封装UIBarButtonItem

/**
 *  创建一个item
 *  
 *  @param target    点击item后调用哪个对象的方法
 *  @param action    点击item后调用target的哪个方法
 *  @param image     图片
 *  @param highImage 高亮的图片
 *
 *  @return 创建完的item
 */
+ (UIBarButtonItem *)itemWithTarget:(id)target action:(SEL)action image:(NSString *)image highImage:(NSString *)highImage
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    [btn addTarget:target action:action forControlEvents:UIControlEventTouchUpInside];
    // 设置图片
    [btn setBackgroundImage:[UIImage imageNamed:image] forState:UIControlStateNormal];
    [btn setBackgroundImage:[UIImage imageNamed:highImage] forState:UIControlStateHighlighted];
    // 设置尺寸
    btn.size = btn.currentBackgroundImage.size;
    return [[UIBarButtonItem alloc] initWithCustomView:btn];
}

+ (UIBarButtonItem *)itemWithTarget:(id)target action:(SEL)action image:(NSString *)image highImage:(NSString *)highImage;

self.navigationItem.leftBarButtonItem = [UIBarButtonItem itemWithTarget:self action:@selector(sweep) image:@"navigationbar_pop" highImage:@"navigationbar_pop"];
    self.navigationItem.rightBarButtonItem = [UIBarButtonItem itemWithTarget:self action:@selector(message) image:@"navigationbar_friendsearch" highImage:@"navigationbar_friendsearch"];
注意：我这里把高亮图片和默认图片设置为了同一张图片，如果公司需求没有要求设置高亮，你就和我一样设置同一张图片就可，如果你要设置为空的话，会报一个警告，不过没有关系，我们可以给他设置一个空格@“ ”就把图片设置为@+ “ + 空格 +”就可以了

UIBarButtonItem *item = [UIBarButtonItem appearance];
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    dict[NSForegroundColorAttributeName] = [UIColor redColor];
    [item setTitleTextAttributes:dict forState:UIControlStateNormal];  
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"哈哈" style:UIBarButtonItemStylePlain target:self action:@selector(click)];
}