I had an issue in my project and attempted to create a sample project to reproduce it and I was able to.
https://bitbucket.org/theonlylawislove/xamarinnavigationcontrollermemoryleak
The issue is that, when I present a UINavigationController, the navigation controller or its root view controller never gets garbage collected. It DOES work in the iOS simulator though. Why does this memory leak only happen on the device? If you run the sample project on the device, you will never see the Console.WriteLine in the deconstructors called.
I am using XCode5 and Xamarin.iOS 7.0.4.171 (Business Edition)
Here is the AppDelegate I am using to demonstrate the leak.
[Register ("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
UIWindow window;
public override bool FinishedLaunching (UIApplication app, NSDictionary options)
{
window = new UIWindow (UIScreen.MainScreen.Bounds);
window.RootViewController = new UINavigationController(new RootController ());
window.MakeKeyAndVisible ();
return true;
}
class RootController : UIViewController
{
public RootController ()
{
NavigationItem.RightBarButtonItem = new UIBarButtonItem("Present", UIBarButtonItemStyle.Bordered, (o,e) => {
PresentViewController(new NavigationController(), true, new NSAction(() => {}));
});
}
}
class NavigationController : UINavigationController
{
public NavigationController ()
:base(new TestController())
{
}
~NavigationController()
{
Console.WriteLine("~NavigationController");
}
class TestController : UIViewController
{
~TestController()
{
Console.WriteLine("~TestController");
}
public override void ViewDidAppear (bool animated)
{
base.ViewDidAppear (animated);
Task.Factory.StartNew (() => {
Thread.Sleep(2000);
NSThread.MainThread.InvokeOnMainThread(new NSAction(() => {
DismissViewController(true, new NSAction(() => {
}));
}));
});
}
}
}
}
This is merely a side effect of the conservative collector, there might be some junk on the stack, but using your application will eliminate the junk and allow the object to be released.
If you use SGen, which uses a precise system, you will see the object vanish right away.
Related
I'm using mvvmcross and implementing the view's interface in code behind. I would like to hide the navigation bar but I have not found a solution yet.
I tried
NavigationController.SetNavigationBarHidden(true, false);
and
NavigationController.NavigationBarHidden = true;
in different methods (ViewDidAppear and ViewWillAppear) but they don't have an impact on the UI.
Maybe someone could give me a hint. :-)
#Edit: Some more information:
My AppDelegate.cs
[Register("AppDelegate")]
public partial class AppDelegate : MvxApplicationDelegate
{
UIWindow _window;
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
_window = new UIWindow(UIScreen.MainScreen.Bounds);
var setup = new Setup(this, _window);
setup.Initialize();
var startup = Mvx.Resolve<IMvxAppStart>();
startup.Start();
_window.MakeKeyAndVisible();
return true;
}
}
Additionally I'm using a BaseView class which inherits from MvxViewController.
Okay, found the solution by myself:
Just paste the following code into the ViewDidLoad method in your MvxViewController class( for example FirstView.cs in many mvvmcross tutorials):
var navController = base.NavigationController;
navController.NavigationBarHidden = true;
I know it is a +6 years old question but came across finding a solution for this using MVVMCross and found out that using this into the xaml of your view should be enough: <NavigationPage.HasNavigationBar>False</NavigationPage.HasNavigationBar>
It should apply for both Xamarin Android and iOS.
This will kill it, let me know if you have questions.
[Register ("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
// class-level declarations
UIWindow window;
MyViewController viewController;
MainViewController mainViewController;
UINavigationController navController;
public UINavigationController NavController { get { return navController; }}
//
// This method is invoked when the application has loaded and is ready to run. In this
// method you should instantiate the window, load the UI into it and then make the window
// visible.
//
// You have 17 seconds to return from this method, or iOS will terminate your application.
//
public override bool FinishedLaunching (UIApplication app, NSDictionary options)
{
var navController = new UINavigationController();
navController.SetNavigationBarHidden (true, false);
window = new UIWindow (UIScreen.MainScreen.Bounds);
viewController = new MyViewController();
app.SetStatusBarStyle (UIStatusBarStyle.LightContent, true);
navController.PushViewController(viewController, false);
window.RootViewController = navController;
window.MakeKeyAndVisible ();
return true;
}
}
}
The default presenter uses a UINavigationController for the RootController on the window; so you can manipulate the navigation bar globally in the AppDelegate by grabbing it off the window and casting:
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
window = new UIWindow(UIScreen.MainScreen.Bounds);
new Setup(this, window).Initialize();
Mvx.Resolve<IMvxAppStart>().Start();
var navigationBar = ((UINavigationController)window.RootViewController).NavigationBar;
navigationBar.BackgroundColor = UIColor.Black;
navigationBar.BarTintColor = UIColor.Black;
navigationBar.TintColor = UIColor.White;
window.MakeKeyAndVisible();
return true;
}
I'm searching a way how can i bind ios gesture like UILongPressGestureRecognizer to ICommand or MvxCommand in MvvmCross, thanks.
PS : I found an example here but i can't figure out how to do that.
From the example you found and from the current MVVM Cross source I did the following
public static class MvxBehaviourExtensions
{
public static MvxLongPressGestureRecognizerBehaviour LongPress(this UIView view)
{
var toReturn = new MvxLongPressGestureRecognizerBehaviour(view);
return toReturn;
}
}
and
public class MvxLongPressGestureRecognizerBehaviour
: MvxGestureRecognizerBehavior<UILongPressGestureRecognizer>
{
protected override void HandleGesture(UILongPressGestureRecognizer gesture)
{
// Long press recognizer fires continuously. This will ensure we fire
// the command only once. Fire as soon as gesture is recognized as
// a long press.
if (gesture.State == UIGestureRecognizerState.Began)
{
FireCommand();
}
}
public MvxLongPressGestureRecognizerBehaviour(UIView target)
{
var lp = new UILongPressGestureRecognizer(HandleGesture);
AddGestureRecognizer(target, lp);
}
}
and to bind
set.Bind(this.LongPress()).For(lp => lp.Command).To(c => c.DoTheStuffCommand);
EDIT 2: If you're looking for an answer to a similar problem, check Stuart's answer and my comments on it.
EDIT: I am actually getting a Mono.Debugger.Soft.VMDisconnectedException. I also recently installed Windows 8.1 and Resharper (though Resharper is suspended now).
When I access a very simple list property of my view model in my MVVMCross Xamarin iOS application, the program fails. It doesn't quit most of the time: it acts like it's running. The simulator has a black screen and there is no exception. If I breakpoint on if (messagesViewModel != null) source.ItemsSource = messagesViewModel.Messages; and then type messagesViewModel.Messages into the Immediate Window, everything stops, so I can tell it is failing at this line. If instead I "step over", it never moves to the next line.
I was having similar behavior when I was toggling this code in the MvxTableViewSource:
public override int RowsInSection(UITableView tableview, int section)
{
return 1;
}
My view model looks like this:
public class MessagesViewModel : MvxViewModel
{
private List<BaseMessage> _messages = null;
public List<BaseMessage> Messages
{
get
{
return _messages; //yes, I know I'm returning null
//I wasn't at first.
}
}
public MessagesViewModel()
{
}
}
This is my ViewDIdLoad on the MvxTableViewController:
public override void ViewDidLoad()
{
base.ViewDidLoad();
var source = new MessagesTableViewSource(TableView);
//was binding here, removed it for debug purposes
//failure on second line here
var messagesViewModel = ViewModel as MessagesViewModel;
if (messagesViewModel != null) source.ItemsSource = messagesViewModel.Messages;
TableView.Source = source;
TableView.ReloadData();
}
Some initialization code:
public class App : MvxApplication
{
public App()
{
var appStart = new MvxAppStart<MessagesViewModel>();
Mvx.RegisterSingleton<IMvxAppStart>(appStart);
}
}
public partial class AppDelegate : MvxApplicationDelegate
{
//empty functions removed.
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
Window = new UIWindow(UIScreen.MainScreen.Bounds);
var presenter = new MvxTouchViewPresenter(this, Window);
var setup = new Setup(this, presenter);
setup.Initialize();
var startup = Mvx.Resolve<IMvxAppStart>();
startup.Start();
Window.MakeKeyAndVisible();
return true;
}
}
I suspect whatever the error is, it isn't in any of the code you have posted.
I just created a simple ViewModel:
public class FirstViewModel
: MvxViewModel
{
private List<string> _items = new List<string>() { "One", "Two", "Three"};
public List<string> Items
{
get { return _items; }
set { _items = value; RaisePropertyChanged(() => Items); }
}
}
And a simple View:
[Register("FirstView")]
public class FirstView : MvxTableViewController
{
public override void ViewDidLoad()
{
base.ViewDidLoad();
// ios7 layout
if (RespondsToSelector(new Selector("edgesForExtendedLayout")))
EdgesForExtendedLayout = UIRectEdge.None;
var firstViewModel = ViewModel as FirstViewModel;
var source = new MessagesTableViewSource(TableView);
source.ItemsSource = firstViewModel.Items;
TableView.Source = source;
}
public class MessagesTableViewSource : MvxTableViewSource
{
public MessagesTableViewSource(UITableView tableView) : base(tableView)
{
tableView.RegisterClassForCellReuse(typeof(MessagesCell), new NSString("MessagesCell"));
}
protected override UITableViewCell GetOrCreateCellFor(UITableView tableView, NSIndexPath indexPath, object item)
{
return tableView.DequeueReusableCell("MessagesCell");
}
}
public class MessagesCell : MvxTableViewCell
{
public MessagesCell(IntPtr handle)
: base(handle)
{
var txt = new UILabel(new RectangleF(0, 0, 320, 44));
Add(txt);
this.DelayBind(() =>
{
this.CreateBinding(txt).Apply();
});
}
}
}
And this code runs fine...
I wouldn't completely trust the integration of Xamarin.iOS with the Immediate window - it is better now than it used to be, but I've seen several problems with it before.
Some things to possibly check:
does the above code work for you?
if it does, then what's in your BaseMessage and MessagesTableViewSource classes - perhaps they are causing the problem?
can you use Mvx.Trace("The list is {0}", messagesViewModel.Messages ?? "-null") to view the list? Can you use trace within the ViewModel property get - is it being called? Can you use trace within the ViewModel constructor?
are all your assemblies building against the same versions of things? Are all your assemblies definitely rebuilt? (Check "Build|Configuration Manager")- what version of Xamarin.iOS are you running in VS and in the Mac?
I added 3 gesture recognizers to my MapView in IB, a long press, a pan & a pinch. Their delegate is the file's owner. I set them up like so -
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
PanGestureRecognizer.AddTarget(s => { Console.WriteLine("Pan"); } );
LongPressGestureRecognizer.AddTarget(s => { Console.WriteLine("Long press"); } );
PinchGestureRecognizer.AddTarget(s => { Console.WriteLine("Pinch"); } );
}
I also implement this -
public bool ShouldRecognizeSimultaneously (UIGestureRecognizer gestureRecognizer, UIGestureRecognizer otherGestureRecognizer)
{
return true;
}
The problem is, only the Long Press gesture recognizer does anything, the others are completely ignored.
Any ideas/suggestions welcome!
Being fairly new to Monotouch, I didn't realise that when I set the delegate of the MapView in IB to my ViewController, that wouldn't actually work. I needed to create a delegate which is a subclass of UIGestureRecognizerDelegate, and set the delegate of the gestureRecognizer to this, and I added the gestureRecognizer programmatically (though that's probably not necessary) -
private class GestureRecognizerDelegate : UIGestureRecognizerDelegate
{
public override bool ShouldRecognizeSimultaneously (UIGestureRecognizer gestureRecognizer, UIGestureRecognizer otherGestureRecognizer)
{
return true;
}
}
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
UIPinchGestureRecognizer pinchGestureRecognizer = new UIPinchGestureRecognizer(s => { /* do stuff here */ } );
GestureRecognizerDelegate gestureRecognizerDelegate = new GestureRecognizerDelegate();
pinchGestureRecognizer.Delegate = gestureRecognizerDelegate;
MapView.AddGestureRecognizer(pinchGestureRecognizer);
}
Then, by setting the ZoomEnabled property of the MapView to false, I can control how the map zooms (in my case, I had to prevent the map zooming in beyond a certain threshold, my client wasn't happy with the way you could zoom in & it would then bounce back out to my preset value, which I had working using RegionChanged in the MapView delegate). Don't you love clients!
I have a custom button which inherits from UIButton. I'm handling the TouchUpInside event and want to display a view on top of the current View. Is there such a thing as Dialogs like in Windows development? Or should I do this in another way?
[MonoTouch.Foundation.Register("HRPicker")]
public class HRPicker : UIButton
{
public HRPicker () : base()
{
SetUp();
}
public HRPicker(NSCoder coder) : base(coder)
{
SetUp();
}
public HRPicker(NSObjectFlag t) : base(t)
{
SetUp();
}
public HRPicker(IntPtr handle) : base(handle)
{
SetUp();
}
public HRPicker(RectangleF frame) : base(frame)
{
SetUp();
}
public void SetUp()
{
TouchUpInside += HandleTouchUpInside;
}
void HandleTouchUpInside (object sender, EventArgs e)
{
//I want to display a View here on top of the current one.
}
}
Thanks,
Yes, you have a couple options:
ModalViewController - is called from any UIViewController and overlays a ViewController in the foreground.
UIPopoverController - is a native control that takes a UIViewController and has hooks for presentation and dismissal
WEPopoverController - is a re-implementation of UIPopoverController and allows you to customize the layout, size, and color of the Popover container.
ModalViewController: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html
UIPopoverController: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIPopoverController_class/Reference/Reference.html
WEPopoverController: https://github.com/mono/monotouch-bindings/tree/master/WEPopover
Update: Regardless of which option you use you must call the presentation of the Popover / Modal view from the main thread:
using(var pool = new NSAutoReleasePool()) {
pool.BeginInvokeOnMainThread(()=>{
// Run your awesome code on the
// main thread here, dawg.
});
}
The equivalent of dialog in Cocoa is UIAlertView: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIAlertView_Class/UIAlertView/UIAlertView.html
Check out this question for an example of how to use it: Showing an alert with Cocoa
The code should be pretty easy to translate to c# and MonoTouch. But here is a simple example: http://monotouchexamples.com/#19