iOS 模态转场动画一(初识)

1.转场动画在iOS开发中是非常重要的，现在有时间记录一下自己的学习过程。
2.模态转场过程中有几个重要的类非常重要，要实现自定义需要很好的了解它们。

UIViewControllerAnimatedTransitioning

// 自定义转场动画时间
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
    return 0.34f;
}


// 自定义转成动画具体实现
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
    
    // 到哪个vc
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    
    // 从哪个vc来
    UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    
    // 获取过渡时候的容器view
    UIView *contentView  = [transitionContext containerView];;
    
    //...
}

我们看到这个协议主要有两个方法，我们可以通过实现上面的方法来自定义实现转场的过程

UIViewControllerAnimatedTransitioning UIPercentDrivenInteractiveTransition

其中UIPercentDrivenInteractiveTransition主要是实现UIViewControllerAnimatedTransitioning协议主要涉及到的函数

//更新转场的进度
- (void)updateInteractiveTransition:(CGFloat)percentComplete;
//取消转场 
- (void)cancelInteractiveTransition;
//完成转场 
- (void)finishInteractiveTransition;

UIViewControllerTransitioningDelegate协议

// 设置继承自UIPresentationController 的自定义类的属性
- (UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented presentingViewController:(UIViewController *)presenting sourceViewController:(UIViewController *)source
{
    
    ZJPresentationController *presentVC = [[ZJPresentationController alloc]initWithPresentedViewController:presented presentingViewController:presenting];
    // 设置距离顶部的高度
    presentVC.height = STATUSBAR_H;
    
    return presentVC;
}

//控制器创建执行的动画（返回一个实现UIViewControllerAnimatedTransitioning协议的类）
- (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{
    
    //创建实现UIViewControllerAnimatedTransitioning协议的类（命名为AnimatedTransitioning）
    ZJPresentAnimation *animation = [[ZJPresentAnimation alloc] init];
    
    //将其状态改为出现
    animation.presented = YES;
    
    
    return animation;
}

// 控制器销毁执行的动画（返回一个实现UIViewControllerAnimatedTransitioning协议的类）
- (nullable id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed{

    ////创建实现UIViewControllerAnimatedTransitioning协议的类（命名为AnimatedTransitioning）
    ZJPresentAnimation *animation = [[ZJPresentAnimation alloc] init];

    //将其状态改为出现
    animation.presented = NO;
    NSLog(@"ZJPresentAnimation  %d",self.isRight);
    animation.isRight = self.isRight;
    return animation;
}

// 返回一个交互的对象（实现UIViewControllerInteractiveTransitioning协议的类）
-(id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator{
    return self.interactiveTransition;
}

可以实现自定转场的View样式

UIPresentationController

这个是系统自带的presentController，通过继承它可以实现一定的自定义

/即将出现调用
- (void)presentationTransitionWillBegin{
    [super presentationTransitionWillBegin];
    
    // 设置present视图的高度
    self.presentedView.frame = CGRectMake(0, _height, SCREEN_W, SCREEN_H);
    
    
    //    self.presentedView.backgroundColor = [UIColor whiteColor];
    self.presentedView.layer.cornerRadius = 7;
    // 添加到containerView 上
    [self.containerView addSubview:self.presentedView];
    
    
    //self.presentedView.layer.shadowRadius = _configuration.shadowRadius;
    //self.presentedView.layer.shadowOpacity = _configuration.shadowOpacity;
    
}

//出现调用
- (void)presentationTransitionDidEnd:(BOOL)completed{
    // 如果呈现没有完成，那就移除背景 View
    [super presentationTransitionDidEnd:completed];
   
}

//即将销毁调用
- (void)dismissalTransitionWillBegin{
    [super dismissalTransitionWillBegin];
    //self.containerView.backgroundColor = [UIColor redColor];
}

//销毁调用
- (void)dismissalTransitionDidEnd:(BOOL)completed{
    [super dismissalTransitionDidEnd:completed];
    if (completed) {
        //一旦要自定义动画，必须自己手动移除控制器
        [self.presentedView removeFromSuperview];
        
    }
    
}

UIViewControllerContextTransitioning

这个是很重要的一个协议，转场动画的上下文定义了转场时需要的元素，转场过程中的视图属性可以通过它获取

 // 到哪个vc
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    
    // 从哪个vc来
    UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    
    // 获取过渡时候的容器view
    UIView *contentView  = [transitionContext containerView];;

基本的改了我们已经又了一个了解,真正的实现一些功能还需要自己动手去写一些demo