iOS button文字居中

新建一个UIButton的category

.h

@interface UIButton (QXTitleInCenter)
-(instancetype)init;
@end

.m

@implementation UIButton (QXTitleInCenter)
-(instancetype)init{
    self = [super init];
    self.contentEdgeInsets = UIEdgeInsetsMake(-(self.intrinsicContentSize.height) * 0.18（调节文字上下高度的，数值越大文字越靠上方）,0, 0, 0);
    return self;
}
@end

　　然后引入这个category，直接用UIButton就OK了