What is the correct way to detect when a NSView is resized ?.
I do not see any resize event available on the view or any delegate for the view.
I have added this hack, where I use the drawRect to detect the change in size, but I'm sure there must be a more correct way to do this.
CGRect m_resizeRect = CGRect.Empty;
public override void DrawRect(CGRect dirtyRect)
{
base.DrawRect(dirtyRect);
if (this.InLiveResize) {
if (m_resizeRect.Size != this.Bounds.Size) {
m_resizeRect = this.Bounds;
this.OnResize();
}
}
}
public override void ViewWillStartLiveResize()
{
m_resizeRect = this.Bounds;
base.ViewWillStartLiveResize();
}
public override void ViewDidEndLiveResize()
{
m_resizeRect = CGRect.Empty;
base.ViewDidEndLiveResize();
}
protected void OnResize() {
Console.WriteLine("OnResize " + this.Bounds.ToString() );
}
You can subscribe to the resize notifications.
Add observer to default notification center:
NSObject NSWindowDidResizeNotificationObject;
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
NSWindowDidResizeNotificationObject = NSNotificationCenter.DefaultCenter.AddObserver (new NSString ("NSWindowDidResizeNotification"), ResizeObserver, null);
}
NSNotification Action:
public void ResizeObserver (NSNotification notify)
{
var r = this.View.Frame;
Console.WriteLine ("{0}:{1}:{1}", notify.Name, r.Height, r.Width);
}
Remove observer (and release memory):
NSNotificationCenter.DefaultCenter.RemoveObserver (NSWindowDidResizeNotificationObject);
Sample Output:
NSWindowDidResizeNotification:740:740
NSWindowDidResizeNotification:715:715
NSWindowDidResizeNotification:681:681
NSWindowDidResizeNotification:642:642
You can override the setFrameSize method and do your own stuff every time the frame is updated.
class MyView: NSView {
...
override func setFrameSize(newSize: NSSize) {
super.setFrameSize(newSize)
Swift.print("new size is \(frame)")
}
...
}
The accepted answer only seems to respond to window size changes and not e.g. when the split-bar of a splitview causes the resize.
See the NSView postsBoundsChangedNotifications and postFrameChangedNotifications properties. You can set those and register for those notifications.
You can use NSViewController.viewDidLayout() overriden method:
class MyViewController: NSViewController {
...
override func viewDidLayout() {
Swift.print("view has been resize to \(self.view.frame)")
}
...
}
Related
Its very common problem in iOS mobile development and that is while you are done with your UI and It contains too many UITextFields, If you try to input value in UITextFields those are added center bottom of the screen; these fields hides behind the keyboard. How can we get rid of this general problem?
You could use the AddObserver method in NSNotificationCenter for when keyboard is visible and hidden.
sample code(FYI: Got the code below from another post sometime last year, I can't remember link to the post but it works fine.)
Call the AddObserver in your viewdidload method
// Keyboard popup NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.DidShowNotification, KeyBoardUpNotification);
// Keyboard Down NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.WillHideNotification, KeyBoardDownNotification);
you can add the methods below in your base controller base if you have one
public void KeyBoardUpNotification(NSNotification notification) {
CGRect keyboardSize = UIKeyboard.BoundsFromNotification(notification);
// Find what opened the keyboard
foreach (UIView view in this.View.Subviews) {
if (view.IsFirstResponder)
activeview = view;
}
bottom = (activeview.Frame.Y + activeview.Frame.Height + offset);
scrollamount = (keyboardSize.Height - (View.Frame.Size.Height - bottom));
if (scrollamount > 0) {
moveViewUp = true;
MoveView(moveViewUp);
} else {
moveViewUp = false;
}
}
public void KeyBoardDownNotification(NSNotification notification) {
if (moveViewUp) {
MoveView(false);
}
}
private void MoveView(bool move) {
UIView.BeginAnimations(string.Empty, IntPtr.Zero);
UIView.SetAnimationDuration(0.3);
CGRect frame = View.Frame;
if (move) {
frame.Y -= scrollamount;
} else {
frame.Y += scrollamount;
scrollamount = 0;
}
View.Frame = frame;
UIView.CommitAnimations();
}
I have used a nuget package to get rid of this problem. I have overrides two methods and initialized code inside these methods.
Download KeyboardHandler and use as following:
using KeyboardHandler;
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
this.yourScrollView.SubscribeKeyboardManaqger();
}
public override void ViewWillDisappear(bool animated)
{
base.ViewWillDisappear(animated);
this.yourScrollView.UnsubscribeKeyboardManaqger();
}
I am currently trying to center a UIIView inside of a UIScrollView and am having some difficulty in doing so.
Here is the image of my current view:
Here is the code snippet I'm working with:
public void AddView(UIViewController viewCont)
{
this.AddChildViewController(viewCont);
this.mainScrollView.AddSubview(viewCont.View);
viewCont.DidMoveToParentViewController(this);
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
var m = new Menu();
//var c = new Camera();
AddView(m);
AddView(c);
CGRect cFrame = c.View.Frame;
cFrame.X = this.View.Frame.Width;
c.View.Frame = cFrame;
this.mainScrollView.ContentSize = new CGSize(this.View.Frame.Width * 2, 1.0);
}
I want to fill this whole view with Green but as you can see, the bottom quarter of the View does not stretch all the way to the bottom.
For the time being, I have removed all constraints because every attempt in adding them results in no successes. I was hoping to get a concrete answer here as to how I could go about centering this view within this UIScrollView.
Thanks
UPDATE: 3-21-2017
My main goal is to have 2 ViewControllers side by side within my UIScrollView that I can navigate to and from using a swipe gesture, like SnapChat. Following, #Digitalsa1nt suggestions, I unfortunately come up with the same issue.
Here are some more pictures:
This first one shows what happens when I only add the 1 view:
This next one shows what happens when I try to add both views to my UIScrollView, only the camera shows:
Finally, here is the code that I am using to back my Camera view:
using Foundation;
using UIKit;
using AVFoundation;
namespace BRB.iOS
{
public partial class Camera : UIViewController
{
AVCaptureSession captureSession;
AVCaptureStillImageOutput stillImageOutput;
AVCaptureVideoPreviewLayer previewLayer;
public Camera() : base("Camera", null)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
}
public override void DidReceiveMemoryWarning()
{
base.DidReceiveMemoryWarning();
// Release any cached data, images, etc that aren't in use
}
public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
previewLayer.Frame = cameraView.Bounds;
}
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
captureSession = new AVCaptureSession();
captureSession.SessionPreset = AVCaptureSession.Preset1920x1080;
var backCamera = AVCaptureDevice.GetDefaultDevice(AVMediaType.Video);
NSError error;
var input = AVCaptureDeviceInput.FromDevice(backCamera, out error);
if (error == null && captureSession.CanAddInput(input))
{
captureSession.AddInput(input);
stillImageOutput = new AVCaptureStillImageOutput();
stillImageOutput.OutputSettings = new NSDictionary(AVVideo.CodecKey, AVVideo.CodecJPEG);
if (captureSession.CanAddOutput(stillImageOutput))
{
captureSession.AddOutput(stillImageOutput);
previewLayer = new AVCaptureVideoPreviewLayer(captureSession);
previewLayer.VideoGravity = AVLayerVideoGravity.ResizeAspect;
previewLayer.Connection.VideoOrientation = AVCaptureVideoOrientation.Portrait;
cameraView.Layer.AddSublayer(previewLayer);
captureSession.StartRunning();
}
}
}
}
}
I usually override 'didlayoutsubviews' for making changes to the views within my UIScrollViews. The below worked for me.
public void AddView(UIViewController viewCont)
{
AddChildViewController(viewCont);
mainScrollView.AddSubview(viewCont.View);
viewCont.DidMoveToParentViewController(this);
}
public override void ViewDidLayoutSubviews()
{
base.ViewDidLayoutSubviews();
// Ensure our contentinsets are 0 so we don't have any blank space
mainScrollView.ContentInset = new UIEdgeInsets(0, 0, 0, 0);
// set the contentsize to the bounds of the container view within.
mainScrollView.ContentSize = View.Bounds.Size;
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
var m = new Menu();
//var c = new Camera();
AddView(m);
AddView(c);
}
I'm trying to handle the keyDown event for NSTextField using monoMac and Xamarin Studio.
I have created a NSTextFieldDelegate derived class and set the editors delegate to an instance of this class. However, I only see the Changed method being called, never the DoCommandBySelector
class TextPathDelegate : NSTextFieldDelegate {
public override void Changed(NSNotification notification)
{
Console.WriteLine("changed");
}
public override void DidChangeValue(string forKey)
{
Console.WriteLine("didchange = {0}", forKey);
}
public override void WillChangeValue(string forKey)
{
Console.WriteLine("willchange = {0}", forKey);
}
public override bool DoCommandBySelector(NSControl control, NSTextView textView, MonoMac.ObjCRuntime.Selector commandSelector)
{
Console.WriteLine("DoCommandBySelector = {0}", commandSelector.ToString());
return false;
}
}
Any idea what I might be missing ?
Edit-2:
I just noticed that DoCommandBySelector is being called if I use the arrow keys and page up/down. Still not able to catch the keydown event
Edit-1:
I tried to make a small project with Xamarin.mac, just 2 edit fields, with a derived edit control and the delegate.
This is the code
class TextPathDelegate : NSTextFieldDelegate {
string Id { get; set; }
public TextPathDelegate(string id) { Id = id; }
public override void Changed(NSNotification notification)
{
Console.WriteLine(Id + "changed");
}
public override bool DoCommandBySelector(NSControl control, NSTextView textView, ObjCRuntime.Selector commandSelector)
{
Console.WriteLine(Id + "DoCommandBySelector = {0}", commandSelector.ToString());
return false;
}
public override void EditingBegan(NSNotification notification)
{
Console.WriteLine(Id + "EditingBegan");
}
public override void EditingEnded(NSNotification notification)
{
Console.WriteLine(Id + "EditingEnded");
}
}
[Register("MyNSTextField")]
class MyNSTextField : NSTextField {
public MyNSTextField(IntPtr handle) : base(handle){}
public override void KeyDown(NSEvent theEvent)
{
Console.WriteLine("KeyDown");
base.KeyDown(theEvent);
}
public override void KeyUp(NSEvent theEvent)
{
Console.WriteLine("KeyUp");
base.KeyUp(theEvent);
}
}
and the output. No call to keyDown or DoCommandBySelector. I must be missing something very basic
1-EditingBegan
1-changed
KeyUp
1-changed
KeyUp
1-changed
KeyUp
1-EditingEnded
2-EditingBegan
2-changed
KeyUp
2-changed
KeyUp
2-changed
KeyUp
Thanks
Text editing is in Cocoa is really different than WPF ;-) NSTextField and like controls normally do not deal with the actual editing as a NSTextView field editor is used... Strange? Depends upon on how you look at it, for Windows' style controls yes, for Cocoa it is the norm:
Field editor is an NSTextView which is maintained by NSWindow. The field editor replaces any NSTextField or NSTextFieldCell in the window for editing purposes.
Semi-required Reading material : Text Fields, Text Views, and the Field Editor
NSTextField does not respond to a KeyDown as the field editor handles it and all the related functions that it provides (word completion, accent letter popups, etc..., and thus creating a custom NSTextField and overriding KeyDown and KeyUp, only KeyUp will be called:
public override void KeyDown(NSEvent theEvent)
{
throw new Exception("NSTextField KeyDown never gets called");
}
public override void KeyUp(NSEvent theEvent)
{
Console.WriteLine("NSTextField KeyUp");
}
Thus the same goes for NSTextFieldDelegate, you will never get a commandSelector for keydown/keyup... you will get insertNewline:, cancelOperation:, deleteBackward:, etc...
public override void Changed(NSNotification notification)
{
Console.WriteLine("changed"); // after the field editor is done
}
public override bool DoCommandBySelector(NSControl control, NSTextView textView, Selector commandSelector)
{
Console.WriteLine("DoCommandBySelector = {0}", commandSelector.Name);
return false;
}
What to do?
First do you really need keydown? Altering the normal Cocoa UIX is not the norm, but if you really do, one way is to use a custom NSTextView instead of a NSTextField and the KeyDown override will be called:
[Register("CustomTextView")]
public class CustomTextView : NSTextView
{
public CustomTextView() : base() {
Console.WriteLine("CustomTextView");
}
public CustomTextView(IntPtr handle) : base(handle) {
Console.WriteLine("CustomTextView IntPtr");
}
[Export("initWithCoder:")]
public CustomTextView(NSCoder coder) : base(coder) {
Console.WriteLine("CustomTextView initWithCoder");
}
public override void KeyDown(NSEvent theEvent) {
Console.WriteLine("CustomTextView KeyDown");
}
public override void KeyUp(NSEvent theEvent) {
Console.WriteLine("CustomTextView KeyUp");
}
}
If you are using .xib for your interface design, just create a NSTextView subclass in C#, register it and the .h will show up in Xcode and use it to replace the NSTextView with your class.
Depending on what you really need keyDown for, maybe editing begin/end will work for your NSTextField:
this.EditingBegan += (object sender, EventArgs e) => {
Console.WriteLine("EditingBegan");
};
this.EditingEnded += (object sender, EventArgs e) => {
Console.WriteLine("EditingEnded");
};
You can also hook that NSWindow's field editor and listen for all keyDown:, filter the controls and only react if it is a control that you are interested in...
In my Xamarin forms application I want to show a confirmation message when user clicks the back button from Main-page. Is there any way to achieve this?
I overrided the OnBackButtonPressed method in my MainPage. But still the app is closing while back key press. Here is my code
protected override bool OnBackButtonPressed ()
{
//return base.OnBackButtonPressed ();
return false;
}
You can override OnBackButtonPressed for any Xamarin.Form Page. But it only will work for the physical button in Android and Windows Phone devices.
protected override bool OnBackButtonPressed () {
DisplayAlert("title","message","ok");
return true;
}
For the virtual one, you will need to create CustomRenderers and to intercept the click handler. In iOS it can be tricky because the user can go back doing other actions (e.g. the swipe gesture). Once you intercept it you just need to create your Confirmation Message (which I assume that you know how to do it).
For iOS you can do something like this:
[assembly: ExportRenderer (typeof (YourPage), typeof (YourPageRenderer))]
namespace YourNamespace {
public class YourPageRenderer : PageRenderer {
public override void ViewWillAppear (bool animated) {
base.ViewWillAppear (animated);
Action goBack = () => page.DisplayAlert("title","message","ok");
var backButton = new NavBackButton (goBack);
navigationItem.LeftBarButtonItem = new UIBarButtonItem (backButton);
}
}
public class NavBackButton : UIView {
public NavBackButton (Action onButtonPressed) {
SetButton (onButtonPressed);
}
UILabel text;
UIImageView arrow;
void SetButton(Action onButtonPressed){
arrow = new UIImageView(new CGRect(-25,0, 50, 50)) {
Image = new UIImage("Images/back").ImageWithRenderingMode(UIImageRenderingMode.AlwaysTemplate)
};
arrow.TintColor = Colors.DarkGreen.ToUIColor ();
text = new UILabel(new CGRect(arrow.Frame.Width + arrow.Frame.X -15, arrow.Frame.Height /2 - 10, 40, 20)) { Text = "Back" };
text.TextColor = Colors.DarkGreen.ToUIColor ();
Frame = new CGRect(0,0,text.Frame.Size.Width + arrow.Frame.Width, arrow.Frame.Height);
AddSubviews (new UIView[] { arrow, text });
var tapGesture = new UITapGestureRecognizer (onButtonPressed);
AddGestureRecognizer (tapGesture);
}
public override void TouchesBegan (Foundation.NSSet touches, UIEvent evt) {
base.TouchesBegan (touches, evt);
text.TextColor = UIColor.YourColor;
arrow.TintColor = UIColor.YourColor;
}
public override void TouchesEnded (Foundation.NSSet touches, UIEvent evt){
base.TouchesEnded (touches, evt);
arrow.TintColor = UIColor.YourColor;
text.TextColor = UIColor.YourColor;
}
}
}
PS You will need to provide an arrow image ("Images/back")
I have looked around the web for some time looking for any resources on this topic and have come up with nothing that solves my dilemma.
I have a dialog view controller and its root is simply displaying a list of strings similar to how the iphone music song scrollable view is laid out. What I need is a subview located at the top of the screen and the scrollable DVC below it. I need to the top view to be always in view while the user can scroll through the root element because the top view will be holding statistics.
I have tried adding a subview but it simply overlaps the dvc below it, and I have not been able to figure out a way to add a dvc as a subview to a UIView.
Any help would be much appreciated.
What is needed to achieve this is a single root view controller that hosts two subview controllers. One subview contains the statistics at the top of the window. The bottom subview contains a navigation controller that holds the dialog view.
using System;
using System.Collections.Generic;
using System.Linq;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.Dialog;
using System.Drawing;
namespace delete201205203
{
[Register ("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
UIWindow window;
MyUIViewController _mvc;
public override bool FinishedLaunching (UIApplication app, NSDictionary options)
{
window = new UIWindow (UIScreen.MainScreen.Bounds);
_mvc = new MyUIViewController ();
window.RootViewController = _mvc;
window.MakeKeyAndVisible ();
return true;
}
}
public class MyUIViewController : UIViewController
{
MyDialogViewController _dvc;
UINavigationController _nav;
StatisticsViewController _statistics;
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
var root = new RootElement ("Root") {
new Section ("Section") {
new EntryElement ("caption", "placeholder", ""),
new RootElement ("Root 2") {
new Section ("Section") {
new EntryElement ("caption", "placeholder", ""),
new StringElement ("Back", () => {
_nav.PopViewControllerAnimated (true);
})
}
}
}
};
_dvc = new MyDialogViewController (root);
_nav = new UINavigationController (_dvc);
_nav.SetNavigationBarHidden (true, false);
_nav.View.Frame = new RectangleF (0, 70f,
this.View.Bounds.Width,
this.View.Bounds.Height -70f);
_statistics = new StatisticsViewController ();
_statistics.View.Frame = new RectangleF (0, 0,
this.View.Bounds.Width,
70f);
this.AddChildViewController (_nav);
this.View.AddSubview (_nav.View);
this.AddChildViewController (_statistics);
this.View.AddSubview (_statistics.View);
}
public override void ViewWillLayoutSubviews ()
{
base.ViewWillLayoutSubviews ();
_nav.View.Frame = new RectangleF (0, 70f,
this.View.Bounds.Width,
this.View.Bounds.Height -70f);
_statistics.View.Frame = new RectangleF (0, 0,
this.View.Bounds.Width,
70f);
}
public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
{
return true;
}
}
public class StatisticsViewController : UIViewController
{
UILabel _label;
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
this.View.BackgroundColor = UIColor.White;
_label = new UILabel (new RectangleF (this.View.Bounds.Width * .5f - 50f,
this.View.Bounds.Height * .5f -10f,
100f, 20f));
_label.AutoresizingMask = UIViewAutoresizing.FlexibleMargins;
_label.Text = "statistics";
this.View.AddSubview (_label);
}
public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
{
return true;
}
}
// This overrde is needed to ensure the pop view animation
// works correctly in landscape mode
public class MyDialogViewController : DialogViewController
{
public MyDialogViewController (RootElement root) : base (root) {}
public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
{
return true;
}
}
}