在实际开发中，UIBarButtonItem使用是比较多的，也经常需要自定义

//第一步继承系统的
@interface PRBarButtonItem : UIBarButtonItem

//在.m文件中咱们来实现自定义
#import "PRBarButtonItem.h"
@property (nonatomic, copy) dispatch_block_t callback;


//使用类方法
+ (PRBarButtonItem *)getWithTitle:(NSString *)title
                         callback:(dispatch_block_t)callback {
    return [[PRBarButtonItem alloc] initWithTitle:title callback:callback];
}
+ (PRBarButtonItem *)getWithImage:(UIImage *)normal
                         callback:(dispatch_block_t)callback {
    return [[PRBarButtonItem alloc] initWithImage:normal callback:callback];
}

- (instancetype)initWithTitle:(NSString *)title
                     callback:(dispatch_block_t)callback {
    PRBarButtonItem *item = [super initWithTitle:title style:UIBarButtonItemStylePlain target:self action:@selector(onClick:)];
    item.callback = callback;
    [item setTitleTextAttributes:@{NSFontAttributeName:SLGetMediumFontWithSize(17),NSForegroundColorAttributeName:SLTextColor_000000_80()} forState:UIControlStateNormal];
    [item setTitleTextAttributes:@{NSFontAttributeName:SLGetMediumFontWithSize(17),NSForegroundColorAttributeName:SLTextColor_000000_80()} forState:UIControlStateHighlighted];
    [item setTitleTextAttributes:@{NSFontAttributeName:SLGetMediumFontWithSize(17),NSForegroundColorAttributeName:SLTextColor_000000_40()} forState:UIControlStateDisabled];
    return item;
}

- (instancetype)initWithImage:(UIImage *)normal
                     callback:(dispatch_block_t)callback {
    PRBarButtonItem *item = [super initWithImage:[normal imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal] style:UIBarButtonItemStylePlain target:self action:@selector(onClick:)];
    item.callback = callback;
    return item;
}

- (void)onClick:(id)sender {
    if (self.callback) {
        self.callback();
    }
}

//带文字与图片 
+ (UIBarButtonItem *)getBarBtnItemWithTarget:(id)target withSEL:(SEL)sel  image:(NSString *)imageStr title:(NSString *)string{
    UIButton *someButton = [[UIButton alloc]init];
    [someButton setFrame:CGRectMake(0, 0, 22, 30)];
    [someButton setImage:[UIImage imageNamed:imageStr] forState:0];
    [someButton addTarget:target action:sel forControlEvents:UIControlEventTouchUpInside];
    [someButton setTitleColor: UIColorRGB(0x333333) forState:0];
    someButton.titleLabel.font = [UIFont systemFontOfSize:10];
    [someButton setTitle:string forState:0];
    someButton.titleEdgeInsets = UIEdgeInsetsMake(20, -7,0, 0);
    someButton.imageEdgeInsets = UIEdgeInsetsMake(-10, 22, 0, 0);
    
    UIBarButtonItem *item = [[UIBarButtonItem alloc]initWithCustomView:someButton];
    return item;
}

使用下

   PRBarButtonItem *shareBarItem = [PRBarButtonItem getWithImage:[UIImage imageNamed:""] callback:^{
        
    }];
    PRBarButtonItem *mailBarItem = [PRBarButtonItem getWithTitle:@"邮件" callback:^{
        [weakSelf operator];
    }];
    self.navigationItem.rightBarButtonItems = @[ shareBarItem, mailBarItem ];