Line Messenger应用程序(日本的事实上的信使应用程序)中有一种行为,我试图模仿.
基本上,它们有一个模态视图控制器,里面有滚动视图.当滚动动作到达其内容的顶部时,视图控制器无缝切换到交互式解雇动画.此外,当手势将视图返回到屏幕顶部时,控制返回到滚动视图.
这是它的外观的GIF.
对于我的生活,我无法弄清楚他们是如何做到的.我尝试了几种不同的方法,但它们都失败了,而且我没有想法.谁能指出我正确的方向?
EDIT2
为了澄清,我想要模仿的行为不仅仅是向下拖动窗口.我能做到,没问题.
我想知道相同的滚动手势(不抬起手指)如何触发解雇转换,然后在将视图拖回原始位置后将控制权转移回滚动视图.
这是我无法弄清楚的部分.
结束EDIT2
EDIT1
这是我到目前为止所拥有的.我能够使用滚动视图委托方法添加处理常规解雇动画的目标选择器,但它仍然无法按预期工作.
我创建了一个UIViewController,其UIWebView作为属性.然后我把它放在UINavigationController中,它以模态方式呈现.
导航控制器使用动画/转换控制器进行常规交互式解雇(可以通过导航栏上的手势来完成).
从这里开始,一切正常,但无法从滚动视图触发解雇.
NavigationController.h
@interface NavigationController : UINavigationController <UIViewControllerTransitioningDelegate>
@property (nonatomic, strong) UIPanGestureRecognizer *gestureRecog;
- (void)handleGesture:(UIPanGestureRecognizer*)gestureRecognizer;
@end
NavigationController.m
#import "NavigationController.h"
#import "AnimationController.h"
#import "TransitionController.h"
@implementation NavigationController {
AnimationController *_animator;
TransitionController *_interactor;
}
- (instancetype)init {
self = [super init];
self.transitioningDelegate = self;
_animator = [[AnimationController alloc] init];
_interactor = [[TransitionController alloc] init];
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Set the gesture recognizer
self.gestureRecog = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
[self.view addGestureRecognizer:_gestureRecog];
}
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator {
if (animator == _animator && _interactor.hasStarted) {
return _interactor;
}
return nil;
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed {
if (dismissed == self || [self.viewControllers indexOfObject:dismissed] != NSNotFound) {
return _animator;
}
return nil;
}
- (void)handleGesture:(UIPanGestureRecognizer *)gestureRecog {
CGFloat threshold = 0.3f;
CGPoint translation = [gestureRecog translationInView:self.view];
CGFloat verticalMovement = translation.y / self.view.bounds.size.height;
CGFloat downwardMovement = fmaxf(verticalMovement, 0.0f);
CGFloat downwardMovementPercent = fminf(downwardMovement, 1.0f);
switch (gestureRecog.state) {
case UIGestureRecognizerStateBegan: {
_interactor.hasStarted = YES;
[self dismissViewControllerAnimated:YES completion:nil];
break;
}
case UIGestureRecognizerStateChanged: {
if (!_interactor.hasStarted) {
_interactor.hasStarted = YES;
[self dismissViewControllerAnimated:YES completion:nil];
}
_interactor.shouldFinish = downwardMovementPercent > threshold;
[_interactor updateInteractiveTransition:downwardMovementPercent];
break;
}
case UIGestureRecognizerStateCancelled: {
_interactor.hasStarted = NO;
[_interactor cancelInteractiveTransition];
break;
}
case UIGestureRecognizerStateEnded: {
_interactor.hasStarted = NO;
if (_interactor.shouldFinish) {
[_interactor finishInteractiveTransition];
} else {
[_interactor cancelInteractiveTransition];
}
break;
}
default: {
break;
}
}
}
@end
现在,我必须在滚动视图到达顶部时触发手势处理.所以,这就是我在视图控制器中所做的.
WebViewController.m
#import "WebViewController.h"
#import "NavigationController.h"
@interface WebViewController ()
@property (weak, nonatomic) IBOutlet UIWebView *webView;
@end
@implementation WebViewController {
BOOL _isHandlingPan;
CGPoint _topContentOffset;
}
- (void)viewDidLoad {
[super viewDidLoad];
[self.webView.scrollView setDelegate:self];
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if ((scrollView.panGestureRecognizer.state == UIGestureRecognizerStateBegan ||
scrollView.panGestureRecognizer.state == UIGestureRecognizerStateChanged) &&
! _isHandlingPan &&
scrollView.contentOffset.y < self.navigationController.navigationBar.translucent ? -64.0f : 0) {
NSLog(@"Adding scroll target");
_topContentOffset = CGPointMake(scrollView.contentOffset.x, self.navigationController.navigationBar.translucent ? -64.0f : 0);
_isHandlingPan = YES;
[scrollView.panGestureRecognizer addTarget:self action:@selector(handleGesture:)];
}
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
NSLog(@"Did End Dragging");
if (_isHandlingPan) {
NSLog(@"Removing action");
_isHandlingPan = NO;
[scrollView.panGestureRecognizer removeTarget:self action:@selector(handleGesture:)];
}
}
- (void)handleGesture:(UIPanGestureRecognizer*)gestureRecognizer {
[(NavigationController*)self.navigationController handleGesture:gestureRecognizer];
}
这仍然无法正常工作.即使在解雇动画期间,滚动视图仍然会以手势滚动.
结束EDIT1
最佳答案 这是一个自定义的交互式过渡.
首先,您需要设置UIViewController的transitioningDelegate
id<UIViewControllerTransitioningDelegate> transitioningDelegate;
然后将这两种方法实现
//Asks your delegate for the transition animator object to use when dismissing a view controller.
- animationControllerForDismissedController:
//Asks your delegate for the interactive animator object to use when dismissing a view controller.
- interactionControllerForDismissal:
当拖动到顶部时,您开始转换,您可以使用UIPercentDrivenInteractiveTransition来控制滚动期间的进度.
您也可以参考ZFDragableModalTransition的源代码
ZFDragableModalTransition的图片