iOS手势识别的详细使用方法(拖动,缩放,旋转,点击,手势依赖,自定义手势)_IOS开发教程-查字典教程网
iOS手势识别的详细使用方法(拖动,缩放,旋转,点击,手势依赖,自定义手势)
iOS手势识别的详细使用方法(拖动,缩放,旋转,点击,手势依赖,自定义手势)
发布时间:2016-12-28 来源:查字典编辑
摘要:手势识别在iOS上非常重要,手势操作移动设备的重要特征,极大的增加了移动设备使用便捷性。1、UIGestureRecognizer介绍手势识...

手势识别在iOS上非常重要,手势操作移动设备的重要特征,极大的增加了移动设备使用便捷性。

1、UIGestureRecognizer介绍

手势识别在iOS上非常重要,手势操作移动设备的重要特征,极大的增加了移动设备使用便捷性。

iOS系统在3.2以后,为方便开发这使用一些常用的手势,提供了UIGestureRecognizer类。手势识别UIGestureRecognizer类是个抽象类,下面的子类是具体的手势,开发这可以直接使用这些手势识别。

UITapGestureRecognizer UIPinchGestureRecognizer UIRotationGestureRecognizer UISwipeGestureRecognizer UIPanGestureRecognizer UILongPressGestureRecognizer

上面的手势对应的操作是:

Tap(点一下) Pinch(二指往內或往外拨动,平时经常用到的缩放) Rotation(旋转) Swipe(滑动,快速移动) Pan (拖移,慢速移动) LongPress(长按)

UIGestureRecognizer的继承关系如下:

2、使用手势的步骤

使用手势很简单,分为两步:

创建手势实例。当创建手势时,指定一个回调方法,当手势开始,改变、或结束时,回调方法被调用。

添加到需要识别的View中。每个手势只对应一个View,当屏幕触摸在View的边界内时,如果手势和预定的一样,那就会回调方法。

ps:一个手势只能对应一个View,但是一个View可以有多个手势。

建议在真机上运行这些手势,模拟器操作不太方便,可能导致你认为手势失效。

3、Pan 拖动手势:

UIImageView *snakeImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snake.png"]]; snakeImageView.frame = CGRectMake(50, 50, 100, 160); UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; [snakeImageView addGestureRecognizer:panGestureRecognizer]; [self.view setBackgroundColor:[UIColor whiteColor]]; [self.view addSubview:snakeImageView];

新建一个ImageView,然后添加手势

回调方法:

- (void) handlePan:(UIPanGestureRecognizer*) recognizer { CGPoint translation = [recognizer translationInView:self.view]; recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y); [recognizer setTranslation:CGPointZero inView:self.view]; }

4、Pinch缩放手势

UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)];<p>[<span>snakeImageView</span> <span>addGestureRecognizer</span>:pinchGestureRecognizer];</p>

- (void) handlePinch:(UIPinchGestureRecognizer*) recognizer { recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale); recognizer.scale = 1; }

5、Rotation旋转手势

UIRotationGestureRecognizer *rotateRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotate:)]; [snakeImageView addGestureRecognizer:rotateRecognizer];

- (void) handleRotate:(UIRotationGestureRecognizer*) recognizer { recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation); recognizer.rotation = 0; }

添加了这几个手势后,运行看效果,程序中的imageView放了一个

/^/^

_|__| O|

/ /~ _/

____|__________/

_______

`

| |

/ /

/ /

/ /

/ /

/ / _----_

/ / _-~ ~-_ | |

( ( _-~ _--_ ~-_ _/ |

~-____-~ _-~ ~-_ ~-_-~ /

~-_ _-~ ~-_ _-~

~--______-~ ~-___-~

的图片,在模拟器上拖动是没问题的。缩放和旋转有点问题,估计是因为在模拟器上的模拟的两个接触点距离在imageView的边界外了,所以操作无效果。

建议在真机上运行这个手势。

在模拟器上缩放和选择的操作技巧:

可以把imageView的frame值设置大一点,按住alt键,按下触摸板(不按下不行),这样就可以旋转和缩放了。

6、添加第二个ImagView并添加手势

记住:一个手势只能添加到一个View,两个View当然要有两个手势的实例了

- (void)viewDidLoad { [super viewDidLoad]; UIImageView *snakeImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snake.png"]]; UIImageView *dragonImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"dragon.png"]]; snakeImageView.frame = CGRectMake(120, 120, 100, 160); dragonImageView.frame = CGRectMake(50, 50, 100, 160); [self.view addSubview:snakeImageView]; [self.view addSubview:dragonImageView]; for (UIView *view in self.view.subviews) { UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinch:)]; UIRotationGestureRecognizer *rotateRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotate:)]; [view addGestureRecognizer:panGestureRecognizer]; [view addGestureRecognizer:pinchGestureRecognizer]; [view addGestureRecognizer:rotateRecognizer]; [view setUserInteractionEnabled:YES]; } [self.view setBackgroundColor:[UIColor whiteColor]]; }

多添加了一条龙的view,两个view都能接收上面的三种手势。运行效果如下:

7、拖动(pan手势)速度(以较快的速度拖放后view有滑行的效果)

如何实现呢?

监视手势是否结束 监视触摸的速度

- (void) handlePan:(UIPanGestureRecognizer*) recognizer { CGPoint translation = [recognizer translationInView:self.view]; recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y); [recognizer setTranslation:CGPointZero inView:self.view]; if (recognizer.state == UIGestureRecognizerStateEnded) { CGPoint velocity = [recognizer velocityInView:self.view]; CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); CGFloat slideMult = magnitude / 200; NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult); float slideFactor = 0.1 * slideMult; // Increase for more of a slide CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor), recognizer.view.center.y + (velocity.y * slideFactor)); finalPoint.x = MIN(MAX(finalPoint.x, 0), self.view.bounds.size.width); finalPoint.y = MIN(MAX(finalPoint.y, 0), self.view.bounds.size.height); [UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ recognizer.view.center = finalPoint; } completion:nil]; }

代码实现解析:

计算速度向量的长度(估计大部分都忘了)这些知识了。 如果速度向量小于200,那就会得到一个小于的小数,那么滑行会很短 基于速度和速度因素计算一个终点 确保终点不会跑出父View的边界 使用UIView动画使view滑动到终点

运行后,快速拖动图像view放开会看到view还会在原来的方向滑行一段路。

8、同时触发两个view的手势

手势之间是互斥的,如果你想同时触发蛇和龙的view,那么需要实现协议

UIGestureRecognizerDelegate,

@interface ViewController : UIViewController<UIGestureRecognizerDelegate> @end

并在协议这个方法里返回YES。

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { return YES; }

把self作为代理设置给手势:

panGestureRecognizer.delegate = self; pinchGestureRecognizer.delegate = self; rotateRecognizer.delegate = self;

这样可以同时拖动或旋转缩放两个view了。

9、tap点击手势

这里为了方便看到tap的效果,当点击一下屏幕时,播放一个声音。

为了播放声音,我们加入AVFoundation.framework这个框架。

- (AVAudioPlayer *)loadWav:(NSString *)filename { NSURL * url = [[NSBundle mainBundle] URLForResource:filename withExtension:@"wav"]; NSError * error; AVAudioPlayer * player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error]; if (!player) { NSLog(@"Error loading %@: %@", url, error.localizedDescription); } else { [player prepareToPlay]; } return player; }

我会在最后例子代码给出完整代码,添加手势的步骤和前面一样的。

#import <UIKit/UIKit.h> #import <AVFoundation/AVFoundation.h> @interface ViewController : UIViewController<UIGestureRecognizerDelegate> @property (strong) AVAudioPlayer * chompPlayer; @property (strong) AVAudioPlayer * hehePlayer; @end - (void)handleTap:(UITapGestureRecognizer *)recognizer { [self.chompPlayer play]; }

运行,点一下某个图,就会播放一个咬东西的声音。

不过这个点击播放声音有点缺陷,就是在慢慢拖动的时候也会播放。这使得两个手势重合了。怎么解决呢?使用手势的:

requireGestureRecognizerToFail方法。

10、手势的依赖性

在viewDidLoad的循环里添加这段代码:

[tapRecognizer requireGestureRecognizerToFail:panGestureRecognizer];

意思就是,当如果pan手势失败,就是没发生拖动,才会出发tap手势。这样如果你有轻微的拖动,那就是pan手势发生了。tap的声音就不会发出来了。

11、自定义手势

自定义手势继承:UIGestureRecognizer,实现下面的方法:

– touchesBegan:withEvent: – touchesMoved:withEvent: – touchesEnded:withEvent: - touchesCancelled:withEvent:

新建一个类,继承UIGestureRecognizer,代码如下:

.h文件

#import <UIKit/UIKit.h> typedef enum { DirectionUnknown = 0, DirectionLeft, DirectionRight } Direction; @interface HappyGestureRecognizer : UIGestureRecognizer @property (assign) int tickleCount; @property (assign) CGPoint curTickleStart; @property (assign) Direction lastDirection; @end

.m文件

#import "HappyGestureRecognizer.h" #import <UIKit/UIGestureRecognizerSubclass.h> #define REQUIRED_TICKLES 2 #define MOVE_AMT_PER_TICKLE 25 @implementation HappyGestureRecognizer - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch * touch = [touches anyObject]; self.curTickleStart = [touch locationInView:self.view]; } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { // Make sure we've moved a minimum amount since curTickleStart UITouch * touch = [touches anyObject]; CGPoint ticklePoint = [touch locationInView:self.view]; CGFloat moveAmt = ticklePoint.x - self.curTickleStart.x; Direction curDirection; if (moveAmt < 0) { curDirection = DirectionLeft; } else { curDirection = DirectionRight; } if (ABS(moveAmt) < MOVE_AMT_PER_TICKLE) return; // 确认方向改变了 if (self.lastDirection == DirectionUnknown || (self.lastDirection == DirectionLeft && curDirection == DirectionRight) || (self.lastDirection == DirectionRight && curDirection == DirectionLeft)) { // 挠痒次数 self.tickleCount++; self.curTickleStart = ticklePoint; self.lastDirection = curDirection; // 一旦挠痒次数超过指定数,设置手势为结束状态 // 这样回调函数会被调用。 if (self.state == UIGestureRecognizerStatePossible && self.tickleCount > REQUIRED_TICKLES) { [self setState:UIGestureRecognizerStateEnded]; } } } - (void)reset { self.tickleCount = 0; self.curTickleStart = CGPointZero; self.lastDirection = DirectionUnknown; if (self.state == UIGestureRecognizerStatePossible) { [self setState:UIGestureRecognizerStateFailed]; } } - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { [self reset]; } - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { [self reset]; } @end

调用自定义手势和上面一样,回到这样写:

- (void)handleHappy:(HappyGestureRecognizer *)recognizer{ [self.hehePlayer play]; }

手势成功后播放呵呵笑的声音。

在真机上运行,按住某个view,快速左右拖动,就会发出笑的声音了。

代码解析:

先获取起始坐标:curTickleStart

通过和ticklePoint的x值对比,得出当前的放下是向左还是向右。再算出移动的x的值是否比MOVE_AMT_PER_TICKLE距离大,如果太则返回。

再判断是否有三次是不同方向的动作,如果是则手势结束,回调。

源代码:源代码下载。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持查字典教程网。

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