前言
- 最近做了一个这样子的需求，在CollectionView上面移动Item并且不影响正常CollectionView的左右滑动
- 核心其实就是解决左右滚动和上下滑动冲突处理
- TableView和CollectionView道理是一样的，可以采用同样的方式去处理
Demo地址
这里提供两种思路
第一种，在Item添加Pan手势，
大致思路，在Pan手势当中去做逻辑判断处理回调出去，然后改变CollectionView 的contentOffset
__block bool move = false;
__block CGPoint beginPoint = CGPointZero;
[self.scanImageView kj_AddGestureRecognizer:(KJGestureTypePan) block:^(UIView * _Nonnull view, UIGestureRecognizer * _Nonnull gesture) {
CGPoint point = [gesture locationInView:view];
if (gesture.state == UIGestureRecognizerStateBegan) {
beginPoint = [gesture locationInView:view];
}else if (point.y <= 5 && move == false) {
move = true;
CGPoint pt = [gesture locationInView:kKeyWindow];
if (weakself.kMoveBlock) weakself.kMoveBlock(weakself,pt,0);
}else if (move && point.y < 5 && gesture.state == UIGestureRecognizerStateChanged) {
CGPoint pt = [gesture locationInView:kKeyWindow];
if (weakself.kMoveBlock) weakself.kMoveBlock(weakself,pt,1);
}else if (gesture.state == UIGestureRecognizerStateRecognized) {
move = false;
beginPoint = CGPointZero;
CGPoint pt = [gesture locationInView:kKeyWindow];
if (weakself.kMoveBlock) weakself.kMoveBlock(weakself,pt,2);
}else {
point.x = beginPoint.x - point.x;
point.y = beginPoint.y - point.y;
if (weakself.kMoveTableBlock) weakself.kMoveTableBlock(weakself,point);
}
}];
改变CollectionView的contentOffset，
/// 拖动手势回调
cell.kMoveBlock = ^(UICollectionViewCell *item,CGPoint point,NSInteger move){
if (weakSelf.matterImageMoveBlock) {
NSIndexPath *idx = kIndexpathSubviewCollectionview(item, self.collectView);
weakSelf.matterImageMoveBlock(move,point,idx.row-1);
}
};
cell.kMoveTableBlock = ^(UICollectionViewCell *item,CGPoint point) {
NSLog(@"---:%.2f,%.2f",weakSelf.collectView.contentOffset.x,point.x);
if (abs(point.x) < 5) {
return;
}
weakSelf.collectView.contentOffset = CGPointMake(point.x,0);
};
总结：这种方式缺点就是手动改变contentOffset排除点不完美的情况，会导致左右拖动的时候出现CollectionView跳动的情况
第二种，获取CollectionView的Touch事件
大致思路，方法交换获取到Touch事件，然后以回调的方式传递出来
+ (void)load {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
[self kj_swizzleMethod:@selector(touchesBegan:withEvent:) Method:@selector(kj_touchesBegan:withEvent:)];
[self kj_swizzleMethod:@selector(touchesMoved:withEvent:) Method:@selector(kj_touchesMoved:withEvent:)];
[self kj_swizzleMethod:@selector(touchesEnded:withEvent:) Method:@selector(kj_touchesEnded:withEvent:)];
[self kj_swizzleMethod:@selector(touchesCancelled:withEvent:) Method:@selector(kj_touchesCancelled:withEvent:)];
});
}
- (void)kj_touchesBegan:(NSSet<UITouch*>*)touches withEvent:(UIEvent*)event{
if (self.kOpenExchange && self.moveblock) {
CGPoint point = [[touches anyObject] locationInView:self];
self.moveblock(KJMoveStateTypeBegin,point);
}
[self kj_touchesBegan:touches withEvent:event];
}
- (void)kj_touchesMoved:(NSSet<UITouch*>*)touches withEvent:(UIEvent*)event{
if (self.kOpenExchange && self.moveblock) {
CGPoint point = [[touches anyObject] locationInView:self];
self.moveblock(KJMoveStateTypeMove,point);
}
[self kj_touchesMoved:touches withEvent:event];
}
- (void)kj_touchesEnded:(NSSet<UITouch*>*)touches withEvent:(UIEvent*)event{
if (self.kOpenExchange && self.moveblock) {
CGPoint point = [[touches anyObject] locationInView:self];
self.moveblock(KJMoveStateTypeEnd,point);
}
[self kj_touchesEnded:touches withEvent:event];
}
- (void)kj_touchesCancelled:(NSSet<UITouch*>*)touches withEvent:(UIEvent*)event{
if (self.kOpenExchange && self.moveblock) {
CGPoint point = [[touches anyObject] locationInView:self];
self.moveblock(KJMoveStateTypeCancelled,point);
}
[self kj_touchesEnded:touches withEvent:event];
}
Property & API
这里定义回调的4种状态，开始触摸，移动，触摸结束和异常中断
typedef NS_ENUM(NSInteger, KJMoveStateType) {
KJMoveStateTypeBegin = 0,
KJMoveStateTypeMove,
KJMoveStateTypeEnd,
KJMoveStateTypeCancelled,
};
typedef void(^KJMoveBlock)(KJMoveStateType state,CGPoint point);
kOpenExchange 控制是否开启方法交换
- (bool)kOpenExchange{
return [objc_getAssociatedObject(self,_cmd) boolValue];
}
- (void)setKOpenExchange:(bool)kOpenExchange{
objc_setAssociatedObject(self,@selector(kOpenExchange),@(kOpenExchange),OBJC_ASSOCIATION_ASSIGN);
}
moveblock 该属性是Touch里面移动回调，需要开启kOpenExchange方法交换才能处理
- (KJMoveBlock)moveblock{
return (KJMoveBlock)objc_getAssociatedObject(self, _cmd);
}
- (void)setMoveblock:(KJMoveBlock)moveblock{
objc_setAssociatedObject(self, @selector(moveblock), moveblock, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
使用示例
_collectView.kOpenExchange = true;
_weakself;
__block bool move = false;
__block CGPoint beginPoint = CGPointZero;
_collectView.moveblock = ^(KJMoveStateType state, CGPoint point) {
if (point.y <= 30 && move == false) {
move = true;
point = [weakself.collectView convertPoint:point toView:kKeyWindow];
NSIndexPath *idx = [weakself.collectView indexPathForItemAtPoint:point];
UICollectionViewCell *nextCell = [weakself.collectView cellForItemAtIndexPath:idx];
weakself.imageView.backgroundColor = nextCell.backgroundColor;
weakself.imageView.center = point;
weakself.imageView.hidden = NO;
}else if (move && point.y < 30 && state == KJMoveStateTypeMove) {
point = [weakself.collectView convertPoint:point toView:kKeyWindow];
weakself.imageView.center = point;
weakself.collectView.scrollEnabled = NO;
return;
}else if (state == KJMoveStateTypeEnd || state == KJMoveStateTypeCancelled) {
move = false;
point = [weakself.collectView convertPoint:point toView:kKeyWindow];
weakself.imageView.center = CGPointZero;
weakself.imageView.hidden = YES;
}
weakself.collectView.scrollEnabled = YES;
};
备注说明
move 开关用来控制滑动距离，满足point.y <= 30 && move == false两个条件的时刻就开启Item的上下移动处理
convertPoint:toView: 将触摸CollectView的点转换到窗口
indexPathForItemAtPoint:和cellForItemAtIndexPath:获取到当初触摸的Item，方便取数据
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