拖拽cell 交换cell位置

#import "ViewController.h"

@interface ViewController ()<UITableViewDelegate ,UITableViewDataSource>

@end

@implementation ViewController

{

    UITableView * _tableView;

    NSMutableArray * _obj;

}

- (void)viewDidLoad {
    [super viewDidLoad];

    _tableView = [[UITableView alloc]init];

    _tableView.frame = self.view.bounds;

    [self.view addSubview:_tableView];

    _tableView.delegate = self;

    _tableView.dataSource = self;

//    [_tableView setEditing:YES animated:YES];

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

    [_tableView addGestureRecognizer:longpress];

    _obj = [NSMutableArray arrayWithCapacity:10];

    for (int i = 0; i<50 ; i++) {

        [_obj addObject:[NSNumber numberWithInt:i]];

    }

    _tableView.backgroundView =  [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"1"]];

//    [self tableView:nil moveRowAtIndexPath:nil toIndexPath:nil];

}

//-(BOOL)tableView:(UITableView *) tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
//{
//    //打开编辑
//    return YES;
//}
//- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
//{
//    //允许移动
//    return YES;
//    //return NO;
//}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    return _obj.count;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];

    if (!cell) {

        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];

    }
    cell.textLabel.text = [NSString stringWithFormat:@"%ld" , indexPath.row];
    cell.contentView.backgroundColor = [UIColor lightGrayColor];
    return cell;
}

- (void)longpress:(id)sender {

    UILongPressGestureRecognizer * longpress = (UILongPressGestureRecognizer *)sender;

    UIGestureRecognizerState state = longpress.state;

    CGPoint location = [longpress locationInView:_tableView];

    NSIndexPath * indexPath = [_tableView indexPathForRowAtPoint:location];

    static UIView * snapshot = nil;

    static NSIndexPath * sourceIndexPath = nil;

    switch (state) {
        case UIGestureRecognizerStateBegan:

            if (indexPath) {

                sourceIndexPath = indexPath;

                UITableViewCell * cell = [_tableView cellForRowAtIndexPath:indexPath];
                ／／截屏快照
                snapshot = [self customSnapsFromView:cell];

                __block CGPoint center = cell.center;

                snapshot.center = center;

                snapshot.alpha = 0.0;

                [_tableView addSubview:snapshot];

                [UIView animateWithDuration:0.25 animations:^{

                    center.y = location.y;

                    snapshot.center = center;

                    snapshot.transform = CGAffineTransformMakeScale(1.05, 1.05);

                    snapshot.alpha = 0.98;

                    cell.alpha = 0.0f;

                }completion:^(BOOL finished) {

                    cell.hidden = YES;

                }];

            }

            break;

        case UIGestureRecognizerStateChanged:{

            CGPoint center = snapshot.center;

            center.y = location.y;

            snapshot.center = center;

            if (indexPath && ![indexPath isEqual:sourceIndexPath]) {

                ／／交换数组元素的位置
                [_obj exchangeObjectAtIndex:indexPath.row withObjectAtIndex:sourceIndexPath.row];
                  　　　　　　　　／／交换cell的位置
                [_tableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];

                sourceIndexPath = indexPath;
            }

            break;
        }

        default:

        {

            UITableViewCell * cell = [_tableView cellForRowAtIndexPath:indexPath];

            [UIView animateWithDuration:0.25 animations:^{

                snapshot.center = cell.center;

                snapshot.transform = CGAffineTransformIdentity;

                snapshot.alpha = 0.0;

                cell.alpha = 1.0f;
            }completion:^(BOOL finished) {

                cell.hidden = NO;

                [snapshot removeFromSuperview];

                snapshot = nil;

            }];

            sourceIndexPath = nil;
              break;
        }

    }

}

-(UIView *)customSnapsFromView:(UIView *)inputView {

    UIView * snapshot = nil;
    ／／7.0一下的系统版本 截图快照
    if ([[[UIDevice currentDevice]systemVersion]doubleValue]<7.0) {

        snapshot = [self customSnapShortFromViewEx:inputView];

    }else{

        snapshot = [inputView snapshotViewAfterScreenUpdates:YES];
    }

    snapshot.layer.masksToBounds = NO;

    snapshot.layer.cornerRadius = 0.0;

    snapshot.layer.shadowOffset = CGSizeMake(-5.0, 0.0);

    snapshot.layer.shadowRadius = 5.0;

    snapshot.layer.shadowOpacity = 0.4;

    return snapshot;

}

-(UIView *)customSnapShortFromViewEx:(UIView *)inputView {

    CGSize inSize = inputView.bounds.size;

// 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕分辨率

    UIGraphicsBeginImageContextWithOptions(inSize, NO, [UIScreen mainScreen].scale);

    [inputView.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageView * snapshot = [[UIImageView alloc]initWithImage:image];

    return snapshot;

}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    [tableView deselectRowAtIndexPath:indexPath animated:NO];

}

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{

    return 64.0f;
}

@end