My goal is to force landscape orientation on a single view controller, not the entire app (to be exact: I want to make my camera view controller to be landscape only)
I've been running into the issue not being able to force landscape on iOS 10 devices with Xamarin.iOS.
I've got it working on iOS 9 or lower by overriding the following methods in the view controller that is supposed to be in landscape only. However, these methods don't seem to be called on iOS 10.
public override bool ShouldAutorotate()
{
return true;
}
public override UIInterfaceOrientation PreferredInterfaceOrientationForPresentation()
{
return UIInterfaceOrientation.LandscapeLeft;
}
public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations()
{
return UIInterfaceOrientationMask.Landscape;
}
I also tested calling this method from ViewDidLoad (I'm not using this line anymore and can't tell if it has any effect)
//AppDelegate
public void ChangeOri()
{
UIDevice.CurrentDevice.SetValueForKey(new NSNumber((int)UIInterfaceOrientation.LandscapeLeft), new NSString("orientation"));
}
Any suggestions on a possible workaround?
I finally found an answer, it has nothing to do with iOS 10 itself.
I had the issue on iPad devices. iPads with iOS9 or higher have received a new function: "Multitasking". Refer to this thread to learn more about.
The crux is, when your app is set to be multitasking you can no longer change orientations from code. You have to enable fullscreen mode for the whole app to make the lines of code be called that I posted in my question above.
Set in your plist: UIRequiresFullScreen to true to do so.
Related
How to terminate a Xamarin application from any of the activities?
I have tried both System.Environment.Exit(0) and System.Environment.Exit(1) as well as Finish() and killing all the activities.
It still opens one blank page with default activity name and a black screen.
Is there any specific solution for this?
If you are using Xamarin.Forms create a Dependency Service.
Interface
public interface ICloseApplication
{
void closeApplication();
}
Android : Using FinishAffinity() won't restart your activity. It will simply close the application.
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
var activity = (Activity)Forms.Context;
activity.FinishAffinity();
}
}
IOS : As already suggested above.
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
Thread.CurrentThread.Abort();
}
}
UWP
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
Application.Current.Exit();
}
}
Usage in Xamarin Forms
var closer = DependencyService.Get<ICloseApplication>();
closer?.closeApplication();
A simple way to make it work cross platform is by this command:
System.Diagnostics.Process.GetCurrentProcess().CloseMainWindow();
Got it from this link.
EDIT: After using it for a while, I discovered that .CloseMainWindow() don't kill the application, only Closes it (well, thats obvious). If you want to terminate the app (kill), you shoud use the following:
System.Diagnostics.Process.GetCurrentProcess().Kill();
For Android, you can do
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
iOS explicitly does not provide any API for existing an App. Only the OS can close an App.
For iOS, you can use this code:
Thread.CurrentThread.Abort();
For Android, as #Jason mentioned here:
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
System.Environment.Exit(0);
Works for me.
In your activity, use this code
this.FinishAffinity();
I tried this code
protected override bool OnBackButtonPressed()
{
Device.BeginInvokeOnMainThread(async () =>
{
var result = await DisplayAlert("", "Would you like to exit from application?", "Yes", "No");
if (result)
{
if (Device.OS == TargetPlatform.Android)
{
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
}
else if (Device.OS == TargetPlatform.iOS)
{
Thread.CurrentThread.Abort();
}
}
});
return true;
}
In this, iOS and Android application close when a user chooses to terminate the application. Maybe it helps you.
A simple all-in-one combination of the previous answers, instead of the interface/dependency:
protected override bool OnBackButtonPressed()
{
Device.BeginInvokeOnMainThread(async () =>
{
var result = await this.DisplayAlert("Alert!", "want to exit?", "Yes", "No");
if (result)
{
#if __ANDROID__
var activity = (Android.App.Activity)Forms.Context;
activity.FinishAffinity();
#endif
#if __IOS__
Thread.CurrentThread.Abort();
#endif
}
});
return true;
}
System.Diagnostics.Process.GetCurrentProcess().CloseMainWindow();
System.Diagnostics.Process.GetCurrentProcess().Kill();
None of the methods above helped my Xamarin Android app to completely shut down. I tried to close it from Activity B, having Activity A also open under it.
A clever guy left a trick here.
First call FinishAffinity() in Activity B (closes both activities,
however, the app is still alive in the background)
Then call JavaSystem.Exit(0) to kill the background app (I think it can be replaced with Android.OS.Process.KillProcess(Android.OS.Process.MyPid()); or System.Diagnostics.Process.GetCurrentProcess().Kill();)
My method to close the app:
private void CloseBtn_Click(object sender, EventArgs e){
FinishAffinity();
JavaSystem.Exit(0);
}
As your original question mentions activities, your question is specifically for Android, you should probably update the question title with that in mind to avoid people looking for a cross-platform solution coming here.
For iOS and Android (say in Xamarin Forms) you can just throw an exception, which while being the "heavy handed" approach, will do the job:
throw new Exception();
As this isn't the best user experience and you may only want to use this for iOS because on Android, you are likely to get a system popup telling you the app crashed. However, unlike other iOS methods like calling exit(0) or calling private iOS methods like "terminateWithSuccess" via a selector, it shouldn't fail app store validation purely based on how you do it. They may still fail you because your app tries to terminate itself.
You may want to implement something different specifically for Android, in which case Jason's answer is sufficient, again if not a little on the nose i.e. using this approach may not allow your app to clean itself up:
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
Either way, you should really question why you need to provide this option. Unlike desktop applications where closing an application is needed because apps reside inside windows which by design allow multi-tasking and are not task orientated, mobile platforms are primarily designed for users to focus on one task at a time. Once the user is finished the task, they should decide to exit this task by clicking the home button, back button or change app (task) button. This really applies to all platforms.
None of these work with Android 8. They all left the app in the background.
I can prove this by pressing the close all button and the app is still there.
For my testing I used a brand new simple Android app and tried all of your answers.
Application.Quit();
I'm assuming you are using C#
Call
public void Quit ();
This will quit the application the correct way without it "crashing".
Is it possible to keep audio from a WebView, in particular, an embedded Webtorrent client (which plays video), running in the background on android? I've seen conflicting answers on this, and I'm curious what you guys know about the topic. I've seen some confirmed answers on ways to do it in android studio but not seen any for Xamarin.
I've been told that the WebView is considered a UI element; therefore, this makes it impossible to keep the video/audio running while in the background. So if that's the case, do you think with some clever coding I could override the android OS to fool it into thinking that the WebView is still in the foreground?
I know that it's possible to keep the audio running using MediaPlayer, if for example say, you're playing an MP3.. So another possibility might be using a service to maintain audio focus; but then, would the video stop playing (seeing as how that doesn't fix WebView being a UI element)?
One other possibility would be porting the entire app into a service.. but I'm not sure if that's possible. If I get an answer that it is, I'll do the work to make it happen.
I'm not looking for you guys to do the coding; I'm just looking for guidance on which method (if any) would be possible/plausible/most effective.
and here is some sample code I'm currently using to construct my WebView (not sure if that matters)
//what's on
[Activity]
//this class should be an aggregate subscription feed
public class WhatsOnActivity : Activity
{
public override void OnBackPressed()
{
WebView whatsOnWebView = FindViewById<WebView>(Resource.Id.webViewWhatsOn);
whatsOnWebView.GoBack();
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.whatsOn);
//declare webview and tell our code where to find the XAML resource
WebView whatsOnWebView = FindViewById<WebView>(Resource.Id.webViewWhatsOn);
whatsOnWebView.SetBackgroundColor(Android.Graphics.Color.Green);
//set the webview client
whatsOnWebView.SetWebViewClient(new WebViewClient());
//load the 'whats on' url, will need webscript for curated subscribed feed
whatsOnWebView.LoadUrl("https://www.bitchute.com/#listing-subscribed");
//enable javascript in our webview
whatsOnWebView.Settings.JavaScriptEnabled = true;
//zoom control on? This should perhaps be disabled for consistency?
//we will leave it on for now
whatsOnWebView.Settings.BuiltInZoomControls = true;
whatsOnWebView.Settings.SetSupportZoom(true);
//scrollbarsdisabled
// subWebView.ScrollBarStyle = ScrollbarStyles.OutsideOverlay;
whatsOnWebView.ScrollbarFadingEnabled = false;
}
}
EDIT: Also, my opensource project can be found here
https://github.com/hexag0d/bitchute_mobile_android_a2
Thanks, in advance. =]
I think it is quite late to answer this question, but the project I am working on is similar to this one.
I am currently working on this project by calling Activity with WebView through Foreground Service.
This is the code that calls Activity with Webview in Service.
Put this in the onStartCommand() of the Service.
Context context = getApplicationContext();
Intent dialogIntent = new Intent(context, WebViewActivity.class);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(dialogIntent);
I'm creating a Xamarin.Forms App and want to use UITest to test the correct behavior of my View. The View does not only react on user input like button click or the like. Instead there are background operations which should lead to changes in the View like hiding one element and showing another element at this point. Another example is filling a ListView with elements which would be produced by a background operation. These changes would be made on the ViewModel whose properties are bound to the View.
Now I want to simulate the background operation and test that my View behaves correctly. But I can not manipulate my ViewModel while in the UITest project because I cannot reference Xamarin.Forms in the Test class.
It seems like it isn't intended to test the application this way. The whole app is a black box for the UITest and you can only interact through mouse and keyboard input with it.
How can I access internals of my app, the corresponding ViewModel for example.
I already searched for this problem but found nothing. Maybe I'm searching in the wrong direction.
Any help would be highly appreciated.
You can use a back door to access a method in a platform project, and from there you should be able to access Forms code since your app project references the Forms core project. See: https://developer.xamarin.com/guides/testcloud/uitest/working-with/backdoors/
Create backdoor method in Android project:
In MainActivity:
[Export("MyBackdoorMethod")]
// Can optionally take a parameter of string, int, or bool.
// Can optionally return string or Java.Lang.String.
public void MyBackdoorMethod()
{
// In through the backdoor - do some work.
}
To call the Android backdoor method from a test:
app.Invoke("MyBackdoorMethod");
Create backdoor method in iOS project:
In AppDelegate:
[Export("myBackdoorMethod:")] // notice the colon at the end of the method name
// Must take an NSString and return an NSString.
public NSString MyBackdoorMethod(NSString value)
{
// In through the backdoor - do some work.
}
To call the iOS backdoor method from a test:
app.Invoke("myBackdoorMethod:", "the value");
More details at the link, but this should suffice to get one going.
On iOS, you already have a method to achieve it called SendAppToBackground. You can also pass the time to be in the background with a TimeSpan object (wiki info). However, you cannot achieve this on Android.
Here is a sample to use it on your UITest project:
public void SendAppToBackground(IApp app, TimeSpan timeSpan)
{
if (OnAndroid)
{
return;
}
((iOSApp)app).SendAppToBackground(timeSpan);
app.Screenshot("Return from background state.");
return this;
}
I'm working on a Xamarin application, which I will at first have working on iOS, but plan to later expand to Android and other mobile platforms.
As such, I'm trying to keep as much common code in PCLs as possible.
My question: what is the best practise - in Xamarin.iOS for now - to initialize any dependent PCL code?
For now I have it in the RootViewController inside ViewDidLoad()
public override void ViewDidLoad()
{
base.ViewDidLoad();
_engine = new MyEngine();
View = new MainView(_engine);
}
Is this the right spot? I'd considered putting it in the ctor for the RootViewController, but there's a fair bit going on in the initialization code, which thus ran against "don't put heavy duty init code into a constructor".
Things that happen are:
Load app settings
If app is run for first time ever, load basic defaults
Initialise other PCL libraries, such as a TextToSpeech module, a state engine (hence the name of the class above), etc
Prepare a data grid based on XML or JSON input
Alternately, I though it should possibly go into the AppDelegate section, but that didn't sound right.
I'm still fairly new to mobile app dev in general and Xamarin in specific, though I've done C# native code for Windows for years. I just want to make sure I follow best practises, but there doesn't seem to be a "thou shalt" in this case.
Edit: I've extracted the solution based on #wishmaster's suggestions.
For iOS the Appdelegate method is the best place for initialization code. The appdelegate also provides multiple delegate methods to give you feedback on application lifecyle events such as the method "DidFinishLauchingWithOptions"
. if you have a lot of data to download or long running tasks that your app depends on I would suggest you take a look backgrounding for iOS.
A technique I have also used is for my first viewcontroller on IOS (or activity on Android) to display a splash screen and a loading indicator while i run some code to refresh the cache.
Using #wishmaster's pointers, this solution works like a charm:
In AppDelegate.cs
// in the global section put any data you may make available elsewhere
private var _engine;
public Engine => _engine;
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
/*
* Do whatever init needs to happen here, if you need to make this
* available elsewhere, ensure you have properties or accessors,
* as above.
*/
_engine = new MyEngine();
return true;
}
Then in RootViewController.cs using a similar approach to these examples in Obc-C or Swift you can access the information through a property pointing at the AppDelegate.
var myappdelegate = UIApplication.SharedApplication.Delegate as AppDelegate;
var engine = myappdelegate.Engine;
View = new MainView(engine);
The result resulted in a snappier start up of the application, because the initialisation now happens during the splash screen and no longer between splash screen and appearance of the UI.
Although I think this is a fairly trivial question, I could not find any answers out there.
My question is:
Is there a way to get a notification in a MonoTouch iPhone application when my application is being closed or sent to background (by a user clicking the home button)?
I thought the WillTerminate override was good for this, but in the debugger, it is never called.
There are two ways to get notified when an app goes to the background:
a. Override the appropriate method in your AppDelegate:
public override void DidEnterBackground(UIApplication application)
{
// App entered background, do some light stuff here,
// there is not much time before getting suspended
}
b. Add notification observers through the NSNotificationCenter class:
NSObject observer = NSNotificationCenter.DefaultCenter.AddObserver(
UIApplication.DidEnterBackgroundNotification,
delegate(NSNotification ntf) {
// Same as above
});
You can use the NSObject object returned from the AddObserver method to remove the observer when you no longer need it:
NSNotificationCenter.DefaultCenter.RemoveObserver(observer);