在timerBar.bounds.size.width赋值中出现错误“表达式不可分配”

Question

我正在尝试创建一个计时器栏，但我收到错误＆＃34;表达式不可分配＆＃34;在timerBar.bounds.size.width = 0

(void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

self.view.backgroundColor = [UIColor blueColor];  

timerBar = [[UIView alloc]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH , 5)];
timerBar.backgroundColor = [UIColor whiteColor];
[self.view addSubview:timerBar];

[UIView animateWithDuration:2 delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
    timerBar.bounds.size.width = 0;
} completion:^(BOOL finished) {

}];

}

我做错了什么？为什么不能分配值？

Answer 1

您不能将设置的边界宽度指向零！

CGFloat width = 0;
timerBar.bounds = CGRectMake(0, 0, width , 5)