iOS开发 - 手势识别(UIGestureRecognizer)

UIGestureRecognizer

为了完成手势识别，必须借助于手势识别器—-UIGestureRecognizer

利用UIGestureRecognizer，能轻松识别用户在某个view上面做的一些常见手势

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

UITapGestureRecognizer       //(敲击)UIPinchGestureRecognizer     //(捏合，用于缩放)UIPanGestureRecognizer       //(拖拽)UISwipeGestureRecognizer     //(轻扫)UIRotationGestureRecognizer  //(旋转)UILongPressGestureRecognizer //(长按)

敲击 UITapGestureRecognizer

每一个手势识别器的用法都差不多，比如UITapGestureRecognizer的使用步骤如下

创建手势识别器对象UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];设置手势识别器对象的具体属性// 连续敲击2次tap.numberOfTapsRequired = 2;// 需要2根手指一起敲击tap.numberOfTouchesRequired = 2;添加手势识别器到对应的view上[self.iconView addGestureRecognizer:tap];监听手势的触发[tap addTarget:self action:@selector(tapIconView:)];

敲击实例

@interface GRViewController () <UIGestureRecognizerDelegate>@property (weak, nonatomic) IBOutlet UIImageView *iconView;@end@implementation GRViewController- (void)viewDidLoad{    [super viewDidLoad];    [self testTap2];}- (void)testTap2{    UIGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapView)];    tap.delegate = self;    [self.iconView addGestureRecognizer:tap];}#pragma mark - 代理方法/** *  当点击view的时候,会先调用这个方法 */- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{    CGPoint pos = [touch locationInView:touch.view];    if (pos.x <= self.iconView.frame.size.width * 0.5) {        return YES;    }    return NO;}- (void)testTap{    // 1.创建手势识别器对象    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];    // 连续敲击2次,手势才能识别成功    tap.numberOfTapsRequired = 2;    tap.numberOfTouchesRequired = 2;    // 2.添加手势识别器对象到对应的view    [self.iconView addGestureRecognizer:tap];    // 3.添加监听方法(识别到了对应的手势,就会调用监听方法)    [tap addTarget:self action:@selector(tapView)];}- (void)tapView{    NSLog(@"-----我敲击了屏幕！！");}@end

长按和轻扫实例

@interface GRViewController ()@property (weak, nonatomic) IBOutlet UIView *redView;@end@implementation GRViewController- (void)viewDidLoad{    [super viewDidLoad];    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeView)];    swipe.direction = UISwipeGestureRecognizerDirectionUp;    [self.redView addGestureRecognizer:swipe];}- (void)swipeView{    NSLog(@"swipeView");}- (void)testLongPress{    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] init];    [longPress addTarget:self action:@selector(longPressView)];    // 至少长按2秒    longPress.minimumPressDuration = 2;    // 在触发手势之前,50px范围内长按有效    longPress.allowableMovement = 50;    [self.redView addGestureRecognizer:longPress];}- (void)longPressView{    NSLog(@"长按了红色的view");}@end

缩放和旋转实例

@interface GRViewController () <UIGestureRecognizerDelegate>@property (weak, nonatomic) IBOutlet UIImageView *iconView;@end@implementation GRViewController- (void)viewDidLoad{    [super viewDidLoad];    [self testPinchAndRotate];}#pragma mark - 手势识别器的代理方法/** *  是否允许多个手势识别器同时有效 *  Simultaneously : 同时地 */- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{    return YES;}#pragma mark - 缩放 + 旋转- (void)testPinchAndRotate{    [self testPinch];    [self testRotate];}#pragma mark - 缩放手势(捏合手势)- (void)testPinch{    UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchView:)];    pinch.delegate = self;    [self.iconView addGestureRecognizer:pinch];}- (void)pinchView:(UIPinchGestureRecognizer *)pinch{    pinch.view.transform = CGAffineTransformScale(pinch.view.transform, pinch.scale, pinch.scale);    pinch.scale = 1; // 这个真的很重要!!!!!}#pragma mark - 旋转手势- (void)testRotate{    UIRotationGestureRecognizer *recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateView:)];    recognizer.delegate = self;    [self.iconView addGestureRecognizer:recognizer];}- (void)rotateView:(UIRotationGestureRecognizer *)recognizer{    recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);    recognizer.rotation = 0; // 这个很重要!!!!!}@end

拖拽实例

@interface GRViewController ()@property (weak, nonatomic) IBOutlet UIView *purpleView;@end@implementation GRViewController- (void)viewDidLoad{    [super viewDidLoad];    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];    [self.purpleView addGestureRecognizer:pan];}- (void)panView:(UIPanGestureRecognizer *)pan{    switch (pan.state) {        case UIGestureRecognizerStateBegan: // 开始触发手势            break;        case UIGestureRecognizerStateEnded: // 手势结束            break;        default:            break;    }    // 1.在view上面挪动的距离    CGPoint translation = [pan translationInView:pan.view];    CGPoint center = pan.view.center;    center.x += translation.x;    center.y += translation.y;    pan.view.center = center;    // 2.清空移动的距离    [pan setTranslation:CGPointZero inView:pan.view];}@end

手势识别的状态

typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {    // 没有触摸事件发生，所有手势识别的默认状态    UIGestureRecognizerStatePossible,    // 一个手势已经开始但尚未改变或者完成时    UIGestureRecognizerStateBegan,    // 手势状态改变    UIGestureRecognizerStateChanged,    // 手势完成    UIGestureRecognizerStateEnded,    // 手势取消，恢复至Possible状态    UIGestureRecognizerStateCancelled,     // 手势失败，恢复至Possible状态    UIGestureRecognizerStateFailed,    // 识别到手势识别    UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded};