如何在iOS 7中仅为一个视图禁用后退手势
我正在尝试使用下面的一组代码禁用视图控制器的后退手势。
在FirstViewController.m中，我设置了interactivePopGestureRecognizer的委托
- (void) viewWillLoad {
// Other stuff..
self.navigationController.interactivePopGestureRecognizer.delegate = self;
}然后实现<UIGestureRecognizerDelegate>方法并返回NO。
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
return NO;
}在dealloc中，我将委托设置为nil。(我在某处读到过，在iOS 7中，您必须手动将委托设置为零)
- (void)dealloc {
self.navigationController.delegate = nil;
self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}这在FirstViewController中有效。但当我将SecondViewController推到这一点时，手势也不起作用。如何仅在FirstViewController中禁用手势？
同样，当我弹出FirstViewController转到RootViewController，然后再次尝试推送FirstViewController时，我得到对象已释放错误：
[FirstViewController gestureRecognizer:shouldReceiveTouch:]: message sent to deallocated instance 0x14ed0280除了将委托设置为零之外，我还需要做什么？或者我把它放在了错误的地方？
回答 5
Stack Overflow用户
发布于 2013-10-01 13:38:57
在您的FirstViewController中尝试以下未经测试的代码：
-(void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
}
-(void) viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
self.navigationController.interactivePopGestureRecognizer.enabled = YES;
}Stack Overflow用户
发布于 2013-10-16 11:46:40
我最初把这些答案放在接受的答案下面的评论中，但我觉得这需要作为一个答案来说，以获得更多的可见性。
通常情况下，你会发现被接受的答案不起作用。这是因为可以在将视图添加到导航控制器的视图层次结构之前调用viewWillAppear:，因此self.navigationController将为nil。因此，在某些情况下可能不会禁用interactivePopGestureRecognizer。您最好在viewDidAppear:中调用它。
下面是可以工作的代码(假设视图控制器被正确地添加到导航控制器的视图层次结构中)：
Objective-C
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[[[self navigationController] interactivePopGestureRecognizer] setEnabled:NO];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[[self navigationController] interactivePopGestureRecognizer] setEnabled:YES];
}斯威夫特
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
navigationController?.interactivePopGestureRecognizer?.isEnabled = false
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
navigationController?.interactivePopGestureRecognizer?.isEnabled = true
}Stack Overflow用户
发布于 2014-04-25 03:04:36
我发现将手势设置为仅禁用并不总是有效。它确实起作用了，但对我来说，它只是在我使用一次回手势之后才起作用的。第二次它不会触发回击手势。此外，正如John Rogers所说，使用viewDidAppear和viewWillAppear作为navigationController是很重要的，否则将是零。
我的修复方法是委托手势并实现shouldbegin方法以返回NO：
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
// Disable iOS 7 back gesture
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// Enable iOS 7 back gesture
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.navigationController.interactivePopGestureRecognizer.enabled = YES;
self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
return NO;
}https://stackoverflow.com/questions/19108601
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