Animate UILabel width with fixed center

问题

How to animate a change in width while keeping the view centered?

Currently when I do it, it doesn't grow from the center.

self.textLabel = UILabel()
self.textLabel.frame = CGRectMake(0, 0, Globals.voterTextLabel, Globals.voterTextLabel)
self.textLabel.center = CGPointMake(self.view.frame.width/2, self.view.frame.height/2)
self.textLabel.text = "VS"
self.textLabel.layer.cornerRadius = Globals.voterTextLabel/2
self.textLabel.layer.masksToBounds = true
self.textLabel.clipsToBounds = true
self.textLabel.backgroundColor = UIColor.whiteColor()
self.textLabel.textColor = Colors.voterTextLabel
self.textLabel.textAlignment = .Center
self.textLabel.autoresizingMask = .FlexibleWidth
self.view.addSubview(self.textLabel) 

 UIView.animateWithDuration(2, animations: {
    self.textLabel.frame.size.width = 150
    self.textLabel.center.x = self.view.frame.width/2
 }, completion: nil)

回答1:

This will work for you. You just need to give scale for width and height (default 1, which will have no effect). And this will animate your view's frame.

    UIView.animateWithDuration(2, delay: 0, options: UIViewAnimationOptions.BeginFromCurrentState, animations: { () -> Void in
        self.textLabel.transform=CGAffineTransformMakeScale(3, 1);
    }, completion: nil)

And if you don't want to stretch the content, than you may try this:

        UIView.animateWithDuration(2, delay: 0, options: UIViewAnimationOptions.CurveEaseInOut, animations: { () -> Void in

        var newWidth:CGFloat = 200.0;

        var oldWidth:CGFloat = self.textLabel.frame.width;

        var totalChangeWidth:CGFloat = newWidth - oldWidth;

        var newHeight:CGFloat = 200.0;

        var oldHeight:CGFloat = self.textLabel.frame.width;

        var totalChangeHeight:CGFloat = newHeight - oldHeight;

        self.textLabel.bounds.size = CGSizeMake(self.textLabel.frame.size.width + totalChangeWidth, self.textLabel.frame.size.height + totalChangeHeight);

        self.textLabel.center = CGPointMake(self.view.frame.width/2, self.view.frame.height/2)

    }, completion:nil)

来源：https://stackoverflow.com/questions/32777134/animate-uilabel-width-with-fixed-center

标签

swift

uiview

uilabel

uianimation