I want to make a container-app for my web application, and I decided to do so in Xamarin because the rest of the project is also .NET.
Initially I downloaded and setup the project from Xamarin Sample Pages:
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/webview?tabs=windows
I simply changed a few variables in WebPage.cs: https://github.com/xamarin/xamarin-forms-samples/blob/master/WorkingWithWebview/WorkingWithWebview/WebPage.cs
using Xamarin.Forms;
namespace WorkingWithWebview
{
public class WebPage : ContentPage
{
public WebPage()
{
var browser = new WebView();
browser.Source = "https://xamarin.swappsdev.net";
Content = browser;
}
}
}
Secondly I updated App.cs to suit my needs: https://github.com/xamarin/xamarin-forms-samples/blob/master/WorkingWithWebview/WorkingWithWebview/App.
using Xamarin.Forms;
namespace WorkingWithWebview
{
public class App : Application
{
public App ()
{
MainPage = new WebPage();
}
}
}
And boom! I had an app.
Then came the real struggle. In the web application I can – when opening the site (https://xamarin.swappsdev.net) in the browser – click on a button which requests permissions from the device and then display the camera feed in the same window.
When doing the same action in the app nothing happens.
I then started googling for an answer and really didn’t find a lot. And the answers I found seems to be of an older version of Xamarin (?), since I wasn’t able to compare the files and structure in the answer compared to the one of the Xamarin Sample Page.
https://stackoverflow.com/a/50560855
I tried implementing the answer from Robbit here. After a long struggle I managed to compile it and install it on my device but it doesn't actually ask for permissions.
I am at a loss and could need some help/guidance.
Updated:
In my previous answer, it shows how to add camera permission on webview.
The link you provided, it works now. https://xamarin.swappsdev.net/ It seems to provide a camera preview function. It need to check permissions on API 23+.
On Xamarin.Forms, you could use Permissions Plugin. https://github.com/jamesmontemagno/PermissionsPlugin
First, add the camera permission in Android Manifest.
Your Project.Android> Properties> Android Manifest> Required permissions> Camera. After that, it would generate the user permission in AndroidManifest.xml.
<uses-permission android:name="android.permission.CAMERA" />
Create a Utils.cs.
public static class Utils
{
public static async Task<PermissionStatus> CheckPermissions(Permission permission)
{
var permissionStatus = await CrossPermissions.Current.CheckPermissionStatusAsync(permission);
bool request = false;
if (permissionStatus == PermissionStatus.Denied)
{
if (Device.RuntimePlatform == Device.iOS)
{
var title = $"{permission} Permission";
var question = $"To use this plugin the {permission} permission is required. Please go into Settings and turn on {permission} for the app.";
var positive = "Settings";
var negative = "Maybe Later";
var task = Application.Current?.MainPage?.DisplayAlert(title, question, positive, negative);
if (task == null)
return permissionStatus;
var result = await task;
if (result)
{
CrossPermissions.Current.OpenAppSettings();
}
return permissionStatus;
}
request = true;
}
if (request || permissionStatus != PermissionStatus.Granted)
{
var newStatus = await CrossPermissions.Current.RequestPermissionsAsync(permission);
if (!newStatus.ContainsKey(permission))
{
return permissionStatus;
}
permissionStatus = newStatus[permission];
if (newStatus[permission] != PermissionStatus.Granted)
{
permissionStatus = newStatus[permission];
var title = $"{permission} Permission";
var question = $"To use the plugin the {permission} permission is required.";
var positive = "Settings";
var negative = "Maybe Later";
var task = Application.Current?.MainPage?.DisplayAlert(title, question, positive, negative);
if (task == null)
return permissionStatus;
var result = await task;
if (result)
{
CrossPermissions.Current.OpenAppSettings();
}
return permissionStatus;
}
}
return permissionStatus;
}
}
In MainActivity.cs, add the code in OnCreate method.
Plugin.CurrentActivity.CrossCurrentActivity.Current.Init(this, savedInstanceState);
OnRequestPermissionsResult is needed in MainActivity.cs.
public override void OnRequestPermissionsResult(int requestCode, string[] permissions,
[GeneratedEnum] Android.Content.PM.Permission[] grantResults)
{
PermissionsImplementation.Current.OnRequestPermissionsResult(requestCode, permissions, grantResults);
base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}
And then impletement it.
private async void _button_Clicked(object sender, EventArgs e)
{
webView.Source = "https://xamarin.swappsdev.net/";//"https://test.webrtc.org/";
var status = PermissionStatus.Unknown;
status = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Camera);
if (status != PermissionStatus.Granted)
{
status = await Utils.CheckPermissions(Permission.Camera);
}
}
I have upload on my GitHub. Check the folder. Test/CameraRuntimePermission_WebView/RuntimePermission
https://github.com/WendyZang/Test.git
Edit:
If you do not want to call this in button click event, you could delete the button in MainPage.xaml.
MainPage.xaml.cs
public MainPage()
{
InitializeComponent();
webView.Source = "https://xamarin.swappsdev.net/";
}
protected override void OnAppearing()
{
base.OnAppearing();
RunTimePermission();
}
public async void RunTimePermission()
{
var status = PermissionStatus.Unknown;
status = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Camera);
if (status != PermissionStatus.Granted)
{
status = await Utils.CheckPermissions(Permission.Camera);
}
}
After following several guides to enable the WebView's camera, I have finally succeeded.
I followed all of the above steps, and despite getting prompts for allowing the camera I could never get rid of the permissions error (even when debug showed the permissions were granted). I then replaced the MyWebViewRenderer code (as given above by Wendy) with the following (as given on https://forums.xamarin.com/discussion/183988/how-to-give-camera-and-microphone-permission-to-webview-with-xamarin-forms-on-android):
[assembly: ExportRenderer(typeof(CustomWebView), typeof(CustomWebViewRenderer))]
namespace App19F_8.Droid
{
public class CustomWebViewRenderer : WebViewRenderer
{
public CustomWebViewRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
Control.SetWebChromeClient(new MyWebChromeClient(MainActivity.Instance));
Control.Settings.JavaScriptEnabled = true;
}
}
}
public class MyWebChromeClient : WebChromeClient
{
Activity mActivity = null;
public MyWebChromeClient(Activity activity)
{
mActivity = activity;
}
public override void OnPermissionRequest(PermissionRequest request)
{
mActivity.RunOnUiThread(() => {
request.Grant(request.GetResources());
});
}
}
}
In case the link above becomes invalid, I should mention that in Android's MainActivity you should insert the following:
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
public static MainActivity Instance { get; private set; }
protected override void OnCreate(Bundle savedInstanceState)
{
...
base.OnCreate(savedInstanceState);
Instance = this;
global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
LoadApplication(new App());
}
}
Now finally the camera is working :-) I'm not exactly sure what the culprit was in the previous code. Thanks a lot to Wendy, Yelinzh and all for the thorough responses.
I tried implementing the answer from Robbit here. After a long struggle I managed to compile it and install it on my device but it doesn't actually ask for permissions.
I try the code provided by Robbit from the link.
Camera on Xamarin WebView
Actually, it works well. For better understanding, you could use the link below to check. https://test.webrtc.org/
If I use the webview to load the url directly, it would throw the error like below.
If I use the custom renderer from Robbit, it would ask for permission with the code in MyWebViewRenderer.
public override void OnPermissionRequest(PermissionRequest request)
{
mContext.RunOnUiThread(() =>
{
request.Grant(request.GetResources());
});
}
I have also check the link you used, nothing happened. The link would not open the camera in Android device.
Usage of the code from Robbit.
Create the MyWebView in your project.
public class MyWebView : WebView
{
}
Create the MyWebViewRenderer.cs in Android part of your project.
[assembly: ExportRenderer(typeof(MyWebView), typeof(MyWebViewRenderer))]
namespace WebViewDemo.Droid
{
public class MyWebViewRenderer : WebViewRenderer
{
Activity mContext;
public MyWebViewRenderer(Context context) : base(context)
{
this.mContext = context as Activity;
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
Control.Settings.JavaScriptEnabled = true;
Control.ClearCache(true);
Control.SetWebChromeClient(new MyWebClient(mContext));
}
public class MyWebClient : WebChromeClient
{
Activity mContext;
public MyWebClient(Activity context)
{
this.mContext = context;
}
[TargetApi(Value = 21)]
public override void OnPermissionRequest(PermissionRequest request)
{
mContext.RunOnUiThread(() =>
{
request.Grant(request.GetResources());
});
}
}
}
}
Usage:
MainPage.xaml
<StackLayout>
<Button x:Name="_button" Clicked="_button_Clicked" />
<local:MyWebView
x:Name="webView"
HeightRequest="500"
WidthRequest="500" />
</StackLayout>
MainPage.xaml.cs
private void _button_Clicked(object sender, EventArgs e)
{
webView.Source = "https://test.webrtc.org/";//"https://xamarin.swappsdev.net/";
}
You could download the whole project from GitHub folder CameraRuntimePermission_WebView. The Page1 is used to test the link with webview. The MainPage is used to test with custom renderer.
https://github.com/WendyZang/Test.git
Related
I need to make a simple callback in Xamarin, to check if the network status is connected or disconnected.
I have so far been doing it with this code:
class NetworkControl : INetworkControl
{
private readonly INetworkControl.ICallback _callback;
private readonly Context _context;
private readonly NetworkBroadcastReceiver _receiver = new NetworkBroadcastReceiver();
public NetworkControl(INetworkControl.ICallback callback, Context context)
{
_callback = callback;
_context = context;
IntentFilter filter = new IntentFilter(ConnectivityManager.ConnectivityAction);
context.RegisterReceiver(_receiver, filter);
}
public INetworkControl.ICallback Callback => _callback;
public INetworkControl.NetworkStatus Status
{
get
{
var current = Connectivity.NetworkAccess;
if (current == NetworkAccess.Internet)
{
return INetworkControl.NetworkStatus.Connected;
}
return INetworkControl.NetworkStatus.Disconnected;
}
}
}
class NetworkBroadcastReceiver : BroadcastReceiver
{
private static String TAG = "NetworkBroadcastReceiver";
public override void OnReceive(Context context, Intent intent)
{
if (ShellBridge.Instance != null)
{
if (intent.Action.Equals(ConnectivityManager.ConnectivityAction))
{
NetworkInfo ni = (NetworkInfo)intent.Extras.Get(ConnectivityManager.ExtraNetworkInfo);
if (ni.isConnected)
{
// do something if connected
ShellBridge.Instance.NetworkBridge.Callback.NetworkStatusChanged(INetworkControl.NetworkStatus.Connected);
} else
{
ShellBridge.Instance.NetworkBridge.Callback.NetworkStatusChanged(INetworkControl.NetworkStatus.Connected);
}
}
}
}
The problem is, the function ConnectivityManager.ConnectivityAction in the Intent creating is depricated, and will soon be obsolete. After searching, I found that the pendingIntent should be used for that, but I could not find any valid example of how to use it.
The closest to what I need is this:
https://stackoverflow.com/questions/58588132/how-to-use-registernetworkcallback-with-pendingintent
But, it has not all the information I need.
I need it to be all programmatically, without changing the manifest, for, my app should be a fore- and background app.
Please help, and thank you for your time.
You can take a look at NetworkCallback .
public class ConnectionStateMonitor : NetworkCallback
{
NetworkRequest networkRequest;
public ConnectionStateMonitor()
{
networkRequest = new NetworkRequest.Builder().
AddTransportType(TransportType.Cellular).
AddTransportType(TransportType.Wifi).Build();
}
public void enable(Context context) {
ConnectivityManager connectivityManager = context.GetSystemService(Context.ConnectivityService) as ConnectivityManager;
connectivityManager.RegisterNetworkCallback(networkRequest, this);
}
public override void OnAvailable(Network network)
{
//network available
}
public override void OnLost(Network network)
{
//network lost
}
}
Usage
You just need to instantiate the class ConnectionStateMonitor and enable it , you could detect the network status with the method OnAvailable and OnLost .
ConnectionStateMonitor m = new ConnectionStateMonitor ();
m.enable(context);
Refer
https://github.com/xamarin/Essentials/issues/512
ConnectivityManager.CONNECTIVITY_ACTION deprecated
You don't need to reinvent the wheel. You can achieve all that with Xamarin Essentials' Connectivity.
Besides checking if there is a connectivity like this:
var current = Connectivity.NetworkAccess;
if (current == NetworkAccess.Internet)
{
// Connection to internet is available
}
you can also track when the connectivity type changes:
public class ConnectivityTest
{
public ConnectivityTest()
{
// Register for connectivity changes, be sure to unsubscribe when finished
Connectivity.ConnectivityChanged += Connectivity_ConnectivityChanged;
}
void Connectivity_ConnectivityChanged(object sender, ConnectivityChangedEventArgs e)
{
var access = e.NetworkAccess;
var profiles = e.ConnectionProfiles;
}
}
How can i add a .AddOnCompleteListener(this) to SignOut() method in Xamarin.Android.
I want to navigate back to the login page after signing out. I'm using Xamarin.Firebase.Auth to login and I'm logging in like this:
private void InitFirebaseAuth()
{
app = FirebaseApp.Instance;
auth = FirebaseAuth.GetInstance(app);
var user = auth.CurrentUser;
if (user != null)
{
StartActivity(new Intent(this, typeof(HomeActivity)));
Finish();
}
}
Then after logging in, I want to log out and navigate to the logging page again, and I want to be sure that I have successfully logged out, but SignOut() has not a .AddOnCompleteListener(this).
example:
public class HomeActivity : AppCompatActivity, IOnCompleteListener
{
#region Public Properties
private FirebaseAuth auth;
#endregion
FirebaseUser user;
private DatabaseReference RealTimeDatabase;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.home);
auth = FirebaseAuth.GetInstance(MainActivity.app);
user = auth.CurrentUser;
//Init Firebase
RealTimeDatabase = FirebaseDatabase.Instance.GetReference("Users");
var welcomeMessage = FindViewById<TextView>(Resource.Id.welcomeMessage);
var LogOutBtn = FindViewById<Button>(Resource.Id.logOutBtn);
welcomeMessage.Text = $"Welcome {user.DisplayName}!";
LogOutBtn.Click += delegate
{
auth.SignOut().AddOnCompleteListener(this);
};
}
public void OnComplete(Task task)
{
if (task.IsSuccessful)
{
StartActivity(new Intent(this, typeof(MainActivity)));
Finish();
}
else
{
Snackbar snackbar = Snackbar.Make(activity_main, "Failed", Snackbar.LengthShort);
snackbar.Show();
}
}
}
Any help, please?
The SignOut operation is synchronous, so the sign out is completed as soon as the method is done. That's why it doesn't have/need a completion handler. You can just put any code that needs to happen after signing out, right after the method call:
auth.SignOut();
// whatever needs to happen after signing out
I created an app with Windows Template Studio on Visual Studio 2017.
The app is mainly a NavigationDrawer with different pages.
Everything was ok, until I wanted to add a login page.
So I created the XAML of the login page, etc. But now I want it to show before the NavigationDrawer page on app startup.
I seeked some documentation about the App.xaml.cs to know what to change to do that but, because of the use of Windows Template Studio, the code is not really vanilla anymore.
I tried a few things and the only thing I'm able to do right now is to change the shell page of the NavigationDrawer to my Login page.
That's not exactly what I want because my first intention was to make the app unavailable until you log in, and because the NavigationDrawer is still usable the user can still do what he wants to.
My app.xaml.cs looks like this :
using System;
using BasePosteMobilite.Services;
using Windows.ApplicationModel.Activation;
using Windows.UI.Xaml;
namespace BasePosteMobilite
{
public sealed partial class App : Application
{
private Lazy<ActivationService> _activationService;
private ActivationService ActivationService
{
get { return _activationService.Value; }
}
public App()
{
InitializeComponent();
// Deferred execution until used. Check https://msdn.microsoft.com/library/dd642331(v=vs.110).aspx for further info on Lazy<T> class.
_activationService = new Lazy<ActivationService>(CreateActivationService);
}
protected override async void OnLaunched(LaunchActivatedEventArgs args)
{
if (!args.PrelaunchActivated)
{
await ActivationService.ActivateAsync(args);
}
}
protected override async void OnActivated(IActivatedEventArgs args)
{
await ActivationService.ActivateAsync(args);
}
private ActivationService CreateActivationService()
{
return new ActivationService(this, typeof(ViewModels.LoginViewModel), new Lazy<UIElement>(CreateShell));
}
private UIElement CreateShell()
{
return new Views.ShellPage();
}
}
}
ShellPage.xaml.cs :
using System;
using BasePosteMobilite.ViewModels;
using Windows.UI.Xaml.Controls;
namespace BasePosteMobilite.Views
{
// TODO WTS: Change the icons and titles for all NavigationViewItems in ShellPage.xaml.
public sealed partial class ShellPage : Page
{
private ShellViewModel ViewModel
{
get { return ViewModelLocator.Current.ShellViewModel; }
}
public ShellPage()
{
InitializeComponent();
DataContext = ViewModel;
ViewModel.Initialize(shellFrame, navigationView, KeyboardAccelerators);
}
}
}
ViewModel.Initialize :
public void Initialize(Frame frame, WinUI.NavigationView navigationView, IList<KeyboardAccelerator> keyboardAccelerators)
{
_navigationView = navigationView;
_keyboardAccelerators = keyboardAccelerators;
NavigationService.Frame = frame;
NavigationService.NavigationFailed += Frame_NavigationFailed;
NavigationService.Navigated += Frame_Navigated;
_navigationView.BackRequested += OnBackRequested;
}
You can create a project with login required feature and you will see the following code from ActivateAsync method:
var silentLoginSuccess = await IdentityService.AcquireTokenSilentAsync();
if (!silentLoginSuccess || !IdentityService.IsAuthorized())
{
await RedirectLoginPageAsync();
}
That's it. If you want to redirect to your own page, write the detectation code under ActivationService.ActivateAsync(args) method. If you see the customer is not logged in. Call redirect login method. Here is the code from template studio about redirectlogin:
public async Task RedirectLoginPageAsync()
{
var frame = new Frame();
NavigationService.Frame = frame;
Window.Current.Content = frame;
await ThemeSelectorService.SetRequestedThemeAsync();
NavigationService.Navigate<Views.LogInPage>();
}
I created a very basic Service for dictionary playback using TTS (see the complete code below) and running into the same issue on all my 3 android devices (android versions 5, 7 and 8).
Gist: The app plays vocabulary entries, definitions and examples. Between each of them the app takes pause.
Symptoms:
The issue is happening mostly when I use 8 seconds for pause and the app is in the background mode (the screen is turned off). The playback simply gets frozen.
Sometimes the playback continues on its own with screen turned off after a lengthy pause sometimes being up to 20 - 30 minutes or even longer (but then the next entry is played after a very lenghty pause too, provided that we haven't activated screen). Could be some other process partly waking the phone?
Also, playback continues straight after I pressed Power button and screen turns on.
Debug info:
I was reckoning to press pause in Visual Studio after the app got frozen in order to see which bit of code is the cause - unfortunately the debugger seems to keep the device awake and this issue is extremely difficult to reveal.
In order to prevent my app from being frozen I acquire Partial WakeLock in my service (but this still doesn't help, even though app manifest contains permission for WAKE_LOCK)
private void AcquireWakeLock(MainActivity activity)
{
var mgr = (PowerManager)activity.ApplicationContext.GetSystemService(Context.PowerService);
WakeLock = mgr.NewWakeLock(WakeLockFlags.Partial, "myWakeLock");
WakeLock.Acquire();
}
My app also has Play/Pause button and I use TaskCompletionSource for the app to wait until I resume playback
public async Task PlayPause(bool isChecked, MainActivity mainActivity)
{
if (isChecked)
{
ReleaseWakeLock();
AppSuspended = new TaskCompletionSource<bool>();
Tts.Stop();
}
else
{
AcquireWakeLock(mainActivity);
AppSuspended.TrySetResult(true);
}
}
Then, before each next word/phrase is about to be played I use the following code for my app to wait for my resuming playback
await AppSuspended.Task;
Complete code
[Service(Name = "com.my_app.service.PlaybackService")]
public class PlaybackService : Service, TextToSpeech.IOnInitListener, TextToSpeech.IOnUtteranceCompletedListener
{
public IBinder Binder { get; private set; }
private Java.Util.Locale Lang;
private bool Playing;
private int EntryIndex;
private int DefinitionIndex;
private DictionaryDto Dictionary;
private EntryDto CurrentEntry;
private DefinitionDto CurrentDefinition;
private TaskCompletionSource<bool> AppSuspended;
protected TextToSpeech Tts;
private TaskCompletionSource<bool> PlaybackFinished;
private WakeLock WakeLock;
public override void OnCreate()
{
base.OnCreate();
Tts = new TextToSpeech(this, this);
Lang = Tts.DefaultLanguage;
AppSuspended = new TaskCompletionSource<bool>();
AppSuspended.TrySetResult(true);
}
public override IBinder OnBind(Intent intent)
{
Binder = new PlaybackBinder(this);
return Binder;
}
public override bool OnUnbind(Intent intent)
{
return base.OnUnbind(intent);
}
public override void OnDestroy()
{
Binder = null;
base.OnDestroy();
}
void TextToSpeech.IOnUtteranceCompletedListener.OnUtteranceCompleted(string utteranceId)
{
if (utteranceId.Equals("PlaybackFinished")) { PlaybackFinished.TrySetResult(true); }
}
void TextToSpeech.IOnInitListener.OnInit(OperationResult status)
{
// if we get an error, default to the default language
if (status == OperationResult.Error)
Tts.SetLanguage(Java.Util.Locale.Default);
// if the listener is ok, set the lang
if (status == OperationResult.Success)
{
Tts.SetLanguage(Lang);
Tts.SetOnUtteranceCompletedListener(this);
}
}
public async Task Play(string text)
{
Dictionary<string, string> myHashRender = new Dictionary<string, string>();
myHashRender.Add(TextToSpeech.Engine.KeyParamUtteranceId, "PlaybackFinished");
PlaybackFinished = new TaskCompletionSource<bool>();
Tts.Speak(text, QueueMode.Flush, myHashRender);
await PlaybackFinished.Task;
}
public async Task PlaySilence(long ms)
{
Dictionary<string, string> myHashRender = new Dictionary<string, string>();
myHashRender.Add(TextToSpeech.Engine.KeyParamUtteranceId, "PlaybackFinished");
PlaybackFinished = new TaskCompletionSource<bool>();
Tts.PlaySilence(ms, QueueMode.Flush, myHashRender);
await PlaybackFinished.Task;
}
private async Task PlayDictionary(MainActivity activity)
{
EntryIndex = 0;
for (; EntryIndex < Dictionary.Entries.Count;)
{
CurrentEntry = Dictionary.Entries.ElementAt(EntryIndex);
await AppSuspended.Task;
if (!Playing) { return; }
if (!string.IsNullOrEmpty(CurrentEntry.Text))
{
await AppSuspended.Task;
if (!Playing) { return; }
await Play(CurrentEntry.Text);
}
DefinitionIndex = 0;
for (; DefinitionIndex < CurrentEntry.Definitions.Count();)
{
CurrentDefinition = CurrentEntry.Definitions.ElementAt(DefinitionIndex);
await PlayDefinition();
await PlayExamples();
DefinitionIndex++;
}
if (Playing)
{
DefinitionIndex++;
}
EntryIndex++;
}
}
private async Task PlayExamples()
{
if (!Playing) { return; }
foreach (var example in CurrentDefinition.Examples)
{
if (!string.IsNullOrEmpty(example))
{
await AppSuspended.Task;
if (!Playing) { return; }
await Play(example);
if (Playing)
{
await PlaySilence((long)TimeSpan.FromSeconds(8).TotalMilliseconds);
}
}
}
}
private async Task PlayDefinition()
{
if (!Playing) { return; }
if (!string.IsNullOrEmpty(CurrentEntry.Definitions.ElementAt(DefinitionIndex).Text))
{
await AppSuspended.Task;
if (!Playing) { return; }
await PlayDefinitionText();
if (Playing)
{
await PlaySilence((long)TimeSpan.FromSeconds(7).TotalMilliseconds);
}
}
}
private async Task PlayDefinitionText()
{
await AppSuspended.Task;
await Play($"{CurrentEntry.Definitions.ElementAt(DefinitionIndex).Text}");
}
private void ReleaseWakeLock()
{
if (WakeLock != null)
{
WakeLock.Release();
}
}
private void AcquireWakeLock(MainActivity activity)
{
var mgr = (PowerManager)activity.ApplicationContext.GetSystemService(Context.PowerService);
WakeLock = mgr.NewWakeLock(WakeLockFlags.Partial, "myWakeLock");
WakeLock.Acquire();
}
public async Task PlayPause(bool isChecked, MainActivity mainActivity)
{
if (isChecked)
{
ReleaseWakeLock();
AppSuspended = new TaskCompletionSource<bool>();
Tts.Stop();
}
else
{
AcquireWakeLock(mainActivity);
AppSuspended.TrySetResult(true);
}
}
}
Additional info:
The issue happens on all of my devices
Galaxy C7 (Oreo)
Galaxy Tab A3 (Nougat)
Galaxy A3 (Lollipop)
I investigated the issue thoroughly and followed the recommendation to switch to Foreground Service which solved my problem perfectly.
Tested with Lollipop, Nougat, Oreo.
Foreground Service aproach
Put the following method in your MainActivity class
public void StartForegroundServiceSafely(Intent intent)
{
if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.O)
{
StartForegroundService(intent);
}
else
{
StartService(intent);
}
}
You then start your service via Intent
public void PlayFromFile(Android.Net.Uri uri)
{
AcquireWakeLock();
Intent startIntent = new Intent(this, typeof(PlaybackService));
startIntent.SetAction(PlaybackConsts.Start);
startIntent.PutExtra("uri", uri.ToString());
StartForegroundServiceSafely(startIntent);
}
Implement OnStartCommand method in your service
public class PlaybackService : Service, TextToSpeech.IOnInitListener, TextToSpeech.IOnUtteranceCompletedListener
[return: GeneratedEnum]
public override StartCommandResult OnStartCommand(Intent intent, [GeneratedEnum] StartCommandFlags flags, int startId)
{
if (intent.Action.Equals(PlaybackConsts.Start))
{
var notification =
new Notification.Builder(this)
.SetContentTitle(Resources.GetString(Resource.String.ApplicationName))
.SetContentText("HELLO WORLD")
.SetOngoing(true)
.Build();
StartForeground(SERVICE_RUNNING_NOTIFICATION_ID, notification);
}
if (intent.Action.Equals(PlaybackConsts.Start))
{
var uri = Android.Net.Uri.Parse(intent.GetStringExtra("uri"));
var content = MiscellaneousHelper.GetTextFromStream(ContentResolver.OpenInputStream(uri));
Dictionary = DictionaryFactory.Get(content);
Playing = true;
Task.Factory.StartNew(async () =>
{
await PlayDictionary();
});
}
if (intent.Action.Equals(PlaybackConsts.PlayPause))
{
bool isChecked = intent.GetBooleanExtra("isChecked", false);
PlayPause(isChecked);
}
if (intent.Action.Equals(PlaybackConsts.NextEntry))
{
NextEntry();
}
if (intent.Action.Equals(PlaybackConsts.PrevEntry))
{
PrevEntry();
}
if (intent.Action.Equals(PlaybackConsts.Stop))
{
Task.Factory.StartNew(async () =>
{
await Stop();
});
StopForeground(true);
StopSelf();
}
return StartCommandResult.Sticky;
}
From the code above we've learned how to trigger service's functionality in OnStartCommand method.
How to broadcast events from Service
Define your BroadcastReceiver
[BroadcastReceiver(Enabled = true, Exported = false)]
public class PlaybackBroadcastReceiver : BroadcastReceiver
{
public override void OnReceive(Context context, Intent intent)
{
var activity = MainActivity.GetInstance(); // if you need your activity here, see further code below
if (intent.Action == "renderEntry")
{
string entryHtml = intent.GetStringExtra("html");
// omitting code to keep example concise
}
}
}
Declare receiver field in your MainActivity class.
Also encase you need your activity in BroadcastReceiver class you can declare GetInstance method (singleton approach).
public class MainActivity : AppCompatActivity
{
PlaybackBroadcastReceiver receiver;
protected DrawerLayout drawerLayout;
protected NavigationView navigationView;
protected WakeLock WakeLock;
private static MainActivity instance;
public static MainActivity GetInstance()
{
return instance;
}
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
receiver = new PlaybackBroadcastReceiver();
instance = this;
}
protected override void OnStart()
{
base.OnStart();
RegisterReceiver(receiver, new IntentFilter("renderEntry"));
}
In order to unregister receiver use the following line:
UnregisterReceiver(receiver);
Broadcasting events from service
In your service you must also use intent
private void SendRenderEntryBroadcast(EntryDto entry)
{
Intent intent = new Intent("renderEntry");
intent.PutExtra("html", GetEntryHtml(entry));
SendBroadcast(intent);
}
I tried doing this in my main app I'm writing but can't seem to get it to work. So I created a Single View Application to try it out and figure it out but I still seem to be stuck. He's what i got.
public partial class HelloViewController : UIViewController
{
partial class VideoPickerController : UIViewController
{
MediaPicker videoPicker;
readonly TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();
public VideoPickerController (IntPtr handle) : base (handle)
{
}
public override void DidReceiveMemoryWarning ()
{
// Releases the view if it doesn't have a superview.
base.DidReceiveMemoryWarning ();
// Release any cached data, images, etc that aren't in use.
}
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
var picker = new MediaPicker ();
PresentViewController (picker.GetPickPhotoUI (), true, null);
}
}
}
Basically all I get is a white screen and nothing happens. Thanks!
I don't think you need need to to manually present it. This is code that I used and it automatically presents the UI for me. This code is not in it's own viewcontroller, it is just in whatever viewcontroller that I have the button it to take the pic. There are similar methods for the photo album and for taking videos.
Here is a link to the github page where I have this sample app hosted.
var picker = new Xamarin.Media.MediaPicker();
btnCamera.Hidden = !picker.IsCameraAvailable;
btnCamera.TouchUpInside += async (sender, e) =>
{
try
{
MediaFile file =
await picker.TakePhotoAsync(new StoreCameraMediaOptions());
processImage(file);
}
catch { }
};
btnPhoto.Hidden = !picker.PhotosSupported;
btnPhoto.TouchUpInside += async (sender, e) =>
{
try
{
MediaFile file = await picker.PickPhotoAsync();
processImage(file);
}
catch { }
};
private void processImage(MediaFile file)
{
if (file != null)
{
viewModel.Image = file.GetStream();
viewModel.ImagePath = file.Path;
setImage();
}
}
private void setImage()
{
try
{
System.Diagnostics.Debug.WriteLine(viewModel.ImagePath);
if (!string.IsNullOrEmpty(viewModel.ImagePath) &&
System.IO.File.Exists(viewModel.ImagePath))
{
imgImage.Image = new UIImage(NSData.FromFile(viewModel.ImagePath));
}
else if (viewModel.Image != null && viewModel.Image.Length != 0)
{
imgImage.Image = new UIImage(NSData.FromStream(viewModel.Image));
}
}
//just don't load image
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.Message);
}
}