objective-c – 如何动态放大UILabel(标签和字体大小)？

我目前正在开发一个iPhone项目.我想动态扩展Objective-C中的UILabel,如下所示：

alt text http://img268.imageshack.us/img268/9683/bildschirmfoto20100323u.png

这怎么可能？我认为我必须使用CoreAnimation,但我没有工作.这是我试过的代码：

UILabel * fooL = //[…]
fooL.frame = CGRectMake(fooL.frame.origin.x,fooL.frame.origin.y,fooL.frame.size.width,fooL.frame.size.height);   
fooL.font = [UIFont fontWithName:@"Helvetica" size:80];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
[UIView setAnimationDelegate:self];
[UIView setAnimationDuration:0.5];
[UIView setAnimationBeginsFromCurrentState:YES];
fooL.font = [UIFont fontWithName:@"Helvetica" size:144]; //bigger size
fooL.frame = CGRectMake(20,44,728,167); //bigger frame
[UIView commitAnimations];

此代码的问题在于它不会动态更改fontsize.

解决方法

您需要做的就是将仿射变换应用于UILabel对象.

CGFloat scaleFactor = 2.0f;
label.transform = CGAffineTransformMakeScale(scaleFactor,scaleFactor); // Enlarge by a factor of 2.