在 iPhone 或 iPad 的開發中，除了用 touchesBegan / touchesMoved / touchesEnded 這組方法來控制使用者的手指觸控外，也可以用 UIGestureRecognizer 的衍生類別來進行判斷。用 UIGestureRecognizer 的好處在于有現成的手勢，開發者不用自己計算手指移動軌跡。UIGestureRecognizer的衍生類別有以下幾種：
UITapGestureRecognizer
UIPinchGestureRecognizer
UIRotationGestureRecognizer
UISwipeGestureRecognizer
UIPanGestureRecognizer
UILongPressGestureRecognizer
從命名上不難了解這些類別所對應代表的手勢，分別是 Tap（點一下）、Pinch（二指往內或往外撥動）、Rotation（旋轉）、Swipe（滑動，快速移動）、Pan （拖移，慢速移動）以及 LongPress（長按）。這些手勢別在使用上也很簡單，只要在使用前定義并添加到對應的視圖上即可。
The concrete subclasses of UIGestureRecognizer
are the following:
UITapGestureRecognizer
一個gesture recognizer是針對一個特定的view的（包含其subview），用UIView的方法addGestureRecognize：去關聯一個view
一個gesture recognizer是不參與UIView的事件響應鏈的
各個手勢使用時的代碼：
UITapGestureRecognizer
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![tapGesture respondsToSelector:@selector(locationInView:)]) {
[tapGesture release];
tapGesture = nil;
}else {
tapGesture.delegate = self;
tapGesture.numberOfTapsRequired = 1; // The default value is 1.
tapGesture.numberOfTouchesRequired = 1; // The default value is 1.
[self.view addGestureRecognizer:tapGesture];
}
}
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded // 正常情況下只響應這個消息
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
break;
}
case UIGestureRecognizerStateFailed:{ //
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{ //
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
// 詢問一個手勢接收者是否應該開始解釋執行一個觸摸接收事件
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{
// CGPoint currentPoint = [gestureRecognizer locationInView:self.view];
// if (CGRectContainsPoint(CGRectMake(0, 0, 100, 100), currentPoint) ) {
// return YES;
// }
//
// return NO;
return YES;
}
// 詢問delegate，兩個手勢是否同時接收消息，返回YES同事接收。返回NO，不同是接收（如果另外一個手勢返回YES，則并不能保證不同時接收消息）the default implementation returns NO。
// 這個函數一般在一個手勢接收者要阻止另外一個手勢接收自己的消息的時候調用
-
(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return NO;
}
// 詢問delegate是否允許手勢接收者接收一個touch對象
// 返回YES，則允許對這個touch對象審核，NO，則不允許。
// 這個方法在touchesBegan:withEvent:之前調用，為一個新的touch對象進行調用
-
(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
return YES;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![pinchGesture respondsToSelector:@selector(locationInView:)]) {
[pinchGesture release];
pinchGesture = nil;
}else {
pinchGesture.delegate = self;
[self.view addGestureRecognizer: pinchGesture];
}
}
- (void)handleGesture:(UIPinchGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
CGFloat scale = gestureRecognizer.scale;
NSLog(@"======scale: %f", scale);
CGFloat velocity = gestureRecognizer.velocity;
NSLog(@"======scvelocityale: %f", velocity);
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
break;
}
case UIGestureRecognizerStateBegan:{ //
NSLog(@"======UIGestureRecognizerStateBegan");
break;
}
case UIGestureRecognizerStateChanged:{ //
NSLog(@"======UIGestureRecognizerStateChanged");
gestureRecognizer.view.transform = CGAffineTransformScale(gestureRecognizer.view.transform, gestureRecognizer.scale, gestureRecognizer.scale);
gestureRecognizer.scale = 1; // 重置，很重要！！！
break;
}
case UIGestureRecognizerStateCancelled:{ //
NSLog(@"======UIGestureRecognizerStateCancelled");
break;
}
case UIGestureRecognizerStateFailed:{ //
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{ //
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
recognizer.scale是pinch手勢的scale值，它每次都是從1開始，以兩指的距離為參考，如果捏合兩指，則scale變小；如果兩指向外拉，則scale變大
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![rotationGesture respondsToSelector:@selector(locationInView:)]) {
[rotationGesture release];
rotationGesture = nil;
}else {
rotationGesture.delegate = self;
[self.view addGestureRecognizer:rotationGesture];
}
}
- (void)handleGesture:(UIRotationGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
CGFloat rotation = gestureRecognizer.rotation;
NSLog(@"===rotation: %f", rotation);
CGFloat velocity = gestureRecognizer.velocity;
NSLog(@"======velocity: %f", velocity);
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
break;
}
case UIGestureRecognizerStateBegan:{ //
NSLog(@"======UIGestureRecognizerStateBegan");
break;
}
case UIGestureRecognizerStateChanged:{ //
NSLog(@"======UIGestureRecognizerStateChanged");
gestureRecognizer.view.transform = CGAffineTransformRotate(gestureRecognizer.view.transform, gestureRecognizer.rotation);
gestureRecognizer.rotation = 0; // 重置 這個相當重要！！！
break;
}
case UIGestureRecognizerStateCancelled:{ //
NSLog(@"======UIGestureRecognizerStateCancelled");
break;
}
case UIGestureRecognizerStateFailed:{ //
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{ //
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
// right
UISwipeGestureRecognizer *swipeGestureRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![swipeGestureRight respondsToSelector:@selector(locationInView:)]) {
[swipeGestureRight release];
swipeGestureRight = nil;
}else {
swipeGestureRight.delegate = self;
swipeGestureRight.numberOfTouchesRequired = 1;// 手指個數 The default value is 1.
swipeGestureRight.direction = UISwipeGestureRecognizerDirectionRight;// 同一個手勢只能指定一個方向，不能同時指定多個方向，要指定多個方向 必須用多個手勢
[self.view addGestureRecognizer:swipeGestureRight];
}
// left
UISwipeGestureRecognizer *swipeGestureLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![swipeGestureLeft respondsToSelector:@selector(locationInView:)]) {
[swipeGestureLeft release];
swipeGestureLeft = nil;
}else {
swipeGestureLeft.delegate = self;
swipeGestureLeft.numberOfTouchesRequired = 1;// 手指個數 The default value is 1.
swipeGestureLeft.direction = UISwipeGestureRecognizerDirectionLeft;// 同一個手勢只能指定一個方向，不能同時指定多個方向，要指定多個方向 必須用多個手勢
[self.view addGestureRecognizer:swipeGestureLeft];
}
// Up
UISwipeGestureRecognizer *swipeGestureUp = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![swipeGestureUp respondsToSelector:@selector(locationInView:)]) {
[swipeGestureUp release];
swipeGestureUp = nil;
}else {
swipeGestureUp.delegate = self;
swipeGestureUp.numberOfTouchesRequired = 1;// 手指個數 The default value is 1.
swipeGestureUp.direction = UISwipeGestureRecognizerDirectionUp;// 同一個手勢只能指定一個方向，不能同時指定多個方向，要指定多個方向 必須用多個手勢
[self.view addGestureRecognizer:swipeGestureUp];
}
// Down
UISwipeGestureRecognizer *swipeGestureDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![swipeGestureDown respondsToSelector:@selector(locationInView:)]) {
[swipeGestureDown release];
swipeGestureDown = nil;
}else {
swipeGestureDown.delegate = self;
swipeGestureDown.numberOfTouchesRequired = 1;// 手指個數 The default value is 1.
swipeGestureDown.direction = UISwipeGestureRecognizerDirectionDown;// 同一個手勢只能指定一個方向，不能同時指定多個方向，要指定多個方向 必須用多個手勢
[self.view addGestureRecognizer:swipeGestureDown];
}
}
- (void)handleGesture:(UISwipeGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
UISwipeGestureRecognizerDirection direction = gestureRecognizer.direction;
switch (direction) {
case UISwipeGestureRecognizerDirectionRight:
{
NSLog(@"direction==UISwipeGestureRecognizerDirectionRight");
break;
}
case UISwipeGestureRecognizerDirectionLeft:
{
NSLog(@"direction==UISwipeGestureRecognizerDirectionLeft");
break;
}
case UISwipeGestureRecognizerDirectionUp:
{
NSLog(@"direction==UISwipeGestureRecognizerDirectionUp");
break;
}
case UISwipeGestureRecognizerDirectionDown:
{
NSLog(@"direction==UISwipeGestureRecognizerDirectionDown");
break;
}
default:
break;
}
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIView *view = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
view.backgroundColor = [UIColor blueColor];
[self.view addSubview:view];
UIPanGestureRecognizer *panPressGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![panPressGesture respondsToSelector:@selector(locationInView:)]) {
[panPressGesture release];
panPressGesture = nil;
}else {
panPressGesture.delegate = self;
panPressGesture.maximumNumberOfTouches = NSUIntegerMax;// The default value is NSUIntegerMax.
panPressGesture.minimumNumberOfTouches = 1;// The default value is 1.
[view addGestureRecognizer:panPressGesture];
}
}
// 拖拽手勢
- (void)handleGesture:(UIPanGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateBegan:{
NSLog(@"======UIGestureRecognizerStateBegan");
break;
}
case UIGestureRecognizerStateChanged:{
NSLog(@"======UIGestureRecognizerStateChanged");
CGPoint translation = [gestureRecognizer translationInView:self.view];
view.center = CGPointMake(gestureRecognizer.view.center.x + translation.x, gestureRecognizer.view.center.y + translation.y);
[gestureRecognizer setTranslation:CGPointMake(0, 0) inView:self.view];// 注意一旦你完成上述的移動，將translation重置為0十分重要。否則translation每次都會疊加，很快你的view就會移除屏幕！
break;
}
case UIGestureRecognizerStateCancelled:{
NSLog(@"======UIGestureRecognizerStateCancelled");
break;
}
case UIGestureRecognizerStateFailed:{
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
CGPoint velocity = [gestureRecognizer velocityInView:self.view];// 分別得出x，y軸方向的速度向量長度（velocity代表按照當前速度，每秒可移動的像素個數，分xy軸兩個方向）
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));// 根據直角三角形的算法算出綜合速度向量長度
// 如果長度小于200，則減少基本速度，否則增加它。
CGFloat slideMult = magnitude / 200;
NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);
float slideFactor = 0.1 * slideMult; // Increase for more of a slide
// 基于速度和滑動因子計算終點
CGPoint finalPoint = CGPointMake(view.center.x + (velocity.x * slideFactor),
view.center.y + (velocity.y * slideFactor));
// 確定終點在視圖邊界內
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:^{
view.center = finalPoint;
} completion:nil];
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
if (![longPressGesture respondsToSelector:@selector(locationInView:)]) {
[longPressGesture release];
longPressGesture = nil;
}else {
longPressGesture.delegate = self;
longPressGesture.numberOfTapsRequired = 0; // The default number of taps is 0.
longPressGesture.minimumPressDuration = 0.1f; // The default duration is is 0.5 seconds.
longPressGesture.numberOfTouchesRequired = 1; // The default number of fingers is 1.
longPressGesture.allowableMovement = 10; // The default distance is 10 pixels.
[self.view addGestureRecognizer:longPressGesture];
}
}
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 這個view是手勢所屬的view，也就是增加手勢的那個view
switch (gestureRecognizer.state) {
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
break;
}
case UIGestureRecognizerStateBegan:{ //
NSLog(@"======UIGestureRecognizerStateBegan");
break;
}
case UIGestureRecognizerStateChanged:{ //
NSLog(@"======UIGestureRecognizerStateChanged");
break;
}
case UIGestureRecognizerStateCancelled:{ //
NSLog(@"======UIGestureRecognizerStateCancelled");
break;
}
case UIGestureRecognizerStateFailed:{ //
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{ //
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
default:{
NSLog(@"======Unknow gestureRecognizer");
break;
}
}
}
// 詢問一個手勢接收者是否應該開始解釋執行一個觸摸接收事件
-
(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{
CGPoint currentPoint = [gestureRecognizer locationInView:self.view];
if (CGRectContainsPoint(CGRectMake(0, 0, 100, 100), currentPoint) ) {
return YES;}
return NO;
}
// 詢問delegate，兩個手勢是否同時接收消息，返回YES同事接收。返回NO，不同是接收（如果另外一個手勢返回YES，則并不能保證不同時接收消息）the default implementation returns NO。
// 這個函數一般在一個手勢接收者要阻止另外一個手勢接收自己的消息的時候調用
-
(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return NO;
}
// 詢問delegate是否允許手勢接收者接收一個touch對象
// 返回YES，則允許對這個touch對象審核，NO，則不允許。
// 這個方法在touchesBegan:withEvent:之前調用，為一個新的touch對象進行調用
-
(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
return YES;
}
