简单实现控制器过渡动画

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自己实现控制器动画的方法,还是比较常见的. 这个是 UINavigationController的 Push 和 Dismiss 动画.

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//
//  GUIViewController.m
//  GUIControllerTransitionDemo
//
//  Created by Kenny on 8/29/15.
//  Copyright (c) 2015 Kenny. All rights reserved.
//

#import "GUIViewController.h"
#import "GUIHeader.h"
#import "GUISubViewController.h"
@interface GUIViewController ()
@property(nonatomic,weak)UIButton * pushButton;
@end

@implementation GUIViewController


#pragma mark -life cycle
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = GUIRandomColor;
    
    [self configPushButton];
    
}

#pragma mark -  delegate

#pragma mark -event response
-(void)pushNewController:(UIButton*)button{
    
    GUISubViewController * subVC = [GUISubViewController new];
    [self.navigationController pushViewController:subVC animated:YES];
}
#pragma mark -private methods
-(void)configPushButton{
    
    UIButton * pushButton = [UIButton new];
    [pushButton setTitle:@"push new controller button" forState:UIControlStateNormal];
    [pushButton setBackgroundColor:GUIRandomColor];
    [pushButton addTarget:self action:@selector(pushNewController:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:pushButton];
    self.pushButton = pushButton;
    
}

#pragma mark -getters and setters

#pragma mark - layout method
-(void)viewWillLayoutSubviews{
    [super viewWillLayoutSubviews];
    
    WSE(ws);
    [self.pushButton mas_makeConstraints:^(MASConstraintMaker *make) {
        make.size.mas_equalTo(CGSizeMake(GUIScreenWidth, 30));
        make.leading.mas_equalTo(ws.view);
        make.bottom.mas_equalTo(ws.view).with.offset(-100);
    }];
    
}

@end

然后在 AppDelegate中,为控制器包装一个导航控制器

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- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   
    GUIViewController * vc = [GUIViewController new];
    UINavigationController * nav = [[UINavigationController alloc]initWithRootViewController:vc];
    [application.delegate window].rootViewController = nav;
    
    return YES;
}

以上纯碎是简单的布局代码,和主题无关.

接下来进入正题:

在Apple的设计中, 实现自定义的切换动画,依赖的是协议中的方法,而不是具体的对象的具体方法,所以我们需要创建一个类

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#import <UIKit/UIKit.h>

@interface GUINavigationControllerDelegate : NSObject<UINavigationControllerDelegate>

@end

.m 文件

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#import "GUINavigationControllerDelegate.h"

@implementation GUINavigationControllerDelegate

/**

    当控制器切换的时候被调用,返回一个没有交互性的动画对象
 *
 *  @param navigationController 导航控制器
 *  @param operation            操作
 *  @param fromVC               当前控制器
 *  @param toVC                 目标控制器
 *
 *  @return 动画对象
 */
-(id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC{

    
    
    return nil;
}


@end

描述的非常明确了, 那么现在我们需要一个动画对象,这个对象需要遵守UIViewControllerAnimatedTransitioning协议

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//
//  GUIAnimator.h
//  GUIControllerTransitionDemo
//
//  Created by Kenny on 8/29/15.
//  Copyright (c) 2015 Kenny. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface GUIAnimator : NSObject <UIViewControllerAnimatedTransitioning>

@end

具体的实现

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//
//  GUIAnimator.m
//  GUIControllerTransitionDemo
//
//  Created by Kenny on 8/29/15.
//  Copyright (c) 2015 Kenny. All rights reserved.
//

#import "GUIAnimator.h"

@implementation GUIAnimator


/**
 *  动画执行时间
 *
 *  @param transitionContext 过渡动画上下文环境
 *
 *  @return 动画时长
 */
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 1;
}

/**
 *  具体动画行为
 *
 *  @param transitionContext 过渡动画上下文环境
 */
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    //将要切换到的控制器
    UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    //当前的控制器
    UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    //container view充当一个虚拟的superView的角色
    [[transitionContext containerView] addSubview:toViewController.view];
    
    //设置初始状态
    toViewController.view.alpha = 0;
    
    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        fromViewController.view.transform = CGAffineTransformMakeScale(0.1, 0.1);
        toViewController.view.alpha = 1;
    } completion:^(BOOL finished) {
        
         fromViewController.view.transform = CGAffineTransformIdentity;
        
        //通知系统,过渡已经完成
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
        
    }];
}

@end

注释已经写的非常清楚,在此不再赘述.