I have the following in a Section:
_favElement = new StyledStringElement (string.Empty);
_favElement.Alignment = UITextAlignment.Center;
if (_room.IsFavourite) {
_favElement.Image = UIImage.FromBundle ("Images/thumbs_up.png");
_favElement.Caption = "Unmark as Favourite";
} else {
_favElement.Image = null;
_favElement.Caption = "Mark as Favourite";
}
_favElement.Tapped += favElement_Tapped;
Then when I press the element I want the following to happen:
private void favElement_Tapped ()
{
if (_room.IsFavourite) {
_favElement.Image = null;
_favElement.Caption = "Mark as Favourite";
} else {
_favElement.Image = UIImage.FromBundle ("Images/thumbs_up.png");
_favElement.Caption = "Unmark as Favourite";
}
_room.IsFavourite = !_room.IsFavourite;
}
However the image and text does not change in the actual element when the element is tapped. Is there a refresh method or something that must be called? I've also tried changing the Accessory on Tapped as well and nothing changes. The properties behind do reflect the correct values though.
An alternative to reloading the UITableView is to reload the Element using code like this (copied from Touch.Unit):
if (GetContainerTableView () != null) {
var root = GetImmediateRootElement ();
root.Reload (this, UITableViewRowAnimation.Fade);
}
assuming that your code is in DialogViewController,add this
this.ReloadData();
but in your case I recommend you to use BooleanImageElement
Related
Coding in Xamarin IOS. I have a drop down list type popup, where, if The end user types in a new value, I want to ask a yes/no question: Do You want to add a new row?
The control is inside a UIStackView, which is inside a container UIView, which is in turn inside another which is presented via segue. Xamarin demanded a UIPopoverController, which I implemented. Here is The code I have so far:
using System.Threading.Tasks;
using Foundation;
using UIKit;
namespace PTPED_Engine
{
public enum MessagePopupType
{
YesNo = 1,
OKCancel = 2,
OKOnly = 3
}
public enum PopupResultType
{
OK = 1,
Cancel = 2,
Yes = 3,
No = 4
}
public static class AlertPopups
{
static NSObject nsObject;
public static void Initialize(NSObject nsObject)
{
AlertPopups.nsObject = nsObject;
}
public static Task<PopupResultType> AskUser(UIViewController parent, UIView V, string strTitle, string strMsg, MessagePopupType mpt)
{
using (UIPopoverController pc = new UIPopoverController(parent))
{
// pc.ContentViewController
// method to show an OK/Cancel dialog box and return true for OK, or false for cancel
var taskCompletionSource = new TaskCompletionSource<PopupResultType>();
var alert = UIAlertController.Create(strTitle, strMsg, UIAlertControllerStyle.ActionSheet);
// set up button event handlers
if (mpt == MessagePopupType.OKCancel)
{
alert.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.OK)));
alert.AddAction(UIAlertAction.Create("Cancel", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.Cancel)));
}
if (mpt == MessagePopupType.YesNo)
{
alert.AddAction(UIAlertAction.Create("Yes", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.Yes)));
alert.AddAction(UIAlertAction.Create("No", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.No)));
}
if (mpt == MessagePopupType.OKOnly)
{
alert.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, a => taskCompletionSource.SetResult(PopupResultType.OK)));
}
// show it
nsObject.InvokeOnMainThread(() =>
{
pc.PresentFromRect(V.Bounds, V, UIPopoverArrowDirection.Any, true);
});
return taskCompletionSource.Task;
}
}
}
}
and I invoke it as follows:
LookupCombo.Completed += async (object sender, CompletedEventArgs e) =>
{
C1AutoComplete AC = (C1AutoComplete)sender;
if (AC.Text.Trim() != "")
{
string sColName = AC.AccessibilityIdentifier.Trim();
var ValuesVC = (List<Lookupcombo_Entry>)AC.ItemsSource;
var IsThisAHit = from Lookupcombo_Entry in ValuesVC
where Lookupcombo_Entry.sDispVal.ToUpper().Trim() == e.value.ToUpper().Trim()
select Lookupcombo_Entry.sMapVal;
if (!IsThisAHit.Any())
{
string sTitle = "";
string sFull = _RM.GetString(sColName);
if (sFull == null) { sFull = "???-" + sColName.Trim(); }
sTitle = " Add New " + sFull.Trim() + "?";
string sPPrompt = "Do you want to add a new " + sFull.Trim() + " named " + AC.Text.Trim() + " to the Database?";
var popupResult = await AlertPopups.AskUser(CurrentViewController(), V, sTitle, sPPrompt, MessagePopupType.YesNo);
}
}
};
CurrentViewController is defined like this:
private UIViewController CurrentViewController()
{
var window = UIApplication.SharedApplication.KeyWindow;
var vc = window.RootViewController;
while (vc.PresentedViewController != null)
{
vc = vc.PresentedViewController;
}
return vc;
}
This does nothing. It hangs The user interface.
This should be built in, but it is only built in in Xamarin.Forms, which I do not want to use.
I have no problem in doing this stuff with an await, but this is simply not working. Can anyone help?
Thanks!
You can just use the ACR UserDialogs library:
https://github.com/aritchie/userdialogs
This is a solution I provided a few years ago, I think it is an ugly hack, compared to your elegant approach. You did not say what part does not work exactly, that might help spot the problem.
Here is my solution from a few years back:
iphone UIAlertView Modal
I have a modal Navigation page with an image which acts like a button;
<Image Source ="share.png" HeightRequest="32" WidthRequest="32">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="On_Share" />
</Image.GestureRecognizers>
</Image>
And the method behind;
async void On_Share(object sender, EventArgs e)
{
if (CrossConnectivity.Current.IsConnected)
{
var message = "Share this";
var title = "Share";
await CrossShare.Current.Share(new ShareMessage { Text = message, Title = title}, new ShareOptions { ExcludedUIActivityTypes = new[] { ShareUIActivityType.PostToFacebook } });
}
else
{
NoInternetLabel.IsVisible = true;
}
}
I'm getting the error when I try to click on the share image/button. I've put breakpoints into the first line of the On_Share method & they're not being hit.
Warning: Attempt to present <UIActivityViewController: 0x141b60f70> on <Xamarin_Forms_Platform_iOS_ModalWrapper: 0x1419a0920> whose view is not in the window hierarchy!
Please note this works fine in Android, I'm only seeing issues in iOS. I'm not sure what is going on - I'm not trying to present any other windows or anything when I click the image. Regardless, the error appears before the process reaches the beginning of the On_Share method. What am I missing here?
EDIT: The method does get hit now, and I'm still getting the error. It must be trying to send up the share sheet and failing...
There was a problem with the Share plugin in the end - we resolved it by making part of the code recursive.
the GetVisibleViewController used to look like this;
UIViewController GetVisibleViewController()
{
var rootController = UIApplication.SharedApplication.KeyWindow.RootViewController;
if (rootController.PresentedViewController == null)
return rootController;
if (rootController.PresentedViewController is UINavigationController)
{
return ((UINavigationController)rootController.PresentedViewController).VisibleViewController;
}
if (rootController.PresentedViewController is UITabBarController)
{
return ((UITabBarController)rootController.PresentedViewController).SelectedViewController;
}
return rootController.PresentedViewController;
}
whereas it needed to cycle through to find the top UIViewController;
UIViewController GetVisibleViewController(UIViewController controller = null)
{
controller = controller ?? UIApplication.SharedApplication.KeyWindow.RootViewController;
if (controller.PresentedViewController == null)
return controller;
if (controller.PresentedViewController is UINavigationController)
{
return ((UINavigationController)controller.PresentedViewController).VisibleViewController;
}
if (controller.PresentedViewController is UITabBarController)
{
return ((UITabBarController)controller.PresentedViewController).SelectedViewController;
}
return GetVisibleViewController(controller.PresentedViewController);
}
I've raised the issue and submitted a pull request on the github
given the following code, I am having an issue when clicking on each element. If we assume I have 5 exercises and therefore create 5 elements in the foreach() loop, when the table is rendered and I click on any element, the delegate always gets the exercise of the 5th (last) element.
The elements are displayed properly, each showing the associated exercise's name. It is just the delegate that does not work as expected.
If I do not use a foreach loop and hardcode each element instead it works as expected. However if I cannot dynamically populate the dialogViewController and use the element tapped event for each one, is not good.
private void CreateExerciseTable()
{
Section section = new Section();
foreach (var exercise in exercises)
{
var element = new StyledStringElement(exercise.ExerciseName,
delegate { AddExercise(exercise); })
{
Font = Fonts.H3,
TextColor = UIColor.White,
BackgroundColor = RGBColors.LightBlue,
Accessory = UITableViewCellAccessory.DisclosureIndicator
};
section.Elements.Add(element);
}
var root = new RootElement("Selection") {
section
};
var dv = new DialogViewController(root, true);
dv.Style = UITableViewStyle.Plain;
//Remove the extra blank table lines from the bottom of the table.
UIView footer = new UIView(new System.Drawing.RectangleF(0,0,0,0));
dv.TableView.TableFooterView = footer;
dv.TableView.SeparatorColor = UIColor.White;
dv.TableView.BackgroundColor = UIColor.White;
tableFitnessExercises.AddSubview(dv.View);
}
private void AddExercise(FitnessExercise exercise)
{
NavigationManager.FitnessRoutine.Add(exercise);
PerformSegue(UIIdentifierConstants.SegAddExerciseToFitnessRoutine, this);
}
This is a classic closure bug!
The problem is that you are accessing the loop reference.
Try:
foreach (var exercise in exercises)
{
var localRef = exercise;
var element = new StyledStringElement(exercise.ExerciseName,
delegate { AddExercise(localRef); })
{
Font = Fonts.H3,
TextColor = UIColor.White,
BackgroundColor = RGBColors.LightBlue,
Accessory = UITableViewCellAccessory.DisclosureIndicator
};
section.Elements.Add(element);
}
For more on this see http://blogs.msdn.com/b/ericlippert/archive/2009/11/12/closing-over-the-loop-variable-considered-harmful.aspx
I have created a view that shows lost connection messages to users which pops over the current view. I want to update the view periodically based on connection status changes.
I can properly get the view and change the text of a label (verified with WriteLines), but nothing changes on the actual display. I even tried removing the view and readding it and calling SetNeedsDisplay, but nothing seems to help.
I have a global variable called OverView:
public static UIView OverView;
I create the label subview, add it to the overview and pop the overview in front of the current view:
UILabel labelTitle = new UILabel();
labelTitle.Text = title;
UIView labelTitleView = (UIView) labelTitle;
labelTitleView.Tag = 5000;
OverView.AddSubview(labelTitleView);
curView.InsertSubviewAbove(OverView, curView);
curView.BringSubviewToFront(OverView);
And then at a later time, I try to modify it like this from another function:
if ((OverView != null) && (OverView.Subviews != null))
{
for (int i = 0; i < OverView.Subviews.Length; i++)
{
WriteToConsole("Type: " + OverView.Subviews[i].GetType());
if (OverView.Subviews[i] is UILabel)
{
WriteToConsole("Found Label with Tag: " + ((UILabel)(OverView.Subviews[i])).Tag + " Text: " + ((UILabel)(OverView.Subviews[i])).Text);
if (((UILabel)(OverView.Subviews[i])).Tag == 5000)
{
WriteToConsole("Setting subview Title to: " + lostConnectionTitle);
lock (overViewLocker)
{
appReference.InvokeOnMainThread(delegate
{
UILabel tempLabel = ((UILabel)(OverView.Subviews[i]));
tempLabel.Text = lostConnectionTitle;
OverView.Subviews[i].RemoveFromSuperview();
OverView.AddSubview(tempLabel);
OverView.BringSubviewToFront(tempLabel);
OverView.SetNeedsLayout();
OverView.SetNeedsDisplay();
WriteToConsole("SetNeedsDisplay");
});
}
}
}
}
}
Have you tried to use delegate methods on your label, and change their value when events occur ?
For example, if your event is clicking on a button, you should have something like that:
yourLabel.Text = "Init";
buttonExample.TouchUpInside += (sender, e) => {
yourLabel.Text = "I touched my button";
};
When your View loads, you'll see "Init" and your button and once you click on it, the label text changed.
Xamarin has some explanation about events and delegate methods here.
I hope that helped.
I have problem that I don't seem to be able to solve. I have a created a test project, using MEF and Prism4. I've created a test project where I have 2 views and each of them register themselves inside a region, and also a button in another region. When the button is clicked, I want the view of change to the correct view. The code I think is wrong is below, anyone have any ideas what I am doing wrong here ?
public void Initialize()
{
regionManager.RegisterViewWithRegion(RegionNames.MainRegion, typeof(Views.Module1View));
Button button = new Button() { Content = "Module1" };
button.Click += (o, i) =>
{
var region = this.regionManager.Regions[RegionNames.MainRegion];
if (region != null)
{
region.Activate(typeof(Views.Module1View));
}
};
regionManager.AddToRegion(RegionNames.NavigationRegion, button);
}
I get the following error ...
The region does not contain the specified view.
Parameter name: view
Solved it - amazing what a good nights sleep will do! I had to get the view from the ServiceLocator.
public void Initialize()
{
regionManager.RegisterViewWithRegion(RegionNames.MainRegion, () =>
ServiceLocator.Current.GetInstance<Views.Module2View>());
Button button = new Button() { Content = "Module2" };
button.Click += (o, i) =>
{
var view = ServiceLocator.Current.GetInstance<Views.Module2View>();
var region = this.regionManager.Regions[RegionNames.MainRegion];
if (region != null)
{
region.Activate(view);
}
};
regionManager.AddToRegion(RegionNames.NavigationRegion, button);
}