手势操作知识大餐 ——iOS

1.点击（非连续型）

UITapGestureRecognizer类

Eg:

1)定义元素

UIView* view = [[UIView alloc]initWithFrame:CGRectMake(0, 100, 300, 200)];

view.backgroundColor = [UIColor yellowColor];

[self.view addSubview:view];

注意：当元素为UIImageView时，一定要设置它的userInteractionEnabled值为YES.

2）元素上添加手势

UITapGestureRecognizer* clickRecognizer = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGestureRecognizer:)];

clickRecognizer.numberOfTouchesRequired = 2;//1.一根手指头 2.两根手指头 。。。（指头个数）

clickRecognizer.numberOfTapsRequired = 2;//1.单击 2.双击（敲击次数）

// clickRecognizer.numberOfTouches = 1;//暂时未知功能

[view addGestureRecognizer:clickRecognizer];

2.拖动（连续型）

UIPanGestureRecognizer类

Eg:
1)定义元素（同上）

2）元素上添加手势

UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];

[imageView addGestureRecognizer:recognizer];

3）拖动方法

-(void)handlePan:(UIPanGestureRecognizer*)recognizer{//可以根据自己需求修改拖动元素时的算法

//视图前置操作

[recognizer.view.superview bringSubviewToFront:recognizer.view];

CGPoint center = recognizer.view.center;

CGFloat cornerRadius = recognizer.view.frame.size.width / 2;

CGPoint translation = [recognizer translationInView:self.view];

//NSLog(@"%@", NSStringFromCGPoint(translation));

recognizer.view.center = CGPointMake(center.x + translation.x, center.y + translation.y);

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

if (recognizer.state == UIGestureRecognizerStateEnded) {

//计算速度向量的长度，当他小于200时，滑行会很短

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); //e.g. 397.973175, slideMult: 1.989866

//基于速度和速度因素计算一个终点

float slideFactor = 0.1 * slideMult;

CGPoint finalPoint = CGPointMake(center.x + (velocity.x * slideFactor),

center.y + (velocity.y * slideFactor));

//限制最小［cornerRadius］和最大边界值［self.view.bounds.size.width - cornerRadius］，以免拖动出屏幕界限

finalPoint.x = MIN(MAX(finalPoint.x, cornerRadius),

self.view.bounds.size.width - cornerRadius);

finalPoint.y = MIN(MAX(finalPoint.y, cornerRadius),

self.view.bounds.size.height - cornerRadius);

//使用 UIView 动画使 view 滑行到终点

[UIView animateWithDuration:slideFactor*2

delay:0

options:UIViewAnimationOptionCurveEaseOut

animations:^{

recognizer.view.center = finalPoint;

}

completion:nil];

}

NSLog(@"test move.");

}

待续。。。