- UIImage *backButtonImage = [[UIImage imageNamed:@"Graphics/Shared/navigation_back_button.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
- [[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
- [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, backButtonImage.size.height*2) forBarMetrics:UIBarMetricsDefault];
但第二種方法只能自定義返回按鈕的背景和文字,如果要自定義上面的圖標則不行。所以使用leftBarButtonItem是最佳方式。
但是在iOS7系統中,自帶了可以通過右滑返回上一級頁面的手勢,如果僅僅修改leftBarButtonItem是無法響應這個手勢的。可以在pushViewController之後加入如下代碼:
- [_currentNav pushViewController:viewController animated:YES];
- //開啓iOS7的滑動返回效果
- if ([_currentNav respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
- _currentNav.interactivePopGestureRecognizer.delegate = nil;
- }
這樣即可完美解決iOS7上無法滑動的問題。
當然網上還有一種解決方法是在設置leftBarButtonItem之後加上:
- self.navigationItem.backBarButtonItem = backButton;
- self.navigationController.interactivePopGestureRecognizer.delegate = self;
但這兩行代碼必須放在viewWillAppear中,相比上一種方式要修改的代碼更多,因此建議使用上一種方式。
響應了iOS7的滑動返回手勢之後,我們還會發現一個問題,iOS7的滑動返回不會調用我們給leftBarButtonItem設置的回調,那麼返回的事件如何捕捉呢?可以通過以下代碼:
- - (void)viewWillDisappear: (BOOL)animated
- {
- [super viewWillDisappear: animated];
- if (![[self.navigationController viewControllers] containsObject: self])
- {
- // the view has been removed from the navigation stack, back is probably the cause
- // this will be slow with a large stack however.
- }
- }
至此,我們就完美解決了iOS7上使用leftBarButtonItem的滑動返回問題。
有朋友提出以上方式在多次滑動之後會導致界面假死,這裏再給出一種解決方案:
在所有除一級頁面之外的頁面的viewDidAppear和viewWillDisappear中加入以下代碼:
- - (void)viewWillDisappear:(BOOL)animated {
- [super viewWillDisappear:animated];
- //代理置空,否則會閃退
- if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
- self.navigationController.interactivePopGestureRecognizer.delegate = nil;
- }
- }
- - (void)viewDidAppear:(BOOL)animated {
- [super viewDidAppear:animated];
- //開啓iOS7的滑動返回效果
- if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
- //只有在二級頁面生效
- if ([self.navigationController.viewControllers count] == 2) {
- self.navigationController.interactivePopGestureRecognizer.delegate = self;
- }
- }
- }
在uinavigationcontroller的delegate中實現以下方法:
- - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
- //開啓滑動手勢
- if ([navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
- navigationController.interactivePopGestureRecognizer.enabled = YES;
- }
- }
在pushviewcontroller之前加入以下代碼:
- //在切換界面的過程中禁止滑動手勢,避免界面卡死
- if ([_currentNav respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
- _currentNav.interactivePopGestureRecognizer.enabled = NO;
- }
- [_currentNav pushViewController:viewController animated:YES];
即可在實現滑動返回的同時,避免界面卡死的問題。