iOS开发-手势

UIGestureRecognizer 用于检测和处理手势的抽象基类。提供了检测用户手势的基本功能，如点按、滑动、捏合、旋转等。通过使用 UIGestureRecognizer 子类，可以为视图添加手势识别功能，增强用户交互体验。

常见的 UIGestureRecognizer 子类

一些常见的手势识别器子类：

1. UITapGestureRecognizer ：检测点按手势。
2. UIPinchGestureRecognizer ：检测捏合（缩放）手势。
3. UIRotationGestureRecognizer ：检测旋转手势。
4. UISwipeGestureRecognizer ：检测滑动手势。
5. UIPanGestureRecognizer ：检测平移（拖动）手势。
6. UILongPressGestureRecognizer ：检测长按手势。

使用 UIGestureRecognizer

添加手势识别器

1. 创建手势识别器
2. 配置手势识别器
3. 将手势识别器添加到视图

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        self.view.backgroundColor = [UIColor whiteColor];        UIView *gestureView = [[UIView alloc] initWithFrame:CGRectMake(50, 100, 300, 400)];    gestureView.backgroundColor = [UIColor lightGrayColor];    [self.view addSubview:gestureView];        // 添加点按手势识别器    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];    [gestureView addGestureRecognizer:tapGesture];        // 添加捏合手势识别器    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)];    [gestureView addGestureRecognizer:pinchGesture];        // 添加旋转手势识别器    UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotation:)];    [gestureView addGestureRecognizer:rotationGesture];        // 添加滑动手势识别器    UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];    swipeGesture.direction = UISwipeGestureRecognizerDirectionRight; // 设置滑动方向    [gestureView addGestureRecognizer:swipeGesture];        // 添加平移手势识别器    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];    [gestureView addGestureRecognizer:panGesture];        // 添加长按手势识别器    UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];    [gestureView addGestureRecognizer:longPressGesture];}// 点按手势处理方法- (void)handleTap:(UITapGestureRecognizer *)gesture {    NSLog(@"Tap detected");}// 捏合手势处理方法- (void)handlePinch:(UIPinchGestureRecognizer *)gesture {    if (gesture.state == UIGestureRecognizerStateChanged) {        gesture.view.transform = CGAffineTransformScale(gesture.view.transform, gesture.scale, gesture.scale);        gesture.scale = 1.0;    }}// 旋转手势处理方法- (void)handleRotation:(UIRotationGestureRecognizer *)gesture {    if (gesture.state == UIGestureRecognizerStateChanged) {        gesture.view.transform = CGAffineTransformRotate(gesture.view.transform, gesture.rotation);        gesture.rotation = 0.0;    }}// 滑动手势处理方法- (void)handleSwipe:(UISwipeGestureRecognizer *)gesture {    NSLog(@"Swipe detected");}// 平移手势处理方法- (void)handlePan:(UIPanGestureRecognizer *)gesture {    CGPoint translation = [gesture translationInView:gesture.view];    gesture.view.center = CGPointMake(gesture.view.center.x + translation.x, gesture.view.center.y + translation.y);    [gesture setTranslation:CGPointZero inView:gesture.view];}// 长按手势处理方法- (void)handleLongPress:(UILongPressGestureRecognizer *)gesture {    if (gesture.state == UIGestureRecognizerStateBegan) {        NSLog(@"Long press detected");    }}@end

手势识别器的属性和方法

• 属性

  • enabled ：一个布尔值，指示手势识别器是否启用。
  • state ：手势识别器的当前状态（例如 UIGestureRecognizerStatePossible 、 UIGestureRecognizerStateBegan 等）。
  • view ：手势识别器附加的视图。
  • cancelsTouchesInView ：一个布尔值，指示手势识别器是否阻止触摸事件传递到视图。

• 方法

  • - (void)addTarget:(id)target action:(SEL)action; ：添加目标和动作。
  • - (void)removeTarget:(id)target action:(SEL)action; ：移除目标和动作。
  • - (void)requireGestureRecognizerToFail:(UIGestureRecognizer *)otherGestureRecognizer; ：要求另一个手势识别器失败，才能识别当前手势。

手势识别器的状态

手势识别器的状态（ UIGestureRecognizerState ）有以下几种：

• UIGestureRecognizerStatePossible ：手势识别器没有识别到手势，但可能会在未来识别到。
• UIGestureRecognizerStateBegan ：手势识别器识别到手势开始。
• UIGestureRecognizerStateChanged ：手势识别器识别到手势发生变化。
• UIGestureRecognizerStateEnded ：手势识别器识别到手势结束。
• UIGestureRecognizerStateCancelled ：手势识别器识别到手势被取消。
• UIGestureRecognizerStateFailed ：手势识别器识别到手势失败。