(具体解释都写在了Demo里面的注释)
1. //
2. // HMTMainViewController.m
3. // UIScrollView
4. //
5. // Created by HMT on 14-6-25.
6. // Copyright (c) 2014年 humingtao. All rights reserved.
7. //
8.
9. #import "HMTMainViewController.h"
10. #import "HMTFirstViewController.h"
11. #import "HMTSecondViewController.h"
12. #import "HMTThirdViewController.h"
13.
14. @interface HMTMainViewController () <UIScrollViewDelegate>
15.
16. @property (nonatomic ,strong) HMTThirdViewController *thirdVC;
17. @property (nonatomic ,strong) HMTFirstViewController *firstVC;
18. @property (nonatomic ,strong) HMTSecondViewController *secondVC;
19.
20. @property (nonatomic ,strong) UIViewController *currentVC;
21.
22. @property (nonatomic ,strong) UIScrollView *headScrollView; // 顶部滚动视图
23.
24. @property (nonatomic ,strong) NSArray *headArray;
25.
26. @end
27.
28. @implementation HMTMainViewController
29.
30. - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
31. {
32. self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
33. if (self) {
34. // Custom initialization
35. }
36. return self;
37. }
38.
39. - (void)viewDidLoad
40. {
41. super viewDidLoad];
42. // Do any additional setup after loading the view.
43.
44. self.navigationItem.title = @"网易新闻Demo";
45.
46. self.headArray = @[@"头条",@"娱乐",@"体育",@"财经",@"科技",@"NBA",@"手机"];
47. /**
48. * automaticallyAdjustsScrollViewInsets 又被这个属性坑了
49. * 我"UI高级"里面一篇文章着重讲了它,大家可以去看看
50. */
51. self.automaticallyAdjustsScrollViewInsets = NO;
52. self.headScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, 320, 40)];
53. self.headScrollView.backgroundColor = [UIColor purpleColor];
54. self.headScrollView.contentSize = CGSizeMake(560, 0);
55. self.headScrollView.bounces = NO;
56. self.headScrollView.pagingEnabled = YES;
57. self.view addSubview:self.headScrollView];
58. for (int i = 0; i < [self.headArray count]; i++) {
59.
60. UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
61. .frame = CGRectMake(0 + i*80, 0, 80, 40);
62. setTitle:[self.headArray objectAtIndex:i] forState:UIControlStateNormal];
63. .tag = i + 100;
64. addTarget:self action:@selector(didClickHeadButtonAction:) forControlEvents:UIControlEventTouchUpInside];
65. self.headScrollView addSubview:button];
66.
67. }
68.
69. /*
70. 苹果新的API增加了addChildViewController方法，并且希望我们在使用addSubview时，同时调用[self addChildViewController:child]方法将sub view对应的viewController也加到当前ViewController的管理中。
71. 对于那些当前暂时不需要显示的subview，只通过addChildViewController把subViewController加进去；需要显示时再调用transitionFromViewController方法。将其添加进入底层的ViewController中。
72. 这样做的好处：
73.
74. 1.无疑，对页面中的逻辑更加分明了。相应的View对应相应的ViewController。
75. 2.当某个子View没有显示时，将不会被Load，减少了内存的使用。
76. 3.当内存紧张时，没有Load的View将被首先释放，优化了程序的内存释放机制。
77. */
78.
79. /**
80. * 在iOS5中，ViewController中新添加了下面几个方法：
81. * addChildViewController:
82. * removeFromParentViewController
83. * transitionFromViewController:toViewController:duration:options:animations:completion:
84. * willMoveToParentViewController:
85. * didMoveToParentViewController:
86. */
87. self.firstVC = [[HMTFirstViewController alloc] init];
88. self.firstVC.view setFrame:CGRectMake(0, 104, 320, 464)];
89. self addChildViewController:_firstVC];
90.
91. self.secondVC = [[HMTSecondViewController alloc] init];
92. self.secondVC.view setFrame:CGRectMake(0, 104, 320, 464)];
93.
94. self.thirdVC = [[HMTThirdViewController alloc] init];
95. self.thirdVC.view setFrame:CGRectMake(0, 104, 320, 464)];
96.
97. // 默认,第一个视图(你会发现,全程就这一个用了addSubview)
98. self.view addSubview:self.firstVC.view];
99. self.currentVC = self.firstVC;
100.
101. }
102.
103. - (void)didClickHeadButtonAction:(UIButton *)button
104. {
105. // 点击处于当前页面的按钮,直接跳出
106. if ((self.currentVC == self.firstVC && button.tag == 100)||(self.currentVC == self.secondVC && button.tag == 101.)) {
107. return;
108. else{
109.
110. // 展示2个,其余一样,自行补全噢
111. switch (button.tag) {
112. case 100:
113. self replaceController:self.currentVC newController:self.firstVC];
114. break;
115. case 101:
116. self replaceController:self.currentVC newController:self.secondVC];
117. break;
118. case 102:
119. //.......
120. break;
121. case 103:
122. //.......
123. break;
124. case 104:
125. //.......
126. break;
127. case 105:
128. //.......
129. break;
130. case 106:
131. //.......
132. break;
133. //.......
134. default:
135. break;
136. }
137. }
138.
139. }
140.
141. // 切换各个标签内容
142. - (void)replaceController:(UIViewController *)oldController newController:(UIViewController *)newController
143. {
144. /**
145. * 着重介绍一下它
146. * transitionFromViewController:toViewController:duration:options:animations:completion:
147. * fromViewController 当前显示在父视图控制器中的子视图控制器
148. * toViewController 将要显示的姿势图控制器
149. * duration 动画时间(这个属性,old friend 了 O(∩_∩)O)
150. * options 动画效果(渐变,从下往上等等,具体查看API)
151. * animations 转换过程中得动画
152. * completion 转换完成
153. */
154.
155. self addChildViewController:newController];
156. self transitionFromViewController:oldController toViewController:newController duration:2.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:nil completion:^(BOOL finished) {
157.
158. if (finished) {
159.
160. didMoveToParentViewController:self];
161. willMoveToParentViewController:nil];
162. removeFromParentViewController];
163. self.currentVC = newController;
164.
165. else{
166.
167. self.currentVC = oldController;
168.
169. }
170. }];
171. }
