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。