iOS 7 自定义Back按钮 与 Pop interactive gesture 问题

转载自:  http://www.cnblogs.com/angzn/p/3696901.html

1、自定义Back按钮

iOS中很多时候我们都会自定义返回按钮，也是一件easy的事，类似如下：

 // 返回按钮
 1 - (void)showNavBackButton
 2 {
 3     UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
 4     [backButton addTarget:self action:@selector(backButtonAction:)
 5          forControlEvents:UIControlEventTouchUpInside];
 6     [backButton setBackgroundImage:[UIImage imageNamed:@"00_back_button"]
 7                           forState:UIControlStateNormal];
 8     [backButton setTitle:kLoc(@"Back") forState:UIControlStateNormal];
 9     [backButton setTitleEdgeInsets:UIEdgeInsetsMake(0, 5, 1, 0)];
10     backButton.titleLabel.font = kMediumFont(12);
11     backButton.frame = CGRectMake(0, 0, 51, 31);
12     self.navigationItem.leftBarButtonItem
13     = [[UIBarButtonItem alloc] initWithCustomView:backButton];
14 }

但是，这样在iOS7下Pop interactive gesture就不好使了。

这里 Here 有一个解决方法。

但是，测试发现在栈中推入一个controller后，快速向左平滑，将会引起崩溃。

查看崩溃日志，发现如下信息：

nested pop animation can result in corrupted navigation bar

2、解决Pop interactive gesture问题

优化的解决方案是简单的让NavigationController自己成为响应的接受者，最好用一个UINavigationController的子类。

1)在过渡的时候禁用interactivePopGestureRecognizer

2)当新的视图控制器加载完成后再启用，建议使用UINavigationController的子类操作

 // 自定义NavigationController
 1 @interface DCBaseNavigationController ()
 2 <
 3 UINavigationControllerDelegate,
 4 UIGestureRecognizerDelegate
 5 >
 6 @end
 7 
 8 @implementation DCBaseNavigationController
 9 
10 - (void)dealloc
11 {
12     self.interactivePopGestureRecognizer.delegate = nil;
13     self.delegate = nil;
14     
15     [super dealloc];
16 }
17 
18 #pragma mark - View lifecycle
19 
20 - (void)viewDidLoad
21 {
22     [super viewDidLoad];
23     // Do any additional setup after loading the view.
24     
25     if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
26         self.interactivePopGestureRecognizer.delegate = self;
27         self.delegate = self;
28     }
29 }
30 
31 - (void)didReceiveMemoryWarning
32 {
33     [super didReceiveMemoryWarning];
34     // Dispose of any resources that can be recreated.
35 }
36 
37 #pragma mark - Override
38 
39 - (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
40 {
41     // Hijack the push method to disable the gesture
42     if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
43         self.interactivePopGestureRecognizer.enabled = NO;
44     }
45     
46     [super pushViewController:viewController animated:animated];
47 }
48 
49 #pragma mark - UINavigationControllerDelegate
50 
51 - (void)navigationController:(UINavigationController *)navigationController
52        didShowViewController:(UIViewController *)viewController
53                     animated:(BOOL)animate
54 {
55     if ([navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
56         navigationController.interactivePopGestureRecognizer.enabled = YES;
57     }
58 }
59 
60 @end

 

3、Pop interactive gesture冲突，造成页面假死问题

我遇到的情况是，Push/Pop页面时，没有立即得到想要的效果，页面没有显出出来，NavigationController的didShowViewController:回调方法也没有调用。

页面布局情况是这样的：视图A，有一个Pan手势；视图B是TabBarController，其ViewControllers都是NavigationController。视图B是视图A的子视图。

后来找到原因是：navigationController的interactive pop手势与视图A的pan手势冲突。

具体原因是：rootViewController加载时，调用了didShowViewController:，设置interactivePopGestureRecognizer可用，其实我们并不需要在root的时候也触发这个手势。所以稍加优化如下：

 // 优化
 1 - (void)navigationController:(UINavigationController *)navigationController
 2        didShowViewController:(UIViewController *)viewController
 3                     animated:(BOOL)animate
 4 {
 5     if ([navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
 6         //if ([[navigationController.viewControllers firstObject] isEqual:viewController]) {
 7         if ([navigationController.viewControllers count] == 1) {
 8             // Disable the interactive pop gesture in the rootViewController of navigationController
 9             navigationController.interactivePopGestureRecognizer.enabled = NO;
10         } else {
11             // Enable the interactive pop gesture
12             navigationController.interactivePopGestureRecognizer.enabled = YES;
13         }
14     }
15 }

当前显示的是root时，设置interactivePopGestureRecognizer不可用，非root时设置interactivePopGestureRecognizer可用。

参考文章：http://keighl.com/post/ios7-interactive-pop-gesture-custom-back-button/