I have a blackberry application in which i want to show a "please wait" modal screen(which is a FullScreen push as modal screen) while sending a server request and if the user hitting the device back button , pop the modal screen and current active screen.This works fine.
My problem is that : I used a callback for server request in the active screen.But the callback executed even after popped up the screen.
Exactly whats happening while calling popScreen()? How can i remove all callbacks and refresh the screen if the user pressing back button while server request happens?
Thanks in Advance
There are several solutions to this problem of course. I guess the server request is sent asynchronously.
The simplest way I think out is having a flag and when the callback
is triggered check whether the user cancelled the action (pressing
the back button).
Another solution, perhaps not that nice is to check whether the
Loading Screen is still in the display stack.
What I think would be a proper solution is to have a stack of
cancelled http operations, so you can stop requests at any time. Then
if the request to the server has been sent, before calling the
callbacks you can check if the operation has been cancelled.
Otherwise, you just avoid sending the request to the server.
When you call popScreen, the screen which is on top of the display stack (the screen in the foreground) is removed from the stack and the Screen is refreshed (a paint event is triggered) to reflect the changes. Make sure you execute Screen.pop() on the UiThread:
UiApplication.getUiApplication().invokeLater(runnable)
In your scenario, how is the callback handled? Is it a delegate you passed along with the request or is a listener you register?
When I refer to delegate I mean something like the following:
Server.sendRequest(request, objectWithCallbacks)
and callbacks of the objectWithCallbacks (and only objectWithCallbacks) will be called accordingly. On the other hand, a listener would be something like:
Server.addListener(objectWithCallbacks, request)
Server.sendRequest(request);
this way, all the objects listening to "eventName" will get their callbacks triggered accordingly.
As far as I see, your callback will be always executed but in the callback itself you can check if the screen is currently displayed.
if( this.isDisplayed() ) {
// Do the magic
}else{
// Do nothing
}
Good Luck
Related
First of all I'd like to say sorry in case my question is dummy, I'm really new to iOS and what to understand how thing are going on. Imagine such a situation - user taps on home button and the app starts to collapse, but immediately after taping on home button user taped on some UI element. So, I'm wondering how the iOS will handle this? I tried to do some tests using breakpoints, but since it just test I can't be 100% sure. It seems that if the UI interaction event will happen before the system will call willResignActive then the event will be fully processed and if the system will call willResignActive first, then the even will be discarded and won't be handled at all. Is this correct, or I missed something? Thanks
First, why do you want to use this in your app? If a user presses a button exactly in this time, it's okay that the action is not handled.
The only thing you have to keep track of is that whenever the button gets pressed and let's say you store a file without a completion handler it could be that you present an alert which is saying that everything went well but you actually not saved the file because the user left the app in this time.
But since you're never doing critical actions without completion handlers, in my opinion, there's no need to make sure that this doesn't happen.
If I got you wrong, just comment!
Lets say a user starts async request in PageViewController flow then dismisses. If they quickly bring back PageViewController it won't navigate to the correct page because an async request (that determines the next logical page to show) is underway. Is it standard to prevent the user from dismissing controller or asking them not to? If not, how do I manage background tasks, so I know to keep loading screen up and wait to navigate pages until last request completes and changes state/server side data?
I have an app that I call the method SKStoreReviewController.requestReview () after 10 times that the user performs some action. The prompt stoped to appear even the debug show me that the method requesrReview is being called.
What's can be happening?
From the Apple docs:
Although you should call this method when it makes sense in the user
experience flow of your app, the actual display of a rating/review
request view is governed by App Store policy. Because this method may
or may not present an alert, it's not appropriate to call it in
response to a button tap or other user action.
The popup will only display sometimes, and it's dictated by the SKStoreReviewController as to when this will be, so you can't guarantee it will ever be displayed.
Is there any way to manage callback when user go through web view and click button - back to app?
You can bind the UIApplicationDidBecomeActiveNotification to an action do whatever you wish when you come back to your application. It should be thrown whenever your application gains back focus for any reason.
Note that this notification will be thrown every time you app becomes active, so make sure to unbind the action after it is called once. Also it will be thrown even if the user does not tap the back button, but goes back to home screen and reopens your app.
You can also use the delegate methods in your AppDelegate class and store the status of the app with some variables to determine when the user comes back to your app.
I would to do a remote call before the app is started (in AppDelegate, when the splash screen is showed). Then i would to choose which view controller to load based on url response.
Is right to do this on AppDelegate? Or I need a different approach?
I think the best approach is creating a ViewController where you make this choice. Once this VC is loaded you make your remote call while showing in the UI that your app is actually working and waiting for a network response - the best approach is probably showing a message with a UIActivityIndicatorView spinning.
Once you get the response you load the VC that you need. You should also handle errors - what are you going to show if the network request fails? Are you showing an error message?
You should not do any synchronous network calls from willFinishLaunchingWithOptions. If you take more than a few seconds to return that method or (didFinishLaunchingWithOptions, or the other app delegate methods that the system calls in the process of launching your app) then the springboard will terminate your app as unresponsive.
#Tanzolone has the right idea. Have your app display a view controller that shows your app's UI, THEN invoke the network request and decide what second screen to switch to based on the response.