CODEWITHSUNDEEP
iosiphoneuser-interface
user268743
user268743

Reputation: 343

iPhone CATextLayer doesn't show its text

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;
    }

Upvotes: 12

Views: 13119

Answers (7)

Aleksey Gureiev
Aleksey Gureiev

Reputation: 1759

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

Upvotes: 5

Suragch
Suragch

Reputation: 511676

Swift

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

enter image description here

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.

Upvotes: 4

NightFury
NightFury

Reputation: 13546

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.

Upvotes: 7

Andrew Gubanov
Andrew Gubanov

Reputation: 21

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];

Upvotes: 0

Arunjack
Arunjack

Reputation: 621

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...

Upvotes: 2

Matt Long
Matt Long

Reputation: 24466

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.

Upvotes: 5

Ole Begemann
Ole Begemann

Reputation: 135548

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

Upvotes: 0

Related Questions