IOS开发之手势

灰太狼 2022-08-13 11:29 241阅读 0赞

在IOS系统3.2过后apple公司提供了一个抽象类，UIGestureRecognizer类用于手势识别，它的子类有主要有六个分别是：

UITapGestureRecognizer（轻击一下）

UIPinchGestureRecognizer（两指控制的缩放）

UIRotationGestureRecognizer（旋转）

UISwipeGestureRecognizer（滑动，快速移动）

UIPanGestureRecognizer（拖移，慢慢移动）

UILongPressGestureRecognizer（长按）

继承关系如下：

![1361893916_7845.png][]

手势的使用

1.创建手势的实例。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。

2.将实例添加到需要识别的view中，每个手势只对应一个view，但每个view可对应多个手势，当手势发生在view  边界内时，回调方法。

在虚拟机上调试时有可能会不灵敏，因此尽量在真机上运行，尤其是多指手势。

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UITapGestureRecognizer使用

UITapGestureRecognizer \*tap = \[

\[UITapGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

\[self.view addGestureRecognizer:tap\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是tap,

如下

\-（void）huidiaohanshu：（UITapGestureRecognizer \*）tap

｛

//使用手势你想要达到的效果

｝

UIPinchGestureRecognizer使用

UIPinchGestureRecognizer \*pinch = \[\[UIPinchGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

\[self.view addGestureRecognizer:pinch\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是pinch,

如下

\-（void）huidiaohanshu：（UIPinchGestureRecognizer \*）

｛

scale = pinchGestureRecognizer.scale;

\[self transformImageView\];

if (pinchGestureRecognizer.state == UIGestureRecognizerStated)

previousScale == scale\*previousScale;

scale = 1;

其中scale和previousScale是预先定义好的实例变量，scale代表当前的缩放比例，previousScale代表先前的缩放比例。

UIRotationGestureRecognizer使用

UIRotationGestureRecognizer \*rotation = \[\[UIRotationGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

\[self.view addGestureRecognizer:rotation\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是rotation,

如下

\-（void）huidiaohanshu：（UIRotationGestureRecognizer \*）rotation

｛

rotation = rotationGestureRecognizer.rotation;

\[self transformImageView\];

if(rotationGestureRecognizer.state == UIGestureRecognizerStateEnded)

previousrotation = rotation+prevoiusrotation;

rotation = 0;

其中rotation和previousrotation是预先定义好的实例变量，rotation代表当前的缩放比例，previousrotation代表先前的缩放比例。

UISwipeGestureRecognizer的使用

UISwipeGestureRecognizer \*swipe = \[\[UISwipeGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

swipe.direction = UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown；//如果需要横向的就用Left | Right

\[self.view addGestureRecognizer:swipe\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是swipe如下

\-（void）huidiaohanshu：（UISwipeGestureRecognizer \*）swipe

//使用手势所要达到的效果

UIPanGestureRecognizer的使用

UIPanGestureRecognizer \*pan = \[\[UIPanGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

\[self.view addGestureRecognizer:pan\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是pan,

如下

\-（void）huidiaohanshu：（UIPanGestureRecognizer \*）panGestureRecognize

//使用手势所要达到的效果  
    CGPoint translation = \[panGestureRecognize translationInView:self.view\];  
   panGestureRecognize.view.center = CGPointMake(panGestureRecognize.view.center.x + translation.x,  
                                       panGestureRecognize.view.center.y + translation.y);  
    \[panGestureRecognize setTranslation:CGPointZero inView:self.view\];  
    
    if (panGestureRecognize.state == UIGestureRecognizerStateEnded) \{  
        
        CGPoint velocity = \[panGestureRecognize velocityInView:self.view\];  
        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(panGestureRecognize.view.center.x + (velocity.x \* slideFactor),  
                                         panGestureRecognize.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);  
        
        \[UIView animateWithDuration:slideFactor\*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^\{  
            panGestureRecognize.view.center = finalPoint;  
        \} completion:nil\];

以上代码解析：

1.  计算速度向量的长度（估计大部分都忘了）这些知识了。
2.  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
3.  基于速度和速度因素计算一个终点
4.  确保终点不会跑出父View的边界
5.  使用UIView动画使view滑动到终点

UILongPressGestureRecognizer的使用

UILongPressGestureRecognizer \*longpress = \[\[UILongPressGestureRecognizer alloc\]initWithTarget:self action:@selector(huidiaohanshu:)\];

longpress.minimumPressDuration = 1.0;

\[self.view addGestureRecognizer:longpress\];

以上内容添加到viewcontroller里面的viewDidLoad函数中，然后再定义huidiaohanshu参数就是longpress如下

\-（void）huidiaohanshu：（UILongPressGestureRecognizer  \*）longpress

if(longpress.state == UIGestureRecognizerStateBegan)

CGPoint point = \[longpress locationInView:self.tableView\];

if(indexPath == nil)

return;

//使用手势所要达到的效果

自定义手势

继承UIGestureRecognizer，并实现以下方法

\-touchesBegan:withEvent:

\-touchesMoved:withEvent:

\-touchesEnded:withEvent:

\-touchesCancelled:withEvent:

具体如下：

新建一个类，继承UIGestureRecognizer，代码如下：

.h文件

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\#import  
typedef enum \{  
    DirectionUnknown = 0,  
    DirectionLeft,  
    DirectionRight  
\} Direction;

@interface HappyGestureRecognizer : UIGestureRecognizer  
@property (assign) int tickleCount;  
@property (assign) CGPoint curTickleStart;  
@property (assign) Direction lastDirection;

@end

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.m文件

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\#import "HappyGestureRecognizer.h"  
\#import  
\#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

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调用自定义手势和以前一样

HappyGestureRecognizer \*happy = \[\[HappyGestureRecognizer alloc\]initWithTarget:self action:@selector(handleHappy:)\];

\[self.view addGestureRecognizer:happy\];

回调函数

\-(void)handleHappy:(HappyGestureRecognizer \*)happy

//所要达到的效果

资料来源：[http://blog.csdn.net/totogo2010/article/details/8615940][http_blog.csdn.net_totogo2010_article_details_8615940]

[ http://www.cnblogs.com/salam/archive/2013/04/30/iOS\_gesture.html][http_www.cnblogs.com_salam_archive_2013_04_30_iOS_gesture.html]

[ http://mobile.51cto.com/iphone-403791.htm][http_mobile.51cto.com_iphone-403791.htm]

精通IOS开发（第五版）David Mark         Jack Nutting 等著

[1361893916_7845.png]: https://img-my.csdn.net/uploads/201302/26/1361893916_7845.png
[http_blog.csdn.net_totogo2010_article_details_8615940]: http://blog.csdn.net/totogo2010/article/details/8615940
[http_www.cnblogs.com_salam_archive_2013_04_30_iOS_gesture.html]: http://www.cnblogs.com/salam/archive/2013/04/30/iOS_gesture.html
[http_mobile.51cto.com_iphone-403791.htm]: http://mobile.51cto.com/iphone-403791.htm