Swift3.0 实现模态/非模态loading框和toast

本文要实现Android的toast效果， 同时实现loading框， 包括模态和非模态（即是否拦截控件的焦点）。

1、 因为toast文字有长有短， 所有要动态判断toast文字的宽度。
<pre>
extension UILabel {
//根据最大宽度计算高
func getLableSize(text: String, maxWidth: CGFloat) -> CGRect {
let maxSize = CGSize(width: maxWidth, height: 0) //注意高度是0
// size = text.boundingRectWithSize(size2, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: attributes , context: nil);
let size = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin,
attributes: [NSFontAttributeName:self.font], context: nil)
return size

}

}</pre>

2、 按钮的点击事件：
<pre>
@IBAction func clickButton2(_ sender: Any) {
let toast = ToastView()
toast.showLoadingDlg()
}

@IBAction func clickButton3(_ sender: Any) {
    let toast = ToastView()
    toast.showToast(text: "网络连接异常，请稍候再试", pos: .Bottom)
}


@IBAction func showToastTop(_ sender: Any) {
    let toast = ToastView()
    toast.showToast(text: "您的申请已受理，请耐心等待", pos: .Top)
}


@IBAction func showNoModal(_ sender: Any) {
    let toast = ToastView()
    toast.showToastExt(text: "非模态toast", pos: .Bottom)

}</pre>

3、以显示loading为例讲解语法， 注意模态和非模态是根据window大小决定的。 如果window的大小跟应用根窗口大小一样， 那么就是模态， 反之是非模态。
<pre>
func showLoadingDlg() {
let rootRect = UIApplication.shared.windows.first?.frame //应用屏幕大小

    let container = UIView()   //全屏且透明，盖在最上面， 可以自定义点击事件， 从而实现模态和非模态框效果。
    container.backgroundColor = UIColor.clear
    container.frame = rootRect!
    
    //添加中间矩形黑色区域, 80*80
    let bgLength = 90
    let bgView = UIView()  //黑色半透明方形区域
    bgView.frame = CGRect(x: Int((rootRect?.width)!/2) - bgLength/2,
                          y: Int((rootRect?.height)!/2) - bgLength/2,
                          width: bgLength,
                          height: bgLength)
    bgView.layer.cornerRadius = 10   //黑色矩形区域的角弧度
    bgView.backgroundColor = UIColor(hue: 0, saturation: 0, brightness: 0, alpha: 0.8)
    
    container.addSubview(bgView)   //全屏透明背景在中心位置添加矩形黑色区域
    
    //添加圈圈
    let indicatorLength: CGFloat = 50  //黑色矩形区域里的旋转
    let indicatorView = UIActivityIndicatorView(activityIndicatorStyle: .white)
    indicatorView.frame = CGRect(x: (rootRect?.width)!/2 - indicatorLength/2,
                                 y: (rootRect?.height)!/2 - indicatorLength/2 - 10,
                                 width: indicatorLength,
                                 height: indicatorLength)
    indicatorView.startAnimating()   //动画
    
    container.addSubview(indicatorView)  //添加旋转动画view
    
    //添加文字
    let lableX = (rootRect?.width)!/2 - CGFloat(bgLength/2) + 5
    let lableY = (rootRect?.height)!/2 + indicatorLength/2 - 10
    let lableView = UILabel(frame: CGRect(x: Int(lableX),
                                          y: Int(lableY),
                                          width: bgLength-10,
                                          height: bgLength/2-Int(indicatorLength)/2-5))
    lableView.font = UIFont.systemFont(ofSize: 15)    //设置系统字体和字号
    lableView.textColor = UIColor.white
    lableView.text = "加载中"
    lableView.textAlignment = .center
    container.addSubview(lableView)
    
    //-------------测试代码-------------
    //let size = lableView.getLableSize(text: "网络异常，请稍候再试", maxWidth: 100)
    //-------------测试代码-------------
    
    
    let window = UIWindow()
    window.backgroundColor = UIColor.clear
    window.frame = rootRect!    //全屏大小
    window.center = CGPoint(x: (rootRect?.width)!/2, y: (rootRect?.height)!/2)
    window.windowLevel = UIWindowLevelAlert
    window.isHidden = false
    window.addSubview(container)
    
    //添加点击事件
    container.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(tapGesture(sender:))))
    
    bufWindows.append(window)
    perform(#selector(showFinished(sender:)), with: window, afterDelay: delay)
}

</pre>

4、toast和loading框都是window， 可以动态关闭， 就像gif图里演示的那样点击window所在区域就可以关闭。
<pre>
//添加点击事件
func tapGesture(sender: UITapGestureRecognizer) {
print("点击uiview")

    //移除最后一个
    if bufWindows.count > 0 {
        bufWindows.removeLast()
    }
    NSObject.cancelPreviousPerformRequests(withTarget: self)  //可以关闭window， 如果注释该语句则相当于盖住了一层透明界面
}
</pre>

代码： https://github.com/brycegao/SwiftToast