面试题：Objective-C在iOS触摸事件处理中，如何实现复杂手势识别与动画联动？

实现思路

手势识别：
- 创建一个自定义的手势识别器，继承自UIGestureRecognizer类。在自定义手势识别器中，重写touchesBegan:withEvent:、touchesMoved:withEvent:和touchesEnded:withEvent:等方法，通过这些方法来跟踪手指的移动轨迹，判断是否符合特定轨迹的滑动手势。
- 例如，在touchesMoved:withEvent:方法中，可以记录每次手指移动的位置，将这些位置点保存到一个数组中，然后根据数组中的点判断是否符合设定的轨迹。
动画效果：
- 一旦手势识别成功，利用UIView的动画方法来实现视图的旋转、缩放等效果。可以使用UIView的类方法animateWithDuration:animations:来创建动画块，在动画块中设置视图的transform属性来实现旋转和缩放。
- 比如，要实现旋转，可以设置CGAffineTransformMakeRotation，要实现缩放，可以设置CGAffineTransformMakeScale，然后将这些变换组合应用到视图的transform属性上。

大致代码架构

自定义手势识别器类：

#import <UIKit/UIKit.h>

@interface CustomGestureRecognizer : UIGestureRecognizer

@end

#import "CustomGestureRecognizer.h"

@implementation CustomGestureRecognizer {
    NSMutableArray<NSValue *> *touchPoints;
}

- (instancetype)init {
    self = [super init];
    if (self) {
        touchPoints = [NSMutableArray array];
    }
    return self;
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];
    for (UITouch *touch in touches) {
        CGPoint point = [touch locationInView:self.view];
        [touchPoints addObject:[NSValue valueWithCGPoint:point]];
    }
}

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];
    for (UITouch *touch in touches) {
        CGPoint point = [touch locationInView:self.view];
        [touchPoints addObject:[NSValue valueWithCGPoint:point]];
        // 这里添加判断轨迹的逻辑，比如判断点的分布是否符合特定轨迹
        // 如果符合，设置手势状态为UIGestureRecognizerStateRecognized
    }
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];
    // 再次确认轨迹是否符合要求，最终确定手势状态
    if (/* 符合特定轨迹 */) {
        self.state = UIGestureRecognizerStateRecognized;
    } else {
        self.state = UIGestureRecognizerStateFailed;
    }
    [touchPoints removeAllObjects];
}
@end

视图控制器中使用手势识别器并实现动画：

#import "ViewController.h"
#import "CustomGestureRecognizer.h"

@interface ViewController ()

@property (nonatomic, strong) UIView *targetView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.targetView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
    self.targetView.backgroundColor = [UIColor redColor];
    [self.view addSubview:self.targetView];
    
    CustomGestureRecognizer *customGesture = [[CustomGestureRecognizer alloc] init];
    [customGesture addTarget:self action:@selector(handleCustomGesture:)];
    [self.view addGestureRecognizer:customGesture];
}

- (void)handleCustomGesture:(CustomGestureRecognizer *)gesture {
    if (gesture.state == UIGestureRecognizerStateRecognized) {
        [UIView animateWithDuration:0.5 animations:^{
            CGAffineTransform rotation = CGAffineTransformMakeRotation(M_PI_4);
            CGAffineTransform scale = CGAffineTransformMakeScale(1.2, 1.2);
            self.targetView.transform = CGAffineTransformConcat(rotation, scale);
        }];
    }
}
@end

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面试题：Objective-C在iOS触摸事件处理中，如何实现复杂手势识别与动画联动？

知识考点

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实现思路

大致代码架构