当某些视图隐藏时，如何调整UIView宽度？

Question

上面的图片是从storyboard捕获的。 它的构造如下： UIView（包括UILabel和UIProgressView）＆lt; - 2px spacing - ＆gt; UIActivityIndicatorView＆lt; --- 6px间距---＆gt; UIButton

我希望UIView在隐藏UIActivityIndicatorView时将其宽度增加到按钮，如下所示：    UIView（包括UILabel和UIProgressView）＆lt; --- 6 space ---＆gt; UIButton

我该怎么做？让我知道。请。

Answer 1

https://github.com/bilobatum/ActivityIndicatorDemo

使按钮的固有内容大小沿所需的水平轴（即优先级1000）。这可以防止布局沿水平轴模糊。

@interface ViewController ()
@property (strong, nonatomic) IBOutlet NSLayoutConstraint *activityIndicatorWidthConstraint;
@property (strong, nonatomic) IBOutlet UIActivityIndicatorView *activityIndicator;
// spacerConstraint is the horizontal spacer constraint between the activity indicator and the gray view
@property (strong, nonatomic) IBOutlet NSLayoutConstraint *spacerConstraint;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.activityIndicator startAnimating];
}

- (IBAction)stopButtonTapped:(UIButton *)sender
{
    sender.enabled = NO;

    self.activityIndicatorWidthConstraint.constant = 0;
    self.spacerConstraint.constant = 0;

    [UIView animateWithDuration:1.0 animations:^{
        self.activityIndicator.alpha = 0.0;
        [self.view layoutIfNeeded];
    } completion:^(BOOL finished) {
       [self.activityIndicator stopAnimating];
        //[NSLayoutConstraint reportAmbiguity:nil];
    }];
}

@end

Answer 2

如果您使用自动布局，请考虑在禁用UIActivityIndi​​catorView时将其设置为0。这不仅仅是你所需要的，但它已经接近了。

Answer 3

我们假设您的UILabel被称为_label，UIProgressView被称为_progressView而UIActivityIndicator被称为_activityIndicator。

隐藏_activityIndicator时，请调用此代码块：

[_label setFrame:CGRectMake(_label.frame.origin.x, _label.frame.origin.y, _label.frame.size.width + _activityIndicator.frame.size.width + 2, _label.frame.size.height)];
[_progressView setFrame:CGRectMake(_progressView.frame.origin.x, _progressView.frame.origin.y, _progressView.frame.size.width + _activityIndicator.frame.size.width + 2, _progressView.frame.size.height)];

再次显示_activityIndicator时：

[_label setFrame:CGRectMake(_label.frame.origin.x, _label.frame.origin.y, _label.frame.size.width - _activityIndicator.frame.size.width - 2, _label.frame.size.height)];
[_progressView setFrame:CGRectMake(_progressView.frame.origin.x, _progressView.frame.origin.y, _progressView.frame.size.width - _activityIndicator.frame.size.width - 2, _progressView.frame.size.height)];

请记住，如果您想手动设置帧，则应关闭Autolayout！这很简单：只需取消选中File Inspector中的“Use Autolayout”功能：