Question

I have a UIView with it’s subclass set in interface builder to a UIView subclass I created. I want to update labels within the UIView class holding them. I cannot seem to update the text of any labels drawn in drawRect. What are my options for drawing elements I need to change within a UIView subclass?

// Using UILabel subclass (FontLabel)

- (void)drawRect:(CGRect)rect {
    scoreLabel = [[FontLabel alloc] initWithFrame:CGRectMake(0,0, 400, 50) fontName:@"Intellect" pointSize:80.0f];
    scoreLabel.textColor = [[UIColor alloc] initWithRed:0.8157 green:0.8000 blue:0.0706 alpha:1.0f];

    [scoreLabel sizeToFit];
    [scoreLabel setText:@"Initial text"];
    [self addSubview:scoreLabel];

    [self setNeedsDisplay]; 
    //Also tried [self setNeedsLayout];
}

- (void)updateScoreLabel:(int)val 
{
    [scoreLabel setText:[NSString stringWithFormat:@"%d", val]];
}   



// Using CATextLayer

- (void)drawRect:(CGRect)rect {
    scoreLabel = [CATextLayer layer];
    [scoreLabel setForegroundColor:[UIColor whiteColor].CGColor];
    [scoreLabel setFrame:CGRectMake(0,0, 200, 20)];
    [scoreLabel setAlignmentMode:kCAAlignmentCenter];
    [[self layer] addSublayer:scoreLabel];
    [scoreLabel setString:@"Initial text"];


    [self setNeedsDisplay]; 
    //Also tried [self setNeedsLayout];
}

- (void)updateScoreLabel:(int)val 
{
    [scoreLabel setString:[NSString stringWithFormat:@"%d", val]];
}   

Answer 1

In order to change the text of labels programmatically, you need to do the following:

In your .h file:

• Define them as UILabels in your @interface section

• Add IBOutlets to them in your @property declarations

In your .m file:

• Put in @synthesize lines for them in your .m file.

After that, you can refer to them as any other self. variable, and set their text property to change how they appear in your display.

In general, trying to subclass UIView can be a bit tricky (as you’re finding), but hopefully the above will help you at least a bit.