问题
I installed Xcode 8.1 and the storyboard shows only blue lines, for all UI elements. If someone has figured it out let me know. I am unable to revert it to even Xcode 8.0.
回答1:
Ok, So finally I too got the blue line problem in Xcode 8.1
Here is the screenshot
We can see the error message:
An internal error occurred. Editing functionality may be limited
with a Report a Bug button on the right side.
Don't know why it happened. But I just quit Xcode and Simulator and restarted it. That fixed it and I got the UI elements back.
回答2:
Don't worry revert back to old xcode
To remove the blue lines,
First, select a view controller in the storyboard.
Then, go to Editor > Canvas > Show Bounds Rectangles
This will hide the blue lines.
You may have to repeat this 2 or 3 times to make it work.
回答3:
Seeing the blue rectangles is actually a feature of Xcode editor. You can turn this On/Off by going to Editor menu->Canvas->Show Bounds Rectangles
But yes, seeing just the blue boxes seems to be a bug. Usually happens if you have been switching between various versions of Xcode frequently. I guess quitting and reopening Xcode shall resolve this temporary issue.
回答4:
I had this same issue when I had upgraded to Mojave and then installed an older Xcode (10.1) version. To fix I deleted all Xcode (10.2/10.1) versions and then installed Xcode 10 and it fixed the issue.
回答5:
This has happened to me on several occasions. For me it almost always occurred after dragging a UILabel from a UITableViewCell into a different view.
I was able to fix the problem by deleting the view controller in the storyboard that I did the dragging to/from, closing the app, and reopening the project.
回答6:
I had a similar problem in XCode 11, in my case even the view controllers was completely black. The problem was a Custom Class assigned to an UIButton. After a while i deleted the class because i didn't need it anymore, but the Button still had the class assigned.
Open the particular storyboard file, delete the assignment in Identity Inspector, restart Xcode. This fixed it for me.
来源：https://stackoverflow.com/questions/40301394/xcode-8-1-storyboard-showing-blue-lines-only