I have an ReactiveCommand in a VM and subscribed to exceptions:
var configuration = new Configuration();
var vm = new ConfigurationViewModel(configuration, true, false);
ConfigurationDialog.Handle(vm).Subscribe(saved =>
{
if (saved)
{
SelectConfiguration(configuration);
}
});
It shows a dialog and that dialog have a command including exception subscription:
SaveCommand.ThrownExceptions
.SelectMany(ex => Interactions.ShowAndLogException.Handle(ex))
.Subscribe();
Unfortunately the ShowAndLogException is not called immedatel but right after the parent dialog (ConfigurationDialog) is closed.
Subscribing on TaskPoolScheduler solves this problem but child dialog is as a shown non-modal one.
If I do not use interaction in child dialog then everything works as intended.
Is there a way to execute an interaction when the exception thrown?
Related
The NWJS documentation states that after opening a window, you have to wait for the loaded event before you can interact with it:
You should wait for the Window’s loaded event before interacting with any of its components.
So I tried to add a loaded event handler for the win object after opening it.
nw.Window.open('test.html', {}, (win) => {
win.showDevTools()
win.addEventListener("loaded", () => {
console.log("NW Window loaded not working...")
})
}
I get the following error:
Uncaught TypeError: win.addEventListener is not a function
How can I listen for NWWindow events in NWJS? Sidenote: I CAN listen for DOM window load events, but that's not the same is it?
nw.Window.open('test.html', options, (win) => {
win.showDevTools()
win.window.addEventListener("load", () => {
console.log("dom window load IS working...")
})
}
There is an example on how to use the Event Listener on the nw.Window:
nw.Window.open('test.html', {}, win => {
win.showDevTools();
win.on("loaded", () => {
console.log("NW Window loaded not working...")
})
}
Example from here, I changed it so that it fits to your problem
Edit: I changed the nw.Window.get() to win
addEventListener is from DOM. Refer https://nodejs.org/api/events.html#events_emitter_addlistener_eventname_listener & then try again. Also console may work as win.window.console here.
I am developing an app in Xamarin.Forms, before I was trying to make a master detail page to become my MainPage when I logged in to my app, this I have already achieved. Now I have the problem that when I use the button behind the phone my app is miimiza and goes to the background which is the behavior I hope, but when I return to my app does not continue showing my master detail page, but returns to my LginPage.
It is as if my app was running twice or at least there were two instances of LoginPage existing at the same time, this is because in my LoginPage I trigger some DisplayAlert according to some messages that my page is listening through the MessaginCenter and they are they shoot twice.
Can someone tell me how I can return the same to my app on the master detail page and not restart in the strange way described?
LoginView.xaml.cs:
public partial class LogonView : ContentPage
{
LogonViewModel contexto = new LogonViewModel();
public LogonView ()
{
InitializeComponent ();
BindingContext = contexto;
MessagingCenter.Subscribe<LogonViewModel>(this, "ErrorCredentials", async (sender) =>
{
await DisplayAlert("Error", "Email or password is incorrect.", "Ok");
}
);
}
protected override void OnDisappearing()
{
base.OnDisappearing();
MessagingCenter.Unsubscribe<LogonViewModel>(this, "ErrorCredentials");
}
}
Part of my ViewModel:
if (Loged)
{
App.token = token;
Application.Current.MainPage = new RootView();
}
else
{
MessagingCenter.Send(this, "ErrorCredentials");
}
Thanks.
I hope this is in Android. All you can do is, you can override the backbuttonpressed method in MainActivity for not closing on back button pressed of the entry page. like below, you can add some conditions as well.
public override void OnBackPressed()
{
Page currentPage = Xamarin.Forms.Application.Current.MainPage.Navigation.NavigationStack.LastOrDefault();
if (currentPage != null)
{
if (currentPage.GetType().Name == "HomePage" || currentPage.GetType().Name == "LoginPage")
{
return;
}
}
base.OnBackPressed();
}
When you press the Home button, the application is paused and the
current state is saved, and finally the application is frozen in
whatever state it is. After this, when you start the app, it is
resumed from the last point it was saved with.
However, when you use the Back button, you keep traversing back in
the activity stack, closing one activity after another. in the end,
when you close the first activity that you opened, your application
exits. This is why whenever you close your application like this, it
gets restarted when you open it again.
Answer taken from this answer. The original question asks about the native Android platform, but it still applies here.
It means you have to Use Setting Plugin or save data in Application properties.
You have to add below code in App.xaml.cs file:
if (SettingClass.UserName == null)
MainPage = new LoginPage();
else
MainPage = new MasterDetailPage();
For Setting Plugin you can refer this link.
I have a slightly odd issue and unfortunately it's not one I can easily write a standalone class for.
Within my application I have a TableView (on a tab) which is clickable. Clicking on a row in this TableView opens a new Tab with a data relating to the clicked row in a new TableView.
The TableViews are bound to a custom class that extends ModifiableObservableListBase. This allows a Scrollbar to be used to request new data from the server based on the top and bottom rows of the viewport.
This all works well.
I also have a Service in my subclass of ModifiableObservableListBase that is used to improve the rendering of data under high load. It uses a LinkedBlockingQueue and countDownLatch so that only most recent view is updated to the UI preventing unnecessary redraws. Using the following:
setAll(list);
This also works well.
So far so good!
What I've noticed is that when I open and close these tabs multiple times (no fixed number), at some point the TableView will stop updating with data. The data is requested from the server and received but the Service which is used to control how data is added to the ModifiableObservableListBase fails to move out of the SCHEDULED state. This means that the Task that has been created never runs. I'm struggling to see why this would work correctly x times and then stop working.
Any help would be really welcomed, sorry I don't have a standaone application that replicates this issue. I will try to recreate it.
The following Service is constructed in the constructor of my subclass of ModifiableObservableListBase which is constructed each time a new tab(including the corresponding TableView which is bound to the ModifiableObservableListBase ) is added to the UI.
Service upDateService = new Service() {
#Override
protected Task createTask() {
//when the code fails it still calls to here.
return new Task() {
#Override
protected Object call() throws Exception {
//when the code fails it doesn't call the call() method
while (true) {
List<T> list = updateQueue.take();
updateLatch = new CountDownLatch(1);
//now put on the FX Application Thread
Platform.runLater(() -> {
if (list.size() > 0 && list.get(0) instanceof TableStructure) {
totalRowCount.set(((TableStructure) list.get(0)).getTotalDbRowCount());
}
setAll(list);
updateLatch.countDown();
});
try {
updateLatch.await(1, TimeUnit.MINUTES);
updateLatch = null;
}
catch (InterruptedException ex) {
ex.printStackTrace();
}
}
}
};
}
};
upDateService.start();
When I try to add menuitems to a webview with this code:
my_webview.connect('context-menu', Lang.bind(this, function(webview, c_menu, event, hit_test){
var action = new Gtk.Action({name:"some_name", label:"Some Label"});
action.connect('activate', Lang.bind(this, function(){
print("Your Menu Item !");
}))
var m_item = new WebKit.ContextMenuItem(action);
c_menu.append(m_item);
m_item.show();
return false;
}));
the app exit with the error "Segmentation fault (core dumped)"
What's the correct way to add a menuitem to the context menu of a WebView ?
Small correction:
var m_item = WebKit.ContextMenuItem.new(action);
This is confusing to say the least, it's because WebKit.ContextMenuItem has a custom constructor and not the usual GObject constructor that would be invoked with new WebKit.ContextMenuItem. The segmentation fault is due to WebKit choking when its context menu item doesn't receive an action; however, it would be good if GJS at least warned you what was going on here.
I've opened a bug report for GJS here.
I am using MvvmCross for creation my Android-app and I faced with the following problem:
When I'm trying to show AlertDialog, that was created in ViewModel, the
"Unhandled Exception: Android.Views.WindowManagerBadTokenException" appears.
public class MyViewModel : MvxViewModel
{
public ICommand ShowAlertCommand { get; private set; }
public AuthorizationViewModel()
{
ShowAlertCommand = new MvxCommand(() =>
{
var adb = new AlertDialog.Builder(Application.Context);
adb.SetTitle("Title here");
adb.SetMessage("Message here");
adb.SetIcon(Resource.Drawable.Icon);
adb.SetPositiveButton("OK", (sender, args) => { /* some logic */});
adb.SetNegativeButton("Cancel", (sender, args) => { /* close alertDialog */});
adb.Create().Show();
});
}
}
When I was researching I have found that it happens because of transmission of the reference to the Context but not on the Activity in the AlertDialog.Builder.
In this topic I found the following decision:
Receive references to the current Activity through the use of GetService(), but I didn't found mvvmcross plugins for work with IMvxServiceConsumer, IMvxAndroidCurrentTopActivity interfaces.
My question is can I show AlertDialog from ViewModel? And how can I get the reference to Activity, but not to the Application.Context?
And what is the correct way to close AlertDialog that the user would stay on the current View?
In general, you should try not to put this type of code into ViewModels
because ViewModels should stay platform independent
because ViewModels should be unit testable - and it's hard to unit test when the code shows a dialog
I'd also recommend you don't put code like this inside a ViewModel Constructor - these constructors are generally called during navigations and displaying a Dialog during a transition is likely to be problematic.
With those things said, if you do want to get hold of the current top Activity within any code, then you can do this using the IMvxAndroidCurrentTopActivity
public interface IMvxAndroidCurrentTopActivity
{
Activity Activity { get; }
}
Using this, any code can get the current Activity using:
var top = Mvx.Resolve<IMvxAndroidCurrentTopActivity>();
var act = top.Activity;
if (act == null)
{
// this can happen during transitions
// - you need to be sure that this won't happen for your code
throw new MvxException("Cannot get current top activity");
}
var dlg = new AlertDialog.Builder(act);
//...
dlg.Create().Show();
The use of IMvxAndroidCurrentTopActivity is discussed in MvvmCross: How to pass Android context down to MvxCommand?
The approach taken in that question/answer is also one of the ways I would generally approach showing dialogs from a ViewModel:
I would create an IFooDialog interface
Ideally I would probably make this interface asynchronous - e.g. using async or using an Action<DialogResult> callback parameter
on each platform I would implement that in the UI project
the ViewModels can then use IFooDialog when a dialog is needed and each platform can respond with an appropriate UI action
This 'Dialog Service' type of approach is common in Mvvm - e.g. see articles like http://www.codeproject.com/Articles/36745/Showing-Dialogs-When-Using-the-MVVM-Pattern (although that article is very Windows specific!)
There are also a few other questions on here about MvvmCross and dialogs - although they may contain reference to older v1 or vNext code - e.g. Alerts or Popups in MvvmCross and Unable run ProgressDialog - BadTokenException while showind