参考：

调整UIButton中的imageView和titleLabel的相对位置

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通过调整子控件的【边缘内边距】edgeInset来实现：imageEdgeInsets 、titleEdgeInsets

这种方式感觉不好调，调起来貌似不太准

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还是建议自定义按钮的方式，而且其他地方用起来也方便

h文件

#import <UIKit/UIKit.h>

@interface Btn : UIButton

@end

m文件

#import "Btn.h"

@implementation Btn

// 自定义按钮的frame方法
- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.titleLabel.textAlignment = NSTextAlignmentCenter;
        // 字体不分状态
        self.titleLabel.font = [UIFont systemFontOfSize:14];
        self.titleLabel.lineBreakMode = NSLineBreakByTruncatingTail;
        [self setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
        self.backgroundColor = [UIColor clearColor];

    }
    return self ;
}



- (void)layoutSubviews
{
    [super layoutSubviews];
    
    CGFloat buttonW = self.frame.size.width;
    CGFloat buttonH = self.frame.size.height;
    
    CGFloat imageW = 20;
    self.titleLabel.frame = CGRectMake(0, 0,buttonW - imageW + 5, buttonH);
    self.imageView.frame = CGRectMake(self.titleLabel.frame.size.width - 5, 5, imageW, imageW);

}

@end

使用

    _btn = [[Btn alloc] initWithFrame:CGRectMake(0, 0, left_width, 28)];