105使用滚动的方式查看图片

效果如下：

ViewController.h

1 #import <UIKit/UIKit.h>
2
3 @interface ViewController : UIViewController<UIScrollViewDelegate>
4 @property (strong, nonatomic) UIScrollView *scrVCustom;
5
6 @end

ViewController.m

 1 #import "ViewController.h"
 2
 3 @interface ViewController ()
 4 - (void)layoutUI;
 5 - (void)scaleToBigDidPush:(UIButton *)sender;
 6 - (void)scaleToSmallDidPush:(UIButton *)sender;
 7 @end
 8
 9 @implementation ViewController
10
11 - (void)viewDidLoad {
12     [super viewDidLoad];
13
14     [self layoutUI];
15 }
16
17 - (void)didReceiveMemoryWarning {
18     [super didReceiveMemoryWarning];
19     // Dispose of any resources that can be recreated.
20 }
21
22 - (void)layoutUI {
23     _scrVCustom = [[UIScrollView alloc] initWithFrame:CGRectInset(self.view.bounds, 0, 0)];
24     //设置滚动视图_scrVCustom中的图片
25     UIImageView *imgVCustom = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"CoolMan.jpg"]];
26     [_scrVCustom addSubview:imgVCustom];
27
28     _scrVCustom.contentSize = imgVCustom.bounds.size;
29     [self.view addSubview:_scrVCustom];
30
31     //设置滚动视图_scrVCustom放大和缩小初始值
32     _scrVCustom.delegate = self;
33     _scrVCustom.minimumZoomScale = 0.2;
34     _scrVCustom.maximumZoomScale = 2.0;
35     _scrVCustom.zoomScale = 1.0;
36
37     CGFloat y = self.view.frame.size.height - 50;
38     UIButton *btnScaleToBig = [UIButton buttonWithType:UIButtonTypeCustom];
39     btnScaleToBig.frame = CGRectMake(20, y, 80, 40);
40     [btnScaleToBig setTitle:@"放大" forState:UIControlStateNormal];
41     [btnScaleToBig setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
42     [btnScaleToBig setBackgroundColor:[UIColor greenColor]];
43     [btnScaleToBig addTarget:self
44                       action:@selector(scaleToBigDidPush:)
45             forControlEvents:UIControlEventTouchUpInside];
46     [self.view addSubview:btnScaleToBig];
47
48     UIButton *btnScaleToSmall = [UIButton buttonWithType:UIButtonTypeCustom];
49     btnScaleToSmall.frame = CGRectMake(120, y, 80, 40);
50     [btnScaleToSmall setTitle:@"缩小" forState:UIControlStateNormal];
51     [btnScaleToSmall setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
52     [btnScaleToSmall setBackgroundColor:[UIColor greenColor]];
53     [btnScaleToSmall addTarget:self
54                       action:@selector(scaleToSmallDidPush:)
55             forControlEvents:UIControlEventTouchUpInside];
56     [self.view addSubview:btnScaleToSmall];
57
58 }
59
60 - (void)scaleToBigDidPush:(UIButton *)sender {
61     _scrVCustom.zoomScale += 0.2; //调整缩放值触发委托事件viewForZoomingInScrollView
62 }
63
64 - (void)scaleToSmallDidPush:(UIButton *)sender {
65     _scrVCustom.zoomScale -= 0.2; //调整缩放值触发委托事件viewForZoomingInScrollView
66 }
67
68 #pragma mark - ScrollView
69 - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
70     UIView *imgVCustom = nil;
71     for (id subview in scrollView.subviews) {
72         if ([subview isKindOfClass:[UIImageView class]]) {
73             imgVCustom = subview;
74             break;
75         }
76     }
77     return imgVCustom;
78 }
79
80 @end