iOS7中的ViewController切換

實現控制器之間的切換:(實現彈跳的效果:)

先實現一個自定義的相似的modal present的效果，與普通效果不一樣的是，咱們但願modalVC出現的時候不要那麼乏味的就簡單從底部出現，而是帶有一個彈性效果:

 

ViewController的實現:

 

 1 //
 2 //  ViewController.m
 3 //  ViewController切換
 4 //
 5 //  Created by 思 彭 on 16/3/29.
 6 //  Copyright © 2016年 combanc. All rights reserved.
 7 //
 8 
 9 #import "ViewController.h"
10 #import "ModalViewController.h"
11 #import "BouncePresentAnimation.h"
12 
13 
14 
15 @interface ViewController ()<ModalViewControllerDelegate,UIViewControllerTransitioningDelegate>
16 
17 @property (nonatomic, strong) BouncePresentAnimation *presentAnimation;
18 
19 
20 @end
21 
22 @implementation ViewController
23 
24 
25 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
26 {
27     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
28     if (self) {
29         
30         _presentAnimation = [BouncePresentAnimation new];
31         
32     }
33     return self;
34 }
35 
36 
37 
38 - (void)viewDidLoad {
39     [super viewDidLoad];
40     self.view.backgroundColor = [UIColor lightGrayColor];
41     
42     UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
43     button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
44     button.backgroundColor = [UIColor redColor];
45     [button setTitle:@"Dismiss me" forState:UIControlStateNormal];
46     [button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
47     [self.view addSubview:button];
48     
49     
50 }
51 
52 
53 // 按鈕點擊觸發方法
54 
55 -(void) buttonClicked:(id)sender
56 {
57     ModalViewController *mvc = [[ModalViewController alloc] init];
58     
59     mvc.delegate = self;
60     mvc.transitioningDelegate = self;
61     
62     //模態到ModalViewController
63     [self presentViewController:mvc animated:YES completion:nil];
64 }
65 
66 
67 //實現協議方法
68 
69 -(void)modalViewControllerDidClickedDismissButton:(ModalViewController *)viewController
70 {
71     [self dismissViewControllerAnimated:YES completion:nil];
72 }
73 
74 
75 
76 - (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
77 {
78     return self.presentAnimation;
79 }
80 
81 
82 
83 
84 - (void)didReceiveMemoryWarning {
85     [super didReceiveMemoryWarning];
86     // Dispose of any resources that can be recreated.
87 }
88 
89 @end

 

ModalViewController的實現:

 1 #import <UIKit/UIKit.h>
 2 
 3 @class ModalViewController;
 4 
 5 @protocol  ModalViewControllerDelegate<NSObject>
 6 
 7 
 8 -(void) modalViewControllerDidClickedDismissButton:(ModalViewController *)viewController;
 9 
10 
11 @end
12 
13 
14 @interface ModalViewController : UIViewController
15 
16 @property (nonatomic, weak) id<ModalViewControllerDelegate> delegate;
17 
18 @end

 1 //
 2 //  ModalViewController.m
 3 //  ViewController切換
 4 //
 5 //  Created by 思 彭 on 16/3/29.
 6 //  Copyright © 2016年 combanc. All rights reserved.
 7 //
 8 
 9 #import "ModalViewController.h"
10 
11 @implementation ModalViewController
12 
13 
14 - (void)viewDidLoad{
15 
16     [super viewDidLoad];
17     
18     // Do any additional setup after loading the view.
19     self.view.backgroundColor = [UIColor grayColor];
20     
21     UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
22     button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
23     button.backgroundColor = [UIColor greenColor];
24     [button setTitle:@"Dismiss me" forState:UIControlStateNormal];
25     [button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
26     [self.view addSubview:button];
27     
28 }
29 
30 // 按鈕點擊觸發方法
31 
32 -(void) buttonClicked:(id)sender
33 {
34     if (self.delegate && [self.delegate respondsToSelector:@selector(modalViewControllerDidClickedDismissButton:)]) {
35         [self.delegate modalViewControllerDidClickedDismissButton:self];
36     }
37 }
38 
39     
40 
41 @end

BouncePresentAnimation的代碼實現:

 

 1 #import <Foundation/Foundation.h>
 2 #import <UIKit/UIKit.h>
 3 
 4 
 5 // 在遵照協議UIViewControllerAnimatedTransitioning記得導入UIKit框架
 6 
 7 @interface BouncePresentAnimation : NSObject<UIViewControllerAnimatedTransitioning>
 8 
 9 
10 @end

 1 //
 2 //  BouncePresentAnimation.m
 3 //  ViewController切換
 4 //
 5 //  Created by 思 彭 on 16/3/29.
 6 //  Copyright © 2016年 combanc. All rights reserved.
 7 //
 8 
 9 #import "BouncePresentAnimation.h"
10 
11 @implementation BouncePresentAnimation
12 
13 
14 
15 #pragma mark - UIViewControllerAnimatedTransitioning代理
16 
17 - (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext{
18     
19     return .6f;
20     
21     
22 }
23 
24 
25 - (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext{
26     
27     // 1. Get controllers from transition context
28     UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
29     
30     // 2. Set init frame for toVC
31     CGRect screenBounds = [[UIScreen mainScreen] bounds];
32     CGRect finalFrame = [transitionContext finalFrameForViewController:toVC];
33     toVC.view.frame = CGRectOffset(finalFrame, 0, screenBounds.size.height);
34     
35     // 3. Add toVC's view to containerView
36     UIView *containerView = [transitionContext containerView];
37     [containerView addSubview:toVC.view];
38     
39     // 4. Do animate now
40     NSTimeInterval duration = [self transitionDuration:transitionContext];
41     [UIView animateWithDuration:duration
42                           delay:0.0
43          usingSpringWithDamping:0.6
44           initialSpringVelocity:0.0
45                         options:UIViewAnimationOptionCurveLinear
46                      animations:^{
47                          toVC.view.frame = finalFrame;
48                      } completion:^(BOOL finished) {
49                          // 5. Tell context that we completed.
50                          [transitionContext completeTransition:YES];
51                      }];
52     
53     
54 }
55 
56 
57 @end

解釋一下這個實現：

 

1.咱們首先須要獲得參與切換的兩個ViewController的信息，使用context的方法拿到它們的參照；

 

2.對於要呈現的VC，咱們但願它從屏幕下方出現，所以將初始位置設置到屏幕下邊緣；

 

3.將view添加到containerView中；

 

4.開始動畫。這裏的動畫時間長度和切換時間長度一致，都爲0.8s。usingSpringWithDamping的UIView動畫API是iOS7新加入的，描述了一個模擬彈簧動做的動畫曲線，咱們在這裏只作使用，更多信息能夠參看相關文檔；（順便多說一句，iOS7中對UIView動畫添加了一個很方便的Category，UIViewKeyframeAnimations。使用其中方法能夠爲UIView動畫添加關鍵幀動畫）

 

5.在動畫結束後咱們必須向context報告VC切換完成，是否成功（在這裏的動畫切換中，沒有失敗的可能性，所以直接pass一個YES過去）。系統在接收到這個消息後，將對VC狀態進行維護。