How would one present a UIViewController (from Storyboard say) that is modal, and slides up from the bottom of the presenting view controller. Requirements would be:
I do not use storyboards so I wrote it all out. You can copy paste this into a brand new project and run it to see it working.
Your PresentingController needs to conform to two things. The first protocol is: UIViewControllerTransitioningDelegate
which allows the controller to provide a custom presenter (namely itself in our case below). Whatever you return here (be it self, or some other object) needs to conform to UIViewControllerAnimatedTransitioning
and provide the custom animations. For this self-contained example, I chose the current viewController to be the presenter and animator.
Next, it needs to conform to protocol: UIViewControllerAnimatedTransitioning
which provides the custom animation for any presenting or dismissing controllers.
In other words, when we present or dismiss a viewController, animateTransition
from the UIViewControllerAnimatedTransitioning
protocol will be called to determine how the child controller should animate into perspective or dismiss from the view-port.
Example (With Transition Animation):
//
// ViewController.m
// SO
//
// Created by Brandon T on 2017-01-23.
// Copyright © 2017 XIO. All rights reserved.
//
#import "ViewController.h"
//Some view controller that will be presented modally.
//I have coloured it red.
@interface ModalController : UIViewController
@end
@implementation ModalController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor redColor];
}
@end
//The view controller that will present or dismiss some other view controller modally.
//I have coloured it white.
@interface ViewController () <UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning>
@property (nonatomic, assign) bool presentingModalController;
@property (nonnull, nonatomic, strong) ModalController *modalController;
@property (nonnull, nonatomic, strong) UIButton *button;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
//For this example, I add a button to present and dismiss the redViewController.
self.button = [[UIButton alloc] initWithFrame:CGRectMake(15, self.view.center.y - 100, self.view.frame.size.width - 30, 45)];
[self.button setTitle:@"Present" forState:UIControlStateNormal];
[self.button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[self.button setBackgroundColor:[UIColor lightGrayColor]];
[self.button.layer setCornerRadius:5.0];
[self.button addTarget:self action:@selector(onButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.button];
//Create the redViewController and set its transitioning delegate to self (this controller will be providing the animation and presenter).
//We also set the style to OverFullScreen because we don't want this controller to disappear.
//When a view controller is presented, the one that presented it usually disappears or gets removed from the hierarchy until the child is dismissed. In the case of alerts, or controllers that need to display OVER the current one, we need to set the modalPresentationStyle.
self.modalController = [[ModalController alloc] init];
self.modalController.transitioningDelegate = self;
self.modalController.modalPresentationStyle = UIModalPresentationOverFullScreen;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)onButtonClicked:(UIButton *)button {
if (self.modalController.view.window == nil) {
[self presentViewController:self.modalController animated:YES completion:nil];
[self.button setTitle:@"Dismiss" forState:UIControlStateNormal];
//not a good idea but meh.. I need to keep this example short.
[self.view.window addSubview:self.button];
}
else {
[self.modalController dismissViewControllerAnimated:YES completion:nil];
[self.button setTitle:@"Present" forState:UIControlStateNormal];
[self.view addSubview:self.button];
}
}
//Custom Animations and Presenters.
- (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source {
self.presentingModalController = true; //We are presenting the controller.
return self; //Who is animating it? We are.
}
- (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed {
self.presentingModalController = false; //We are dismissing the view controller.
return self; //Who animated it? We did.
}
//How fast should it present? I chose 0.5 seconds.
- (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext {
return 0.5;
}
//The actual animation code.
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext {
if (self.presentingModalController) {
//If we are presenting, we need to add the new controller's view as a sub-view.
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
//We need a starting frame for the animation.
CGRect startingFrame = transitionContext.containerView.bounds;
startingFrame.origin.y = startingFrame.size.height; //Starts from the bottom of the parent.
startingFrame.size.height = 100; //Has a height of 100.
//We need an end frame for the animation.
CGRect finalFrame = transitionContext.containerView.bounds;
finalFrame.origin.y = finalFrame.size.height - 100; //100 from the bottom of the parent.
finalFrame.size.height = 100; //Present with a size of 100 height.
//Add the controller's view as a subview of the context.
[transitionContext.containerView addSubview:toViewController.view];
[toViewController.view setFrame:startingFrame];
//Start animating from "startFrame" --> "endFrame" with 0.5 seconds duration and no delay. I chose easeIn style.
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
[toViewController.view setFrame:finalFrame];
} completion:^(BOOL finished) {
//We are finished animating, complete the transition!
[transitionContext completeTransition:YES];
}];
}
else {
//If we are dismissing the view controller, we need to animate it down the screen and then remove its view from the context.
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
//We only need one frame. This is the first frame. We are animating from "endFrame" --> "startingFrame" (backwards/reverse animation).
CGRect startingFrame = transitionContext.containerView.bounds;
startingFrame.origin.y = startingFrame.size.height; //Starts from the bottom of the parent.
startingFrame.size.height = 100; //Has a height of 100.
//Start the animation with 0.5 seconds duration and I chose easeOut style.
[UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{
[fromViewController.view setFrame:startingFrame];
} completion:^(BOOL finished) {
//Remove the view controller's view from the context and complete the transition!
[fromViewController.view removeFromSuperview];
[transitionContext completeTransition:YES];
}];
}
}
@end
Example (Without Transition Animation):
//
// ViewController.m
// SO2
//
// Created by Brandon Thomas on 2017-01-23.
// Copyright © 2017 XIO. All rights reserved.
//
#import "ViewController.h"
@interface ModalController : UIViewController
@end
@implementation ModalController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor redColor];
}
@end
@interface ViewController ()
@property (nonatomic, assign) bool presentingModalController;
@property (nonnull, nonatomic, strong) ModalController *modalController;
@property (nonnull, nonatomic, strong) UIButton *button;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
self.button = [[UIButton alloc] initWithFrame:CGRectMake(15, self.view.center.y - 100, self.view.frame.size.width - 30, 45)];
[self.button setTitle:@"Present" forState:UIControlStateNormal];
[self.button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[self.button setBackgroundColor:[UIColor lightGrayColor]];
[self.button.layer setCornerRadius:5.0];
[self.button addTarget:self action:@selector(onButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.button];
self.modalController = [[ModalController alloc] init];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)onButtonClicked:(UIButton *)button {
if (self.modalController.view.window == nil) {
//Present
CGRect startingFrame = self.view.bounds;
startingFrame.origin.y = startingFrame.size.height; //Starts from the bottom of the parent.
startingFrame.size.height = 100; //Has a height of 100.
CGRect finalFrame = self.view.bounds;
finalFrame.origin.y = finalFrame.size.height - 100; //100 from the bottom of the parent.
finalFrame.size.height = 100; //Present with a size of 100 height.
[self.modalController.view setFrame:startingFrame];
[self.modalController willMoveToParentViewController:self];
[self addChildViewController:self.modalController];
[self.view addSubview:self.modalController.view];
[self.modalController didMoveToParentViewController:self];
[UIView animateWithDuration:0.5 animations:^{
[self.modalController.view setFrame:finalFrame];
} completion:^(BOOL finished) {
}];
}
else {
//Dismiss
CGRect startingFrame = self.view.bounds;
startingFrame.origin.y = startingFrame.size.height; //Starts from the bottom of the parent.
startingFrame.size.height = 100; //Has a height of 100.
[UIView animateWithDuration:0.5 animations:^{
[self.modalController.view setFrame:startingFrame];
} completion:^(BOOL finished) {
[self.modalController.view removeFromSuperview];
[self.modalController willMoveToParentViewController:nil];
[self.modalController removeFromParentViewController];
[self.modalController didMoveToParentViewController:nil];
}];
}
}
@end