Question

I have a view with a scrollview. I use code to add labels to the scrollview. Since there’s a lot of redundant code, I tried to move the label creation to a separate function that returns a UILabel. Here’ that function:

- (UILabel *)   f_MakeLabelWithL:(float)MyLeft T:(float)MyTop W:(float)MyWidth H:(float)MyHeight Align:(UITextAlignment)MyAlign 
                      Font:(UIFont *)MyFont TextColor:(UIColor *)MyTextColor BGColor:(UIColor *)MyBGColor {

CGRect rect = CGRectMake(MyLeft, MyTop, MyWidth, MyHeight);
UILabel *label = [[[UILabel alloc] initWithFrame:rect] autorelease];

label.adjustsFontSizeToFitWidth = YES;
label.backgroundColor = MyBGColor;
label.font = MyFont;
label.numberOfLines = 0;
label.textAlignment = MyAlign;
label.textColor = MyTextColor;

return label;
}

I set the text of the label after it is returned. Or so I intended. In fact, a label that is told to have a blue background appears as a solid black rectangle. One with a clear background is entirely clear. Worse than that: the scrollview won’t scroll, and attempting to make it do so crashes the app without any explanation in the debugger console.

Yet all this code works inline just fine and dandy.

Anyone know why?

Update: Putting the code inline fixed the display of the labels. But I was also using a function to create images:

- (UIImageView *) f_MakeImageWithL:(float)MyLeft T:(float)MyTop W:(float)MyWidth H:(float)MyHeight File:(NSString *)MyFile {
CGRect rect = CGRectMake(MyLeft, MyTop, MyWidth, MyHeight);
UIImageView *oImageView = [[[UIImageView alloc] initWithFrame:rect] autorelease];

NSString *s = [[Isystant f_DocumentsPath] stringByAppendingPathComponent:MyFile];
UIImage *oImage = [UIImage imageWithContentsOfFile:s];
[oImageView setImage:oImage];
oImageView.backgroundColor = [UIColor redColor];
oImageView.opaque = YES; // explicitly opaque for performance

return oImageView;
}

It was creating the images, but the frozen scroll/crash problem didn’t go away until I put this code back inline also.

Answer 1

Looks to me like you are over-releasing the UILabel. You shouldn’t have to release the label after adding it to your scrollview if it was never retained anywhere prior to that (and you’ve autoreleased it in the makeImageWithL method).

That’s probably why it is working when you put it inline… because in that scenario, I would bet you are removing the autorelease, right?

-S