为了方便快速实现导航栏左右键的操作，特意封装了一个类
#import "UIBarButtonItem+Extension.h"
@implementation UIBarButtonItem (Extension)
+(UIBarButtonItem *)itemWithTarget:(id)target action :(SEL)action image:(UIImage *)image{
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setBackgroundImage:image forState:UIControlStateNormal];
[button addTarget:target action:action forControlEvents:UIControlEventTouchUpInside];
button.size = button.currentBackgroundImage.size;
return [[UIBarButtonItem alloc] initWithCustomView:button];
}
+(UIBarButtonItem *)itemWithTarget:(id)target action :(SEL)action title:(NSString *)title{
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
//button.backgroundColor = [UIColor blueColor];
[button setTitle:title forState: UIControlStateNormal];
[button addTarget:target action:action forControlEvents:UIControlEventTouchUpInside];
CGRect frame = [title boundingRectWithSize:CGSizeMake(50, 50) options: NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:18]} context:nil];
button.size = frame.size;
return [[UIBarButtonItem alloc] initWithCustomView:button];
}
