理清思路

||转场动画可以理解为一个对象,在这个对象里封装了一个动画.具体的我们跟着代码走

!.实现协议的方法

在一个继承NSObject的类中遵守协议实现代理

 #import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface PushTranstion : NSObject<UIViewControllerAnimatedTransitioning>
@property (nonatomic,strong)id transitationContext; 
@end

在这里遵守一个协议,声明一个属性变量全局操作

方法实现

//  PushTranstion.m
//  专场动画
//
//  Created by MAc on 16/5/27.
//  Copyright © 2016年 MAc. All rights reserved.
//

#import "PushTranstion.h"

@implementation PushTranstion
//转场动画实现的时间  这里设置的长便于观察
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
    return 4.0;
}
//设置动画效果
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
      _transitationContext=transitionContext;
    UIViewController *fromViewController = [transitionContext  viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController * toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIView * containerView = [transitionContext containerView];
    [containerView addSubview:fromViewController.view];
    [containerView addSubview:toViewController.view];
    
    /* 创建一个矩阵The identity transform: [1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1]. */

    CATransform3D  transform = CATransform3DIdentity;
//设置影射效果,是转场显得更真实
    transform.m34 = - 1/1500.0;
    toViewController.view.layer.transform =transform;
    //设置锚点:(边长为1,锚点指的是(0.5,0.5))
    toViewController.view.layer.anchorPoint = CGPointMake(1.0, 0.5);
    
    //设置锚点之后,试图左移动了0.5个View.With,重写设置position(锚点在俯视图中的位置,)
    /* The position in the superlayer that the anchor point of the layer's
     * bounds rect is aligned to. Defaults to the zero point. Animatable. */
    toViewController.view.layer.position= CGPointMake(CGRectGetMaxX(fromViewController.view.frame), CGRectGetMidY(fromViewController.view.frame));
    CABasicAnimation * animation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.y"];
    animation.duration = [self transitionDuration:transitionContext];
    //从pi/2开始旋转
    animation.fromValue = @(M_PI_2);
    animation.toValue=@(0);
    animation.delegate =self;
    [toViewController.view.layer addAnimation:animation forKey:@"rotateAnimation"];
    
}
//动画结束的时候通知上下文
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
    if (flag) {
        //[_transitationContext finishInteractiveTransition];
       [_transitationContext completeTransition:YES];
    }
}
@end

转场对象设定好了,下面就去vc中实现转场动画

在这之前,要理解一件事.转场动画的两个界面是放在一个容器里面的,即前面提到的containerView中放着的两个view,一个fromView 一个toView

其实就是toView旋转铺在fromView上的操作 ,接着看vc中的代码

//
//  ViewController.m
//  专场动画
//
//  Created by MAc on 16/5/27.
//  Copyright © 2016年 MAc. All rights reserved.
//

#import "ViewController.h"
#include "PushTranstion.h"
//#import "PushTransitionTest.h"
@interface ViewController ()<UINavigationControllerDelegate>{
    //和手势搭配使用,单独使用会报不知名错
    UIPercentDrivenInteractiveTransition * interaction;
}
 

@end

@implementation ViewController
- (IBAction)push:(id)sender {
    // interaction = [[UIPercentDrivenInteractiveTransition alloc] init];
    [self performSegueWithIdentifier:@"PushToS" sender:nil];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    
}
-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:YES];
    self.navigationController.delegate = self;
}
 
- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    self.navigationController.delegate = nil;
}
 
- (nullable id <UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                                            animationControllerForOperation:(UINavigationControllerOperation)operation
                                                         fromViewController:(UIViewController *)fromVC
                                                           toViewController:(UIViewController *)toVC
{
    if (operation == UINavigationControllerOperationPush) {
        return [[PushTranstion alloc] init];
    }
    return nil;
}
 
@end

这样,这个转场动画的效果就实现了,后面还有对吴彦祖的视频的分析讲解,不清楚的地方相互交流,欢迎留言!

追寻最真