动画转场和交互 tabBar、Navi、present

转场动画代码下载主要是tabBar、Navi、present ；其实它里面设置到了 主要涉及到了 动画、交互

1 . TabBar的切换

tabbarVC 里面本身含有 这个代理，这个时候我们定义一个 id类型的实例MyTransitionTabbarDelegateManager是现实里面的 动画和交互，让tabBarVC的delegate= MyTransitionTabbarDelegateManager对象

下面是代码实现

MyTransitionTabbarDelegateManager

#import "MyTransitionTabbarDelegateManager.h"
#import "MyTransitionTabBarAnimator.h"

@interface MyTransitionTabbarDelegateManager ()

@property (nonatomic,strong) UIPercentDrivenInteractiveTransition * interactiveTransition;

@end

@implementation MyTransitionTabbarDelegateManager

- (instancetype)init {
    
    if (self = [super init]) {
        
        self.interactiveTransition = [[UIPercentDrivenInteractiveTransition alloc]init];
        self.interactive = NO;
    }
    return self;
}


//切换动画
- (id)tabBarController:(UITabBarController *)tabBarController animationControllerForTransitionFromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC {
    
    NSInteger fromIndex = [tabBarController.viewControllers indexOfObject:fromVC];
    NSInteger toIndex   = [tabBarController.viewControllers indexOfObject:toVC];
    
    NSLog(@"from:%@;to:%@",fromVC,toVC);
    
    /* 确定方向 **/
    MyTransitionTabBarAnimator * animator = [[MyTransitionTabBarAnimator alloc]init];
    animator.isSlideToRight = fromIndex > toIndex?YES:NO;
    return animator;
}

//交互动画
- (id)tabBarController:(UITabBarController *)tabBarController interactionControllerForAnimationController:(id)animationController {
    
    if (self.interactive) {
        
        return self.interactiveTransition;
    }
    return nil;
}



@end

交互主要是 通过继承 UITabBarController 来获得一个子类 然后在里面添加手势

#import "MyScrollTabBarController.h"
#import "MyTransitionTabbarDelegateManager.h"

@interface MyScrollTabBarController ()

/* 处理 页面交换 和 动画 **/
@property (nonatomic,strong) MyTransitionTabbarDelegateManager * tabBarDelegateManager;

@end

@implementation MyScrollTabBarController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    self.tabBarDelegateManager = [[MyTransitionTabbarDelegateManager alloc]init];
    self.delegate = self.tabBarDelegateManager;
    
    UIPanGestureRecognizer * pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panAction:)];
    [self.view addGestureRecognizer:pan];
    
    NSInteger i = 0;
    for (UIViewController * vc in self.viewControllers) {
        
        NSLog(@"vc_%ld:%@",(long)i++,vc);
    }
    
}

#pragma mark - 私有方法
- (void)panAction:(UIPanGestureRecognizer *)pan {
    
    CGFloat translationX = [pan translationInView:self.view].x;
    CGFloat progress = fabs(translationX)/CGRectGetWidth(self.view.frame);
    switch (pan.state) {
        case UIGestureRecognizerStateBegan: {
            
            self.tabBarDelegateManager.interactive = YES;
            /* 
             *根据pan的速度 来判断 滑动的方向
             * 假设 两点（x1，0），（x2，0）；
             * 如果 x1 -》x2 滑动，如果向右边滑动 那么 x2 > x1;那么x1-x2<0;
             ***/
            CGFloat vX = [pan velocityInView:self.view].x;
            if (vX < 0) { // 说明是向右边滑动
                
                NSInteger tmpSelectedIndex = self.selectedIndex +1;
                if (tmpSelectedIndex < self.viewControllers.count) {
                    self.selectedIndex = tmpSelectedIndex;
                }
            } else {
                
                NSInteger tmpSelectedIndex = self.selectedIndex -1;
                if (tmpSelectedIndex >= 0) {
                    self.selectedIndex = tmpSelectedIndex;
                }
            }
            
            break;
        }
        case UIGestureRecognizerStateChanged: {
            
            /* 比例的更新**/
            [self.tabBarDelegateManager.interactiveTransition updateInteractiveTransition:progress];
            break;
        }
        case UIGestureRecognizerStateEnded:
        case UIGestureRecognizerStateCancelled: {
            
            if (progress > 0.5) {
                
                [self.tabBarDelegateManager.interactiveTransition finishInteractiveTransition];
            } else {
                [self.tabBarDelegateManager.interactiveTransition cancelInteractiveTransition];
            }
            self.tabBarDelegateManager.interactive = NO;
            break;
        }
        default: {
            
            break;
        }
           
    }
}





@end

里面的 动画MyTransitionTabBarAnimator 主要是实现动画时间和动画交互 ，接下来就是交互 我们通过 MyTransitionTabbarDelegateManager 里面的 UIPercentDrivenInteractiveTransition 主要是控制百分比、取消和完成

2 . 导航的切换

也是一样我们定义一个对象遵循 协议的一个对象MyNaiTransitionManager 来管理 里面的 动画 和 交互

3 . present的切换

也是一样，假设 vc1 =present =》vc2，这个时候需要实现 vc2的代理UIViewControllerTransitioningDelegate的实例 MyVCTransionManager ,其实我们可以要知道 在vc2 中我们才能获取到 vc1的view 和vc2的view