1、UIGestureRecognizer介紹
- UITapGestureRecognizer 點一下
- UIPinchGestureRecognizer 二指往內或往外撥動,平時經常用到的縮放
- UIRotationGestureRecognizer 旋轉
- UISwipeGestureRecognizer 滑動,快速移動
- UIPanGestureRecognizer 拖移,慢速移動
- UILongPressGestureRecognizer 長按
UIGestureRecognizer的繼承關係如下:
2、使用手勢的步驟
3、Pan 拖動手勢:
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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]; |
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- (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縮放手勢
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UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc]
initWithTarget:self
action:@selector(handlePinch:)];<p class="p1">[<span class="s1">snakeImageView</span> <span class="s2">addGestureRecognizer</span>:pinchGestureRecognizer];</p> |
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- (void) handlePinch:(UIPinchGestureRecognizer*) recognizer
{
recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
recognizer.scale = 1;
} |
5、Rotation旋轉手勢
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UIRotationGestureRecognizer *rotateRecognizer = [[UIRotationGestureRecognizer alloc]
initWithTarget:self
action:@selector(handleRotate:)];
[snakeImageView addGestureRecognizer:rotateRecognizer]; |
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- (void) handleRotate:(UIRotationGestureRecognizer*) recognizer
{
recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
recognizer.rotation = 0;
} |
6、添加第二個ImagView並添加手勢
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- (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]];
} |
多添加了一條龍的view,兩個view都能接收上面的三種手勢。運行效果如下:
7、拖動(pan手勢)速度(以較快的速度拖放後view有滑行的效果)
- 監視手勢是否結束
- 監視觸摸的速度
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- (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];
} |
代碼實現解析:
- 計算速度向量的長度(估計大部分都忘了)這些知識了。
- 如果速度向量小於200,那就會得到一個小於的小數,那麼滑行會很短
- 基於速度和速度因素計算一個終點
- 確保終點不會跑出父View的邊界
- 使用UIView動畫使view滑動到終點
8、同時觸發兩個view的手勢
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@interface ViewController : UIViewController<UIGestureRecognizerDelegate>
@end |
並在協議這個方法裏返回YES。
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-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
} |
把self作爲代理設置給手勢:
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panGestureRecognizer.delegate = self;
pinchGestureRecognizer.delegate = self;
rotateRecognizer.delegate = self; |
這樣可以同時拖動或旋轉縮放兩個view了。
9、tap點擊手勢
這裏爲了方便看到tap的效果,當點擊一下屏幕時,播放一個聲音。
爲了播放聲音,我們加入AVFoundation.framework這個框架。
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- (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;
} |
我會在最後例子代碼給出完整代碼,添加手勢的步驟和前面一樣的。
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#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
@interface ViewController : UIViewController<UIGestureRecognizerDelegate>
@property (strong) AVAudioPlayer * chompPlayer;
@property (strong) AVAudioPlayer * hehePlayer;
@end |
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- (void)handleTap:(UITapGestureRecognizer *)recognizer {
[self.chompPlayer play];
} |
運行,點一下某個圖,就會播放一個咬東西的聲音。
不過這個點擊播放聲音有點缺陷,就是在慢慢拖動的時候也會播放。這使得兩個手勢重合了。怎麼解決呢?使用手勢的:requireGestureRecognizerToFail方法。
10、手勢的依賴性
在viewDidLoad的循環裏添加這段代碼:
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[tapRecognizer requireGestureRecognizerToFail:panGestureRecognizer]; |
意思就是,當如果pan手勢失敗,就是沒發生拖動,纔會出發tap手勢。這樣如果你有輕微的拖動,那就是pan手勢發生了。tap的聲音就不會發出來了。
11、自定義手勢
自定義手勢繼承:UIGestureRecognizer,實現下面的方法:
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– touchesBegan:withEvent:
– touchesMoved:withEvent:
– touchesEnded:withEvent:
- touchesCancelled:withEvent: |
新建一個類,繼承UIGestureRecognizer,代碼如下:
.h文件
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#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
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#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;
// 確認方向改變了
if (self.lastDirection == DirectionUnknown ||
(self.lastDirection == DirectionLeft && curDirection == DirectionRight) ||
(self.lastDirection == DirectionRight && curDirection == DirectionLeft)) {
// 撓癢次數
self.tickleCount++;
self.curTickleStart = ticklePoint;
self.lastDirection = curDirection;
// 一旦撓癢次數超過指定數,設置手勢爲結束狀態
// 這樣回調函數會被調用。
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 |
調用自定義手勢和上面一樣,回到這樣寫:
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- (void)handleHappy:(HappyGestureRecognizer *)recognizer{
[self.hehePlayer play];
} |
手勢成功後播放呵呵笑的聲音。
在真機上運行,按住某個view,快速左右拖動,就會發出笑的聲音了。