iOS轻点、触摸和手势代码开发

//
// ViewController.m
// PinchMe
//
// Created by Jierism on 16/8/4.
// Copyright © 2016年 Jierism. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@property (strong,nonatomic) UIImageView *imageView;

@end

@implementation ViewController

// 当前缩放比例，先前缩放比例
CGFloat scale,previousScale;
// 当前旋转角度，先前旋转角度
CGFloat rotation,previousRotation;

- (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  previousScale = 1;
  
  UIImage *image = [UIImage imageNamed:@"yosemite-meadows"];
  self.imageView = [[UIImageView alloc] initWithImage:image];
  // 对图像启用交互功能
  self.imageView.userInteractionEnabled = YES;
  self.imageView.center = self.view.center;
  [self.view addSubview:self.imageView];
  
  // 建立捏合手势识别器
  UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(doPinch:)];
  pinchGesture.delegate = self;
  [self.imageView addGestureRecognizer:pinchGesture];
  
  // 建立旋转手势识别器
  UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(doRorate:)];
  rotationGesture.delegate = self;
  [self.imageView addGestureRecognizer:rotationGesture];
}


- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
  // 允许捏合手势和旋转手势同时工作。否则，先开始的手势识别器会屏蔽另一个
  return YES;
}

// 根据手势识别器中获得的缩放比例和旋转角度对图像进行变换
- (void)transformImageView
{
  CGAffineTransform t = CGAffineTransformMakeScale(scale * previousScale, scale * previousScale);
  t = CGAffineTransformRotate(t, rotation + previousRotation);
  self.imageView.transform = t;
}

- (void)doPinch:(UIPinchGestureRecognizer *)gesture
{
  scale = gesture.scale;
  [self transformImageView];
  if (gesture.state == UIGestureRecognizerStateEnded) {
    previousScale = scale * previousScale;
    scale = 1;
  }
}


- (void)doRorate:(UIRotationGestureRecognizer *)gesture
{
  rotation = gesture.rotation;
  [self transformImageView];
  if (gesture.state == UIGestureRecognizerStateEnded) {
    previousRotation = rotation + previousRotation;
    rotation = 0;
  }
}


@end

//
// CheckMarkRecognizer.m
// CheckPlease
//
// Created by Jierism on 16/8/4.
// Copyright © 2016年 Jierism. All rights reserved.
//

#import "CheckMarkRecognizer.h"
#import "CGPointUtils.h"
#import <UIKit/UIGestureRecognizerSubclass.h> // 一个重要目的是使手势识别器的state属性可写，子类将使用这个机制断言我们所观察的手势已成功完成

// 设置检测范围
static CGFloat const kMinimunCheckMarkAngle = 80;
static CGFloat const kMaximumCheckMarkAngle = 100;
static CGFloat const kMinimumCheckMarkLength = 10;

@implementation CheckMarkRecognizer{
  // 前两个实例变量提供之前的线段
  CGPoint lastPreviousPoint;
  CGPoint lastCurrentPoint;
  // 画出的线段长度
  CGFloat lineLengthSoFar;
}


// 用lastPreviousPoint和lastCurrentPoint组成第一条线段，跟第二条线段形成角度去完成手势
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
  [super touchesBegan:touches withEvent:event];
  UITouch *touch = [touches anyObject];
  CGPoint point = [touch locationInView:self.view];
  lastPreviousPoint = point;
  lastCurrentPoint = point;
  lineLengthSoFar = 0.0;
}

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
  [super touchesMoved:touches withEvent:event];
  UITouch *touch = [touches anyObject];
  CGPoint previousPoint = [touch previousLocationInView:self.view];
  CGPoint currentPoint = [touch locationInView:self.view];
  CGFloat angle = angleBetweenLines(lastPreviousPoint, lastCurrentPoint, previousPoint, currentPoint);
  if (angle >= kMinimunCheckMarkAngle && angle <= kMaximumCheckMarkAngle && lineLengthSoFar > kMinimumCheckMarkLength) {
    self.state = UIGestureRecognizerStateRecognized;
  }
  lineLengthSoFar += distanceBetweenPoints(previousPoint, currentPoint);
  lastPreviousPoint = previousPoint;
  lastCurrentPoint = currentPoint;
}

@end
								 
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