I'm implementing secure passcode functionality within the app. Part of the solution is based on the PTPasscodeViewController sample code that can be found on GitHub. The issue I am having is when the app is first launched and the PIN is typed the UI is not updated with a circle in each box. If the 4 digits of the PIN that was entered are incorrect my message isn't displaying. It's as if the runloop isn't getting executed or something. If I enter the correct PIN the app is unlocked as expected. The functionality works but the UI isn't updated.
Once the app is unlocked if I go into Settings (in the app) and change the passcode the dots show up just fine and if during PIN confirmation the second PIN does not match the first the UI is also updated correctly.
Background multitasking is enabled in this app. On iOS 4.2.1 when the app becomes active again the same PIN validation logic is used as when the app is first launched. The only difference is it isn't really the first lauch but a return from the background. In this case, the PIN validation logic AND UI works correctly... the same code is executing. The dots and any messages are correctly displayed.
However, on 3.1.2, since background multitasking is not supported the app is always launched from scratch. So every time the app is launched the functionality works but the UI fails to update properly.
I must have a basic misunderstanding of something here but not sure what it is that I don't get. Can anyone point me in the right direction?
I resolved this issue myself and it was a result of a lack of understanding the fact that applicationDidBecomeActive also fires after applicationDidFinishLaunchingWithOptions. Basically the code to show the PIN validation screen was being executed twice in a row when lauching the app for the first time. Removing the PIN validation launch from applicationDidFinishLaunchingWithOptions and calling it only in applicationDidBecomeActive fixed it.
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Our company has an app which is basically an eBook reader.
We use the RMSDK to perform book downloads & read.
Now, something very strange is happening in iOS7 devices (not in the simulator):
I download a book using the fulfillment method in the RMSDK
I wait for the book to finish downloading. The book is saved in the NSCachesDirectory (for App Store guidelines reasons) - so far, everything works fine
I hit the home button, the app moves to the background
I hit the app button to bring the app back, that's when the problem happens:
The app gets completely stuck. Hitting the home button does nothing, hitting the power button shuts down the screen, but then hitting the power button again does nothing.
The device itself has effectively crashed.
After a few minutes, the Apple logo appears on the device and the device comes back to life after a reboot.
I have no idea what in my code could be causing the device to act this way. Shouldn't the iOS7 sandbox prevent me from being able to crash the whole device?
Any ideas on why this could be happening and what I can do to prevent it would be greatly appreciated.
EDIT:
I placed a breakpoint on the -(void)applicationDidBecomeAcvive: method in the AppDelegate, and it's not being called when clicking on the app icon in the last phase before the crash.
EDIT:
The RMSDK is using libcurl to download the books. Could this be a cause for this behavior?
EDIT:
The problem is happening if I click on ANY app after I click on the home button, not just on the same app. So for example, I click on the home button, then I try to open Fruit Ninja, and the device crashes.
We managed to solve this issue by disabling functions in RMSDK, which call mkfifo(). I'm not sure how much I can say here due to NDA but they're all located in one file and can be cleanly converted to no-ops with a nice preprocessor #if defined()
Its an OS level bug. iOS 7 is still unstable in areas, for example my Apps report crashes in places that are part of iOS 7 itself and couldn't be caused by my app.
I have very weird problem. My app works cool on simulator but when installed on iphone it shows strange behavior
Suppose i was at settings page then I closed the app using home button. And then I start the app again after quite a while and I will always first get the settings page for one second and then the main loading screen. This happens for every other page even its not the settings ViewController
What is wrong?
Best Regards
Umar
Standard behavior, UI restoration. Your iOS apps picks up execution right where you left.
This means: if the app is pushed to background, a screenshot is taken. Coming back to the app, this screenshot will be shown and meanwhile your UI gets prepared.
If you have code in your app in applicationDidBecomeActive: or applicationWillEnterForeground: (see here: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIApplicationDelegate_Protocol/Reference/Reference.html) and that will immediately reconfigure the UI, you get the behavior described.
You can turn OFF UI restoration and have your app really quit instead of pushing it to background by changing a key in the info.plist: UIApplicationExitsOnSuspend
My application is an Air-based iPhone app. It opens with the last page I visited before clicking the Home button, each time I relaunch the app, while I need to open with the splash screen onward. How can I resolve this issue?
Thank you for any help.
When you press the Home button, you don't terminate a running app. I'm sure that many of us developers have stuck with this mental model of how iOS used to work without multitasking.
So, the splash screen, or rather, the default image (Default.png) should really appear once (when your application launches). Some times, the default image appears when coming out from the background state, but this happens only if your app takes too long to show its UI. In fact, on fast iPhones, the default image disappears almost instantly even on launch (for well-written apps, that is).
I should also note that Apple actively discourages the use of the default image for splash screens. These should only be used for creating an illusion of transition, from a "launching state" (which the default image is supposed to portray), to the running state.
However, if you really have to show a splash screen every time, you should implement such a mechanism in code. applicationDidBecomeActive: is a good place to start, if you are writing code in Objective-C.
I don't know the event model in Air, so I can't really give you any hints for that.
The above answer, though old, does not answer the question. Sure, Apple gives guidelines regarding splash screen and all, but the poster asks how to prevent the app from resuming from it's previous position. If you want the app to terminate when put in the background you need to look into the UIApplicationExitsOnSuspend option. There's also an Adobe blog post explaining a bit more about different background behaviors.
I'm trying to get the following functionality in my iPhone app:
When backgrounded, stays running (doesn't have to do any background work)
When resumed, app picks up where it was left off
I'm mainly wanting the same screen on my app still up, as there are several UINavigationControllers within a UITabBarController.
I have done all of the following:
Made sure I'm compiling with 4.1 SDK
Set UIApplicationExitsOnSuspend to false
Handle DidEnterBackground and WillEnterForeground in my AppDelegate
Call BeginBackgroundTask in DidEnterBackground, to attempt to keep my app open
I'm using MonoTouch, but that it probably beside the point. I can take answers in Obj-C, for sure.
I've tested my app on a jailbroken phone with Backgrounder, and I see the "app in background" badge disappear immediately after pushing the home button. I also tried setting UIBackgroundModes in my Info.plist, but to no avail.
Is there anything I'm missing?
Or is this something I would have to implement on my own to resume the previous state of my app? Everywhere I've read talks like it should just work automatically.
If you don't want to be doing work in background, don't call beginBackgroundTask. That call is for situations where you want to do some kind of work in the background. And if you don't finish that work fast enough, iOS will terminate your app.
When I upgraded to iOS 4.x, my MT application started exhibiting this behavior without me having to do anything. iOS should take care of it for you.
I finally got in touch with someone on MonoTouch's irc.
In MonoDevelop there is an option to make a dual iPad/iPhone project, which I used. This is causing my app to behave as if it's running with the 3.2 SDK when deployed to the device.
I think my solution is to install the iOS 4.2 SDK that just came out, since this ads the new multi-tasking feature on iPad.
Not only do you need to support going into the background, you also need to support cases where your app has been terminated. In your app’s initialization code, you should resume the state that it was in. For instance, when you push a view controller, use NSUserDefaults to store a value for the currently-displayed screen, and then when you start read that value and display the associated screen.
Example: My Default.png image shows the start screen of my app with an empty interface. When the app is launched from scratch the first time, this is cool. It appears like it started quickly. But when the user quits it and the app just goes to background, and then the user opens it, this sucks. Then I always end up with a wrong "snapshot" as launch image and my app then looks completely different after launch because it is like it was left the last time.
I would have to disable the Default.png when my app just goes to background, or I would have to enable it when it gets really terminated. Any way to do this?
It sounds to me like your app isn't being suspended. Every app that I've used that supports fast-app switching hasn't shown its default png when I open it after suspending it.
Are you sure your app is supporting fast-app switching and that it is being suspended?
Just updating my answer for some clarity that was revealed in the comments:
In order to take advantage of fast-app switching, the following conditions need to be met:
App needs to be compiled against the 4.0 SDK
App needs to be running on a multitasking-capable device such as:
iPhone 4
iPhone 3GS
iPod touch 3rd Generation
info.plist must not contain the UIApplicationExitsOnSuspend key.