permissions prompted to use the camera.", ToastLength.Long).Show();
return;
}
Log.Info(LOG_TAG, $"Permission Granted for {permissions[i]}.");
}
// If we get here then all the permissions we requested were approved and we can now load the Camera interface
StartActivity(typeof(CameraActivity));
break;
}
}
}
}