UIButton的宽和高为零

代码：

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button addTarget:self
              action:@selector(myAction:)
    forControlEvents:UIControlEventTouchDown];

[button setTitle:NSLocalizedString(@"Action", @"")
           forState:UIControlStateNormal];
CGFloat width = button.bounds.size.width;

但是宽度为0？这是为什么。请大家帮忙解答一下。谢谢

你不设 button.frame 它怎么会有宽度呢?