78 lines
2.5 KiB
Objective-C
78 lines
2.5 KiB
Objective-C
//
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// Copyright (c) 2017 Open Whisper Systems. All rights reserved.
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//
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#import "OWSNavigationController.h"
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// We use a category to expose UINavigationController's private
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// UINavigationBarDelegate methods.
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@interface UINavigationController (OWSNavigationController) <UINavigationBarDelegate>
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@end
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#pragma mark -
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@interface OWSNavigationController () <UIGestureRecognizerDelegate>
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@end
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#pragma mark -
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@implementation OWSNavigationController
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- (void)viewDidLoad
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{
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[super viewDidLoad];
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self.interactivePopGestureRecognizer.delegate = self;
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}
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#pragma mark - UINavigationBarDelegate
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// All UINavigationController serve as the UINavigationBarDelegate for their navbar.
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// We override shouldPopItem: in order to cancel some back button presses - for example,
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// if a view has unsaved changes.
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- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item
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{
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OWSAssert(self.interactivePopGestureRecognizer.delegate == self);
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UIViewController *topViewController = self.topViewController;
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// wasBackButtonClicked is YES if the back button was pressed but not
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// if a back gesture was performed or if the view is popped programmatically.
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BOOL wasBackButtonClicked = topViewController.navigationItem == item;
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BOOL result = YES;
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if (wasBackButtonClicked) {
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if ([topViewController conformsToProtocol:@protocol(OWSNavigationView)]) {
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id<OWSNavigationView> navigationView = (id<OWSNavigationView>)topViewController;
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result = ![navigationView shouldCancelNavigationBack];
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}
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}
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// If we're not going to cancel the pop/back, we need to call the super
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// implementation since it has important side effects.
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if (result) {
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// NOTE: result might end up NO if the super implementation cancels the
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// the pop/back.
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result = [super navigationBar:navigationBar shouldPopItem:item];
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}
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return result;
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}
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#pragma mark - UIGestureRecognizerDelegate
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// We serve as the UIGestureRecognizerDelegate of the interactivePopGestureRecognizer
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// in order to cancel some "back" gestures - for example,
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// if a view has unsaved changes.
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- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
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{
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UIViewController *topViewController = self.topViewController;
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if ([topViewController conformsToProtocol:@protocol(OWSNavigationView)]) {
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id<OWSNavigationView> navigationView = (id<OWSNavigationView>)topViewController;
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return ![navigationView shouldCancelNavigationBack];
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} else {
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return YES;
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}
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}
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@end
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