Autolayout - intrinsic size of UIButton does not i

问题:

If I have a UIButton arranged using autolayout, its size adjusts nicely to fit its content.

If I set an image as button.image, the instrinsic size again seems to account for this.

However, if I tweak the titleEdgeInsets of the button, the layout does not account for this and instead truncates the button title.

How can I ensure that the intrinsic width of the button accounts for the inset?

Edit:

I am using the following:

[self.backButton setTitleEdgeInsets:UIEdgeInsetsMake(0, 5, 0, 0)];

The goal is to add some separation between the image and the text.

回答1:

You can solve this without having to override any methods or set an arbitrary width constraint. You can do it all in Interface Builder as follows.

• Intrinsic button width is derived from the title width plus the icon width plus the left and right content edge insets.

• If a button has both an image and text, they’re centered as a group, with no padding between.

• If you add a left content inset, it’s calculated relative to the text, not the text + icon.

• If you set a negative left image inset, the image is pulled out to the left but the overall button width is unaffected.

• If you set a negative left image inset, the actual layout uses half that value. So to get a -20 point left inset, you must use a -40 point left inset value in Interface Builder.

So you provide a big enough left content inset to create space for both the desired left inset and the inner padding between the icon and the text, and then shift the icon left by doubling the amount of padding you want between the icon and the text. The result is a button with equal left and right content insets, and a text and icon pair that are centered as a group, with a specific amount of padding between them.

Some example values:

// Produces a button with the layout:
// |-20-icon-10-text-20-|
// AutoLayout intrinsic width works as you'd desire.
button.contentEdgeInsets = UIEdgeInsetsMake(10, 30, 10, 20)
button.imageEdgeInsets = UIEdgeInsetsMake(0, -20, 0, 0)

回答2:

You can get this to work in Interface Builder (without writing any code), by using a combination of negative and positive Title and Content Insets.

Update: Xcode 7 has a bug where you cannot enter negative values in the Right Inset field, but you can use the stepper control next to it to decrease the value. (Thanks Stuart)

Doing this will add 8pt of spacing between the image and the title and will increase the intrinsic width of the button by the same amount. Like this:

回答3:

Why not override the intrinsicContentSize method on UIView? For example:

- (CGSize) intrinsicContentSize
{
    CGSize s = [super intrinsicContentSize];

    return CGSizeMake(s.width + self.titleEdgeInsets.left + self.titleEdgeInsets.right,
                      s.height + self.titleEdgeInsets.top + self.titleEdgeInsets.bottom);
}

This should tell the autolayout system that it should increase the size of the button to allow for the insets and show the full text. I'm not at my own computer, so I haven't tested this.

回答4:

You haven't specified how you're setting the insets, so I'm guessing that you're using titleEdgeInsets because I see the same effect you're getting. If I use contentEdgeInsets instead it works properly.

- (IBAction)ChangeTitle:(UIButton *)sender {
    self.button.contentEdgeInsets = UIEdgeInsetsMake(0,20,0,20);
    [self.button setTitle:@"Long Long Title" forState:UIControlStateNormal];
}

回答5:

And for Swift worked this:

extension UIButton {
    override open var intrinsicContentSize: CGSize {
        let intrinsicContentSize = super.intrinsicContentSize

        let adjustedWidth = intrinsicContentSize.width + titleEdgeInsets.left + titleEdgeInsets.right
        let adjustedHeight = intrinsicContentSize.height + titleEdgeInsets.top + titleEdgeInsets.bottom

        return CGSize(width: adjustedWidth, height: adjustedHeight)
    }
}

Love U Swift

回答6:

This thread is a bit old, but I just ran into this myself and was able to solve it by using a negative inset. For example, substitute your desired padding values here:

UIButton* myButton = [[UIButton alloc] init];
// setup some autolayout constraints here
myButton.titleEdgeInsets = UIEdgeInsetsMake(-desiredBottomPadding,
                                            -desiredRightPadding,
                                            -desiredTopPadding,
                                            -desiredLeftPadding);

Combined with the right autolayout constraints, you end up with an auto-resizing button which contains an image and text! Seen below with desiredLeftPadding set to 10.

You can see that the actual frame of the button doesn't encompass the label (since the label is shifted 10 points to the right, outside the bounds), but we've achieved 10 points of padding between the text and the picture.

回答7:

For Swift 3 based on pegpeg's answer:

extension UIButton {

    override open var intrinsicContentSize: CGSize {

        let intrinsicContentSize = super.intrinsicContentSize

        let adjustedWidth = intrinsicContentSize.width + titleEdgeInsets.left + titleEdgeInsets.right
        let adjustedHeight = intrinsicContentSize.height + titleEdgeInsets.top + titleEdgeInsets.bottom

        return CGSize(width: adjustedWidth, height: adjustedHeight)

    }

}

回答8:

All above did not work for iOS 9+, what i did is:

• Add a width constraint (for a minimum width when the button doesn't have any text. The button will auto scale if text is provided)
• set the relation to Greater Than or Equal

Now to add a border around the button just use the method:

button.contentEdgeInsets = UIEdgeInsetsMake(0,20,0,20);

回答9:

The option is also available in interface builder. See the Inset. I set left and right to 3. Works like a charm.

回答10:

I wanted to add a 5pt space between my UIButton icon and the label. This is how I achieved it:

UIButton *infoButton = [UIButton buttonWithType:UIButtonTypeCustom];
// more button config etc
infoButton.contentEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 5);
infoButton.titleEdgeInsets = UIEdgeInsetsMake(0, 5, 0, -5);

The way contentEdgeInsets, titleEdgeInsets and imageEdgeInsets relate to each other requires a little give and take from each inset. So if you add some insets to the title's left you have to add negative inset on the right and provide some more space (via a positive inset) on the content right.

By adding a right content inset to match the shift of the title insets my text doesn't go outside the bounds of the button.

回答11:

The solution I use is to add a width constraint on the button. Then somewhere in initialization, after your text is set, update the width constraint like so:

self.buttonWidthConstraint.constant = self.shareButton.intrinsicContentSize.width + 8;

Where 8 is whatever your inset is.

回答12:

calling sizeToFit() makes sure that contentEdgeInset is taken into effect

 extension UIButton {

              open override func draw(_ rect: CGRect) { 
                    self.contentEdgeInsets = UIEdgeInsets(top: 10,left: 40,bottom: 10,right: 40)
                    self.sizeToFit()
              }
           }