手势

最新推荐文章于 2024-11-26 11:45:05 发布

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在cocos2d里面处理的触摸事件都定义在CCLayer的CCStandardTouchDelegate跟CCTargetedTouchDelegate里面。其中对于CCTargetedTouchDelegate的解释是dispatcher会把一个NSSet的触摸事件都拆分好，用户只需要处理一个UITouch就可以了，说是可以更好的处理多点触摸。但是这次我用的是CCStandardTouchDelegate，跟CocoaTouch中处理触摸事件的delegate是一样的，定义如下：

1@protocol CCStandardTouchDelegate <NSObject>

2@optional

3- (void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;

4- (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;

5- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

6- (void)ccTouchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;

7@end

以下是几种常用的手势。

pinch zoom

用2根手指缩放图片，这个动作应该是非常常用的了。

首先要在touchBegan的时候，算出2指的初始距离。

01if ([touches count] == 2) {

02        // Get points of both touches

03        NSArray *twoTouch = [touches allObjects];

04         UITouch *tOne = [twoTouch objectAtIndex:0];

05        UITouch *tTwo = [twoTouch objectAtIndex:1];

06        CGPoint firstTouch = [tOne locationInView:[tOne view]];

07        CGPoint secondTouch = [tTwo locationInView:[tTwo view]];

08        // Find the distance between those two points

09        initialDistance = sqrt(pow(firstTouch.x - secondTouch.x, 2.0f) + pow(firstTouch.y - secondTouch.y, 2.0f));

10}

然后在touchMoved算一下是该zoom in还是out。

01if ([touches count] == 2) {

02        NSArray *twoTouch = [touches allObjects];

03 

04        UITouch *tOne = [twoTouch objectAtIndex:0];

05        UITouch *tTwo = [twoTouch objectAtIndex:1];

06        CGPoint firstTouch = [tOne locationInView:[tOne view]];

07        CGPoint secondTouch = [tTwo locationInView:[tTwo view]];

08        CGFloat currentDistance = sqrt(pow(firstTouch.x - secondTouch.x, 2.0f) + pow(firstTouch.y - secondTouch.y, 2.0f));

09 

10        if (initialDistance == 0) {

11            initialDistance = currentDistance;

12            // set to 0 in case the two touches weren't at the same time

13        } else if (currentDistance - initialDistance > 0) {

14            // zoom in

15            if (currentImage.scale < 1.0f) {

16                zoomFactor += zoomFactor *0.03f;

17                currentImage.scale = zoomFactor;

18            }

19 

20            initialDistance = currentDistance;

21        } else if (currentDistance - initialDistance < 0) {

22            // zoom out

23            if (currentImage.scale > 0.45f) {

24                zoomFactor -= zoomFactor *0.03f;

25                currentImage.scale = zoomFactor;

26            }

27 

28            if (currentImage.position.x > [currentImage boundingBox].size.width / 2 ||

29                currentImage.position.x < 320 - [currentImage boundingBox].size.width / 2 ||

30                currentImage.position.y > [currentImage boundingBox].size.height / 2 ||

31                currentImage.position.y < 480 - [currentImage boundingBox].size.height / 2) {

32                currentImage.position = ccp(160,240);

33            }

34 

35            initialDistance = currentDistance;

36        }

37}