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Simple back button handling for Apportable using UIResponder
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| // | |
| // UIResponder+BackButton.h | |
| // | |
| // Created by Nick Richards | |
| // | |
| #import <UIKit/UIKit.h> | |
| typedef void(^UIResponderBackButtonHandler)(void); | |
| @interface UIResponder (BackButton) | |
| -(void) setBackButtonHandler:(UIResponderBackButtonHandler) handler; | |
| @end |
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| // | |
| // UIResponder+BackButton.m | |
| // | |
| // Created by Nick Richards | |
| // | |
| // USAGE | |
| // * For use with Apportable platform | |
| // * Add UIResponder+BackButton.m and .h to the application's Xcode project | |
| // * Customize UIResponder+BackButton.m's "AppDelegate" references to match the UIApplication's delegate class name | |
| // * Alter the inheritance of the AppDelegate to derive from UIResponder to permit routing of back button events to the new back button handler blocks | |
| // * Add [self setBackButtonHandler:^{ ... }] in desired UIViewControllers and UIViews to handle back button events according to the UIResponder chain | |
| // | |
| // // Example back button handling in view controller. Can also set in e.g viewDidLoad or AppDelegate. | |
| // - (void)viewWillAppear:(BOOL)animated | |
| // { | |
| // [super viewWillAppear:animated]; | |
| // __block __typeof__(self) weakSelf = self; | |
| // [self setBackButtonHandler:^{ | |
| // [weakSelf dismissViewControllerAnimated:YES completion:nil]; | |
| // }]; | |
| // } | |
| #import <objc/runtime.h> | |
| #import <UIKit/UIKit.h> | |
| #import <UIKit/UIEvent.h> | |
| #import "UIResponder+BackButton.h" | |
| #import "AppDelegate.h" // CUSTOMIZE ME (#1) | |
| #ifndef APPORTABLE | |
| // FIXME enables building on non-Apportable targets | |
| //const NSUInteger UIEventButtonCodeBack = NSUIntegerMax; | |
| #endif | |
| static int UIResponderBackButtonHandlerKey; | |
| @implementation UIResponder (BackButton) | |
| -(void) setBackButtonHandler:(UIResponderBackButtonHandler) handler { | |
| objc_setAssociatedObject(self, &UIResponderBackButtonHandlerKey, [handler copy] , OBJC_ASSOCIATION_RETAIN_NONATOMIC); | |
| } | |
| -(UIResponderBackButtonHandler) backButtonHandler { | |
| return objc_getAssociatedObject(self, &UIResponderBackButtonHandlerKey); | |
| } | |
| -(BOOL) searchAndInvokeBackButtonHandler { | |
| UIResponderBackButtonHandler handler = [self backButtonHandler]; | |
| if (handler) { | |
| handler(); | |
| return YES; | |
| } | |
| return [self.nextResponder searchAndInvokeBackButtonHandler]; | |
| } | |
| @end | |
| @interface UIView (BackButton) | |
| -(BOOL) _sendBackButtonEvent; | |
| @end | |
| @implementation UIView (BackButton) | |
| -(UIViewController *) currentViewController { | |
| UIResponder *current = self.nextResponder; | |
| do { | |
| if([current isKindOfClass: [UIViewController class]]) { | |
| return (UIViewController *)current; | |
| } | |
| } while( (current = current.nextResponder) ); | |
| return nil; | |
| } | |
| // FIXME navigate more than two levels deep into a navigation controller hierarchy | |
| -(BOOL) _sendBackButtonEvent { | |
| NSArray *subviews = self.subviews; | |
| // Walk down the view tree | |
| for (UIView *view in subviews.reverseObjectEnumerator) { | |
| if ([view _sendBackButtonEvent]) { | |
| return YES; | |
| } | |
| } | |
| // Leaves and Branches both fall through | |
| if ([self superview]) { | |
| // Majority of nodes | |
| // Handle only with this view's, or its view controller's handler | |
| if ([self backButtonHandler]) { | |
| [self backButtonHandler](); | |
| return YES; | |
| } | |
| // Find the associated view controller | |
| UIViewController *controller = [self currentViewController]; | |
| if ([controller backButtonHandler]) { | |
| [controller backButtonHandler](); | |
| return YES; | |
| } | |
| // Navigates two levels deep into a navigation controller hierarchy | |
| if ([controller isKindOfClass:[UINavigationController class]]) { | |
| UINavigationController *navController = (UINavigationController*)controller; | |
| UIViewController *childController = [[navController viewControllers] lastObject]; | |
| // Find any presenting view controller | |
| UIViewController *targetController = childController; | |
| UIViewController *presentedViewController = [childController presentedViewController]; | |
| if (nil != presentedViewController) { | |
| targetController = presentedViewController; | |
| } | |
| if ([targetController backButtonHandler]) { | |
| [targetController backButtonHandler](); | |
| return YES; | |
| } | |
| }; | |
| } else { | |
| // Special case for root view | |
| return [self searchAndInvokeBackButtonHandler]; | |
| } | |
| return NO; | |
| } | |
| @end | |
| @interface AppDelegate (BackButton) // CUSTOMIZE ME (#2) | |
| @end | |
| @implementation AppDelegate (BackButton) // CUSTOMIZE ME (#3) | |
| - (void)buttonUpWithEvent:(UIEvent *)event { | |
| #if defined(APPORTABLE) | |
| if ([event buttonCode] == UIEventButtonCodeBack) | |
| [[UIApplication sharedApplication].keyWindow _sendBackButtonEvent]; | |
| #endif | |
| } | |
| @end | |
| @interface UIAlertView (BackButton) | |
| @end | |
| @implementation UIAlertView (BackButton) | |
| -(void) _platformShow { | |
| __block __typeof__(self) weakSelf = self; | |
| [self setBackButtonHandler:^{ | |
| [weakSelf dismissWithClickedButtonIndex:0 animated:YES]; | |
| }]; | |
| } | |
| @end | |
| @interface UIActionSheet (BackButton) | |
| @end | |
| @implementation UIActionSheet (BackButton) | |
| -(void) _platformShow { | |
| __block __typeof__(self) weakSelf = self; | |
| [self setBackButtonHandler:^{ | |
| if ([weakSelf.delegate respondsToSelector:@selector(alertView:clickedButtonAtIndex:)]) { | |
| [(id<UIAlertViewDelegate>)weakSelf.delegate alertView:(id)weakSelf clickedButtonAtIndex:weakSelf.cancelButtonIndex]; | |
| } | |
| [weakSelf dismissWithClickedButtonIndex:weakSelf.cancelButtonIndex animated:YES]; | |
| }]; | |
| } | |
| @end |
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