此篇是被面试官问了才想起来写的
iOS7之后苹果导航控制器增加了一个左侧边缘右滑pop的手势,在非栈底的控制器里面,从左边右滑之后相当于出栈(pop)样子。
以下设置均在自定义的UINavigationController里操作
// 默认是YES 设置为NO左侧右滑手势就不可用了
self.interactivePopGestureRecognizer.enabled = YES;
也可以通过手势实现右滑
遵守UIGestureRecognizerDelegate协议,设置代理对象,实现一下代理方法即可:
-(void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; self.navigationController.interactivePopGestureRecognizer.delegate = self; } #pragma mark - UIGestureRecognizerDelegate - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer { if (self.viewControllers.count <= 1) { return NO; } return YES; }
个人的记忆方法:
backBarButtonItem设置下一个页面的返回按钮
leftBarButtonItem设置当前页面的返回按钮
项目中我们多数会自定义左侧返回按钮leftBarButtonItem,这个时候就算设置self.interactivePopGestureRecognizer.enabled = YES了或者实现手势的代理,左边缘的右滑动手势依旧会失效,例如如下代码写过之后,可以验证一下,失效了。
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated { if (self.viewControllers.count > 0) { /* 不是栈底控制器的时候隐藏tabbar */ viewController.hidesBottomBarWhenPushed = YES; // 设置左边的返回按钮leftBarButtonItem UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom]; backBtn.frame = CGRectMake(0, 0, 44, 44); backBtn.imageView.contentMode = UIViewContentModeCenter; backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 34); [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateNormal]; [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateHighlighted]; [backBtn addTarget: self action: @selector(back) forControlEvents: UIControlEventTouchUpInside]; UIBarButtonItem *backBtnItem=[[UIBarButtonItem alloc]initWithCustomView:backBtn]; viewController.navigationItem.leftBarButtonItem = backBtnItem; // 此处改为设置backBarButtonItem 右滑手势可以用,但自定义按钮不展示!! } [super pushViewController:viewController animated:animated]; }
按照如下方式设置backBarButtonItem或leftBarButtonItem,其他不做任何设置,右滑效果可用:
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated { if (self.viewControllers.count > 0) { /* 不是栈底控制器的时候隐藏tabbar */ viewController.hidesBottomBarWhenPushed = YES; } [self.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]]; [self.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]]; UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil]; self.navigationItem.backBarButtonItem = backItem; [super pushViewController:viewController animated:animated]; }
或者
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated { if (self.viewControllers.count > 0) { /* 不是栈底控制器的时候隐藏tabbar */ viewController.hidesBottomBarWhenPushed = YES; [self.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]]; [self.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]]; UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil]; self.navigationItem.leftBarButtonItem = backItem; } [super pushViewController:viewController animated:animated]; }
进过上面的反复测试:在自定义导航栏控制器中backBarButtonItem不能用View视图方法自定义,而leftBarButtonItem可以。
setBackIndicatorImage和setBackIndicatorTransitionMaskImage无论怎么设置都是只能看到setBackIndicatorImage的图片,找不到原因!!!
然后尝试直接在root视图控制器里面设置返回按钮backBarButtonItem的自定义view,右滑手势可用,但是设置leftBarButtonItem就不能使用右滑手势:
- (void)viewDidLoad { [super viewDidLoad]; // 设置左边的返回按钮 UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom]; backBtn.frame = CGRectMake(0, 0, 44, 44); backBtn.imageView.contentMode = UIViewContentModeCenter; backBtn.contentEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 34); [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateNormal]; [backBtn setImage:[UIImage imageNamed:@"rrrr"] forState:UIControlStateHighlighted]; [backBtn addTarget: self action: @selector(back) forControlEvents: UIControlEventTouchUpInside]; backBtn.backgroundColor = [UIColor redColor]; [self.navigationController.navigationBar setBackIndicatorImage:[UIImage imageNamed:@"rrrr"]]; [self.navigationController.navigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"rrrr"]]; UIBarButtonItem *backBtnItem=[[UIBarButtonItem alloc]initWithCustomView:backBtn]; backBtnItem.title = @""; self.navigationItem.backBarButtonItem = backBtnItem; }
以上是自己的验证,留有很多疑问,期待探讨解决。