在做UIlabel的时候一直苦于没有好的方法来实时控制label的宽度，后来发现iOS自带一个sizeToFit的方法可以根据label里的文字来自动适应尺寸。
看下效果图：
SizeToFit副本.gif
附上代码：
@interface
ViewController ()
@property(strong, nonatomic) UITextField *textField;
@property(strong, nonatomic) UILabel *label;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//按钮
UIButton *btn =[[UIButtonalloc]initWithFrame:CGRectMake(60, 50, 200,40)];
btn.backgroundColor = [UIColor grayColor];
[btn setTitle:@"使用SizeToFit" forState:UIControlStateNormal];
[btn addTarget:selfaction:@selector(btnEvent)forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];
//textField
_textField = [[UITextFieldalloc]initWithFrame:CGRectMake(60, 100, 200, 30)];
[[NSNotificationCenterdefaultCenter]addObserver:self elector:@selector(changeTextField)name:UITextFieldTexDidChangeNotification object:nil];
_textField.backgroundColor = [UIColor purpleColor];
[self.view addSubview:_textField];
//label
_label = [[UILabel alloc] initWithFrame:CGRectMake(60, 150, 40, 20)];
_label.backgroundColor = [UIColor orangeColor];
[self.view addSubview:_label];
}
- (void)btnEvent{
[_label sizeToFit];
}
- (void)changeTextField{
_label.text = _textField.text;
}
@end
