手势

定义

1. 为了完成手势识别,必须借助于手势识别器----UIGestureRecognizer
   2. 利用UIGestureRecognizer,能识别用户在某个view上做的一些常见手势
   3. UIGestureRecognizer是一个抽象类,定义了所有手势的基本行为,使用它的子类才能处理具体的手势

#import "ViewController.h"

@interface ViewController ()<UIGestureRecognizerDelegate>

@property (weak, nonatomic) IBOutlet UIView *iconView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
#warning 要实现手势操作userInteractionEnabled必须设为YES;
    // 1.旋转手势
//    [self testRotate];
    
    // 2.捏合手势
//    [self testPinch];
    
    // 3.同时进行捏合和旋转
    // 同时进行捏合和旋转需要实现代理方法
//    [self testPinchAndRotate];
    
    // 4.测试拖拽
    [self testPan];

    
}

#pragma mark - 拖拽手势
- (void)testPan
{
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];
    
    [_iconView addGestureRecognizer:pan];
    
}

/**
 *  拖拽手势
 */
- (void)panView:(UIPanGestureRecognizer *)pan
{
    UIView *panView = pan.view; // 被拖拽的view
    
    //1.view上移动的位置
    CGPoint translation = [pan translationInView:panView];  // 在view上拖拽的位置
    CGPoint center = panView.center;
    center.x += translation.x;
    center.y += translation.y;
    panView.center = center;
    
    // 2.清空移动的位置
    [pan setTranslation:CGPointZero inView:panView];

}

#pragma mark - 代理方法
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

#pragma mark - 旋转和缩放
- (void)testPinchAndRotate
{
    [self testPinch];
    
    [self testRotate];
}


#pragma mark - 缩放手势
- (void)testPinch
{
    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)];

#warning 如果只是实现单个缩放手势可以不用实现代理方法
    pinch.delegate = self;
    
    [_iconView addGestureRecognizer:pinch];
}

/**
 *  捏合
 */
- (void)pinch:(UIPinchGestureRecognizer *)pinch
{
    pinch.view.transform = CGAffineTransformScale(pinch.view.transform, pinch.scale, pinch.scale);
    pinch.scale = 1;    // 可以认为每次捏合后缩放的比例都重新重置为1
}

#pragma mark - 旋转手势
- (void)testRotate
{
    UIRotationGestureRecognizer *rotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
    [_iconView addGestureRecognizer:rotate];
}

/**
 *  旋转
 */
- (void)rotate:(UIRotationGestureRecognizer *)rotate
{
    rotate.view.transform = CGAffineTransformRotate(rotate.view.transform, rotate.rotation);
    rotate.rotation = 0;    // 每次旋转后旋转的角度重置为0
}


@end