I've only really just started on Tornadofx and was having a bit of trouble trying to figure out how to reload a view so the controls in that view are refreshed.
Below is a simplified version of the code I'm working with. I've got a loop to generate radio-button controls based on strings in a list.
class MainView: View("MainView") {
override val root = vbox {
for(x in radioText) {
radiobutton(x, radioGroup) {
action {
radioSelected = this#radiobutton.text
}
}
}
button("Next") {
action {
// Reload View to update radiobuttons with new values
}
}
}
}
In the program I need to go through several sets of these radio buttons, and so the idea was that each time the user presses the "Next" button, the items in the radioText list would be updated to match the next set of radio-buttons. Then I was looking for a way to get the view to update with these new values.
I tried using openWindow() to open a new instance of the view, but then when I used close() to get rid of the previous instance and ended up closing both windows.
button("Next") {
action {
MainView().openWindow()
close()
}
}
Any help with this would be much appreciated,
Thanks.
If I understood correctly, you are trying to have a list of string and generate radiobuttons with it. So, by adding the variables to your example, would be something like this:
class MainView: View("MainView") {
val radioText = ArrayList<String>()
var radioGroup : ToggleGroup by singleAssign()
lateinit var radioSelected : String
override val root = vbox {
radioText.addAll(arrayListOf("One","Two","Three","Four"))
radioGroup = togglegroup(){}
for(x in radioText) {
radiobutton(x,radioGroup) {
action {
radioSelected = text //You don't need this#radiobutton.text
}
}
}
button("Next") {
action {
// Reload View to update radiobuttons with new values
}
}
}
}
I thing is a better idea having your radiobutton created by a listview, wich would be updated by a observable list of string, like I do bellow:
class MainView2: View("MainView") {
// this is a list of observable string, so when the items on his list change
// the listview is updated
val radioText = FXCollections.observableArrayList<String>()
var radioGroup : ToggleGroup by singleAssign()
lateinit var radioSelected : String
override val root = vbox() {
prefWidth = 200.0
prefHeight = 300.0
radioText.setAll("One","Two","Three","Four")
radioGroup = togglegroup(){}
listview<String>(radioText){
// Setting listview height dinamically
fixedCellSize = 25.0
prefHeightProperty().bind(radioText.sizeProperty.multiply(fixedCellSizeProperty().add(2)))
// Generating the radiobutton acording to strings on radioText
cellFormat {
graphic = cache(it){
radiobutton(it,radioGroup){
action {
radioSelected = text
}
}
}
}
}
button("Next") {
action {
radioText.clear()
radioText.setAll("Five","Six","Seven","Eight","Nine","Ten")
}
}
}
}
Please let me know if there is something you don't understand on my aproach.
Related
While creating a CustomIosViewPresenter (of type MvxIosViewPresenter), in MVVMCross 5.x, there was a Show override that I was able to use to get the IMvxIosView so as to update the UIViewController presentation style using the PresentationValues from the ViewModel.
I had this code and it worked:
// Worked before
public override void Show(IMvxIosView view, MvvmCross.ViewModels.MvxViewModelRequest request)
{
if (request.PresentationValues != null)
{
if (request.PresentationValues.ContainsKey("NavigationMode") &&
request.PresentationValues["NavigationMode"] == "WrapInModalWithNavController")
{
var vc = view as IModalPresentation;
vc.ModalPresentationAttribute = new MvxModalPresentationAttribute
{
WrapInNavigationController = true,
ModalPresentationStyle = UIModalPresentationStyle.OverFullScreen,
ModalTransitionStyle = UIModalTransitionStyle.CoverVertical
};
}
}
base.Show(view, request);
}
But after migrating to MvvmCross 7.1, the older override doesn't work anymore and I have to use this instead, but there is no view passed into the Show override, how do I get it?
I tried this code below, but view is null and it's not able to cast it this way var view = viewType as IMvxIosView;
// Doesn't work now
public override Task<bool> Show(MvxViewModelRequest request)
{
if (request.PresentationValues != null)
{
if (request.PresentationValues.ContainsKey("NavigationMode") &&
request.PresentationValues["NavigationMode"] == "WrapInModalWithNavController")
{
var viewsContainer = Mvx.IoCProvider.Resolve<IMvxViewsContainer>();
var viewType = viewsContainer.GetViewType(request.ViewModelType);
var view = viewType as IMvxIosView;
var vc = view as IModalPresentation;
vc.ModalPresentationAttribute = new MvxModalPresentationAttribute
{
WrapInNavigationController = true,
ModalPresentationStyle = UIModalPresentationStyle.OverFullScreen,
ModalTransitionStyle = UIModalTransitionStyle.CoverVertical
};
}
}
return base.Show(request);
}
The reason I need this is because without this function when I close the special flow of view controllers that need this, its not closing all the view controllers in that flow, it closes only one of them at a time.
What you would normally do with MvvmCross if you want to navigate within a Modal ViewController is firstly add a MvxModalPresentationAttribute to the modal that will host the rest of the navigation where you set WrapInNavigationController to true.
For the children, it would just be regular child navigation, no attributes needed.
If you then want to control how the modal is popping you would create your own MvxPresentationHint and register it in your presenter using AddPresentationHintHandler.
Then you would in your ViewModel where you want to change the presentation call NavigationService.ChangePresentation(your hint).
As for the Presentation Hint, it should probably just call CloseModalViewControllers and that would probably do what you want.
TLDR: Feel for the developers that will come after you and build stuff the right way
So I dug into the MvvmCross MvxIosViewPresenter source code and was able to use this new override CreateOverridePresentationAttributeViewInstance()
I needed the request object to see the presentation values so I updated the Show function that gets called before the other override as follows:
MvxViewModelRequest _request;
public override Task<bool> Show(MvxViewModelRequest request)
{
_request = request;
return base.Show(request);
}
And I was able to get the ViewController this way, in order to selectively present it as a modal:
{
var view = base.CreateOverridePresentationAttributeViewInstance(viewType);
if (_request.PresentationValues.ContainsKey("NavigationMode") &&
_request.PresentationValues["NavigationMode"] == "WrapInModalWithNavController")
{
var vc = view as IModalPresentation;
vc.ModalPresentationAttribute = new MvxModalPresentationAttribute
{
WrapInNavigationController = true,
ModalPresentationStyle = UIModalPresentationStyle.OverFullScreen,
ModalTransitionStyle = UIModalTransitionStyle.CoverVertical
};
return vc;
}
return view;
}
And then the closing of the modal was another challenge, that I was able to figure out using the TryCloseViewControllerInsideStack and ChangePresentation overrides
When a user authenticates correctly, it will be directed to the HomeViewModel. I want to remove the possibility that it can return to the login screen so I have created a Custom Presenter to remove all the screens that are below the new screen.
The implementation is as follows:
public class CustomPresenter: MvxFormsIosPagePresenter
{
public CustomPresenter(UIWindow window, MvxFormsApplication mvxFormsApp)
: base(window, mvxFormsApp)
{
}
public override void Show(MvxViewModelRequest request)
{
if (request.PresentationValues?["NavigationCommand"] == "StackClear")
{
var navigation = FormsApplication.MainPage.Navigation;
Debug.WriteLine("Navigation Back Stack Count -> " + navigation.NavigationStack.Count());
navigation.PopToRootAsync();
Debug.WriteLine("Navigation Back Stack Count After PopToRootAsync -> " + navigation.NavigationStack.Count());
return;
}
base.Show(request);
}
}
When the authentication process finishes correctly, I navigate to the home screen by passing a bundle with this special command:
LoginWithFacebookCommand.Subscribe(token => {
Debug.WriteLine("JWT Token -> " + token);
_userDialogs.ShowSuccess(AppResources.Login_Success);
var mvxBundle = new MvxBundle(new Dictionary<string, string> { { "NavigationCommand", "StackClear" } });
ShowViewModel<HomeViewModel>(presentationBundle: mvxBundle);
});
The problem is that it does not change the screen, it stays in the current one. What would be the way to do it correctly ?.
I am using MvvmCross 5.1.1 and MvvmCross.Forms 5.1.1
Thank you very much in advance.
As I understand it, PopToRootAsync() pops everything off the stack to the root. Which means you should then push your view that you wish to navigate to, onto your stack after that method is called i.e. use PushViewController(yourViewController) afterwards. Also, you should be using the new IMvxNavigationService by MvvmCross. You can give this a try:
var navigationService = Mvx.Resolve<IMvxNavigationService>();
LoginWithFacebookCommand.Subscribe(async (token) => {
Debug.WriteLine("JWT Token -> " + token);
_userDialogs.ShowSuccess(AppResources.Login_Success);
await navigationService.Navigate<HomeViewModel>();
});
To clear the backstack you basically need to override the Show method in the presenter and check whether your viewmodel is being called. If it is then set a new array of viewControllers. (Credit to #pnavk!!)
public class CustomPresenter : MvxIosViewPresenter
{
public override void Show(IMvxIosView view, MvxViewModelRequest request)
{
if (MasterNavigationController != null && view.ViewModel.GetType() == typeof(HomeViewModel))
{
var viewController = view as UIViewController;
MasterNavigationController.SetViewControllers(new UIViewController[] { viewController }, true);
}
else
base.Show(view, request);
}
}
Try this:
navigation.SetViewControllers(new UIViewController[] { vc }, true);
vc is the ViewController you want to set as the root of the navigation stack. You will need to get a reference to it which you can using the ViewControllers property on the NavigationController.
true - means you want to animate.
I have a problem and It's 10 days that I am working and can't solve it.I made a layout for each row for ListView.This Layout Contains a linearLayout that there is a TextView and a WebView inside it.Now I Need a C# Project that I can add a new Row to the ListView with new text and url whenever I want.For Example: button.click { ListView.add(Resource.Layout.Items, "Text","Url")}..I know this command is wrong. Just I wanted to clear the problem for you.
I khnow it's custom Row layout and I read manny examples at this site other sites and Xamarin site about that,adapters,... but I can't do it. :(
Please answer me correctly.
It is very important for me.
Thanks a lot.
You need to create an adapter that can work with you custom objects as items. It could look like the following sample:
public class MyAdapter : BaseAdapter<MyItem>
{
readonly LayoutInflater inflater;
List<MyItem> myItemList;
public MyAdapter(Context context)
{
inflater = LayoutInflater.FromContext(context);
myItemList = YOUR_DATASOURCE.GetMyItems();
}
public override MyItem this [int index]
{
get { return myItemList[index]; }
}
public override int Count
{
get { return myItemList.Count; }
}
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
View view = convertView ?? inflater.Inflate(Resource.Layout.MyItemLayout, parent, false);
var item = myItemList[position];
var viewHolder = view.Tag as MyViewHolder;
if (viewHolder == null)
{
viewHolder = new MyViewHolder();
viewHolder.Web = view.FindViewById<WebView>(Resource.Id.MyItemLayout_Icon);
viewHolder.Name = view.FindViewById<TextView>(Resource.Id.MyItemLayout_Title);
view.Tag = viewHolder;
}
viewHolder.Web.Url = item.Url; //You need to check how you have to set the url for a WebView
viewHolder.Name.Text = item.Text;
return view;
}
public override void NotifyDataSetChanged()
{
myItemList = YOUR_DATASOURCE.GetMyItems();
base.NotifyDataSetChanged();
}
}
class MyViewHolder : Java.Lang.Object
{
public WebView Web { get; set; }
public TextView Name { get; set; }
}
You apply the adapter to your ListView with ListView.Adapter = new MyAdapter(Activity);. Each time you change an item in you button click event, you tricker (ListView.Adapter as MyAdapter).NotifyDataSetChanged(); which will force the adapter to reload and refresh the data.
YOUR_DATASOURCE represents the point in your code where you store the informations like the url or text of all your items. This could typically be a database or something similar. While GetMyItems() is a method for example to query your database.
Hope this clears things up.
I have this annoying problem and I don't know how to solve this.
In Xamarin Forms, I'm trying to draw a dynamic layout, for this I load a list of elements (this works). Now i'm trying to display the label for it, so I loop through all the items and add a label for every item. The problem is that the page stays empty.
Yes I initialized the _layout variable as a StackLayout and I also made a ScrollView, then I set the scrollview's content to the _layout variable. But still my page stays empty. I can't share the actual code but I rewrote it using different names.
private void DrawItems()
{
var items = (List<Item>)_database.GetItems();
foreach(var item in items)
{
DrawItem(item);
}
}
private void DrawItem(Item item)
{
AddLabel(item);
}
private void AddLabel(Item item)
{
if (string.IsNullOrEmpty(item.Text)) return;
var label = new Label
{
Text = (!string.IsNullOrEmpty(item.Number)) ? string.Format("{0}: {1}", item.Number, item.Text) : item.Text,
FontSize = Device.GetNamedSize(NamedSize.Small, typeof(Label))
};
_layout.Children.Add(label);
}
For some weird reason, when I start debugging (put a break on var label ...) the label get's created but when I put a break on _layout.Children.Add(label), this never gets called.
When changing UI elements, you need to do it on the main thread.
Try this:
Device.BeginInvokeOnMainThread(() =>
{
_layout.Children.Add(label);
}
I've tried the following code, and it works for me. I'm using Xamarin.Forms 1.4.0.6341
public class MyPage : ContentPage
{
StackLayout stack;
public MyPage()
{
var scroll = new ScrollView();
stack = new StackLayout();
var btn = new Button {Text = "Add Label"};
btn.Clicked += (sender, args) => stack.Children.Add(new Label {Text = "Test"});
stack.Children.Add(btn);
AddLabelEverySecond();
scroll.Content = stack;
Content = scroll;
}
private async void AddLabelEverySecond()
{
for (var i = 0; i < 10; i++)
{
await Task.Delay(1000);
stack.Children.Add(new Label { Text = "1 second" });
}
}
}
Is this applicable to your code? Maybe you could tell us where DrawItems is called from?
How do I create an a slider menu using Xamarin.Forms? Is it baked in or something custom?
You create a new class which contains all the definitions for both the Master - i.e. the menu - and the Detail - i.e. the main page. I know, it sounds back-to-front, but for example..
using System;
using Xamarin.Forms;
namespace testXamForms
{
public class HomePage : MasterDetailPage
{
public HomePage()
{
// Set up the Master, i.e. the Menu
Label header = new Label
{
Text = "MENU",
Font = Font.BoldSystemFontOfSize(20),
HorizontalOptions = LayoutOptions.Center
};
// create an array of the Page names
string[] myPageNames = {
“Main”,
“Page 2”,
“Page 3”,
};
// Create ListView for the Master page.
ListView listView = new ListView
{
ItemsSource = myPageNames,
};
// The Master page is actually the Menu page for us
this.Master = new ContentPage
{
Title = "The Title is required.",
Content = new StackLayout
{
Children =
{
header,
listView
},
}
};
// Define a selected handler for the ListView contained in the Master (ie Menu) Page.
listView.ItemSelected += (sender, args) =>
{
// Set the BindingContext of the detail page.
this.Detail.BindingContext = args.SelectedItem;
Console.WriteLine("The args.SelectedItem is
{0}",args.SelectedItem);
// This is where you would put your “go to one of the selected pages”
// Show the detail page.
this.IsPresented = false;
};
// Set up the Detail, i.e the Home or Main page.
Label myHomeHeader = new Label
{
Text = "Home Page",
HorizontalOptions = LayoutOptions.Center
};
string[] homePageItems = { “Alpha”, “Beta”, “Gamma” };
ListView myHomeView = new ListView {
ItemsSource = homePageItems,
};
var myHomePage = new ContentPage();
myHomePage.Content = new StackLayout
{
Children =
{
myHomeHeader,
myHomeView
} ,
};
this.Detail = myHomePage;
}
}
}
It is built in: MasterDetailPage. You'd set the Detail and Master properties of it to whatever kinds of Pages you'd like. I found Hansleman.Forms to be quite enlightening.
My minimum example (as posted here) is as follows:
public class App
{
static MasterDetailPage MDPage;
public static Page GetMainPage()
{
return MDPage = new MasterDetailPage {
Master = new ContentPage {
Title = "Master",
BackgroundColor = Color.Silver,
Icon = Device.OS == TargetPlatform.iOS ? "menu.png" : null,
Content = new StackLayout {
Padding = new Thickness(5, 50),
Children = { Link("A"), Link("B"), Link("C") }
},
},
Detail = new NavigationPage(new ContentPage {
Title = "A",
Content = new Label { Text = "A" }
}),
};
}
static Button Link(string name)
{
var button = new Button {
Text = name,
BackgroundColor = Color.FromRgb(0.9, 0.9, 0.9)
};
button.Clicked += delegate {
MDPage.Detail = new NavigationPage(new ContentPage {
Title = name,
Content = new Label { Text = name }
});
MDPage.IsPresented = false;
};
return button;
}
}
An example solution is hosted on GitHub.
On iOS the result looks like this (left: menu open, right: after clicking on "B"):
Note that you need to add the menu icon as a resource in your iOS project.
If you are looking for simple example of MasterDetailPage please have a look at my sample repo at GitHub. Very nice example is also presented here
Slideoverkit is a great plugin available for Xamarin Forms. There is a github to see free samples and you could find documentation about it here.