标签:ack params over not equal add cga http post
原创blog。转载请注明出处
blog.csdn.net/hello_hwc
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http://blog.csdn.net/column/details/huangwenchen-ios-sdk.html
前言:AutoLayout定义了View的位置,也就是说,在Auto Layout的project里,假设不改动约束本身,在视图又一次绘制的时候。还会回到最開始的位置。AutoLayout中的动画与视图的位置和大小有关。
在Storyboard上拖拽一个UIImageview。设置约束为:水平垂直正中心,大小非常定100*100
拖拽Imageview以及Constraint为Outlet
注意拖拽Y相关的约束,也就是这个
相应代码
@IBOutlet weak var imageview: UIImageView!
@IBOutlet weak var yConstraints: NSLayoutConstraint!
在viewDidload中设置imageview的初始状态
yConstraints.constant = yConstraints.constant - CGRectGetHeight(UIScreen.mainScreen().bounds)/2
self.imageview.alpha = 0.0;
self.imageview.transform = CGAffineTransformMakeScale(0.1, 0.1)
self.view.layoutIfNeeded();
ViewWillAppear中创建动画
yConstraints.constant = yConstraints.constant + CGRectGetHeight(UIScreen.mainScreen().bounds)/2
UIView.animateWithDuration(1.0, animations: { () -> Void in
self.imageview.alpha = 1.0
self.imageview.transform = CGAffineTransformIdentity
self.view.layoutIfNeeded()
})
原理比較简单。就是利用改动约束NSLayoutConstraint中的属性constant。然后调用
layoutIfNeeded
来实现动画。注意。属性multiplier
眼下(iOS 8.4)还是仅仅读的,不能改动。可是能够通过关系view1.property = view2.property * multiplier + constant
进行转换。
上述动画用纯代码实现
class ViewController: UIViewController {
var imageview:UIImageView?
weak var yConstraint:NSLayoutConstraint?
override func viewDidLoad() {
super.viewDidLoad()
//加入Imageview
let image = UIImage(named: "1_hello_hwc.jpg")
imageview = UIImageView(image: image)
self.imageview?.setTranslatesAutoresizingMaskIntoConstraints(false)
self.view.addSubview(self.imageview!)
//创建约束,定义最開始的位置
let hC = NSLayoutConstraint(item:self.view, attribute:NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.imageview, attribute: NSLayoutAttribute.CenterX, multiplier: 1.0, constant: 0.0)
let vC = NSLayoutConstraint(item:self.view, attribute:NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.imageview, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0)
yConstraint = vC;
yConstraint!.constant = yConstraint!.constant - CGRectGetHeight(UIScreen.mainScreen().bounds)/2
let widthC = NSLayoutConstraint(item:self.imageview!, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem:nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1.0, constant: 100)
let widthH = NSLayoutConstraint(item:self.imageview!, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem:nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1.0, constant: 100)
self.view.addConstraints([hC,vC,widthC,widthH])
//定义最開始的状态
self.imageview?
.alpha = 0.0;
self.imageview?
.transform = CGAffineTransformMakeScale(0.1, 0.1);
self.view.layoutIfNeeded()
}
override func viewWillAppear(animated: Bool) {
yConstraint!.constant = yConstraint!.constant + CGRectGetHeight(UIScreen.mainScreen().bounds)/2
UIView.animateWithDuration(1.0, animations: { () -> Void in
self.imageview!.alpha = 1.0
self.imageview!.transform = CGAffineTransformIdentity
self.view.layoutIfNeeded()
})
}
}
设置属性identifier
yConstraint.identifier = "identifier"
然后在过滤。定义到这个Constraints,
let constraint = filter(self.view.constraints() as! [NSLayoutConstraint], { (constraint:NSLayoutConstraint) -> Bool in
return constraint.identifier == "identifier"
}).first
iOS Core Animation具体解释(四)AutoLayout中的动画
标签:ack params over not equal add cga http post
原文地址:http://www.cnblogs.com/jzssuanfa/p/7053483.html