OS原生是支持边缘滑动返回的,
但如QQ这种全屏全局右划返回显然用户体验更好,
实现起来其实也不麻烦, 但添加这个功能后可能会导致界面卡死问题,
网上的说法有很多而且不全, 其实导致这种问题会有很多种情况, 这里总结一下:
卡死的原因有三种:
1.在push或pop的过程中, 接收到新的滑动返回手势.
主要是界面切换快速操作可能出现
解决办法:
自定义UINavigationController,
在pushViewController/setViewControllers/popViewControllerAnimated/popToRootViewControllerAnimated中禁用手势
在代理方法- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated;中启用手势
2.在根控制器右划返回
在上面的代码中增加判断, 若子控制器数量为1, 禁用手势
3.点击navigationItem返回同时触发了手势.
一般在自定义了返回按钮出现, 例如:自定义button的手势为UIControlEventTouchDown, 全局右划返回手势作用view为self.interactivePopGestureRecognizer.view, 两者可能会同时触发
根据原因, 改变手势作用域
UIView *targetView = [[self.viewControllers lastObject] view];
或改变按钮事件触发条件
UIControlEventTouchUpInside
完整添加全局右滑返回且无BUG代码如下:
@interface LTNavigationController () <UIGestureRecognizerDelegate, UINavigationControllerDelegate>
/**
是否允许右滑返回
*/
@property (nonatomic, assign, getter=isBackGestureEnable) BOOL backGestureEnable;
@end
@implementation LTNavigationController
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationBar.backgroundColor = [UIColor whiteColor];
//设置全局右滑返回
[self setupRightPanReturn];
[self.navigationItem setHidesBackButton:YES];
self.delegate = self;
}
#pragma mark ---每次push之后生成返回按钮----
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{
if (self.viewControllers.count > 0) {
viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem BarButtonItemWithImg:@"back_black" highlightedImg:nil target:self action:@selector(popViewController)];
viewController.hidesBottomBarWhenPushed = YES;
viewController.edgesForExtendedLayout = UIRectEdgeNone;
viewController.automaticallyAdjustsScrollViewInsets = NO;
}
// push的时候禁用手势
if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.interactivePopGestureRecognizer.enabled = NO;
self.backGestureEnable = NO;
}
[super pushViewController:viewController animated:animated];
}
- (void)setViewControllers:(NSArray<UIViewController *> *)viewControllers animated:(BOOL)animated{
for (UIViewController *viewController in viewControllers) {
if (viewController != [viewControllers firstObject]) {
viewController.navigationItem.leftBarButtonItem = [UIBarButtonItem BarButtonItemWithImg:@"back_black" highlightedImg:nil target:self action:@selector(popViewController)];
viewController.hidesBottomBarWhenPushed = YES;
viewController.edgesForExtendedLayout = UIRectEdgeNone;
viewController.automaticallyAdjustsScrollViewInsets = NO;
}
}
// push的时候禁用手势
if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.interactivePopGestureRecognizer.enabled = NO;
self.backGestureEnable = NO;
}
[super setViewControllers:viewControllers animated:animated];
}
- (void)popViewController{
[self popViewControllerAnimated:YES];
}
- (UIViewController *)popViewControllerAnimated:(BOOL)animated{
// pop的时候禁用手势
if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.interactivePopGestureRecognizer.enabled = NO;
}
return [super popViewControllerAnimated:animated];
}
- (NSArray<UIViewController *> *)popToRootViewControllerAnimated:(BOOL)animated{
// pop的时候禁用手势
if ([self respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
self.interactivePopGestureRecognizer.enabled = NO;
}
return [super popToRootViewControllerAnimated:animated];
}
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
// push完成后的时候判断是否在根控制器启用手势
if ([navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
if ([navigationController.viewControllers count] == 1) {
navigationController.interactivePopGestureRecognizer.enabled = NO;
} else {
self.backGestureEnable = YES;
navigationController.interactivePopGestureRecognizer.enabled = YES;
}
}
}
#pragma mark ---处理全局右滑返回---
- (void)setupRightPanReturn{
// 获取系统自带滑动手势的target对象
id target = self.interactivePopGestureRecognizer.delegate;
// 获取返回方法
SEL handler = NSSelectorFromString(@"handleNavigationTransition:");
// 获取添加系统边缘触发手势的View
UIView *targetView = self.interactivePopGestureRecognizer.view;
// 创建pan手势 作用范围是全屏
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:target action:handler];
pan.delegate = self;
[targetView addGestureRecognizer:pan];
// 关闭边缘触发手势 防止和原有边缘手势冲突
[self.interactivePopGestureRecognizer setEnabled:NO];
}
// 什么时候调用：每次触发手势之前都会询问下代理，是否触发。
// 作用：拦截手势触发
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer{
//解决与左滑手势冲突
CGPoint translation = [gestureRecognizer translationInView:gestureRecognizer.view];
if (translation.x <= 0 || !self.isBackGestureEnable) {
return NO;
}
return self.childViewControllers.count == 1 ? NO : YES;
}
