先理解下面 （不理解也行，會調用就可以）
Button有兩個屬性：titleEdgeInsets和imageEdgeInsets，通過設置這兩個，就可以實現所有需要的Button的樣式，如：image在上、image在下、image在左、image在右。
titleEdgeInsets是titleLabel相對于其上下左右的inset，跟tableView的contentInset是類似的；
如果只有title，那titleLabel的上下左右都是相對于Button的；
如果只有image，那imageView的上下左右都是相對于Button的；
如果同時有image和label，那image的上下左是相對于Button的，右是相對于label的；
label的上下右是相對于Button的，左是相對于label的。
寫一個UIbutton的分類
.h文件
#importtypedef NS_ENUM(NSUInteger, MKButtonEdgeInsetsStyle) {
MKButtonEdgeInsetsStyleTop, // image在上，label在下
MKButtonEdgeInsetsStyleLeft, // image在左，label在右
MKButtonEdgeInsetsStyleBottom, // image在下，label在上
MKButtonEdgeInsetsStyleRight // image在右，label在左
};
@interface UIButton (ImageTitleSpacing)
/**
*? 設置button的titleLabel和imageView的布局樣式，及間距
*
*? @param style titleLabel和imageView的布局樣式
*? @param space titleLabel和imageView的間距
*/
- (void)layoutButtonWithEdgeInsetsStyle:(MKButtonEdgeInsetsStyle)style
imageTitleSpace:(CGFloat)space;
@end
.m 文件
#import "UIButton+ImageTitleSpacing.h"
@implementation UIButton (ImageTitleSpacing)
- (void)layoutButtonWithEdgeInsetsStyle:(MKButtonEdgeInsetsStyle)style
imageTitleSpace:(CGFloat)space
{
//? ? self.backgroundColor = [UIColor cyanColor];
/**
*? 前置知識點：titleEdgeInsets是title相對于其上下左右的inset，跟tableView的contentInset是類似的，
*? 如果只有title，那它上下左右都是相對于button的，image也是一樣；
*? 如果同時有image和label，那這時候image的上左下是相對于button，右邊是相對于label的；title的上右下是相對于button，左邊是相對于image的。
*/
// 1. 得到imageView和titleLabel的寬、高
CGFloat imageWith = [UIDevice currentDevice].systemVersion.floatValue >= 8.0?self.imageView.intrinsicContentSize.width:self.imageView.frame.size.width;
CGFloat imageHeight = [UIDevice currentDevice].systemVersion.floatValue >= 8.0?self.imageView.intrinsicContentSize.height:self.imageView.frame.size.height;
CGFloat labelWidth = 0.0;
CGFloat labelHeight = 0.0;
if ([UIDevice currentDevice].systemVersion.floatValue >= 8.0) {
// 由于iOS8中titleLabel的size為0，用下面的這種設置
labelWidth = self.titleLabel.intrinsicContentSize.width;
labelHeight = self.titleLabel.intrinsicContentSize.height;
} else {
labelWidth = self.titleLabel.frame.size.width;
labelHeight = self.titleLabel.frame.size.height;
}
// 2. 聲明全局的imageEdgeInsets和labelEdgeInsets
UIEdgeInsets imageEdgeInsets = UIEdgeInsetsZero;
UIEdgeInsets labelEdgeInsets = UIEdgeInsetsZero;
// 3. 根據style和space得到imageEdgeInsets和labelEdgeInsets的值
switch (style) {
case MKButtonEdgeInsetsStyleTop:
{
imageEdgeInsets = UIEdgeInsetsMake(-labelHeight-space/2.0, 0, 0, -labelWidth);
labelEdgeInsets = UIEdgeInsetsMake(0, -imageWith, -imageHeight-space/2.0, 0);
}
break;
case MKButtonEdgeInsetsStyleLeft:
{
imageEdgeInsets = UIEdgeInsetsMake(0, -space/2.0, 0, space/2.0);
labelEdgeInsets = UIEdgeInsetsMake(0, space/2.0, 0, -space/2.0);
}
break;
case MKButtonEdgeInsetsStyleBottom:
{
imageEdgeInsets = UIEdgeInsetsMake(0, 0, -labelHeight-space/2.0, -labelWidth);
labelEdgeInsets = UIEdgeInsetsMake(-imageHeight-space/2.0, -imageWith, 0, 0);
}
break;
case MKButtonEdgeInsetsStyleRight:
{
imageEdgeInsets = UIEdgeInsetsMake(0, labelWidth+space/2.0, 0, -labelWidth-space/2.0);
labelEdgeInsets = UIEdgeInsetsMake(0, -imageWith-space/2.0, 0, imageWith+space/2.0);
}
break;
default:
break;
}
// 4. 賦值
self.titleEdgeInsets = labelEdgeInsets;
self.imageEdgeInsets = imageEdgeInsets;
}
@end?
調用的話就很簡單了，以圖片在上，title在下為例子
MKButtonEdgeInsetsStyleTop, // image在上，label在下
MKButtonEdgeInsetsStyleLeft, // image在左，label在右
MKButtonEdgeInsetsStyleBottom, // image在下，label在上
MKButtonEdgeInsetsStyleRight // image在右，label在左
調用：
CGRect frame = CGRectMake(x, y, width, height);
UIButton *button = [[UIButton alloc] initWithFrame:frame];
[button layoutButtonWithEdgeInsetsStyle:MKButtonEdgeInsetsStyleTop imageTitleSpace:1.0];
