iOS＋转场动画学习

转场动画学习中...TransitionDemo代码

效果

实现自定义的转场动画(只涉及自定义动画，不管手势驱动)

涉及三个协议：
UIViewControllerAnimatedTransitioning(动画处理)
UIViewControllerTransitioningDelegate(页面modal时指定相关动画代理)
UINavigationControllerDelegate(页面push/pop时指定相关动画代理)

1. 自定义动画类, 遵守协议UIViewControllerAnimatedTransitioning并实现相关动画(类CircleSpreadAnimation)

    #pragma mark - UIViewControllerAnimatedTransitioning
   
    /** 动画时长 */
    - (NSTimeInterval)transitionDuration:(nullable id )transitionContext{
        
        return self.duration;
    }
   
    /** 动画:步骤2、4不能省  */
    - (void)animateTransition:(id )transitionContext{
        
        // 1.获取ToVC
        UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
        
        // 2.将ToVC's View 添加到containerView中
        UIView *containerView = [transitionContext containerView];
        [containerView addSubview:toVC.view];
        
        // 3.圆形扩散动画，对ToVC's View进行动画处理
        CGSize size = containerView.frame.size;
        CGPoint beginP = CGPointMake(size.width*0.5, size.height);//中下
        switch (self.direction) {
            case CircleSpreadAnimationDirectionDown:
                beginP = CGPointMake(size.width*0.5, 0);//中上
                break;
                
            case CircleSpreadAnimationDirectionRight:
                beginP = CGPointMake(0, size.height*0.5);//左中
                break;
                
            case CircleSpreadAnimationDirectionLeft:
                beginP = CGPointMake(size.width, size.height*0.5);//右中
                break;
                
            default:
                break;
        }
   
        UIBezierPath *beginPath = [UIBezierPath bezierPathWithArcCenter:beginP radius:1 startAngle:0 endAngle:M_PI*2 clockwise:YES];
   
        CGFloat endX = beginP.x>size.width*0.5? beginP.x : size.width - beginP.x;
        CGFloat endY = beginP.y>size.height*0.5? beginP.y : size.height - beginP.y;
        CGFloat endRadius = sqrt(pow(endX, 2) + pow(endY, 2));
        UIBezierPath *endPath = [UIBezierPath bezierPathWithArcCenter:beginP radius:endRadius startAngle:0 endAngle:M_PI*2 clockwise:YES];
   
        CAShapeLayer *maskLayer = [CAShapeLayer layer];
        maskLayer.path = endPath.CGPath;
        toVC.view.layer.mask = maskLayer;
   
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"];
        animation.fromValue = (__bridge id )(beginPath.CGPath);
        animation.toValue = (__bridge id )(endPath.CGPath);
        animation.duration = self.duration;
        animation.delegate = self;
        [animation setValue:transitionContext forKey:@"transitionContext"];
        [maskLayer addAnimation:animation forKey:@"pushPath"];
    }
   
    -(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
        
        id transitionContext = [anim valueForKey:@"transitionContext"];
        // 4.告知完成
        [transitionContext completeTransition:YES];
    }
   

2. 自定义转场动画：(相关类FromViewController、ToViewController）

   1. 修改转场代理（为简化，直接让FromViewController成为转场代理）
      /** 从FromViewController 跳转到 ToViewController，使FromViewController成为转场代理 */
      - (void)toBtnClicked{

           ToViewController *toVC =  [[ToViewController alloc] init];
           
           // 1.更换动画过渡代理
           // self是FromViewController
           if (self.push) {
               // push时修改navigationController的代理
               self.navigationController.delegate = self;
               [self.navigationController pushViewController:toVC animated:YES];
           } else {
               // present时修改transitioningDelegate的代理
               toVC.transitioningDelegate = self;
               [self presentViewController:toVC animated:YES completion:nil];
           }
       }
      

   2. 实现代理，返回相关动画代理实例；

   3. modal : FromViewController遵守协议
      UIViewControllerTransitioningDelegate

         #pragma mark - UIViewControllerTransitioningDelegate
      
         // 2.modal方式：指定自定义的动画代理
         - (nullable id )animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{
          
          // present的时候的动画代理
          return self.circleAnimationUP;
          
          // nil代表使用默认过渡效果
          //return nil;
         }
      
         - (id)animationControllerForDismissedController:(UIViewController *)dismissed{
          
          // dismiss的时候的动画代理
          return self.circleAnimationDown;
          
          // nil代表使用默认过渡效果
          //return nil;
        }
      

   4. push/pop：FromViewController遵守协议
      UINavigationControllerDelegate

          #pragma mark - UINavigationControllerDelegate
      
          // 2.push/pop方式：指定自定义的动画代理
          - (id)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC{
              
              // 设置自定义动画
              id animation = nil;//使用默认效果
              
              if (operation == UINavigationControllerOperationPush) {
                  // push的时候的动画代理
                  animation = self.circleAnimationLeft;
              } else if (operation == UINavigationControllerOperationPop) {
                  // pop的时候的动画代理
                  animation = self.circleAnimationRight;
              }
              
              // 3.以便在pop到当前页面的时候恢复默认转场效果
              if (toVC == self) {
                  self.navigationController.delegate = nil;
              }
              
              return animation;
          }
      

参考
WWDC 2013 Session笔记 - iOS7中的ViewController切换
几句代码快速集成自定义转场效果+ 全手势驱动