Where do I detect where the outlet is from in Xcode? - ios

I downloaded a project from GitHub and I'm experiencing some problems when detecting where a referencing outlet comes from.
This is an UIImage called "backgroundImage".
This is a UIViewController called "WalkthroughPageContentViewController".
"backgroundImages" has two outlets references, one of which is connected to the "WalkthroughPageContentViewController" UIViewController.
But there isn't any #IBOutlet connection here.
So where does the first referencing outlet come from?

I had a quick look at this project, and the answer is that the referencing outlet doesn't come from anywhere. It's broken. If you examine the destination, the you'll see that Xcode knows this is a problem:
And if you open up the WalkthroughPageContentViewController.swift file, and add an outlet called backgroundImage, then close and reopen the file, you'll find it's magically been linked back up to the Storyboard:
So, I'd surmise that at some point, there was an outlet in the file called backgroundImage, which was hooked up to the Storyboard, but then it was later deleted, leaving the project in this state.
This is pretty common when editing projects in Xcode. The Storyboard connections are basically just stored in XML in the .xib file, and there's no magic two-way connection between them and the code at design time, so if you delete the lines of code that they point to, you'll end up in this state.

Related

XCode 8.2 Can't connect interface builder IBOutlet to swift file

I'm looking for a solution specifically for the issue with a Swift3 UIViewController having IBOutlets defined, but dragging actions from storyboard does not connect them to existing outlets. I can add new outlets, just with different name, and they work (still cant re-connect them later).
I see old solutions for objective-C dealing with headers and source files, but a swift is a single file per class.
Is there a way to fix "can't connect IBOutlet to swift file" issue?
but dragging actions from storyboard does not connect them to existing outlets
I've noticed this too. But it's not a difficult problem. Here's what to do:
Look carefully at the gutter next to the outlet in the code. There is a circle. Drag from that circle (no need for control-drag) to the view in the Interface Builder canvas.

Swift: accidentally added an outlet to two different files, deleted both outlets

I accidentally created two outlets for the same UI element and, after realizing the issue, went on to delete both outlets from the code and the element (a label) that they were attached to.
Now I'm still getting the "The [name of outlet] outlet from the [view controller] to the UILabel is invalid. Outlets cannot be connected to repeating content."
I deleted the code that created the outlet and the element itself with just select+delete. Is there some other way I should have handled it and how can I fix it now?
Delete the outlets that may be causing the problem and control - click on the object in the storyboard and delete all of the connections using the x. Now, go back and reconnect the outlets and everything should work!
If you need help, check this out.

swift - how to connect UI to code without using XCode interface builder?

So, in Xcode Swift code, you simply drag a UI component to the text editor and create an IBOutlet like #IBOutlet weak var myLabel:UILabel
My questions are:
I read that IBOutlet resolve to nothing during compile time. It's only a keyword for Xcode itself. I assume Xcode generated some code when I drag the UI. So, where is the code and what does it look like?
Say, if I don't have Xcode, where/how should I write code to connect UI with it's behavior programmatically?
After all, is it possible to write, compile, deploy IOS projects without Xcode?
Thanks,
This related question answers about how to program in Xcode not using its storyboard by configuring Xcode.
True, IBOutlet doesn't do anything. In Objective-C this is defined as a macro and will be replaced by nothing while compiling. There is no special code. Interface Builder on the other hand sees this and allows connections for those properties to be configured. The information which outlet property is connected to which object then is saved in the nib file while compiling. After the system loaded all those objects it steps through the saved connection and sets the outlet properties to the appropriate objects using the regular setValue:forKey: mechanism.
You can see this in action if you implement a custom setter for one of your outlets and set a breakpoint on that.
All this is only necessary to support Interface Builder. If you don't use it you don't need the concept of outlets - you just keep references to the objects you need later after you created them.
The same thing also applies to IBAction. In Objective-C this is again defined to be void via a macro. Interface builder sees them and allows you to make connections there. While the nib files are loaded these are connected by sending the addTarget:action:forControlEvents: message to the control this action is connected to. If you don't use IB you can send this message yourself to make the connection.

Xcode 6: can't connect any IBOutlet to ViewController

After upgrading to Xcode 6, I opened an old project (that contains a subproject, so it has many targets)
and I noticed that no link from my Storyboard ViewContoller to the relative Objects works.
For example I have a ViewController with a TableView inside and now I cant do can't do anyhing with it because the connection is missing, I can't even redefine a new IBOutlet in the VC because the arrow in the storyboard from the VC won't connect to anything.
To be more clear:
The class is defined in the Custom Class section, so I can't find the problem
What should I do?
Btw I'm using obj-c not swift, I found some related answer but all about swift.
You can also see that the link between the parent view and the custom class is broken (not visible anymore) which is a huge problem.
I had the exact same issue with the app i'm working on actually, updating XCode from 5.xxx to 6.1. The workaround that worked for me was to remove the reference of every view controller and re-add them to the project...
To everyone facing that issue, here's the (annoying) trick :
Step 1 : select both .h and .m view controller files
Step 2 : remove the reference of those files
Step 3 : re-add the files to your project tree
Step 4 : open the storyboard, eventually re-build the project and smile
I can understand those things could be reaaally annoying, but it worked for me... Hope it will help someone else !
In your storyboard hierarchy select the View Controller,
In the right pane Custom Class section Class, select the drop down and your desired view controller.
I've experienced similar behaviour in Xcode 6.1.1 when trying to add the first outlet to a new view.
Tried removing the references and adding the files again as suggested above with no success.
What I did find worked was writing the first property on the new view by hand. I just popped in:
#property NSString *temp;
I could then attach my outlets in the normal way. Just delete the temporary property once you've added your first outlet.
Hope this helps.
It seems typing the outlet first (swift):
#IBOutlet weak var someViewOutlet: UIView!
and then dragging from IB the outlet to the far right type in the above code works.
Restarting Xcode resolves the issue (sometimes). Using Xcode 6.1
Maybe I can help
In my case the problem was that the viewController.swift file was not connected to the StoryBoard. The solution is to click in the Upper border of the view on the storyboard beside the 3 icons (View Controller, First Responder and Exit)...now look over in the Utility Area choose Identity Inspector, and in "Custom Class" choose the custom view controller.
Hope this helps. Xcode is hard!!
Here's the proper solution i believe.
If you renamed the controller in code, you need to update the .xib file.
I could not find a way to do it in the interface builder, so do this:
Open the .xib file with a text editor: right click the file > open as > source code
In the <objects> node find the <placeholder> node with the property placeholderIdentifier="IBFilesOwner" and replace the value in customClass="MyOldControllerName" with your new controller name: customClass="MyNewControllerName"
And all your IBOutlets will work as normal again.
Thanks to everyone who commented.
It is a bug of Xcode 6 / 6.0.1. Downloaded and installed the 6.1 version and the problem disappeared.
Maybe try to delete the outlet from the menu in the storyboard (in your screenshot) and drag it again of the element.
Okay, let's check iff it is the lack of a module name.
In your storyboard ViewController, type in the name of module. (the project name)
2.Clcick outside in another field. When you go back to the module field it may say none, but now there will be a dropdown menu entry for your project name.
Select your project name and see if everything is good.
If there are still issues I will post photos.
Seems to be a workspace issue. Try to remove project form a workspace and add it again. It helped in my case.
I had this, affected all projects on my machine, swift and objective c and drove me mad for ages. Finally also noticed that I could not use the refractor to rename classes either.
The fix for me was:
Close xcode
Delete ~/Library/Developer/Xcode/DerivedData (just doing this on its own did not work!!)
Delete all user data for all my projects using the following from the directory that contains all my projects e.g. /src (be careful with this command!):
find . -name 'xcuserdata' -exec rm -rf {} \;
If you want to do it by hand just do the following for all your projects
Delete .xcodeproj/project.xcworkspace/xcuserdata
Delete .xcodeproj/xcuserdata/.xcuserdatad
Get Spotlight to re-index the drive all my projects were on (not sure if this was required
Re-boot machine
Everything sprang back into life !
I was having this same issue.
It turns out I renamed my view controller class and file name. In storyboard, I had the stale value in the right pane, Custom Class -> Class. So the IBOutlets were not aligning because there were none in the missing class, which is where it was expecting to find the defined outlets.
Filling in the correct class name of the View Controller in the Custom Class field in the right pane fixed my issue.
XCode needs to be more verbose if you have a bad class name in the Custom Class fields.
no one solution fixed my same problem...
But i have solved by:
close xcode
renaming the folder of the project
open xcode
and then the outlets will be back again
I hope that this solution is the right one for the people who have the same problem
In Xcode 6.3 I needed to close Xcode and restart the Mac. Restarting Xcode alone didn't do it for me.
I've had 6.3 for a long time and my problem was with new projects I was creating to test some things. Definitely not an upgrade issue this time.
I have Xcode 6.3 and saw similar issue. Finally few edits in .h file resolved my issue. If your interface has IBOutlet defined as
#interface NavigationViewController :UIViewController
{
IBOutlet UILabel *lblName;
}
change this to and in .m file add #synthesize lblName;
#interface NavigationViewController :UIViewController
{
__weak UILabel *lblName;
}
#property (nonatomic, weak) IBOutlet UILabel *lblName;
I was having this same problem, with no view outlet available to link to. The only way I was able to fix it was to change the owner class of the XIB file to "UIViewController," make the link, and then change it back to my intended custom view controller class. The link stayed and all was well.

additional NIB for view controller in tabbed app

{Xcode 4.2, deployment target iOS4.3, not storyboard, using ARC}
I started with a tabbed application template & chose the universal platform, which nicely gives me view controller classes & NIB files for an iPhone (ClassName_iPhone.xib) & an iPad (ClassName_iPad.xib) for 2 tabs, with an if statement in the AppDelegate to determine which to run - exactly how I wanted it set up.
I wanted to add a 3rd & 4th tabs, so starting with the 3rd tab (doing 1 at a time) I created a new UIViewController subclass. As it doesn't give the option to create both NIBs at once, I selected "Targeted for iPad", & had intended to create the iPhone NIB manually. I added a "_iPad" suffix to the created NIB file, then I created a user interface view NIB file to which I added the "_iPhone" suffix. I then set up the code for the new view controller in the AppDelegate implementation file to include the 3rd view controller & tab, & I used the other view controller classes as a guide to set up the new class's code.
For the 3rd _iPhone NIB, I dragged a view object from the objects library onto the canvas, & set it up as per the other 2 _iPhone NIBs. But when I went to connect the outlets, there is no view outlet in the referencing outlets of the connections panel to connect with, which I thought there should be. At this point I suspected something was wrong.
I tried running it in the simulator, in iPad mode it works fine (all 3 tabs are clickable). But in iPhone mode clicking the 3rd tab crashes it with a "SIGABRT" on thread 1. It's obvious what I did didn't work. I don't see anything in the output window that gives me any clues.
Being a newbie to obj-c, so not being too sure of the problem, I would have thought that I either:
have used the wrong user interface template (view)
should have used a view controller object from the object library
(not a view)
or that I should have declared some outlets in my view controller
class files.
But if I should have done either of the latter 2, then my question would be why does the iPad NIB work then, when it clearly has a view object in the NIB & no outlets declared in the class files (same with the other 2 view controllers for both devices)?
Does the UITabView class somehow have outlets pre-declared within it for the first 2 tabs? But that still doesn't explain why the _iPad NIB works.
As usual, any help & advice much appreciated, & if there's a link to an explanation somewhere that I've missed, please show me, because I'm happy to do the research.
If what I've done wrong here is not determinable, then I guess ultimately what I'm asking is a clue to how best to create the second NIB file for iPhone to mesh with the class created with iPad NIB.
Sorry to answer my own question but with further searching I found this answer that was the solution, although not quite the whole story. So I thought to put what I did in an asnwer so others can refer to it.
As Piotr Czapla explains in the linked answer, for some reason Xcode doesn't populate the connectionRecords data, as you can see by my first red arrow. Having a look at the view controller that works (where second red arrow is), that's what the data should look like. So the answer is to cut the data & paste it into the NIB file, or type it. You can do this in Xcode by right-clicking the NIB file in the project navigatior & then Open As > Source Code, which is what you see in my screenshots.
The bit I want to add to Piotr Czapla's explanation though is the destination reference pointed to by the second red arrow might not be correct for the NIB file you're pasting into (mine wasn't) & Xcode might not let you go back into IB mode. If so, you need to get the correct reference from the IBUIView class within your NIB file, as pointed to by the third red arrow. Once I copied that reference to my destination reference ref=, as shown by the fourth red arrow, all was ok & the problem was solved. I could then go back into IB mode (right click, Open As > Interface Builder - iOS) & the view works in the simulator.

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