UICollection移动cell

 @interface ViewController ()<UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout>

@property (nonatomic, strong) NSMutableArray *dataArr;

@property (nonatomic, strong) UICollectionView *collectionView;

/**之前选中cell的NSIndexPath*/

@property (nonatomic, strong) NSIndexPath *oldIndexPath;

/**单元格的截图*/

@property (nonatomic, strong) UIView *snapshotView;

/**之前选中cell的NSIndexPath*/

@property (nonatomic, strong) NSIndexPath *moveIndexPath;

@end

2初始化viewDidLoad 

CGFloat SCREEN_WIDTH = [UIScreen mainScreen].bounds.size.width;

    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];

    flowLayout.itemSize=CGSizeMake((SCREEN_WIDTH-40.0)/3, (SCREEN_WIDTH-40.0)/3);

    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 50.0, SCREEN_WIDTH,  [UIScreen mainScreen].bounds.size.height) collectionViewLayout:flowLayout];

    collectionView.dataSource=self;

    collectionView.delegate=self;

    collectionView.backgroundColor = [UIColor whiteColor];

    [collectionViewregisterClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"uicollectionviewcell"];

    [self.viewaddSubview:self.collectionView= collectionView];

    // 添加长按手势

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handlelongGesture:)];

    [collectionViewaddGestureRecognizer:longPress];

加载数据

    self.dataArr = [[NSMutableArray alloc] init];

    for (NSIntegerindex =0; index <50; index ++) {

        [self.dataArr addObject:[NSString stringWithFormat:@"%ld",index]];

    }

#pragma mark - UICollectionViewDataSource

- (NSInteger)collectionView:(UICollectionView*)collectionView numberOfItemsInSection:(NSInteger)section

{

    returnself.dataArr.count;

}

- (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView cellForItemAtIndexPath:(NSIndexPath*)indexPath

{

   // 每次先从字典中根据IndexPath取出唯一标识符

    NSString *identifier = [_cellDic objectForKey:[NSString stringWithFormat:@"%@", indexPath]];

    // 如果取出的唯一标示符不存在，则初始化唯一标示符，并将其存入字典中，对应唯一标示符注册Cell

    if (identifier ==nil) {

        identifier = [NSStringstringWithFormat:@"%@", indexPath];

        [_cellDicsetValue:identifierforKey:[NSStringstringWithFormat:@"%@", indexPath]];

        // 注册Cell

        [self.collectionView registerClass:[UICollectionViewCell class]  forCellWithReuseIdentifier:identifier];

        }

   UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    for(idsubViewincell.contentView.subviews){

        if(subView){

            [subViewremoveFromSuperview];

       }

    }

   CGFloathue = (arc4random()%256/256.0);//0.0 到 1.0

    CGFloatsaturation = (arc4random()%128/256.0)+0.5;//0.5 到 1.0

    CGFloatbrightness = (arc4random()%128/256.0)+0.5;//0.5 到 1.0

    UIColor *color = [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:0.5];

    cell.backgroundColor= color;

    UILabel *lab = [[UILabel alloc]initWithFrame:CGRectMake(10, 10, 100, 20)];

    lab.text=self.dataArr[indexPath.row];

    [cell.contentView addSubview:lab ];

    return cell;

}

#pragma mark - 长按手势

- (void)handlelongGesture:(UILongPressGestureRecognizer*)longPress

{

    if ([[[UIDevice currentDevice] systemVersion] floatValue] < 9.0) {

        [selfaction:longPress];

    } else {

        [selfiOS9_Action:longPress];

    }

}

#pragma mark - iOS9 之后的方法

- (BOOL)collectionView:(UICollectionView*)collectionView canMoveItemAtIndexPath:(NSIndexPath*)indexPath

{

    // 返回YES允许row移动

    returnYES;

}

- (void)collectionView:(UICollectionView*)collectionView moveItemAtIndexPath:(NSIndexPath*)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath

{

    //取出移动row数据

    iddata =self.dataArr[sourceIndexPath.row];

    //从数据源中移除该数据

    [self.dataArrremoveObject:data];

    //将数据插入到数据源中的目标位置

    [self.dataArrinsertObject:dataatIndex:destinationIndexPath.row];

}

- (void)iOS9_Action:(UILongPressGestureRecognizer*)longPress

{

    switch (longPress.state) {

        caseUIGestureRecognizerStateBegan:

        {//手势开始

            //判断手势落点位置是否在row上

            NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:[longPress locationInView:self.collectionView]];

            if (indexPath ==nil) {

                break;

            }

            UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:indexPath];

            [self.view bringSubviewToFront:cell];

            //iOS9方法 移动cell

            [self.collectionView beginInteractiveMovementForItemAtIndexPath:indexPath];

        }

        break;

        caseUIGestureRecognizerStateChanged:

        {// 手势改变

            // iOS9方法 移动过程中随时更新cell位置

            [self.collectionView updateInteractiveMovementTargetPosition:[longPress locationInView:self.collectionView]];

        }

        break;

        caseUIGestureRecognizerStateEnded:

        {// 手势结束

            // iOS9方法 移动结束后关闭cell移动

            [self.collectionView endInteractiveMovement];

        }

        break;

        default://手势其他状态

        [self.collectionView cancelInteractiveMovement];

        break;

    }

}

#pragma mark - iOS9 之前的方法

- (void)action:(UILongPressGestureRecognizer *)longPress

{

    switch (longPress.state) {

        caseUIGestureRecognizerStateBegan:

        {// 手势开始

            //判断手势落点位置是否在row上

            NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:[longPress locationInView:self.collectionView]];

            self.oldIndexPath= indexPath;

            if (indexPath ==nil) {

                break;

            }

            UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:indexPath];

            // 使用系统的截图功能,得到cell的截图视图

            UIView*snapshotView = [cellsnapshotViewAfterScreenUpdates:NO];

            snapshotView.frame= cell.frame;

            [self.viewaddSubview:self.snapshotView= snapshotView];

            // 截图后隐藏当前cell

            cell.hidden=YES;

            CGPointcurrentPoint = [longPresslocationInView:self.collectionView];

            [UIView animateWithDuration:0.25 animations:^{

                snapshotView.transform=CGAffineTransformMakeScale(1.05,1.05);

                snapshotView.center= currentPoint;

            }];

        }

        break;

        caseUIGestureRecognizerStateChanged:

        {// 手势改变

            //当前手指位置 截图视图位置随着手指移动而移动

            CGPointcurrentPoint = [longPresslocationInView:self.collectionView];

            self.snapshotView.center= currentPoint;

            // 计算截图视图和哪个可见cell相交

            for (UICollectionViewCell *cell in self.collectionView.visibleCells) {

                // 当前隐藏的cell就不需要交换了,直接continue

                if ([self.collectionViewindexPathForCell:cell] ==self.oldIndexPath) {

                    continue;

                }

                // 计算中心距

                CGFloatspace =sqrtf(pow(self.snapshotView.center.x- cell.center.x,2) +powf(self.snapshotView.center.y- cell.center.y,2));

                // 如果相交一半就移动

                if (space <=self.snapshotView.bounds.size.width/2) {

                    self.moveIndexPath= [self.collectionViewindexPathForCell:cell];

                    //移动 会调用willMoveToIndexPath方法更新数据源

                    [self.collectionView moveItemAtIndexPath:self.oldIndexPath toIndexPath:self.moveIndexPath];

                    //设置移动后的起始indexPath

                    self.oldIndexPath=self.moveIndexPath;

                    break;

                }

            }

        }

        break;

        default:

        {// 手势结束和其他状态

            UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:self.oldIndexPath];

            // 结束动画过程中停止交互,防止出问题

            self.collectionView.userInteractionEnabled = NO;

            // 给截图视图一个动画移动到隐藏cell的新位置

            [UIView animateWithDuration:0.25 animations:^{

                self.snapshotView.center= cell.center;

                self.snapshotView.transform = CGAffineTransformMakeScale(1.0, 1.0);

            }completion:^(BOOLfinished) {

                // 移除截图视图,显示隐藏的cell并开始交互

                [self.snapshotViewremoveFromSuperview];

                cell.hidden=NO;

                self.collectionView.userInteractionEnabled = YES;

            }];

        }

        break;

    }

}