iPhone CATextLayer doesn't show its text

Question

I was simply trying to add a CATextlayer in an UIView layer. However, according to the following code, I only get the CATextlayer's background color to be displayed in the UIView, without any text. Just wonder what I missed to display the text.

Could anyone offer a hint/sample how to use CATextlayer?

  - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
        if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
            // Custom initialization

            CATextLayer *TextLayer = [CATextLayer layer];
            TextLayer.bounds = CGRectMake(0.0f, 0.0f, 100.0f, 100.0f);
            TextLayer.string = @"Test";
            TextLayer.font = [UIFont boldSystemFontOfSize:18].fontName;
            TextLayer.backgroundColor = [UIColor blackColor].CGColor;
            TextLayer.wrapped = NO;

            //TextLayer.backgroundColor = [UIColor blueColor];
            self.view = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 100.0f, 100.0f)];
            self.view.backgroundColor = [UIColor blueColor];
            [self.view.layer addSublayer:TextLayer];
            [self.view.layer layoutSublayers];

        }
        return self;
    }

I know this is old post, but the problem here is that you add textlayer to the view that you manually created, but you didn't add the view to your current view. — GeneCode, Jan 05 '17 at 05:27

score 7 · Answer 1 · answered May 03 '13 at 12:34

For iOS 5 and beyond, one can use CATextLayer as follows:

CATextLayer *textLayer = [CATextLayer layer];
textLayer.frame = CGRectMake(144, 42, 76, 21);
textLayer.font = CFBridgingRetain([UIFont boldSystemFontOfSize:18].fontName);
textLayer.fontSize = 18;
textLayer.foregroundColor = [UIColor redColor].CGColor;
textLayer.backgroundColor = [UIColor yellowColor].CGColor;
textLayer.alignmentMode = kCAAlignmentCenter;
textLayer.string = @"BAC";
[self.view.layer addSublayer:textLayer];

You can add this code in any function you like. Specially here correct assignment of font is necessary, otherwise your CATextLayer will be rendered as black no matter what textColor you set.

score 5 · Answer 2 · answered Jul 22 '10 at 22:08

Change your code to this:

CATextLayer *TextLayer = [CATextLayer layer];
TextLayer.bounds = CGRectMake(0.0f, 0.0f, 100.0f, 100.0f);
TextLayer.string = @"Test";
TextLayer.font = [UIFont boldSystemFontOfSize:18].fontName;
TextLayer.backgroundColor = [UIColor blackColor].CGColor;
TextLayer.position = CGPointMake(80.0, 80.0f);
TextLayer.wrapped = NO;
[self.view.layer addSublayer:TextLayer];

You should also be doing this in the view controller's -viewDidLoad. That way you know your view is loaded and valid and can now have layers added to it.

Looks like he was trying in a UIView subclass which doesn't have a viewDidLoad. I tried your code in the 'layoutSubviews' method and it worked. Not sure what the best place for a UIView would be. — David, May 23 '11 at 02:29

score 5 · Answer 3 · answered Aug 24 '17 at 14:52

5

You should (counter-intuitively) call textLayer.display() or textLayer.displayIfNeeded() after the initialization is complete or whenever you want it to draw text.

answered Aug 24 '17 at 14:52

Aleksey Gureiev

1,729
15
17

score 4 · Answer 4 · edited Jun 20 '20 at 09:12

Swift

Here is an example that shows a view with a CATextLayer using a custom font with colored text.

import UIKit
class ViewController: UIViewController {

    @IBOutlet weak var myView: UIView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Attributed string
        let myAttributes = [
            NSFontAttributeName: UIFont(name: "Chalkduster", size: 30.0)! , // font
            NSForegroundColorAttributeName: UIColor.cyanColor()             // text color
        ]
        let myAttributedString = NSAttributedString(string: "My text", attributes: myAttributes )
        
        // Text layer
        let myTextLayer = CATextLayer()
        myTextLayer.string = myAttributedString
        myTextLayer.backgroundColor = UIColor.blueColor().CGColor
        myTextLayer.frame = myView.bounds
        myView.layer.addSublayer(myTextLayer)
    }
}

My fuller answer is here.

score 2 · Answer 5 · answered Feb 15 '12 at 08:37

You can customize the CLTextLayer Like this,

    CATextLayer *aTextLayer_= [[CATextLayer alloc] init];

aTextLayer_.frame =CGRectMake(23.0, 160.0, 243.0, 99.0);

aTextLayer_.font=CTFontCreateWithName( (CFStringRef)@"Courier", 0.0, NULL);

    aTextLayer_.string = @"You string put here";

aTextLayer_.wrapped = YES;

aTextLayer_.foregroundColor = [[UIColor greenColor] CGColor];

aTextLayer_.fontSize = 15.f;

   aTextLayer_.backgroundColor = [UIColor blackColor].CGColor;

aTextLayer_.alignmentMode = kCAAlignmentCenter;

[self.view.layer addSublayer:aTextLayer_];

Don,t forgot to import CoreText/CoreText.h in your view-class. Thanks...

score 0 · Answer 6 · answered Jun 18 '10 at 09:11

0

According to the docs, the default text color of a CATextLayer is white. White on white is hard to see.

answered Jun 18 '10 at 09:11

Ole Begemann

135,006
31
278
256

Thanks for your post! After I changed color to black, still no text shown. Any further recommendation? – user268743 Jun 18 '10 at 09:13

score 0 · Answer 7 · edited Dec 14 '12 at 03:44

0

try this one:

self.view = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 100.0f, 100.0f)];
[self.view setWantsLayer:YES];
self.view.backgroundColor = [UIColor blueColor];

edited Dec 14 '12 at 03:44

iDev

23,310
7
60
85

answered Jul 19 '10 at 10:14

Andrew Gubanov

21
2

iPhone CATextLayer doesn't show its text

7 Answers7

Swift

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