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
};
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