The concrete subclasses of UIGestureRecognizer
are the following:
UITapGestureRecognizer
UITapGestureRecognizer
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;
}
}
UIPanGestureRecognizer
// 拖拽手势
- (void)handleGesture:(UIPanGestureRecognizer *)gestureRecognizer
{
UIView *view = [gestureRecognizer view]; // 这个view是手势所属的view，也就是增加手势的那个view switch (gestureRecognizer.state) {
case UIGestureRecognizerStateBegan:{
NSLog(@"======UIGestureRecognizerStateBegan");
break;
}
case UIGestureRecognizerStateChanged:{
NSLog(@"======UIGestureRecognizerStateChanged");
/*
让view跟着手指移动
1.获取每次系统捕获到的手指移动的偏移量translation
2.根据偏移量translation算出当前view应该出现的位置
3.设置view的新frame
4.将translation重置为0（十分重要。否则translation每次都会叠加，很快你的view就会移除屏幕！）
*/
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动，将translation重置为0十分重要。否则translation每次都会叠加，很快你的view就会移除屏幕！
break;
}
case UIGestureRecognizerStateCancelled:{
NSLog(@"======UIGestureRecognizerStateCancelled");
break;
}
case UIGestureRecognizerStateFailed:{
NSLog(@"======UIGestureRecognizerStateFailed");
break;
}
case UIGestureRecognizerStatePossible:{
NSLog(@"======UIGestureRecognizerStatePossible");
break;
}
case UIGestureRecognizerStateEnded:{ // UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
/*
当手势结束后，view的减速缓冲效果
模拟减速写的一个很简单的方法。它遵循如下策略：
计算速度向量的长度（i.e. magnitude）
如果长度小于200，则减少基本速度，否则增加它。
基于速度和滑动因子计算终点
确定终点在视图边界内
让视图使用动画到达最终的静止点
使用“Ease out“动画参数，使运动速度随着时间降低
*/
NSLog(@"======UIGestureRecognizerStateEnded || UIGestureRecognizerStateRecognized");
CGPoint velocity = [gestureRecognizer velocityInView:self.view];// 分别得出x，y轴方向的速度向量长度（velocity代表按照当前速度，每秒可移动的像素个数，分xy轴两个方向）
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));// 根据直角三角形的算法算出综合速度向量长度
// 如果长度小于200，则减少基本速度，否则增加它。
CGFloat slideMult = magnitude / 200;
NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);
float slideFactor = 0.1 * slideMult; // Increase for more of a slide
// 基于速度和滑动因子计算终点
CGPoint finalPoint = CGPointMake(view.center.x + (velocity.x * slideFactor),
view.center.y + (velocity.y * slideFactor));
// 确定终点在视图边界内
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;
}
}
}
