IOS笔记051-手势使用

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是一个抽象类，定义了所有手势的基本行为，使用它的子类才能处理具体的手势

UITapGestureRecognizer(敲击)

UIPinchGestureRecognizer(捏合，用于缩放)

UIPanGestureRecognizer(拖拽)

UISwipeGestureRecognizer(轻扫)

UIRotationGestureRecognizer(旋转)

UILongPressGestureRecognizer(长按)

使用方法

// 创建点按手势

UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap:)];

// 给imageView添加手势，默认imageView不响应事件

// 设置imageView 响应事件

self.imageView.userInteractionEnabled = YES;

[self.imageView addGestureRecognizer:gesture];

响应手势事件，可以在里面进行形变

// 响应手势事件

- (void)tap:(UITapGestureRecognizer *)tap

{

NSLog(@"%s",__func__);

// 旋转

self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, M_PI_4);

}

手势的状态

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

};

手势的一些代理方法

#pragma mark - 手势代理方法

// 是否开始手势

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

return YES;

}

//是否允许同时支持多个手势，默认是不支持多个手势

// 返回yes表示支持多个手势

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer

{

return YES;

}

// 是否允许接收手指的触摸点

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch

{

// NSLog(@"%@",touch);

return YES;

}

逐个实现每个手势

1、点按 UITapGestureRecognizer

#pragma mark - 各种手势

// UITapGestureRecognizer

// 点按

- (void)tapImage

{

// 创建点按手势

UITapGestureRecognizer *gestur = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(tap:)];

// 给imageView添加手势，默认imageView不响应事件

gestur.delegate = self;

gestur.numberOfTapsRequired = 2; // 点击次数

[self.imageView addGestureRecognizer:gestur];

}

// 响应点按手势事件

- (void)tap:(UITapGestureRecognizer *)tap

{

// 连续点按两次就更换显示图片

if (tap.numberOfTapsRequired == 2) {

self.imageView.image = [UIImage imageNamed:@"qianbao"];

}

}

2、捏合 可以使用两个手指进行缩放 UIPinchGestureRecognizer

//UIPinchGestureRecognizer

// 捏合，可以缩放

- (void)pinchImage

{

UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizeralloc] initWithTarget:selfaction:@selector(pinch:)];

//pinch.delegate = self;

[self.imageViewaddGestureRecognizer:pinch];

}

- (void)pinch:(UIPinchGestureRecognizer *)pinch

{

self.imageView.transform = CGAffineTransformScale(self.imageView.transform, pinch.scale,pinch.scale);

// 复位

pinch.scale = 1;

}

3、长按 UILongPressGestureRecognizer

// UILongPressGestureRecognizer

// 长按,默认会触发两次,开始时调用一次，结束时调用一次，可以根据手势状态

- (void)longPressImage

{

UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizeralloc] initWithTarget:selfaction:@selector(longPress:)];

[self.imageView addGestureRecognizer:longPress];

}

- (void)longPress:(UILongPressGestureRecognizer *)longP

{

// 判断手势状态，只在手势开始的时候执行。

if(longP.state == UIGestureRecognizerStateBegan)

{

self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, M_PI);

}

}

4、清扫 轻轻向某个方向滑动

// UISwipeGestureRecognizer

// 清扫手势，默认向右

- (void)swipeImage

{

UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizeralloc] initWithTarget:selfaction:@selector(swipe:)];

[self.imageViewaddGestureRecognizer:swipe];

// 如果以后想要一个控件支持多个方向的轻扫，必须创建多个轻扫手势，一个轻扫手势只支持一个方向

// 默认轻扫的方向是往右

UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizeralloc] initWithTarget:selfaction:@selector(swipe:)];

swipeUp.direction = UISwipeGestureRecognizerDirectionUp;

[self.imageView addGestureRecognizer:swipeUp];

}

- (void)swipe:(UISwipeGestureRecognizer *)swipe

{

// 输出状态

NSLog(@"%s\n%ld",__func__,swipe.direction);

}

5、旋转 UIRotationGestureRecognizer

// UIRotationGestureRecognizer

// 旋转手势

- (void)rotateImage

{

UIRotationGestureRecognizer *rotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];

[self.imageView addGestureRecognizer:rotate];

}

- (void)rotate:(UIRotationGestureRecognizer *)rotate

{

self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotate.rotation);

// 复位

rotate.rotation = 0;

}

6、拖拽 UIPanGestureRecognizer

// 拖拽

- (void)panImage

{

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizeralloc] initWithTarget:selfaction:@selector(pan:)];

[self.imageViewaddGestureRecognizer:pan];

}

- (void)pan:(UIPanGestureRecognizer *)pan

{

// 获取手势移动点

CGPoint curP = [pan translationInView:self.imageView];

self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, curP.x, curP.y);

// 复位,一定要复位

[pan setTranslation:CGPointZeroinView:self.imageView];

}

在视图加载时进行调用即可

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

// 设置imageView 响应事件

self.imageView.userInteractionEnabled = YES;

// 点按图形

[self tapImage];

// 长按

[selflongPressImage];

// 清扫

[self swipeImage];

// 旋转

[self rotateImage];

// 缩放

[self pinchImage];

// 拖拽

// [self panImage];

}

简单效果如下

手势使用例子-抽屉效果

抽屉效果的实现



1、需要三个视图，一个主视图，两个底部视图

@property (nonatomic,weak) UIView *mainView;

@property (nonatomic,weak) UIView *leftView;

@property (nonatomic,weak) UIView *rightView;

2、初始化界面

// 初始化界面

- (void)initUI

{

// 左划显示视图

UIView *left = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];

self.leftView = left;

self.leftView.backgroundColor = [UIColorblueColor];

[self.view addSubview:self.leftView];

// 右划显示视图

UIView *right = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];

self.rightView = right;

self.rightView.backgroundColor = [UIColorgreenColor];

[self.view addSubview:self.rightView];

// 主视图

UIView *main = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];

self.mainView = main;

self.mainView.backgroundColor = [UIColorredColor];

[self.view addSubview:self.mainView];

}

3、添加手势

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

// 初始化界面

[self initUI];

//添加手势

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizeralloc] initWithTarget:selfaction:@selector(pan:)];

[self.view addGestureRecognizer:pan];

}

手势监听方法

#define kLeft -250

#define kRight 275

- (void)pan:(UIPanGestureRecognizer *)pan

{

//获取当前点

CGPoint curP = [pan translationInView:self.view]; // 转换指定view的位置

// x轴偏移，y轴改变，宽度高度都跟着改变

self.mainView.frame = [self frameWithOffsetX:curP.x];

// 更新几个视图的状态

[self observeValueForKeyPath:nil ofObject:nil change:nil context:nil];

// 复位

[pan setTranslation:CGPointZero inView:self.view];

// 定位,手势结束后进行判断

if (pan.state == UIGestureRecognizerStateEnded) {

// 左划

CGFloat target = 0;

// 如果向右滑动操作屏幕的一半就定位到 275

if (self.mainView.frame.origin.x > kWidth * 0.5) {

target = kRight;

}

// 否则就定位到 -250

else if(CGRectGetMaxX(self.mainView.frame) < kWidth * 0.5)

{

target = kLeft;

}

// 获得x轴的偏移量

CGFloat offsetX = target - self.mainView.frame.origin.x ;

[UIView animateWithDuration:0.25 animations:^{

if (target == 0)

{

self.mainView.frame = self.view.bounds;

}

else

{

self.mainView.frame = [self frameWithOffsetX:offsetX];

}

}];

}

}

每次滑动时都要判断要显示的底部视图，显示left还是right,根据x值就可以判断

// 监听frame属性的改变

// 只要监听的属性一改变，就会调用观察者的这个方法，通知你有新值

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{

// 更新几个视图的状态

// 判断x坐标大小，大于0向右滑动，小于0 向左滑动

if(self.mainView.frame.origin.x > 0)

{

self.rightView.hidden = YES;

self.leftView.hidden = NO;

}

else

{

self.rightView.hidden = NO;

self.leftView.hidden = YES;

}

}

每次滑动都要随时判断frame的状态，在方法 frameWithOffsetX 中进行判断

#define kWidth 80 // 距离顶部最大距离

// 计算frame的位置信息

- (CGRect)frameWithOffsetX:(CGFloat)offsetX

{

CGRect frame = self.mainView.frame;

// 获得x轴偏移量

frame.origin.x += offsetX;

// 获得屏幕宽度好高度

CGFloat screenW = [UIScreenmainScreen].bounds.size.width;

CGFloat screenH = [UIScreenmainScreen].bounds.size.height;

// y轴偏移量

CGFloat offsetY = offsetX * kWidth / screenW;

// 获得上一次的高度

CGFloat preH = frame.size.height;

// 获得上一次的宽度

CGFloat preW = frame.size.width;

// 当前的高度

CGFloat curH = preH - 2 * offsetY;

if (frame.origin.x < 0) {

curH = preH + 2 * offsetY;

}

// 获取缩放比例

CGFloat scale = curH / preH;

// 当前的宽度

CGFloat curW = preW * scale;

// 设置frame

frame.origin.y = (screenH - curH) / 2;

frame.size.height = curH;

frame.size.width = curW;

return frame;

}

4、自动提示宏

在使用KVO对某个属性进行监听时，如果参数直接传入字符串，很有可能写错。可以使用自动提示宏来自动提示要监视的属性。

// 使用KVO时刻监听属性的改变

// Observer:观察者 谁想监听

// KeyPath：监听的属性

// options:监听新值的改变

[self.mainViewaddObserver:selfforKeyPath:keyPath(self.mainView, frame) options:NSKeyValueObservingOptionNewcontext:nil];

// 为了防止给属性添加监视器时写错，可以使用自动提示宏来传参数

[self.mainView addObserver:self forKeyPath:@“frame”options:NSKeyValueObservingOptionNew context:nil];

在方法 observeValueForKeyPath 中对属性改变进行监听。

宏的书写规则

// 自动提示宏

// 宏的操作原理，每输入一个字母就会直接把宏右边的拷贝，并且会自动补齐前面的内容。

// 宏里面的#，会自动把后面的参数变成C语言的字符串,

// (obj.keyPath,keyPath) 逗号表达式，最终结果取keyPath

// void表示不使用这个参数的返回结果

// @() 表示把c语言字符串转换成OC字符串

#define keyPath(obj,keyPath) @(((void)obj.keyPath,#keyPath))