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ElasticTransition ObjC Version

This is the Objective-C Version of Elastic Transition written in Swift by lkzhao https://github.com/lkzhao/ElasticTransition

A UIKit custom modal transition that simulates an elastic drag. Written in Objective-C. Feel free to contribute!

Installation

ElasticTransitionObjC is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "ElasticTransitionObjC"

Usage

First of all, in your view controller, create an instance of ElasticTransition

- (void)viewDidLoad {

//...

    ElasticTransition *transition = [[ElasticTransition alloc] init];

    // customization
    transition.sticky           = YES;
    transition.showShadow       = YES;
    transition.panThreshold     = 0.4;
    transition.transformType    = TRANSLATEMID;

//...

}

• Navigation Controller Delegate
• Modal
• Interactive Present
• Interactive Dismiss

Use as navigation controller's delegate

Simply assign the transition to your navigation controller's delegate

    navigationController.delegate =transition

Present as modal

In prepareForSegue, assign the transition to be the transitioningDelegate of the destinationViewController. Also, dont forget to set the modalPresentationStyle to UIModalPresentationCustom

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{

    segue.destinationViewController.transitioningDelegate = transition;
    segue.destinationViewController.modalPresentationStyle = UIModalPresentationCustom;

}

In your modal view controller .h implement the ElasticMenuTransitionDelegate

@interface MenuViewController: UIViewController <ElasticMenuTransitionDelegate>

@end

Then in your .m file synthesize the property and provide the contentLength value

@implementation MenuViewController

@synthesize contentLength;

-(id)initWithCoder:(NSCoder *)aDecoder{

    self = [super initWithCoder:aDecoder];

    if (self) {

        self.contentLength = 320.0;

        //...
    }

    return self;
}

@end

Interactive transition for modal transition

First, construct a pan gesture recognizer

UIPanGestureRecognizer *panGR = [[UIPanGestureRecognizer alloc] init];
[panGR addTarget:self action:@selector(handlePan:)];
[self.view addGestureRecognizer:panGR];

Then implement your gesture handler and fo the following:

-(void)handlePan:(UIPanGestureRecognizer*)pan{

    if (pan.state == UIGestureRecognizerStateBegan){
        // Here, you can do one of two things
        // 1. show a viewcontroller directly
        UIViewController *nextViewController = // construct your VC ...
        [transition startInteractiveTransitionFromViewController:self ToViewController:nextViewController GestureRecognizer:pan];
        // 2. perform a segue
        [transition startInteractiveTransitionFromViewController:self SegueIdentifier:@"menu" GestureRecognizer:pan];
    }else{
        [transition updateInteractiveTransitionWithGestureRecognizer:pan];
    }
}

Interactive transition for dismissing the modal

1. Implement ElasticMenuTransitionDelegate in your modal view controller and set

    self.dismissByBackgroundTouch   = YES;
    self.dismissByBackgroundDrag    = YES;
    self.dismissByForegroundDrag    = YES;

2. Or use your own panGestureRecognizer and call dissmissInteractiveTransition in your handler

-(void)handlePan:(UIPanGestureRecognizer*)pan{
    if (pan.state == UIGestureRecognizerStateBegan){
        [transition dismissInteractiveTransitionViewController:vc GestureRecognizer:pan Completion:nil];
    }else{
        [transition updateInteractiveTransitionWithGestureRecognizer:pan];
    }
}

Authors

lkzhao, taglia3, the.taglia3@gmail.com

License

ElasticTransition is available under the MIT license. See the LICENSE file for more info.