UI基础 - UIRecognizer

▶ UIRecognizer

1 - ⼿势识别器是对触摸事件做了封装，无需⾃己去判断某个手势是否触发

2 - ⼿势识别器有 7 个子类

UITapGestureRecognizer         ：轻拍手势识别器，能识别轻拍操作

UILongPressGestureRecognizer：长按手势识别器，能识别长按操作

UIRotationGestureRecognizer   ：旋转手势识别器，能识别旋转操作

UIPinchGestureRecognizer       ：捏合手势识别器，能识别捏合操作

UIPanGestureRecognizer         ：平移手势识别器，能识别拖拽操作

UISwipeGestureRecognizer      ：轻扫手势识别器，能识别拖拽操作；

UIScreenEdgePanGestureRecognizer：屏幕边缘轻扫识别器，是 iOS7 中新增的手势

3 - 代码示例：如何使用手势

#import "ViewController.h"
@interface ViewController()

@property(nonatomic,strong)UIImageView *imageView;

@end
@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 图片
    self.imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1n.jpeg"]];
    self.imageView.frame = CGRectMake(0, 200, self.view.frame.size.width - 100, 180) ;
    self.imageView.userInteractionEnabled = YES;
    [self.view addSubview:self.imageView];

    // 轻拍
    //[self addTapGesture];
    
    // 长按
    //[self addLongPressGesture];
    
    // 轻扫
    //[self addSwipeGesture];

    // 捏合
    //[self addPinchGesture];
    
    // 旋转
    //[self addRotationGesture];
    
    // 拖动手势
    //[self addPanGesture];
    
    // 边缘手势
    //[self addScreenEdgePanGesture];

}

// 轻拍手势
-(void)addTapGesture{
    
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
    tapGesture.numberOfTapsRequired = 2;// 需连续点2次
    tapGesture.numberOfTouchesRequired = 1;// 需1个手指同时点击
    [self.imageView addGestureRecognizer:tapGesture];
    
}
- (void)handleTapGesture:(UITapGestureRecognizer *)tapGesture{

    UIImageView *imageView = (UIImageView*)tapGesture.view;
    imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%dn.jpeg",arc4random()%3+1]];
}


 // 长按手势
-(void)addLongPressGesture{
    
    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPressGesture:)];
    longPress.minimumPressDuration = 1.0;// 长按时间
    [self.imageView addGestureRecognizer:longPress];
}
-(void)handleLongPressGesture:(UILongPressGestureRecognizer *)longPressGesture{

    UIImageView *imageView = (UIImageView*)longPressGesture.view;

    // 开始长按
    if (longPressGesture.state == UIGestureRecognizerStateBegan) {
        imageView.image = [UIImage imageNamed:@"2n.jpeg"];
    }
    // 结束长按
    else if (longPressGesture.state == UIGestureRecognizerStateEnded){
        imageView.image = [UIImage imageNamed:@"3n.jpeg"];
    }
}


// 轻扫手势
-(void)addSwipeGesture{
    
    UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeGesture:)];
    swipeGesture.direction = UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft;// 轻扫方向
    [self.imageView addGestureRecognizer:swipeGesture];
    
}
- (void)handleSwipeGesture:(UISwipeGestureRecognizer *)swipeGesture{

    UIImageView *imageView = (UIImageView*)swipeGesture.view;
    imageView.image = [UIImage imageNamed:@"3n.jpeg"];
}

// 捏合手势
-(void)addPinchGesture{
    
    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)];
    [self.imageView addGestureRecognizer:pinchGesture];

}
- (void)handlePinchGesture:(UIPinchGestureRecognizer *)pinchGesture{

//    // 方式一
//    CGRect newBounds = pinchGesture.view.bounds;
//    newBounds.size.width *= pinchGesture.scale;
//    newBounds.size.height *= pinchGesture.scale;
//    pinchGesture.view.bounds = newBounds;
//    // 缩放系数：每次计算完以后 必须让 scale 归 1.0
//    pinchGesture.scale = 1.0;

    // 方式二：CGAffineTransformScale
    pinchGesture.view.transform = CGAffineTransformScale(pinchGesture.view.transform, pinchGesture.scale, pinchGesture.scale);
    pinchGesture.scale = 1.0;
}

// 旋转手势
- (void)addRotationGesture{
    
    UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotationGesture:)];
    [self.imageView addGestureRecognizer:rotationGesture];
}
- (void)handleRotationGesture:(UIRotationGestureRecognizer *)rotationGesture{

    rotationGesture.view.transform = CGAffineTransformRotate(rotationGesture.view.transform, rotationGesture.rotation);
    rotationGesture.rotation = 0.0;
}

// 拖动手势
-(void)addPanGesture{
    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
    [self.imageView addGestureRecognizer:panGesture];
}
- (void)handlePanGesture:(UIPanGestureRecognizer *)panGesture{

//    // 方式一
//    CGPoint offSet = [panGesture translationInView:panGesture.view];
//    NSLog(@"%@",NSStringFromCGPoint(offSet));
//    CGPoint newCenter = panGesture.view.center;
//    newCenter.x += offSet.x;
//    newCenter.y += offSet.y;
//    panGesture.view.center = newCenter;
//    [panGesture setTranslation:CGPointZero inView:panGesture.view];// 偏移量是累加的，每次都须清零

    // 方式二
    CGPoint offSet = [panGesture translationInView:panGesture.view];
    panGesture.view.transform = CGAffineTransformTranslate(panGesture.view.transform, offSet.x, offSet.y);
    [panGesture setTranslation:CGPointZero inView:panGesture.view];// 偏移量清零
}


// 边缘手势
-(void)addScreenEdgePanGesture{

    UIScreenEdgePanGestureRecognizer *screenEdgeGesture = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:@selector(handleScreenEdgePanGesture:)];
    screenEdgeGesture.edges = UIRectEdgeLeft;
    [self.view addGestureRecognizer:screenEdgeGesture];
}
- (void)handleScreenEdgePanGesture:(UIScreenEdgePanGestureRecognizer *)screenEdgeGesture{

    self.imageView.image = [UIImage imageNamed:@"2n.jpeg"];
}

@end