How do I increase or decrease the size of a button

问题:

I have a UIButton in my app that I call "buttonPlay". I am using AutoLayout but the button doesn't have any NSLayoutConstraints attached to it.

I would like to code an animation to increase and the decrease the height and the width of the button. Here's how the animation code looks like:

    // "Repeat" because the animation must repeat itself
    UIView.animateWithDuration(1.0, delay: 0.6, options: UIViewAnimationOptions.Repeat, animations: {
        // Animation code goes here
        // nil: the animation is not supposed to end
        }, completion: nil)
}

To get the original values of the x position, y position, width and height I am using the following code:

var frmPlay : CGRect = self.buttonPlay.frame

// get the current x and y positions
        let originXbutton = frmPlay.origin.x
        let originYbutton = frmPlay.origin.y

// get the current width and height of the button     
        let originWidthbutton = frmPlay.size.width
        let originHeightbutton = frmPlay.size.height

// set the frame (frmPlay) to the button frame
        self.buttonPlay.frame = frmPlay

Okay, it's now time to increase or decrease the width and the height of the animation. I'll put this code inside the animation block:

        self.buttonPlay.frame = CGRectMake(
            originXbutton,
            originYbutton,
            originWidthbutton-100,
            originHeightbutton)

        self.buttonPlay.frame = CGRectMake(
            originXbutton,
            originYbutton,
            originWidthbutton+100,
            originHeightbutton)

The animation code will look something like this:

    UIView.animateWithDuration(1.0, delay: 0.6, options: UIViewAnimationOptions.Repeat, animations: {

        println("Animation function animateStuff() started!")

        var frmPlay : CGRect = self.buttonPlay.frame

        let originXbutton = frmPlay.origin.x
        let originYbutton = frmPlay.origin.y

        let originWidthbutton = frmPlay.size.width
        let originHeightbutton = frmPlay.size.height

        self.buttonPlay.frame = frmPlay

        self.buttonPlay.frame = CGRectMake(
            originXbutton,
            originYbutton,
            originWidthbutton-100,
            originHeightbutton)

        self.buttonPlay.frame = CGRectMake(
            originXbutton,
            originYbutton,
            originWidthbutton+100,
            originHeightbutton)

        }, completion: nil)

Let's run the app. Uh oh! The button (also called buttonPlay) doesn't get bigger or smaller in any way. Though it moves from right to left. But hey! I haven't touched the x and the y positions code.

What causes it?

回答1:

use UIViewAnimationOptions.Repeat and UIViewAnimationOptions.Autoreverse together to do that. You just have to set one frame change inside the animation block. You cannot have more than one state change to the same property inside an animation block.

UIView.animateWithDuration(1.0, delay: 0.6, options:
    UIViewAnimationOptions.Repeat | UIViewAnimationOptions.Autoreverse | UIViewAnimationOptions.AllowUserInteraction, animations: {

    println("Animation function animateStuff() started!")

    var frmPlay : CGRect = self.buttonPlay.frame

    let originXbutton = frmPlay.origin.x
    let originYbutton = frmPlay.origin.y

    let originWidthbutton = frmPlay.size.width
    let originHeightbutton = frmPlay.size.height

    self.buttonPlay.frame = frmPlay

    self.buttonPlay.frame = CGRectMake(
        originXbutton,
        originYbutton,
        originWidthbutton+100,
        originHeightbutton)

    }, completion: { finished in

})

UIViewAnimationOptionRepeat : Repeat the animation indefinitely.

UIViewAnimationOptionAutoreverse : Run the animation backwards and forwards. Must be combined with the UIViewAnimationOptionRepeat option.

If you want to scale the button up and down,

UIView.animateWithDuration(1.0, delay: 0.6, options:
    UIViewAnimationOptions.Repeat | UIViewAnimationOptions.Autoreverse | UIViewAnimationOptions.AllowUserInteraction, animations: {

        self.buttonPlay.transform = CGAffineTransformMakeScale(1.5, 1.5)
    }, completion: { finished in

})

回答2:

Put separate animations for increasing and decreasing button size .Try this code .

This will decrease the button size with animation .

    UIView.animateWithDuration(1.0, delay: 0.6, options: UIViewAnimationOptions.Repeat, animations: {

    println("Animation function animateStuff() started!")

    var frmPlay : CGRect = self.buttonPlay.frame

    let originXbutton = frmPlay.origin.x
    let originYbutton = frmPlay.origin.y

    let originWidthbutton = frmPlay.size.width
    let originHeightbutton = frmPlay.size.height

    self.buttonPlay.frame = frmPlay

    self.buttonPlay.frame = CGRectMake(
        originXbutton,
        originYbutton,
        originWidthbutton-100,
        originHeightbutton)
    }, completion: nil)

This will increase the size again to original button .

    UIView.animateWithDuration(1.0, delay: 0.6, options: UIViewAnimationOptions.Repeat, animations: {

    println("Animation function animateStuff() started!")

    var frmPlay : CGRect = self.buttonPlay.frame

    let originXbutton = frmPlay.origin.x
    let originYbutton = frmPlay.origin.y

    let originWidthbutton = frmPlay.size.width
    let originHeightbutton = frmPlay.size.height

    self.buttonPlay.frame = frmPlay

    self.buttonPlay.frame = CGRectMake(
        originXbutton,
        originYbutton,
        originWidthbutton+100,
        originHeightbutton)

    }, completion: nil)

回答3:

My solution in Swift 3:

func animate(sender: UIButton) {

    let buttonSize: CGRect = sender.frame

    let originXbutton = buttonSize.origin.x
    let originYbutton = buttonSize.origin.y

    let originWidthbutton = buttonSize.size.width
    let originHeightbutton = buttonSize.size.height

    UIView.animate(withDuration: 0.2, animations: {
        sender.frame = CGRect(x: originXbutton, y: originYbutton - 5, width: originWidthbutton + 3, height: originHeightbutton + 3)
    }, completion: { finished in
        sender.frame = CGRect(x: originXbutton, y: originYbutton, width: originWidthbutton, height: originHeightbutton)
    })
}