在iOS中移动UICollectionView的单元格？

编辑：这个问题可以分解成2个较小的子问题：

>如何动画细胞
>如何使用拖放重新排序单元格.

您应该将这两个解决方案组合到UICollectionView的子文件夹中,以获得您的主要解决方案.

如何动画细胞

要获得摆动动画,您需要添加2种不同的动画效果：

>垂直移动单元格,上下移动
>旋转单元格
>最后,为每个单元格添加一个随机的间隔时间,所以看起来单元格不能均匀地动画化

这是代码：

@interface DragDropCollectionView ()
@property (assign,nonatomic) BOOL isWiggling;
@end

@implementation DragDropCollectionView

//Start and Stop methods for wiggle
- (void) startWiggle {
    for (UICollectionViewCell *cell in self.visibleCells) {
        [self addWiggleAnimationToCell:cell];
    }
    self.isWiggling = true;
}

- (void)stopWiggle {
    for (UICollectionViewCell *cell in self.visibleCells) {
        [cell.layer removeAllAnimations];
    }
    self.isWiggling = false;
}

//- (UICollectionViewCell *)dequ

- (UICollectionViewCell *)dequeueReusableCellWithReuseIdentifier:(Nsstring *)identifier forIndexPath:(nonnull NSIndexPath *)indexPath{
    UICollectionViewCell *cell = [super dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
    if (self.isWiggling) {
        [self addWiggleAnimationToCell:cell];
    } else {
        [cell.layer removeAllAnimations];
    }
    return [[UICollectionViewCell alloc] init];
}

//Animations
- (void)addWiggleAnimationToCell:(UICollectionViewCell *)cell {
    [CATransaction begin];
    [CATransaction setdisableActions:false];
    [cell.layer addAnimation:[self rotationAnimation] forKey:@"rotation"];
    [cell.layer addAnimation:[self bounceAnimation] forKey:@"bounce"];
    [CATransaction commit];

}

- (CAKeyframeAnimation *)rotationAnimation {
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];
    CGFloat angle = 0.04;
    NSTimeInterval duration = 0.1;
    double variance = 0.025;
    animation.values = @[@(angle),@(-1 * angle)];
    animation.autoreverses = YES;
    animation.duration = [self randomizeInterval:duration withVariance: variance];
    animation.repeatCount = INFINITY;
    return animation;
}

- (CAKeyframeAnimation *)bounceAnimation {
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform.translation.y"];
    CGFloat bounce = 3.0;
    NSTimeInterval duration = 0.12;
    double variance = 0.025;
    animation.values = @[@(bounce),@(-1 * bounce)];
    animation.autoreverses = YES;
    animation.duration = [self randomizeInterval:duration withVariance: variance];
    animation.repeatCount = INFINITY;

    return animation;
}

- (NSTimeInterval)randomizeInterval:(NSTimeInterval)interval withVariance:(double)variance {
    double randomDecimal = (arc4random() % 1000 - 500.0) / 500.0;
    return interval + variance * randomDecimal;
}

如何使用拖放重新排序单元格

所以想法是这样的：你不是移动实际的单元格,而是移动一个UIImageView与单元格内容的UIImage.

算法或多或少是这样的.我把它分解成3个部分,手势识别器,改变和结束

gestureRecognizerBegan：

>当手势识别器开始时,确定长按确实在一个单元格上(而不是在空白的空间)
>获取单元格的UIImage(请参阅我的方法“getRasterizedImageOfCell”)
>隐藏单元格(即alpha = 0),创建具有单元格确切框架的UIImageView,以便用户不会意识到您实际上已隐藏单元格,并且实际上正在使用imageview.

gestureRecognizerChanged：

>更新UIImageView的中心,使其随手指移动.
>如果用户已经停止移动他的眼睛,即他将鼠标悬停在要替换的单元格上,那么现在需要交换单元格. (看看我的函数“shouldSwapCells”,这个方法返回一个bool是否单元格应该交换)
>将要拖动的单元格移动到新的indexPath. (看我的方法“swapDraggedCell”). UICollectionView有一个称为“moveItemAtIndexPath：toIndexPath”的内置方法,我不知道UITableView是否具有相同的东西

gestureRecognizerEnd：

>将UIImageView“放下”回到单元格
>将单元格alpha从0.0更改为1.0,并从视图中删除UIImageView.

这是代码：

@interface DragDropCollectionView ()
@property (strong,nonatomic) NSIndexPath *draggedCellIndexPath;
@property (strong,nonatomic) UIImageView *draggingImageView;
@property (assign,nonatomic) CGPoint touchOffsetFromCenterOfCell;
@property (strong,nonatomic) UILongPressGestureRecognizer *longPressRecognizer;
@end

@implementation DragDropCollectionView

- (void)handleLongPress:(UILongPressGestureRecognizer *)longPressRecognizer {
    CGPoint touchLocation = [longPressRecognizer locationInView:self];
    switch (longPressRecognizer.state) {
        case UIGestureRecognizerStateBegan: {
            self.draggedCellIndexPath = [self indexPathForItemAtPoint:touchLocation];
            if (self.draggedCellIndexPath != nil) {
                UICollectionViewCell *draggedCell = [self cellForItemAtIndexPath:self.draggedCellIndexPath];
                self.draggingImageView = [[UIImageView alloc] initWithImage:[self rasterizedImagecopyOfCell:draggedCell]];
                self.draggingImageView.center = draggedCell.center;
                [self addSubview:self.draggingImageView];
                draggedCell.alpha = 0.0;
                self.touchOffsetFromCenterOfCell = CGPointMake(draggedCell.center.x - touchLocation.x,draggedCell.center.y - touchLocation.y);
                [UIView animateWithDuration:0.4 animations:^{
                    self.draggingImageView.transform = CGAffineTransformMakeScale(1.3,1.3);
                    self.draggingImageView.alpha = 0.8;
                }];
            }
            break;
        }
        case UIGestureRecognizerStateChanged: {
            if (self.draggedCellIndexPath != nil) {
                self.draggingImageView.center = CGPointMake(touchLocation.x + self.touchOffsetFromCenterOfCell.x,touchLocation.y + self.touchOffsetFromCenterOfCell.y);
            }
            float pingInterval = 0.3;
            dispatch_after(dispatch_time(disPATCH_TIME_Now,(int64_t)(pingInterval * NSEC_PER_SEC)),dispatch_get_main_queue(),^{
                NSIndexPath *newIndexPath = [self indexPathToSwapCellWithAtPrevIoUsTouchLocation:touchLocation];
                if (newIndexPath) {
                    [self swapDraggedCellWithCellAtIndexPath:newIndexPath];
                }
            });
            break;
        }
        case UIGestureRecognizerStateEnded: {
            if (self.draggedCellIndexPath != nil ) {
                UICollectionViewCell *draggedCell = [self cellForItemAtIndexPath:self.draggedCellIndexPath];
                [UIView animateWithDuration:0.4 animations:^{
                    self.draggingImageView.transform = CGAffineTransformIdentity;
                    self.draggingImageView.alpha = 1.0;
                    if (draggedCell != nil) {
                        self.draggingImageView.center = draggedCell.center;
                    }
                } completion:^(BOOL finished) {
                    [self.draggingImageView removeFromSuperview];
                    self.draggingImageView = nil;
                    if (draggedCell != nil) {
                        draggedCell.alpha = 1.0;
                        self.draggedCellIndexPath = nil;
                    }
                }];
            }
        }

        default:
            break;
    }
}

- (UIImage *)rasterizedImagecopyOfCell:(UICollectionViewCell *)cell {
    UIGraphicsBeginImageContextWithOptions(cell.bounds.size,false,0.0);
    [cell.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetimageFromCurrentimageContext();
    return image;
}

- (NSIndexPath *)indexPathToSwapCellWithAtPrevIoUsTouchLocation:(CGPoint)prevIoUsTouchLocation {
    CGPoint currentTouchLocation = [self.longPressRecognizer locationInView:self];
    if (!isnan(currentTouchLocation.x) && !isnan(currentTouchLocation.y)) {
        if ([self distanceBetweenPoints:currentTouchLocation secondPoint:prevIoUsTouchLocation] < 20.0) {
            NSIndexPath *newIndexPath = [self indexPathForItemAtPoint:currentTouchLocation];
            return newIndexPath;
        }
    }
    return nil;
}

- (CGFloat)distanceBetweenPoints:(CGPoint)firstPoint secondPoint:(CGPoint)secondPoint {
    CGFloat xdistance = firstPoint.x - secondPoint.x;
    CGFloat ydistance = firstPoint.y - secondPoint.y;
    return sqrtf(xdistance * xdistance + ydistance * ydistance);
}

- (void)swapDraggedCellWithCellAtIndexPath:(NSIndexPath *)newIndexPath {
    [self moveItemAtIndexPath:self.draggedCellIndexPath toIndexPath:newIndexPath];
    UICollectionViewCell *draggedCell = [self cellForItemAtIndexPath:newIndexPath];
    draggedCell.alpha = 0.0;
    self.draggedCellIndexPath = newIndexPath;
}

希望这可以帮助 ：)