ios - Navigation pop view when swipe right like Instagram iPhone app.How i achieve this?

Question

I want to pop a view when swipe right on screen or it's work like back button of navigation bar.

I am using:

self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

This single line of code for pop navigation view and it's a work for me but when i swipe form middle of screen this will not work like Instagram iPhone app.

Here i give a one screen of Instagram app in that you can see the Example of swipe right pop navigation view:

Answer 1

Apple's automatic implementation of the "swipe right to pop VC" only works for the left ~20 points of the screen. This way, they make sure they don't mess with your app's functionalities. Imagine you have a UIScrollView on screen, and you can't swipe right because it keeps poping VCs out. This wouldn't be nice.

Apple says here :

interactivePopGestureRecognizer

The gesture recognizer responsible for popping the top view controller off the navigation stack. (read-only)

@property(nonatomic, readonly) UIGestureRecognizer *interactivePopGestureRecognizer

The navigation controller installs this gesture recognizer on its view and uses it to pop the topmost view controller off the navigation stack. You can use this property to retrieve the gesture recognizer and tie it to the behavior of other gesture recognizers in your user interface. When tying your gesture recognizers together, make sure they recognize their gestures simultaneously to ensure that your gesture recognizers are given a chance to handle the event.

So you will have to implement your own UIGestureRecognizer, and tie its behavior to the interactivePopGestureRecognizer of your UIViewController.

---

Edit :

Here is a solution I built. You can implement your own transition conforming to the UIViewControllerAnimatedTransitioning delegate. This solution works, but has not been thoroughly tested.

You will get an interactive sliding transition to pop your ViewControllers. You can slide to right from anywhere in the view.

Known issue : if you start the pan and stop before half the width of the view, the transition is canceled (expected behavior). During this process, the views reset to their original frames. Their is a visual glitch during this animation.

The classes of the example are the following :

UINavigationController > ViewController > SecondViewController

CustomPopTransition.h :

#import <Foundation/Foundation.h>

@interface CustomPopTransition : NSObject <UIViewControllerAnimatedTransitioning>

@end

CustomPopTransition.m :

#import "CustomPopTransition.h"
#import "SecondViewController.h"
#import "ViewController.h"

@implementation CustomPopTransition

- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext {
    return 0.3;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {

    SecondViewController *fromViewController = (SecondViewController*)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    ViewController *toViewController = (ViewController*)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

    UIView *containerView = [transitionContext containerView];
    [containerView addSubview:toViewController.view];
    [containerView bringSubviewToFront:fromViewController.view];

    // Setup the initial view states
    toViewController.view.frame = [transitionContext finalFrameForViewController:toViewController];

    [UIView animateWithDuration:0.3 animations:^{

        fromViewController.view.frame = CGRectMake(toViewController.view.frame.size.width, fromViewController.view.frame.origin.y, fromViewController.view.frame.size.width, fromViewController.view.frame.size.height);

    } completion:^(BOOL finished) {

        // Declare that we've finished
        [transitionContext completeTransition:!transitionContext.transitionWasCancelled];
    }];

}

@end

SecondViewController.h :

#import <UIKit/UIKit.h>

@interface SecondViewController : UIViewController <UINavigationControllerDelegate>

@end

SecondViewController.m :

#import "SecondViewController.h"
#import "ViewController.h"
#import "CustomPopTransition.h"

@interface SecondViewController ()

@property (nonatomic, strong) UIPercentDrivenInteractiveTransition *interactivePopTransition;

@end

@implementation SecondViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.navigationController.delegate = self;

    UIPanGestureRecognizer *popRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePopRecognizer:)];
    [self.view addGestureRecognizer:popRecognizer];
}

-(void)viewDidDisappear:(BOOL)animated {

    [super viewDidDisappear:animated];

    // Stop being the navigation controller's delegate
    if (self.navigationController.delegate == self) {
        self.navigationController.delegate = nil;
    }
}

- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC {

    // Check if we're transitioning from this view controller to a DSLSecondViewController
    if (fromVC == self && [toVC isKindOfClass:[ViewController class]]) {
        return [[CustomPopTransition alloc] init];
    }
    else {
        return nil;
    }
}

- (id<UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController interactionControllerForAnimationController:(id<UIViewControllerAnimatedTransitioning>)animationController {

    // Check if this is for our custom transition
    if ([animationController isKindOfClass:[CustomPopTransition class]]) {
        return self.interactivePopTransition;
    }
    else {
        return nil;
    }
}

- (void)handlePopRecognizer:(UIPanGestureRecognizer*)recognizer {

    // Calculate how far the user has dragged across the view
    CGFloat progress = [recognizer translationInView:self.view].x / (self.view.bounds.size.width * 1.0);
    progress = MIN(1.0, MAX(0.0, progress));

    if (recognizer.state == UIGestureRecognizerStateBegan) {
        NSLog(@"began");
        // Create a interactive transition and pop the view controller
        self.interactivePopTransition = [[UIPercentDrivenInteractiveTransition alloc] init];
        [self.navigationController popViewControllerAnimated:YES];
    }
    else if (recognizer.state == UIGestureRecognizerStateChanged) {
        NSLog(@"changed");
        // Update the interactive transition's progress
        [self.interactivePopTransition updateInteractiveTransition:progress];
    }
    else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {
        NSLog(@"ended/cancelled");
        // Finish or cancel the interactive transition
        if (progress > 0.5) {
            [self.interactivePopTransition finishInteractiveTransition];
        }
        else {
            [self.interactivePopTransition cancelInteractiveTransition];
        }

        self.interactivePopTransition = nil;
    }
}

@end