我的IOS学习之路（三）：手势识别器

　　在iOS的学习中，对于手势的处理是极为重要的，如对于图片，我们经常需要进行旋转，缩放以及移动等。这里做一下总结，详见代码。

 1 - (void)viewDidLoad
 2 {
 3     [super viewDidLoad];
 4     UIImage *image = [UIImage imageNamed:@"018.png"];
 5     UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
 6     imageView.frame = CGRectMake(80, 80, 200, 350);
 7     [self.view addSubview:imageView];
 8
 9     //开启用户交互
10     imageView.userInteractionEnabled = YES;
11     //缩放手势识别器
12     UIPinchGestureRecognizer *pinGes = [[UIPinchGestureRecognizer alloc] init];
13     pinGes.delegate = self;
14
15     [pinGes addTarget:self action:@selector(pinGes:)];
16     [imageView addGestureRecognizer:pinGes];
17
18     //旋转手势识别器
19     UIRotationGestureRecognizer *rotaGes = [[UIRotationGestureRecognizer alloc] init];
20     rotaGes.delegate = self;
21     imageView.userInteractionEnabled = YES;
22     [rotaGes addTarget:self action:@selector(rota:)];
23     [imageView addGestureRecognizer:rotaGes];
24
25
26     //移动手势识别器
27     UIPanGestureRecognizer *panGes = [[UIPanGestureRecognizer alloc] init];
28     [panGes addTarget:self action:@selector(panGes:)];
29     [imageView addGestureRecognizer:panGes];
30
31     //长按手势识别器
32     UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] init];
33
34     //设置长按时间标准(默认时间为0.5秒)
35     longPress.minimumPressDuration = 1.0;
36     [longPress addTarget:self action:@selector(longPress:)];
37     [imageView addGestureRecognizer:longPress];
38
39 }
40
41 //此方法的返回值表示手势识别器是否支持多手势操作
42 - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
43 {
44     return YES;
45 }
46
47 //长按操作
48 - (void) longPress: (UILongPressGestureRecognizer *)ges
49 {
50     //开始长按时进行的操作
51     if (ges.state == UIGestureRecognizerStateBegan) {
52         NSLog(@"begin");
53         //结束长按时进行的操作
54     }else if (ges.state == UIGestureRecognizerStateEnded){
55         NSLog(@"end");
56     }
57 }
58
59 //移动操作
60 - (void) panGes: (UIPanGestureRecognizer *)ges
61 {
62     //获取相对于父视图移动的距离
63     CGPoint point = [ges translationInView:self.view];
64     //开启动画
65     [UIView beginAnimations:Nil context:Nil];
66     //设置动画时间
67     [UIView setAnimationDuration:1];
68     //通过形变属性移动
69     ges.view.transform = CGAffineTransformTranslate(ges.view.transform, point.x, point.y);
70     //因为手势识别器会对每次移动的距离进行累加，所以当移动一次后，需要将相对移动距离设置为（0，0）；
71     [ges setTranslation:CGPointMake(0, 0) inView:self.view];
72
73     //通过中心点移动
74 //    ges.view.center = CGPointMake(ges.view.center.x + point.x, ges.view.center.y + point.y);
75 //    [ges setTranslation:CGPointMake(0, 0) inView:self.view];
76     //动画结束
77     [UIView commitAnimations];
78 }
79
80 //旋转操作
81 - (void) rota: (UIRotationGestureRecognizer *)ges
82 {
83     //设置形变属性
84     ges.view.transform = CGAffineTransformRotate(ges.view.transform, ges.rotation);
85     //因为CGAffineTransformRotate函数会将每一次的旋转角度进行叠加，所以需要将手势识别器的旋转角度置0；
86     ges.rotation = 0;
87 }
88
89 //缩放操作
90 - (void)pinGes: (UIPinchGestureRecognizer *)ges
91 {
92 //    NSLog(@"get in...");
93     //因为CGAffineTransformScale函数会将缩放比例进行累乘，所以需要将手势识别器的缩放比例设置1
94     ges.view.transform = CGAffineTransformScale(ges.view.transform, ges.scale, ges.scale);
95     ges.scale = 1.0f;
96 }