iOS Cgrectzero

[daproject85]

Hi Forum,

I am a bit confused about initializing views or UIVIEW object / subclasses. I have seen lots of examples and code snippets like below

- (UILabel *)makeActivityLabelWithText:(NSString *)labelText;
{
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectZero];
    
    label.font = [UIFont systemFontOfSize:[UIFont systemFontSize]];
    label.textAlignment = UITextAlignmentLeft;
    label.textColor = [UIColor blackColor];
    label.backgroundColor = [UIColor clearColor];
    label.shadowColor = [UIColor whiteColor];
    label.shadowOffset = CGSizeMake(0.0, 1.0);
    label.text = labelText;
    
    return label;

my question is about the below line <br>

UILabel *label = [[UILabel alloc] initWithFrame:CGRectZero];

so CGRectZero makes a rectangle frame of the view object (in this case UILable) in the superview...basically a tiiiiinny tinnny ( LOL ) rectangle at the very top right corner of the superview....in all the subsequent lines where the text is massaged and stuff would this text even show? isn't the text label so tiny?? or does it resize itself automatically?

 

[xStep]

To confirm your belief, create a minor project to test it. That is what I did and below the the code from the ViewController.m file that I added from your listing. I altered it slightly. Try it out as is, then uncomment the block I have commented out.

- (void) viewWillAppear:(BOOL)animated
{
    [super viewWillAppear: animated];
    
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectZero];
    
    label.hidden = NO;
    label.font = [UIFont systemFontOfSize:[UIFont systemFontSize]];
    label.textAlignment = NSTextAlignmentLeft;
    label.textColor = [UIColor blackColor];
    label.backgroundColor = [UIColor greenColor];
    label.shadowColor = [UIColor whiteColor];
    label.shadowOffset = CGSizeMake(0.0, 1.0);
    label.text = @"Hello World\n\nI am GOD!";
        
/*
    NSLog(@"frame: %f %f %f %f", label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);
    label.numberOfLines = 0;
    [label sizeToFit]; // call after setting numberOfLines.
*/    
    

    NSLog(@"frame: %f %f %f %f", label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);

    NSLog(@"%@", label.text);

    [self.view addSubview: label];
}

 

[dejo]

xStep, here's an easier way to NSLog a frame:

NSLog(@"frame: %@", NSStringFromCGRect(label.frame));

 

[caffeineios]

xStep, here's an easier way to NSLog a frame:

NSLog(@"frame: %@", NSStringFromCGRect(label.frame));

Wow I never knew that, very useful, thanks!

 

[dejo]

Wow I never knew that, very useful, thanks!

There's also NSStringFromCGAffineTransform, NSStringFromCGPoint, NSStringFromCGSize, NSStringFromUIEdgeInsets, and NSStringFromUIOffset.

 

[xStep]

xStep, here's an easier way to NSLog a frame:

NSLog(@"frame: %@", NSStringFromCGRect(label.frame));

Oh man! I don't know why I never thought of that. Thanks for a great tip!

 

[Mark FX]

Thanks Dejo, I never picked upon the NSStringFromCGRect method before.

No more more accessing the different %f values of a CGRect.

Great!

Regards Mark