Xcode 4: 创建 UIView xib，没有正确连接

1. ResultCell should be a subclass of UITableViewCell
2. You should not drag a UIView onto the empty canvas, you should drag a UITableViewCell
3. You should select the cell and change it to be your subclass
4. The owner is most often a controller with an outlet to the cell

Everytime you want to load a new cell, call:

 [[NSBundle mainBundle] loadNibNamed:nibName
owner:controllerWithOutletToCell
options:nil]

after loading, use the cell, and set the ivar/outlet to nil, ready for the next load

there are other ways, but this is common

This might not work for your specific issue, but occasionally I get that error when working with newly created nibs. Deleting and recreating the nibs and View Controllers with the same names as before didn't resolve the issue, but relaunching Xcode did.

I just had this problem and restarting Xcode did not fix it. I removed the class files from the project then added them back in and it started working.

This helped me out:

1. from the project file Panel (left side) select the xib file that is broken.
2. Click on the Files Owner icon from the editor view.
3. from the properties Panel (right side) select the third tab (at the top)
4. specify the "Custom Class"

If you do not see a "panel", please have a look at the top-right corner of the window and enable the proper "view" buttons. If you don't see the "view" buttons then click on the top-right most capsule button.

I got into a similar state just today. It was very odd: I could attach any XIB (new or existing) to any already-existing ViewController class in the project, but I could not create a new ViewController and have it attach properly to any XIB. The "assistant" functionality didn't work, nor did the IB-to-headerfile-connection functionality.

Closing the project and re-opening did not fix it.
Quitting XCode and restarting did not fix it.
Creating a new project and testing the functionality worked fine, which led me to believe there was something corrupt in some cache somewhere.

My solution

• Close your project.
• Go to the ~/Library/Developer/XCode/DerivedData folder and REMOVE all subfolders there referencing the project you are working on.
• Open your project in XCode. The problem should be fixed now.

Incidentally, just running a full clean did not seem to clear things up. I had to trash the derived data. I'm certain I got into this position because of git games I was playing, but I had no idea how to get out, because even switching back to earlier git revisions didn't help. (That was a big clue also that it was something untracked by the project itself.)

If restarting Xcode doesn't work of you, I have found that Toggling the new .m file out and back into the target membership works.

I noticed that .m file was moved inside en.lproj folder.

Just delete (reference only) the .m file from the Xcode and moved .m out of the en.lproj. Add it again.It will fix the issue.

Don't worry, you will get all your connections back.

I had the very same issue. And I tried :

• Restarting Xcode
• Deleting Derived Data
• And many more

None of that worked. What worked for me was simply to :

• Remove 'suspect' class files from Project (just remove References, huh?)
• Re-add them to the project

And done!

I encountered the same problem today. Restarting XCode did not fix the problem for me. I was able to get things back to normal by using "Delete" option of "Derived Data" of the project that can be found under Organizer. Organizer says that, "Derived Data includes index, build output and logs". I guess that either index or build output was causing this issue.

in XCode go to organizer, click project, click delete derived data... than clean the project

If you copied files from other project just make sure you check the 'Add to targets' box

Perhaps what worked for me is this.. (Xcode v4.5)

This did not work

I was trying to control drag into the interface definition of my .h

@interface SearchViewController : UIViewController

@end

This worked (may be that is how it was supposed to work, I did not know it before) See the open and close brackets. Control drag and drop after the closed bracket.

@interface SearchViewController : UIViewController
{
}


@end

Renaming the class files may unlink them from the XIB. This answer helped me discover this:

Ctrl-Drag from button to method not working. Xcode/Interface Builder

Check that your custom class is set correctly in the Identity Inspector.

Similar symptom, but different cause.

Apparently I hit backspace when the focus was on the assistant view, because one of the standard file template comment lines went from // to / which results in the file not compiling.

Fixing the comment allowed the SDK to parse the file, recognize it as a UIViewController, and add in the outlet.

SO -- if you have this problem, do a build or analyze to see if there are errors that need fixing in your view controller .h file. THEN try the other solutions.

In my case it helped to make a "fake change" (just a space) to the according header file.

This might be an old topic but just in case anyone has the same issue in future, try deleting the associated .xib,.h and .m files and create new ones. For me, the UIViewController in my .h file wasn't purple and even backspacing and typing it didn't help.

Just put a line between the @implementation and the @synthesize. Most of the answers here have that in common. It worked for me

@implementation


@synthesize

I just tried everything here and nothing worked (using a Developer Preview for Xcode 5).

The only thing that worked for me was to put this incomplete line in my interface file:

@property (nonatomic, weak)

For whatever reason, adding outlets and actions by drag and drop from a .xib worked fine after that.

This problem seems to be an Xcode bug which creeps up mostly when you replace a file with a new file of the same name. Xcode seems to keep a reference of the older file of the same name.

Anyhow, the way to fix this seems to be:

1. Clean the project
2. Click (Your Project) in Project Navigator view. Go to Compile Sources under Build Phases of the target for which you are building. Remove and add back the .m file which is giving you trouble.
3. Alternatively, in the File Inspector (Utilities view) of the NIB file, under Target Membership, uncheck and check back the target name.
4. Restart Xcode for good measure.
5. Of course, deleting and adding back the .m file alone should fix it too.

(Steps 1 and 2 alone fixed it for me.)

None of the above workarounds resolved the connector issue for me so I shelved my pet project until I came across the following stackoverflow thread:

https://stackoverflow.com/a/15873770/2846800

I had been working on a large project in a previous version of XCode and had turned off indexing. By re-enabling indexing my issue is now fixed:

defaults delete com.apple.dt.XCode IDEIndexDisable

I can now use the D&D features of Interface Builder. I hope this can help others...

For me wether cleaning nor deleting the DerivedData solved the problem.

I tried to delete and recreate my UIViewController class several times and got the problem again and again.

Then I recreated the UIViewController class and gave it a different name. This solved the problem for me.

I have had this problem and found a solution not listed above.

In my case, I could see there was something wrong in the class .h file because my custom view controller did not recognise the class : UIViewController (it was in black not purple). All the other custom view controllers had the : UIViewController in purple.

in my case, and possibly yours, I needed to add the class to targets/build phases/compile Sources drop down. The .m needs to be added. All of the other .m's were there but not this one.

Once I added it, the :UIViewController appeared in purple and everything worked fine.

I had a similar problem with a project written in Swift.

What worked for me was setting up the IBOutlet in code like this

@IBOutlet var foo: UIView?

and afterwards connect it to Interface Builder by dragging to the little circle that appeared right next to the code line.

For my case, I have multiple project with some other dependencies. I tried to solve it by deleting derived data or restarting XCode but it couldn't work. In the end, I tried the following method and it works:

Go to target > Build Target Architectures Only > and set both Debug and Release to NO.

Set this for all projects in the workspace and recompile to make sure there is no other errors. Maybe not making sense but somehow did it. During my compilation, I had other issues such as linker errors and symbols not found.

For *.m file of this class view open "Show File Inspector" and unchecking "Target membership" for this project, then do Clean (menu Product->Clean) and checking again "Target membership" for this project

Using Swift, I had a similar problem. I found out that the comments were part of the problem for me.

I leveraged the default view controller, did some work in it, then created a second view controller by copying the entire first one, stripping it down to only viewDidLoad() and renaming the class to TestViewController. Builds worked, code executed. All was good.

When I went to drag a UITextField in to create an outlet, it would not let me. I noticed that my comments still said "ViewController.swift", so I changed the comment text to "TestViewController.swift" and rebuilt. I was able to connect my outlet!

I wonder if what occurred is that the Indexer was reading the comments as well as the class names, and somehow got confused.

Hope this helps someone out there.

I just had to delete the derived data folder. You need to click Window -> Organizer -> Projects -> Delete Derived Data

AND RESTART XCODE.

You should be good to go!

The new class not being part of the "TARGET" is likely the root cause of this, as alluded to by some of these answers.

When creating a new cocoa class, by default the option to add new class to target is by default checked, but should, for any reason, this not be checked when you hit save, you will have this issue.

Any of these workarounds that add the new class to the apps target will work to resolve the problem, and is something that all these 'fixes' have in common.

I think XCode likely has some bugs that causes a new file to, by default, NOT be added to the apps main target. The fix boils down to adding your 'broken' class to the main TARGET

In XCode 7.1, adding the connector at a different point in my source file worked. The error I was getting referred to one of my variables as if it were a class (didn't make any sense). The error stopped occurring when I added the connector below that variable instead of above it.

There is also a diferent reason for the issue ... if you have created new cocoa class file with template other than ios ... i can happen...

The solution would be to delete it and re create it with right template

I've got the same issue. Rebuilding project helps me Command+B.

When I try to auto generate the action function with below way I came this issue.

But I can done it with below, manual write the action function first, then drag on the region of the @IBAction funciton

I Just ran into this today on Xcode 12.1.

I did the typical delete derived data, and even restarted my computer, but no luck.

In the end I was able to fix this by.

1. Selecting the View Controller in IB
2. Change the class name in the right hand panel under Custom Class > Class to a random class name
3. Change the class name back to the correct class name.