UIButton won't go to Aspect Fit in iPhone

问题

I have a couple UIButtons, and in IB they're set to Aspect Fit, but for some reason they're always stretching. Is there something else you have to set? I tried all the different view modes and none of them work, they all stretch.

回答1:

I've had that problem before. I solved it by putting my image in a UIImageView, where contentMode settings actually work, and putting a transparent custom UIButton over top of that.

EDIT: This answer is obsolete. See @Werner Altewischer's answer for the correct answer in modern versions of iOS.

回答2:

The solution is to set the contentMode on the imageView property of the UIButton. The UIButton has to be created with custom type for this to work I believe (otherwise nil is returned for this property).

回答3:

This method worked for me very well.:

In Xib select the button and set user defined runtime attributes:

Key path: self.imageView.contentMode
Type: Number
Value: 1

We use number because you cant use enum there. But the UIViewContentModeScaleAspectFit is equal to 1.

回答4:

If you are doing this in Interface Builder, you can use the Runtime attributes inspector to set this directly without any code.

Set your Key Path on the button to be "imageView.contentMode" with a type of "Number" and a value of "1" (or whichever mode you would like).

回答5:

Use button's imageView for contentMode. Not directly on the button itself.

homeButton.imageView.contentMode = UIViewContentModeScaleAspectFit;
homeButton.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
homeButton.contentVerticalAlignment = UIControlContentVerticalAlignmentFill;
[homeButton setImage:[UIImage imageNamed:kPNGLogo] forState:UIControlStateNormal];

回答6:

If you put the image in an UIImageView behind the button, you'll loose the built-in functionality of the UIButton class, such as adjustsImageWhenHighlighted and adjustsImageWhenDisabled, and of course the ability to set different images for different states (without the hazzle of doing this yourself).

If we want to have an image unstreched for all control states, one approuch is to get the image using imageWithCGImage:scale:orientation, as in the following method:

- (UIImage *) getScaledImage:(UIImage *)img insideButton:(UIButton *)btn {

    // Check which dimension (width or height) to pay respect to and
    // calculate the scale factor
    CGFloat imgRatio = img.size.width / img.size.height, 
            btnRatio = btn.frame.size.width / btn.frame.size.height,
            scaleFactor = (imgRatio > btnRatio 
                           ? img.size.width / btn.frame.size.width
                           : img.size.height / btn.frame.size.height;

    // Create image using scale factor
    UIImage *scaledImg = [UIImage imageWithCGImage:[img CGImage]
                                             scale:scaleFactor
                                       orientation:UIImageOrientationUp];
    return scaledImg;
}

To implement this we would write:

UIImage *scaledImg = [self getScaledImage:myBtnImg insideButton:myBtn];
[myBtn setImage:scaledImg forState:UIControlStateNormal];

This should prevent the image from stretching in all control states. It worked for me, but let me know if it doesn't!

NOTE: Here we are addressing a problem relating to UIButton, but the insideButton: might as well be insideView:, or whatever one would like to fit the image into.

回答7:

I had this problem a while back. The issue I had was i was trying to apply this effect to the background UIButton which is limited and therefore means you cannot adjust it as easy.

The trick is to set it as just an image then apply @ayreguitar's technique and that should fix it!

UIButton *myButton = [UIButton buttonWithType:UIButtonTypeCustom];
[myButton setContentMode:UIViewContentModeScaleAspectFill];
[myButton setImage:@"myImage.png" forState:UIControlStateNormal];

回答8:

This worked for me

[button.imageView setContentMode:UIViewContentModeScaleAspectFit];

Thanks to @ayreguitar for his comment

回答9:

Here's an alternative answer in swift:

myButton.imageView?.contentMode = .ScaleAspectFit

回答10:

Combining together a few different answers into one solution-- create a button with a custom type, set the button's imageView contentMode property, and set the image for the button (not the background image, which will still scale to fill).

//Objective-C:
UIImage *image = [UIImage imageNamed:"myImageName.png"];
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setImage:image forState:UIControlStateNormal];
button.imageView.contentMode = UIViewContentModeScaleAspectFit;

//Swift:
let image = UIImage(named: "myImageName.png")
let button = UIButton(type: .custom)
button.imageView?.contentMode = .scaleAspectFit
button.setImage(image, for: .normal)

回答11:

btn.imageView.contentMode = UIViewContentModeScaleAspectFit;

回答12:

This answer is based on @WernerAltewischer's answer.

To avoid having connect my button to an IBOutlet to execute the code on it, I subclassed UIButton's class:

// .h
@interface UIButtonWithImageAspectFit : UIButton
@end

// .m
@implementation UIButtonWithImageAspectFit

- (void) awakeFromNib {
    [self.imageView setContentMode:UIViewContentModeScaleAspectFit];
}

@end

Now create a custom button in your xib, and set its image (not the background image):

Then, set its class:

You're done!
Instead of

your button's image aspect fit is now as expected:

回答13:

I had problems with the image not resizing proportionately so the way I fixed it was using edge insets.

fooButton.contentEdgeInsets = UIEdgeInsetsMake(10, 15, 10, 15);

回答14:

UIView content modes apply to the corresponding CALayer's "content". This works for UIImageViews because they set the CALayer content to the corresponding CGImage.

drawRect: ultimately renders to the layer content.

A custom UIButton (as far as I know) has no content (the rounded-rect style buttons might be rendered using content). The button has subviews: the background UIImageView, the image UIImageView, and the title UILabel. Setting the contentMode on the subviews may do what you want, but messing around with the UIButton view hierarchy is a bit of a no-no.

回答15:

Changing UIButton.imageView.contentMode does not worked for me.
I solved the problem by setting the image to 'Background' property.
You can add ratio constraint if you need

回答16:

This overlaps many of the other answers, but the solution for me was to

set the contentMode of the UIImageView for the button to .ScaleAspectFit – which can either be done in the ”User Defined Runtime Attributes” in Interface Builder (ie. self.imageView.contentMode, Number, 1) or in a UIButton subclass;
disable ”Autoresize Subviews”;
set ”Edge” to ”Image” and appropriate ”Top” and ”Bottom” values for ”Inset” (which might only be needed if you, like me, used a PDF as image).

回答17:

ios 12. You need to add also the content Alignment

class FitButton: UIButton {

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)


    }

    override func layoutSubviews() {
        self.imageView?.contentMode = .scaleAspectFill
        self.contentHorizontalAlignment = .fill
        self.contentVerticalAlignment = .fill
        super.layoutSubviews()


    }

}

回答18:

You can use imageWithCGImage as shown above (but without the missing parentheses).

Also... millions of non-4.0 phones won't work with that code at all.

回答19:

[button sizeToFit] worked for me.

回答20:

Similar to @Guillaume, I have created a subclass of UIButton as a Swift-File. Then set my custom class in the Interface Builder:

And here the Swift file:

import UIKit

class TRAspectButton : UIButton {
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.imageView?.contentMode = .ScaleAspectFit
    }
}

回答21:

I had the same issue, but I couldn't get it to work (perhaps it's a bug with the SDK).

Eventually, as a workaround, I placed a UIImageView behind my button and set the options I wanted on that, then simply placed a blank UIButton on top of it.

来源：https://stackoverflow.com/questions/3460694/uibutton-wont-go-to-aspect-fit-in-iphone

标签

ios

iphone

uibutton

aspect-fit