我想在两行文本的左边放置一个图标，这样在图像和文本开始之间有大约2-3像素的空间。控件本身水平居中对齐(通过接口生成器设置)
这个按钮应该是这样的:
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我试图配置这与contenttedgeinset, imageEdgeInsets和titleEdgeInsets无效。我知道，负值会使边缘扩大，而正值会使边缘缩小，使边缘更接近中心。
我试着:
[button setTitleEdgeInsets:UIEdgeInsetsMake(0, -image.size.width, 0, 0)];
[button setImageEdgeInsets:UIEdgeInsetsMake(0, button.titleLabel.bounds.size.width, 0, 0)];
但这并没有正确显示它。我一直在调整这些值，但从-5到-10的左插入值似乎不会以预期的方式移动它。-10将文本一直向左移动，所以我期望-5将它从左侧移动一半，但事实并非如此。
嵌套背后的逻辑是什么?我不熟悉图像放置和相关术语。
我用这个SO问题作为参考，但我的价值观有些不对。
UIButton:如何使用imageEdgeInsets和titleEdgeInsets居中图像和文本?
在swift 5.3和@ravron的启发下回答:
extension UIButton {
/// Fits the image and text content with a given spacing
/// - Parameters:
/// - spacing: Spacing between the Image and the text
/// - contentXInset: The spacing between the view to the left image and the right text to the view
func setHorizontalMargins(imageTextSpacing: CGFloat, contentXInset: CGFloat = 0) {
let imageTextSpacing = imageTextSpacing / 2
contentEdgeInsets = UIEdgeInsets(top: 0, left: (imageTextSpacing + contentXInset), bottom: 0, right: (imageTextSpacing + contentXInset))
imageEdgeInsets = UIEdgeInsets(top: 0, left: -imageTextSpacing, bottom: 0, right: imageTextSpacing)
titleEdgeInsets = UIEdgeInsets(top: 0, left: imageTextSpacing, bottom: 0, right: -imageTextSpacing)
}
}
它增加了一个额外的水平边距，从视图到图像，从标签到视图
下面是我写的代码。它在产品版本中运行良好。支持Swift 4.2 +
extension UIButton{
enum ImageTitleRelativeLocation {
case imageUpTitleDown
case imageDownTitleUp
case imageLeftTitleRight
case imageRightTitleLeft
}
func centerContentRelativeLocation(_ relativeLocation:
ImageTitleRelativeLocation,
spacing: CGFloat = 0) {
assert(contentVerticalAlignment == .center,
"only works with contentVerticalAlignment = .center !!!")
guard (title(for: .normal) != nil) || (attributedTitle(for: .normal) != nil) else {
assert(false, "TITLE IS NIL! SET TITTLE FIRST!")
return
}
guard let imageSize = self.currentImage?.size else {
assert(false, "IMGAGE IS NIL! SET IMAGE FIRST!!!")
return
}
guard let titleSize = titleLabel?
.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize) else {
assert(false, "TITLELABEL IS NIL!")
return
}
let horizontalResistent: CGFloat
// extend contenArea in case of title is shrink
if frame.width < titleSize.width + imageSize.width {
horizontalResistent = titleSize.width + imageSize.width - frame.width
print("horizontalResistent", horizontalResistent)
} else {
horizontalResistent = 0
}
var adjustImageEdgeInsets: UIEdgeInsets = .zero
var adjustTitleEdgeInsets: UIEdgeInsets = .zero
var adjustContentEdgeInsets: UIEdgeInsets = .zero
let verticalImageAbsOffset = abs((titleSize.height + spacing) / 2)
let verticalTitleAbsOffset = abs((imageSize.height + spacing) / 2)
switch relativeLocation {
case .imageUpTitleDown:
adjustImageEdgeInsets.top = -verticalImageAbsOffset
adjustImageEdgeInsets.bottom = verticalImageAbsOffset
adjustImageEdgeInsets.left = titleSize.width / 2 + horizontalResistent / 2
adjustImageEdgeInsets.right = -titleSize.width / 2 - horizontalResistent / 2
adjustTitleEdgeInsets.top = verticalTitleAbsOffset
adjustTitleEdgeInsets.bottom = -verticalTitleAbsOffset
adjustTitleEdgeInsets.left = -imageSize.width / 2 + horizontalResistent / 2
adjustTitleEdgeInsets.right = imageSize.width / 2 - horizontalResistent / 2
adjustContentEdgeInsets.top = spacing
adjustContentEdgeInsets.bottom = spacing
adjustContentEdgeInsets.left = -horizontalResistent
adjustContentEdgeInsets.right = -horizontalResistent
case .imageDownTitleUp:
adjustImageEdgeInsets.top = verticalImageAbsOffset
adjustImageEdgeInsets.bottom = -verticalImageAbsOffset
adjustImageEdgeInsets.left = titleSize.width / 2 + horizontalResistent / 2
adjustImageEdgeInsets.right = -titleSize.width / 2 - horizontalResistent / 2
adjustTitleEdgeInsets.top = -verticalTitleAbsOffset
adjustTitleEdgeInsets.bottom = verticalTitleAbsOffset
adjustTitleEdgeInsets.left = -imageSize.width / 2 + horizontalResistent / 2
adjustTitleEdgeInsets.right = imageSize.width / 2 - horizontalResistent / 2
adjustContentEdgeInsets.top = spacing
adjustContentEdgeInsets.bottom = spacing
adjustContentEdgeInsets.left = -horizontalResistent
adjustContentEdgeInsets.right = -horizontalResistent
case .imageLeftTitleRight:
adjustImageEdgeInsets.left = -spacing / 2
adjustImageEdgeInsets.right = spacing / 2
adjustTitleEdgeInsets.left = spacing / 2
adjustTitleEdgeInsets.right = -spacing / 2
adjustContentEdgeInsets.left = spacing
adjustContentEdgeInsets.right = spacing
case .imageRightTitleLeft:
adjustImageEdgeInsets.left = titleSize.width + spacing / 2
adjustImageEdgeInsets.right = -titleSize.width - spacing / 2
adjustTitleEdgeInsets.left = -imageSize.width - spacing / 2
adjustTitleEdgeInsets.right = imageSize.width + spacing / 2
adjustContentEdgeInsets.left = spacing
adjustContentEdgeInsets.right = spacing
}
imageEdgeInsets = adjustImageEdgeInsets
titleEdgeInsets = adjustTitleEdgeInsets
contentEdgeInsets = adjustContentEdgeInsets
setNeedsLayout()
}
}
下面是一个如何使用imageEdgeInsets的简单示例
这将创建一个30x30的按钮，可点击区域增大10个像素(50x50)
var expandHittableAreaAmt : CGFloat = 10
var buttonWidth : CGFloat = 30
var button = UIButton.buttonWithType(UIButtonType.Custom) as UIButton
button.frame = CGRectMake(0, 0, buttonWidth+expandHittableAreaAmt, buttonWidth+expandHittableAreaAmt)
button.imageEdgeInsets = UIEdgeInsetsMake(expandHittableAreaAmt, expandHittableAreaAmt, expandHittableAreaAmt, expandHittableAreaAmt)
button.setImage(UIImage(named: "buttonImage"), forState: .Normal)
button.addTarget(self, action: "didTouchButton:", forControlEvents:.TouchUpInside)
我同意imageEdgeInsets和titleEdgeInsets的文档应该更好，但我想出了如何获得正确的定位而不求助于试验和错误。
这个问题的大意是，如果你想同时以文本和图像为中心。我们不希望图像和文本分别居中，我们希望图像和文本作为一个单独的实体放在一起。这实际上是UIButton已经做的，所以我们只需要调整间距。
CGFloat spacing = 10; // the amount of spacing to appear between image and title
tabBtn.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, spacing);
tabBtn.titleEdgeInsets = UIEdgeInsetsMake(0, spacing, 0, 0);
我还把它变成了UIButton的一个类别，这样它就很容易使用:
UIButton + h位置。
@interface UIButton(ImageTitleCentering)
-(void) centerButtonAndImageWithSpacing:(CGFloat)spacing;
@end
公元UIButton +位置。
@implementation UIButton(ImageTitleCentering)
-(void) centerButtonAndImageWithSpacing:(CGFloat)spacing {
self.imageEdgeInsets = UIEdgeInsetsMake(0, 0, 0, spacing);
self.titleEdgeInsets = UIEdgeInsetsMake(0, spacing, 0, 0);
}
@end
所以现在我要做的就是
[button centerButtonAndImageWithSpacing:10];
我每次都能得到我想要的。没有更多的混乱与边缘插入手动。
编辑:交换图像和文本
回复@Javal的评论
使用相同的机制，我们可以交换图像和文本。要完成交换，只需使用负间距，但也包括文本和图像的宽度。这将要求帧是已知的和布局已经执行。
[self.view layoutIfNeeded];
CGFloat flippedSpacing = -(desiredSpacing + button.currentImage.size.width + button.titleLabel.frame.size.width);
[button centerButtonAndImageWithSpacing:flippedSpacing];
当然，你可能会想要为此创建一个很好的方法，可能会添加第二个类别方法，这是留给读者的练习。
快4.倍
extension UIButton {
func centerTextAndImage(spacing: CGFloat) {
let insetAmount = spacing / 2
let writingDirection = UIApplication.shared.userInterfaceLayoutDirection
let factor: CGFloat = writingDirection == .leftToRight ? 1 : -1
self.imageEdgeInsets = UIEdgeInsets(top: 0, left: -insetAmount*factor, bottom: 0, right: insetAmount*factor)
self.titleEdgeInsets = UIEdgeInsets(top: 0, left: insetAmount*factor, bottom: 0, right: -insetAmount*factor)
self.contentEdgeInsets = UIEdgeInsets(top: 0, left: insetAmount, bottom: 0, right: insetAmount)
}
}
用法:
button.centerTextAndImage(spacing: 10.0)
