I'm looking for a solution to detect closing a BrowserTab window.
I use the annotation #Push. As a result, the web socket connection is always closed as soon as the Borwser
closes or the page is reloaded by F5.
If the web socket connection is terminated, the AtmospherePushConnection.connectionLost() method is called.
I would like a listener if the value of AtmospherePushConnection.State changes.
Is there a solution for this?
You can detect the event for browser close or page reload with onDetach method.
For E.g.,:
#Override
protected void onDetach(DetachEvent detachEvent) {
// Your custom code here
}
Related
[Question]
On Windows Phone 8.1, what exactly happens in between the time when the user leaves the app and the OnSuspended event fires? I'm having trouble with the ability to manage objects in that span, in particular MediaCpture object.
To better explain the problem, here is the scenario:
The user is on a page with a video preview being pumped to a CaptureElement
The user taps the Start button
The user taps Back button and returns to the page with a broken MediaCapture
With WinRT there isn't an ObscuredEvent and OnNavigatingFrom doesn’t fire unless you’re going to another page in the same Frame. After some investigation, I've found that the only event that fires is Window.Current.VisibilityChanged
I've gone ahead and hook it when the page is NavigatedTo and unhooked in OnNavigatedFrom (see ex2 below). Inside the event, I check for parameter that tells if the app is hiding or showing and dispose/initialize accordingly(see ex.1 below).
[Problem]
However, this only works with the debugger attached. If I do this without the debugger attached, it doesn't reinitialize and frequently crashes the camera and I have to literally reboot the device.
Code Example 1 (note: e.Visible == false is leaving the app and true when returning)
async void Current_VisibilityChanged(object sender, VisibilityChangedEventArgs e)
{
if (!e.Visible) //means leaving the app
{
await DisposeAll(); //cleans the MediaCapture and CaptureElement
}
else
{
if(mediaCaptureManager != null) await DisposeAll();
await Initialization(); //set up camera again
}
}
Example 2 (hooking into the event)
protected override void OnNavigatedTo(NavigationEventArgs e)
{
Window.Current.VisibilityChanged += Current_VisibilityChanged;
this.navigationHelper.OnNavigatedTo(e);
}
protected async override void OnNavigatedFrom(NavigationEventArgs e)
{
Window.Current.VisibilityChanged -= Current_VisibilityChanged;
this.navigationHelper.OnNavigatedFrom(e);
}
[Update: Resolution]
Instead of using VisibilityChanged, hook into Window.Current.Activated on the page's constructor. With the debugger completely detached, the Activated event will provide the WindowActivationState parameter in the WindowActivatedEventArgs. Like this:
private async void CurrentOnActivated(object sender, WindowActivatedEventArgs e)
{
if(e.WindowActivationState == CoreWindowActivationState.Deactivated)
{
//dispose MediaCapture here
}
else if(e.WindowActivationState == CoreWindowActivationState.CodeActivated || e.WindowActivationState == CoreWindowActivationState.PointerActivated)
{
//initialize MediaCapture here
}
}
See my answer in https://stackoverflow.com/a/28592882/3998132. Using Window.VisibilityChanged in conjunction with your Page\UserControl Loaded\Unloaded handler should solve your issue I believe.
Using Window.Activated is less desirable than Window.VisibilityChanged because Activated relates to being visible AND having focus where as VisibilityChanged only pertains to visibility. For showing a preview having focus is not applicable. Since Windows Store apps on Windows Phone can only have one Window showing there is no difference in using either however if your app becomes universal and runs on let's say on Windows 8+ Modern shell (which can show multiple Store apps with the Snap window feature) or Windows 10 desktop (which can support multiple Store apps showing at the same time) you will not want to stop preview when a user changes focus from your app but your app is still showing.
I'm not sure if it wouldn't be more suitable to use Suspending/Resuming events. Note only that in this case, you will have to debug it properly - it behaves little different while being run with/without debugger attached.
As for the code - hooking your event in OnNavigatedTo/OnNavigatedFrom is not a good idea - when the OS suspends the app and you are using SuspensionManager then OnNavigatedFrom will be called, but when you go back to your app (resume it), then OnNavigatedTo will not be called.
Using Window events may also work here, but why not subscribe it once, somewhere in constructor? - it's window-wide and hence in phone there is only one window, which stands for app, then subscribe once. In this case, you may add a line that recognizes the current page in window and if that page contains mediacapture then dispose (create similar). Then you can also dispose/initialize in navigation events in case user doesn't leave your app and just navigate.
I've made a today widget for the german ice hockey league DEL.
I'm loading the next games from our server an show them in a tableView. The loading process is started in the proposed method "widgetPerformUpdateWithCompletionHandler". Initially i'm loading some cached data in "viewWillAppear".
Everything works great so far!
But after a while (one day) the widget stops working. When I open the notification center the widget appears normal, but it is never updated again. I have to remove the widget from the notification center and have to add it again. After that the widget works for a day and then again it stops working.
To see what the widget ist doing, I've added a simple white view with a status text above the table view while loading the data in "widgetPerformUpdateWithCompletionHandler" to see if the widget is doing anything. The white view appears when the widget is working. When it is not working the status view doesn't appear. So I think the method "widgetPerformUpdateWithCompletionHandler" isn't called after the widget is active in the notification center for a while.
I've got no clue what causes the widget to stop working. Any ideas?
I've got the same problem and I resolved it by calling completionHandler(NCUpdateResultNoData);
right after your network request even when the response hasn't been returned. I found that if completion handler is not called the widgetPerformUpdateWithCompletionHandler
will no longer get invoked, and therefore there won't be any more updates. Also make sure you call completion handler in all branches after your request call returns.
As others have mentioned, this is caused by not having previous called the completionHandler after widgetPerformUpdateWithCompletionHandler has been called. You need to make sure that completionHandler is called no matter what.
The way I suggest handling this is by saving the completionHandler as an instance variable, and then calling it with failed in viewDidDisappear:
#property(nonatomic, copy) void (^completionHandler)(NCUpdateResult);
#property(nonatomic) BOOL hasSignaled;
- (void)widgetPerformUpdateWithCompletionHandler:(void (^)(NCUpdateResult))completionHandler {
self.completionHandler = completionHandler;
// Do work.
}
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
if (!self.hasSignaled) [self signalComplete:NCUpdateResultFailed];
}
- (void)signalComplete:(NCUpdateResult)updateResult {
NSLog(#"Signaling complete: %lu", updateResult);
self.hasSignaled = YES;
if (self.completionHandler) self.completionHandler(updateResult);
}
An additional problem is that once widgetPerformUpdateWithCompletionHandler: is stopped being called, there will never be another completion handler to call. I haven't found a way to make the system call widgetPerformUpdateWithCompletionHandler: again. Therefore, make sure your widget will also try to reload data through viewWillAppear: as a fallback, or some users might be stuck with a non-loading widget.
Calling the completionHandler with NCUpdateResultNewData within widgetPerformUpdateWithCompletionHandler before an async call comes back and calls it again with NCUpdateResultNewData or NCUpdateResultFailed seems to work.
I have one swing code written by other person. For swing tabbed pane, he has added both change and container listener and both calls the same method:
addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent theEvent ) {
someMethod();
}
} );
addContainerListener(new ContainerAdapter() {
public void componentAdded(ContainerEvent theEvent) {
someMethod();
}
public void componentRemoved(ContainerEvent theEvent) {
someMethod();
}
} );
Whenever tab is removed from this tabbed pane, it internally calls JTabbedPane.removeTabAt(int index), which in turn calls fireStateChanged() causing new change event listened by change listener.
Now as new component (tab) is removed from tabbed pane, it also calls componentRemoved(ContainerEvent theEvent) method of container listener.
Both change even and container events, then calls same method someMethod(), which does set background and foreground colors.
I would like to know, if this kind code might cause some issues. Recently we are facing random IndexOutOfBoundException exeptions. I am just wondering, if this is causing this issue.
Also as per my understanding in swing, once event is listened, logic inside it should be executed using worker thread (e.g. SwingWorker). Please let me know if this is correct.
I am new to swing, thus any hint would be appreciated.
Thanks.
Whenever tab is removed from this tabbed pane, it internally calls
JTabbedPane.removeTabAt(int index), which in turn calls
fireStateChanged() causing new change event listened by change
listener.
This is true if the removed tab is also the selected tab. In the other cases, you won't be notified.
You need to choose what event you want to listen to:
Addition/Removal of components?--> go for ContainerListener
Selected tab? --> go for ChangeListener
I would like to know, if this kind code might cause some issues.
Recently we are facing random IndexOutOfBoundException exeptions. I am
just wondering, if this is causing this issue.
Since there is no line in your sample code that could throw that Exception, it is impossible to answer your question. Post an SSCCE that shows your issue.
Also as per my understanding in swing, once event is listened, logic
inside it should be executed using worker thread (e.g. SwingWorker).
Please let me know if this is correct.
It depends:
If you need to modify anything in the UI, anything related to Swing, it needs to be executed on the EDT (Event Dispatching Thread) and thus, SwingWorker is not an option.
If you need to perform business logic operations, and especially if they can be lengthy, then you should indeed use a SwingWorker or any other mechanism to execute that code in another thread than the EDT. Consider visiting the Swing tag wiki on "Concurrency"
When i set ActivationPolicy="Resume" in WMAppManifest.xml page tile navigation(navigation URL) is not working in Tombstone state, it reloads the last back stack page(URL). It works fine with Dormant state with out reloading the page. If don't set this property (ActivationPolicy="Resume") it reloads the page in both states [Dormant state and Tombstone state].
But how can we achieve the navigation to secondary url's, when we set that property.
Please help me .
Adding ActivationPolicy="Resume" is not the only step needed to have your app support Fast App Resume. I believe the behavior you are describing is normal when you only set that one property. I think there are a few ways to implement "Fast App Resume", but I found this to be the easiest way.
Set the activation policy like you just described and then do the following:
Go into App.xaml.cs in the "App" class add:
private bool reset
You should then have a method for InitializePhoneApplication that initializes the RootFrame. Add this:
RootFrame.Navigating += RootFrame_Navigating;
RootFrame.Navigated += RootFrame_Navigated;
Then you can go and add those methods:
void RootFrame_Navigating(object sender, NavigatingCancelEventArgs e)
{
if (reset && e.IsCancelable && e.Uri.OriginalString == "/MainPage.xaml")
{
e.Cancel = true;
reset = false;
}
}
void RootFrame_Navigated(object sender, NavigationEventArgs e)
{
reset = e.NavigationMode == NavigationMode.Reset;
}
If you implement this properly, your app should resume from the last page you were on.
Same problem here. I got WP8 application with Fast App Resume enabled. I can pin tiles pointing to specific pages in my apps. It works fine when app is just Suspended, but when the app is Tombstoned, then clicking secondary tile has the same effect as clicking the main tile.
I receive only one RootFrameNavigating event with NavigationMode == Back and Uri == /MainPage.xaml. The app then shows the previous page that was there before I suspended the app.
I guess this is actual bug in the platform for this specific scenario - Fast App Resume + tombstoned app + navigation from pinned tile, that we as developers cannot solve.
We are using LTSP with Thin-Clients. We are using it, to run a Java-Swing-Application. The users should not be able to do anything else, so instead of a Gnome-Session we use a shell-script to start our application.
Nearly everything works perfect but one thing: When the Thin-Client starts, the application starts too but doesn't receive the focus. We have to click once with the mouse inside the application, which is not that good, because the application is designed to be used without a mouse.
I didn't found anything useful, a toFront() on my Main Frame wasn't successful.
Has anyone any better suggestions??
You can use method java.awt.Window#setAlwaysOnTop(boolean) to grab the focus and after the first user interaction reset the alwayOnTop property.
You could try to call requestFocus on your JFrame as soon as it becomes visible:
JFrame frame = new JFrame();
frame.addComponentListener(new ComponentAdapter() {
public void componentShown(ComponentEvent e) {
((JFrame) e.getSource()).requestFocus();
}
});
frame.setVisible(true);