Assertion failure in UITextView _firstBaselineOffsetFromTop

Question

I was learning about the view debugger in Xcode and capturing the view hierarchy with Debug > View Debugging > Capture View Hierarchy. However when I tried it in my app I got the following error:

Assertion failure in -[UITextView _firstBaselineOffsetFromTop], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3512.60.7/UITextView.m:1683

I could reproduce this in the following simple project:

import UIKit
class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let myTextView = UITextView()
        myTextView.frame = CGRect(x: 50, y: 50, width: 200, height: 100)
        myTextView.text = "This is a test."
        view.addSubview(myTextView)

    }
}

I saw here that it could be caused by not using auto layout. Is this really a bug that we have to wait for a fix? Is there a Swift workaround?

Update

The suggested duplicate looks like the same issue I am having. However, unlike that question, I am asking for a Swift workaround. The "answer" to that question was just a link (the same link that I already had above). I am voting to close the other way.

Toulon

Possible duplicate of Not able to use debug view hierachy – Plutonic

Answer 1

Note do this in DEBUG builds only

A workaround to resolve this issue. Keep below category in your project. It worked for me.

@interface UITextView(MYTextView)

@end

@implementation UITextView (MYTextView)
- (void)_firstBaselineOffsetFromTop {

}

- (void)_baselineOffsetFromBottom {

}

@end

For swift

extension UITextView {
    func _firstBaselineOffsetFromTop() {
    }
    func _baselineOffsetFromBottom() {
    }
}

Woad

Ah, I understand now. So this is overriding the methods that were causing the assertion failure. I suppose if those methods were doing anything else important you are losing that functionality, but this is a very useful workaround when needing to capture the view hierarchy. The extension (or category) could then be commented out later. (I tested the Swift code with the sample project in my question and I can confirm that it does work.) – Toulon

Enable in debug mode only by adding this to your .pch file #ifdef DEBUG #import "UITextView+MYTextView.h" #endif – Kraken

Thanks for the clever workaround && Nice Job Apple >=: – Disinherit