统一设置导航栏返回按钮

在开发中经常遇到需要统一设置到航条返回按钮的需求,如果在每次都设置一次明显不符合程序员做事风格,也不契合面向对象的封装思想,所以本文主要介绍在自定义导航控制器中,统一设置导航条,接下来介绍步骤:

• 自定义导航控制器,有没每一个子控制器都需要push为栈顶控制器,所以我们可以拦截导航控制器的push操作,在pus之前设置好导航条的返回按钮:

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{

    UIBarButtonItem *item = [UIBarButtonItem backItemWitnImage:[UIImage imageNamed:@"navigationButtonReturn"] selectImage:[UIImage imageNamed:@"navigationButtonReturnClick"] target:self action:@selector(back) title:@"返回"];
    viewController.navigationItem.leftBarButtonItem = item;
    [super pushViewController:viewController animated:animated];
}
- (void)back
{
    [self popViewControllerAnimated:YES];
}

• 但是这样是不行的,还需要判断当前控制器是否是跟控制器,通过判断当前控制器的子控制器是否大于0,如果大于0,则当前控制器不是跟控制器,此时才能设置返回按钮:

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{
    
    if (self.childViewControllers.count > 0) { // 非根控制器
        UIBarButtonItem *item = [UIBarButtonItem backItemWitnImage:[UIImage imageNamed:@"navigationButtonReturn"] selectImage:[UIImage imageNamed:@"navigationButtonReturnClick"] target:self action:@selector(back) title:@"返回"];
        viewController.navigationItem.leftBarButtonItem = item;
    }
    
    [super pushViewController:viewController animated:animated];
    
}
- (void)back
{
    [self popViewControllerAnimated:YES];
}

• 在上面的代码中的backItemWitnImage方法是对UIBarButtonItem的类方法进行封装,具体代码如下:

+ (UIBarButtonItem *)backItemWitnImage:(UIImage *)aImage selectImage:(UIImage *)aSelectImage target:(id)aTarget action:(SEL)aAction title:(NSString *)aTitle
{
    UIButton *btn = [[UIButton alloc] init];
    [btn setImage:aImage forState:UIControlStateNormal];
    [btn setImage:aSelectImage forState:UIControlStateHighlighted];
    [btn setTitle:aTitle forState:UIControlStateNormal];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateHighlighted];
    btn.contentEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);
    [btn sizeToFit];
    [btn addTarget:aTarget action:aAction forControlEvents:UIControlEventTouchUpInside];
    UIView *containerView = [[UIView alloc] initWithFrame:btn.bounds];
    [containerView addSubview:btn];
    return [[UIBarButtonItem alloc] initWithCustomView:containerView];
}

• 到此为止,所有的导航条非根控制器的返回按钮就一次性完成啦