[BS-25] IOS中手势UIGestureRecognizer概述

IOS中手势UIGestureRecognizer概述

一、概述

iPhone中处理触摸屏的操作,在3.2之前是主要使用的是由UIResponder而来的如下4种方式:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

但是这种方式甄别不同的手势操作实在是麻烦,需要你自己计算做不同的手势分辨。后来苹果就给出了一个比较简便的方式,就是使用UIGestureRecognizer。

二、UIGestureRecognizer

利用UIGestureRecognizer,能轻松识别用户在某个view上面做的一些常见手势。UIGestureRecognizer是一个抽象的基类,定义了所有手势的基本行为,不能直接使用。需使用UIGestureRecognizer的子类才能处理具体的手势,具体如下:

UITapGestureRecognizer //(敲击)

UIPinchGestureRecognizer //(捏合,用于缩放)

UIPanGestureRecognizer //(拖拽)

UISwipeGestureRecognizer //(轻扫)

UIRotationGestureRecognizer //(旋转)

UILongPressGestureRecognizer //(长按)

从名字上我们就能知道, Tap(点击)、Pinch(捏合)、Rotation(旋转)、Swipe(滑动,快速移动,是用于监测滑动的方向的)、Pan (拖移,慢速移动,是用于监测偏移的量的)以及 LongPress(长按)。

举个例子,可以在viewDidLoad函数里面添加:

-(void) viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanFrom:)];
[self.view addGestureRecognizer:panRecognizer];//关键语句,给self.view添加一个手势监测;
panRecognizer.maximumNumberOfTouches = ;
panRecognizer.delegate = self;
[panRecognizer release];
}

其它手势方法类似。

其核心就是设置delegate和在需要手势监测的view上使用addGestureRecognizer添加指定的手势监测。

当然要记得在作为delegate的view的头文件加上<UIGestureRecognizerDelegate>。

不过有些手势是关联的,怎么办呢?例如 Tap 与 LongPress、Swipe与 Pan,或是 Tap 一次与Tap 兩次。

手势识别是具有互斥的原则的,比如单击和双击,如果它识别出一种手势,其后的手势将不被识别。所以对于关联手势,要做特殊处理以帮助程序甄别,应该把当前手势归结到哪一类手势里面。

比如,单击和双击并存时,如果不做处理,它就只能发送出单击的消息。为了能够识别出双击手势,就需要做一个特殊处理逻辑,即先判断手势是否是双击,在双击失效的情况下作为单击手势处理。使用

[A requireGestureRecognizerToFail:B]函数,它可以指定当A手势发生时,即便A已经滿足条件了,也不会立刻触发,会等到指定的手势B确定失败之后才触发。

- (void)viewDidLoad
{
// 单击的 Recognizer
UITapGestureRecognizer* singleRecognizer;
singleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(SingleTap:)];
//点击的次数
singleTapRecognizer.numberOfTapsRequired = ; // 单击 //给self.view添加一个手势监测; [self.view addGestureRecognizer:singleRecognizer]; // 双击的 Recognizer
UITapGestureRecognizer* doubleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(DoubleTap:)];
doubleRecognizer.numberOfTapsRequired = ; // 双击
//关键语句,给self.view添加一个手势监测;
[self.view addGestureRecognizer:doubleRecognizer]; // 关键在这一行,双击手势确定监测失败才会触发单击手势的相应操作
[singleRecognizer requireGestureRecognizerToFail:doubleRecognizer];
[singleRecognizer release];
[doubleRecognizer release];
} -(void)SingleTap:(UITapGestureRecognizer*)recognizer
{
//处理单击操作
} -(void)DoubleTap:(UITapGestureRecognizer*)recognizer
{
//处理双击操作
}
 

三、iphone操作手势的大概种类

1.点击(Tap)
点击作为最常用手势,用于按下或选择一个控件或条目(类似于普通的鼠标点击)、

2.拖动(Drag)
拖动用于实现一些页面的滚动,以及对控件的移动功能。

3.滑动(Flick)
滑动用于实现页面的快速滚动和翻页的功能。

4.横扫(Swipe)
横扫手势用于激活列表项的快捷操作菜单

5.双击(Double Tap)
双击放大并居中显示图片,或恢复原大小(如果当前已经放大)。同时,双击能够激活针对文字编辑菜单。

6.放大(Pinch open)
放大手势可以实现以下功能:打开订阅源,打开文章的详情。在照片查看的时候,放大手势也可实现放大图片的功能。

7.缩小(Pinch close)
缩小手势,可以实现与放大手势相反且对应的功能的功能:关闭订阅源退出到首页,关闭文章退出至索引页。在照片查看的时候,缩小手势也可实现缩小图片的功能。

8.长按(Touch &Hold)
在我的订阅页,长按订阅源将自动进入编辑模式,同时选中手指当前按下的订阅源。这时可直接拖动订阅源移动位置。
针对文字长按,将出现放大镜辅助功能。松开后,则出现编辑菜单。
针对图片长按,将出现编辑菜单。

9.摇晃(Shake)
摇晃手势,将出现撤销与重做菜单。主要是针对用户文本输入的。

四、手势识别的状态

typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {
// 没有触摸事件发生,所有手势识别的默认状态
UIGestureRecognizerStatePossible,
// 一个手势已经开始但尚未改变或者完成时
UIGestureRecognizerStateBegan,
// 手势状态改变
UIGestureRecognizerStateChanged,
// 手势完成
UIGestureRecognizerStateEnded,
// 手势取消,恢复至Possible状态
UIGestureRecognizerStateCancelled,
// 手势失败,恢复至Possible状态
UIGestureRecognizerStateFailed,
// 识别到手势识别
UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
};

五、手势应用实例

每一个手势识别器的用法都差不多,比如UITapGestureRecognizer的使用步骤如下;

//创建手势识别器对象
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init]; //设置手势识别器对象的具体属性
tap.numberOfTapsRequired = ; // 连续敲击2次
tap.numberOfTouchesRequired = ; // 需要2根手指一起敲击 //添加手势识别器到对应的view上
[self.iconView addGestureRecognizer:tap]; //监听手势的触发
[tap addTarget:self action:@selector(tapIconView:)]; //eg1.敲击实例
@interface GRViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *iconView;
@end @implementation GRViewController - (void)viewDidLoad
{
[super viewDidLoad]; [self testTap2];
} - (void)testTap2
{
UIGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapView)];
tap.delegate = self;
[self.iconView addGestureRecognizer:tap];
} #pragma mark - 代理方法
/**
* 当点击view的时候,会先调用这个方法
*/
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
CGPoint pos = [touch locationInView:touch.view];
if (pos.x <= self.iconView.frame.size.width * 0.5) {
return YES;
}
return NO;
} - (void)testTap
{
// 1.创建手势识别器对象
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];
// 连续敲击2次,手势才能识别成功
tap.numberOfTapsRequired = ;
tap.numberOfTouchesRequired = ; // 2.添加手势识别器对象到对应的view
[self.iconView addGestureRecognizer:tap]; // 3.添加监听方法(识别到了对应的手势,就会调用监听方法)
[tap addTarget:self action:@selector(tapView)];
} - (void)tapView
{
NSLog(@"-----我敲击了屏幕!!");
} @end //eg2.长按和轻扫实例 @interface GRViewController ()
@property (weak, nonatomic) IBOutlet UIView *redView;
@end @implementation GRViewController - (void)viewDidLoad
{
[super viewDidLoad]; UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeView)]; swipe.direction = UISwipeGestureRecognizerDirectionUp; [self.redView addGestureRecognizer:swipe];
} - (void)swipeView
{
NSLog(@"swipeView");
} - (void)testLongPress
{
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] init];
[longPress addTarget:self action:@selector(longPressView)]; // 至少长按2秒
longPress.minimumPressDuration = ; // 在触发手势之前,50px范围内长按有效
longPress.allowableMovement = ; [self.redView addGestureRecognizer:longPress];
} - (void)longPressView
{
NSLog(@"长按了红色的view");
} @end //eg3. 缩放和旋转实例
@interface GRViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *iconView;
@end @implementation GRViewController - (void)viewDidLoad
{
[super viewDidLoad]; [self testPinchAndRotate];
} #pragma mark - 手势识别器的代理方法 /**
* 是否允许多个手势识别器同时有效
* Simultaneously : 同时地
*/
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
} #pragma mark - 缩放 + 旋转
- (void)testPinchAndRotate
{
[self testPinch];
[self testRotate];
} #pragma mark - 缩放手势(捏合手势)
- (void)testPinch
{
UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchView:)];
pinch.delegate = self;
[self.iconView addGestureRecognizer:pinch];
} - (void)pinchView:(UIPinchGestureRecognizer *)pinch
{
pinch.view.transform = CGAffineTransformScale(pinch.view.transform, pinch.scale, pinch.scale);
pinch.scale = ; // 这个真的很重要!!!
} #pragma mark - 旋转手势
- (void)testRotate
{
UIRotationGestureRecognizer *recognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateView:)];
recognizer.delegate = self;
[self.iconView addGestureRecognizer:recognizer];
} - (void)rotateView:(UIRotationGestureRecognizer *)recognizer
{
recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
recognizer.rotation = ; // 这个很重要!!!!!
}
@end //eg4. 拖拽实例
@interface GRViewController ()
@property (weak, nonatomic) IBOutlet UIView *purpleView; @end @implementation GRViewController - (void)viewDidLoad
{
[super viewDidLoad]; UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];
[self.purpleView addGestureRecognizer:pan];
} - (void)panView:(UIPanGestureRecognizer *)pan
{ switch (pan.state) {
case UIGestureRecognizerStateBegan: // 开始触发手势 break; case UIGestureRecognizerStateEnded: // 手势结束 break; default:
break;
} // 1.在view上面挪动的距离
CGPoint translation = [pan translationInView:pan.view];
CGPoint center = pan.view.center;
center.x += translation.x;
center.y += translation.y;
pan.view.center = center; // 2.清空移动的距离
[pan setTranslation:CGPointZero inView:pan.view];
} @end

参考:http://blog.csdn.net/likendsl/article/details/7554150

上一篇:关于Ctime库


下一篇:SElinux解决web网站无法访问