在 UIButton 中放置一个 UIActivityIndi​​cator

Question

我知道我错过了一些愚蠢的东西，但无论如何，这是我的代码：

UIActivityIndicatorView indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
indicator.hidesWhenStopped = YES;
indicator.frame = btnLogin.frame;
indicator.center = btnLogin.center;
[self.view addSubview:indicator];
[indicator bringSubviewToFront:indicator];

这是最终结果：

http://img542.imageshack.us/img542/8172/uiactivity.png

提前谢谢你！

Answer 1

我认为您缺少的概念是视图的框架（及其中心）都与其父视图相关。根据您的屏幕截图，我猜您的文本字段和按钮都在充当容器的视图中。因此，您的按钮的框架和中心与该容器视图相关，而不是与视图控制器的整体视图相关。您将相同的框架和中心分配给活动指示器，但随后将指示器添加为主视图的子视图，而不是容器视图。因此，您现在有两个视图（按钮和指示器）具有相同的框架，但该框架与两个不同的超级视图相关。

最简单的更改就是将您的指标添加到您正在使用的容器视图中。但我建议将指示器添加为按钮的子视图，然后只需进行一些数学运算即可调整其位置。

UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
CGFloat halfButtonHeight = btnLogin.bounds.size.height / 2;
CGFloat buttonWidth = btnLogin.bounds.size.width;
indicator.center = CGPointMake(buttonWidth - halfButtonHeight , halfButtonHeight);
[btnLogin addSubview:indicator];
[indicator startAnimating];

附带说明：您在视图框架之后设置视图中心是多余的。此外，作为子视图添加的最后一个视图会自动成为前子视图。

Answer 2

根据@Musa almatri 的回答，我创建了扩展：

extension UIButton {
func loadingIndicator(show show: Bool) {
    let tag = 9876
    if show {
        let indicator = UIActivityIndicatorView()
        let buttonHeight = self.bounds.size.height
        let buttonWidth = self.bounds.size.width
        indicator.center = CGPointMake(buttonWidth/2, buttonHeight/2)
        indicator.tag = tag
        self.addSubview(indicator)
        indicator.startAnimating()
    } else {
        if let indicator = self.viewWithTag(tag) as? UIActivityIndicatorView {
            indicator.stopAnimating()
            indicator.removeFromSuperview()
        }
    }
}}

那么你可以这样使用它：

yourButton.loadingIndicator(show: true) //hide -> show: false

Answer 3

这是一个 Swift 3 版本，没有使用标签。

import UIKit

extension UIButton {
    func loadingIndicator(show: Bool) {
        if show {
            let indicator = UIActivityIndicatorView()
            let buttonHeight = self.bounds.size.height
            let buttonWidth = self.bounds.size.width
            indicator.center = CGPoint(x: buttonWidth/2, y: buttonHeight/2)
            self.addSubview(indicator)
            indicator.startAnimating()
        } else {
            for view in self.subviews {
                if let indicator = view as? UIActivityIndicatorView {
                    indicator.stopAnimating()
                    indicator.removeFromSuperview()
                }
            }
        }
    }
}

Answer 4

小升级：（在superview上添加按钮）

extension UIButton {
    func loadingIndicator(_ show: Bool) {
        let indicatorTag = 808404
        if show {
            isEnabled = false
            alpha = 0
            let indicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
            indicator.center = center
            indicator.tag = indicatorTag
            superview?.addSubview(indicator)
            indicator.startAnimating()
        } else {
            isEnabled = true
            alpha = 1.0
            if let indicator = superview?.viewWithTag(indicatorTag) as? UIActivityIndicatorView {
                indicator.stopAnimating()
                indicator.removeFromSuperview()
            }
        }
    }
}

Answer 5

Swift 解决方案：

var indicator = UIActivityIndicatorView()
var halfButtonHeight = SOME_BUTTON.bounds.size.height / 2;
var buttonWidth = SOME_BUTTON.bounds.size.width;
indicator.center = CGPointMake(buttonWidth - halfButtonHeight , halfButtonHeight);
SOME_BUTTON.addSubview(indicator)
indicator.startAnimating()

并使其位于按钮的中心

indicator.center = CGPointMake(buttonWidth/2, halfButtonHeight);

或者使用优秀的库

https://github.com/souzainf3/RNLoadingButton-Swift

Answer 6

我正在使用约束来使 UIButton 内的指示器居中。 改编@DanielQ 的扩展，就变成了：

extension UIButton {
    func loadingIndicator(show: Bool) {
        let tag = 9876
        if show {
            let indicator = UIActivityIndicatorView()
            indicator.tag = tag
            self.addSubview(indicator)
            indicator.translatesAutoresizingMaskIntoConstraints = false
            let horizontalConstraint = NSLayoutConstraint(item: indicator, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0)
            let verticalConstraint = NSLayoutConstraint(item: indicator, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: self, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0)
            self.addConstraints([horizontalConstraint, verticalConstraint])
            indicator.startAnimating()
        } else {
            if let indicator = self.viewWithTag(tag) as? UIActivityIndicatorView {
                indicator.stopAnimating()
                indicator.removeFromSuperview()
            }
        }
    }
}

Answer 7

我从按钮中删除了标题，然后在动画完成后将其添加回来，而不是覆盖标题的指示器：

extension UIButton {

func loadingIndicator(show: Bool) {
    let tag = 9876

    var color: UIColor?

    if show {
        color = titleColor(for: .normal)
        let indicator = UIActivityIndicatorView()
        let buttonHeight = self.bounds.size.height
        let buttonWidth = self.bounds.size.width
        indicator.center = CGPoint(x: buttonWidth/2, y: buttonHeight/2)
        indicator.tag = tag
        indicator.color = UIColor.white
        setTitleColor(.clear, for: .normal)

        self.addSubview(indicator)
        indicator.startAnimating()
    } else {
        if let indicator = self.viewWithTag(tag) as? UIActivityIndicatorView {
            indicator.stopAnimating()
            indicator.removeFromSuperview()
            setTitleColor(color, for: .normal)
        }
    }
}
}