I am following the Udacity tutorial on Swift, and for some reason when I added the second view, I usually get a black screen (as in the screen print) right when I open the app. Occasionally I get it working but usually not.
What could be the problem?
Noticed that "Did appear" is printed before "Will appear", is that a bug or did I do something wrong?
I have read this and this but it didn't help much. I also have tried several times to clean the project and rebuild it (nothing changed).
One time I just commented out some code (from the second view that should be loaded) and it worked suddenly. When I uncommented the same code it still worked.
Another time it worked when I disconnected the second view on the story board (it was still there, just no way to reach it).
Both have worked at least one time, and not worked many times.
Sorry this seems like I throw in random pieces of information, but I have no idea what could be the reason.
Related
I'm working on the code in a project when I suddenly notice the ViewController in Storyboards is greyed out with the name of the VC in the center.
Here's a screenshot..
I was only editing some code on the right and I'm not sure exactly when, but my eyes adjusted and noticed this VC completely greyed out in Storyboards.
I tried deleting Derived Data, cleaning, quitting Xcode, building again, etc.
Nothing seems to work... ANy help with this would be super appreciated. I'm also very new to programming in general.
Well it turns out if you ever run into this problem, it's because you're not paying close attention and haven't realized you've somehow magically deleted your entire view inside the ViewController.
I did this once before by hitting something randomly on my keyboard (don't know what it was) but that time I saw it happen and just hit "undo".
This time I was passed the point of simply hitting "undo" and had to add a view again and rebuild and reconnect all the components in the view. That was basically it. Problem solved...
I am making a Xamarin.Forms project, and I am in the end of my app, but something really strange have happened. My app starts up with no labels (!?), meaning they are invisible or not created at all. Everything else seems to be working, until I press a button that is supposed to change the label - when I do this, the app freezes. I get no exception in Visual Studio, though.
One problem is that my breakpoints in PLC code never hits, only those I place in the iOS code. However, the buttons not related to changing a label works, so I know the PLC code have been ran. If I let the app run for a little while, and then press the pause-button in VS debugging to see where in the code I am, it stops at
UIApplication.Main(args, null, "AppDelegate");
.. in Main.cs. I dont know if this is correct or not, when I run on Android, I get a Break Mode - No code is currently running.
I have been trying for hours to debug, reinstall, restart, clean and rebuild, but nothing seems to help. My code works perfectly in Android, and it worked in iOS 1 week ago. Anyone have any ideas what is going on, or what I can do to debug some more? Or must I make a new project and try start over?
Edit: I have also tried different starting pages, and all are the same: all views loads except those with text in them. I have a page with an Editor in it, and I can write in it, but no text is appearing inside of it. Only button have visible text. I do not use a custom font for my labels, I have not specified anything.
Waking up fresh in the morning, I found my issue in 15 minutes..
After altering my Google search to TextView iOS instead of Label Xamarin, I found much more answers. Thanks to this question and answer.
Basically, changing anything on the labels in the constructor of the page (even after InitializeComponent()), will mess up the view. I moved my code outside of the constructor (in the protected override void OnAppearing() method), and now it is working again.
The freeze part was not related - this was my custom menu that covered my screen with an invisible layout eating up all clicking events. A bit confusing, none of these issues are present in Android, but there you go.
I am having a problem where my content is repeatedly being shifted to the right in the storyboard for multiple view controllers when I open the project. I have done nothing at this point, simply opened it. Further, undoing the modifications through git does nothing. I fix the problems and go about my day adding new features... the apps run fine in the phone and appear normal in the storyboard. However, when I open the project the next day, same thing happens and I have to fix everything again. Has anyone else experienced this issue, and what was your resolution to the problem?
I figured out what the problem was. On my first View Controller, I had some labels that had somehow become set to a width of zero. After I fixed them, and embedded them in a stack, the problem resolved itself. I have no idea how this screwed up several other view controllers; however, fingers crossed, the corruption hasn't happened again since I fixed it.
Well apparently there is just some display bug in Xcode. When I click on a new size class and click back, the elements are restored to their correct size. This was maddening, but apparently it's working fine now if I do this quick fix.
I've created a simple program where a person can log in with a username and password. Every time I attempt to run it, I simply get a blank white screen. I tried changing the background color to a dark green one in hope that it would change it in the simulator too, however I get the same white screen.
This problem arose before I got that breakpoint error, it first started happening randomly in a previous project, which makes me think something is wrong with my xcode.
See my screenshot below:
I had this same issue where I saw the app briefly, and then it went to solid white. It pays to make sure you edit the "Main" storyboard, not the "LaunchScreen" storyboard when following tutorials...
Maybe my embarrassing mistake will help someone else...
There are a few things to keep in mind here that could be causing thsi error. Firstly, as some of the comments have pointed out the first thing you should do is delete the breakpoints from all the lines. To do that, you have 3 choices:
Press the blue arrow just above the console, that you can see here:This will disable all your breakpoints, so if you are using them intentionally somewhere else, don't use this method.
You can press each breakpoint individually, simply pressing the arrows next to your code on the left-hand side. This will disable the specific breakpoint. They then will become more greyish, like the one below #IBAction func loginTapped()
Last but not least, in my opinion the best method, simply grab the blue arrow and drag it to the right or left. This will make a cloud and zishing noise, symbolizing the deletion of the breakpoint.
Once this is out of the way, let's take the second most important step. Check that the loginViewController is the initial View Controller, so that it's the first page that's displayed. To do that, simply open the file inspector on the right-hand side. You can activate it by pressing the third button here:
Then, select your viewController,, so that it light up's blue like seen below:
Then, on the 3rd tab of The file inspector, by pressing the 4th tab that looks like an arrow pointing down. Now you should see a checkbox saying "isInitialViewController". Tick that so that you get through immediately to this screen. It should look like this down below:
Lastly, I'd like to point you to some more things you should check that could cause this error:
You never actually create the UITextField and UIButton
You have a different view covering your viewController(eg, webView or view)
You are on the wrong storyboard, this could happen but is unlikely.
If all this fails, try restarting Xcode, the simulator and running again by pressing the Play Sign or CMD-R.
Hope that helps, Julian
I don't know who this might help but I solved my problem by reinstalling CocoaPods and installing everything with pod install and pod update. I reset my mac some time back because it's storage was full and I forgot CocoaPods and all the pods uninstalled. Reinstalled them and now I'm back.
Edit:
It didn't fix it but I am getting closer.
It happened to me after exiting Xcode and closing the simulator the simulator device setting changed to the default ipod, when I realized this I changed it back to iPhone11. I got the white background but after waiting a few minutes it just worked.
I have an iOS app that, in one view, makes a toolbar in code. Nothing fancy here; just a bunch of standard UIBarButtonItems (initialized with initWithImage, and each one invoking a different selector), added (along with spacers) to the toolbar using UIToolbar setItems:animated (with no animation).
This works fine most of the time... but sometimes, after going to another view and back to this one many times, the toolbar's touch-handling appears to be off. It highlights and invokes the wrong button. It's not always the same wrong button, either; sometimes it's one right next to the one I actually tapped, but other times it is further away, even clear over on the other side of the toolbar.
There is no pattern to it, but if you try long enough (switching to another view and then back to this one), it always happens. It seems to happen more often when the other view is at a different screen orientation (forced by its shouldAutorotateToInterfaceOrientation implementation), but even when all views have the same orientation, it still happens now and then. When it happens, my selector gets invoked with a sender that matches the button that was actually highlighted, rather than the one I touched. So it really seems to be a matter of something in iOS not processing the touch correctly.
My google-fu has utterly failed to turn up any other reports of this issue... seems like it must be an Apple bug, since none of my code is involved in the toolbar touch handling. This happens both in the simulator and on the device, under iOS 4.3 (haven't tried other versions yet).
Has anyone else run into this issue? Any suggestions on how to avoid it?
OK, I found the problem. It wasn't the code that creates the toolbar itself; it was where (and how often!) it was being called.
This was legacy code, and we hadn't noticed that the create-the-toolbar code was being called from the view's didRotateFromInterfaceOrientation method (for reasons we can't imagine). That method gets invoked quite frequently, and the old toolbar wasn't being torn down, so it was creating toolbars on top of toolbars. Not too surprising that the touch handling went wonky in that situation.
Deleting the call there (and putting it in viewDidLoad like one would expect) solved the problem. Sorry for wasting everybody's time... but maybe the next person to stumble across screwy toolbar behavior will find this helpful.