IOS长按UITableViewCell进行移动

看到iphone上自带的天气APP，可以长按UITableViewCell来移动位置，于是就模仿了一个。思路如下！

1：准备一个带测试数据的UITableView

2：给UITableView添加一个长按的事件，UILongPressGestureRecognizer

3：根据长按时获取到的位置来取得UITableViewCell

4：取得UITableViewCell生成一张截图，添加到view上，手指移动时，截图跟着移动

5：手指移动时，更新NSIndexPath，然后用moveRowAtIndexPath更新表格视图

6：手指松开后，删除截图

代码如下所示

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.    dataArray = [@[@"列表1",@"列表2",@"列表3",@"列表4",@"列表5",@"列表6",@"列表7",@"列表8",@"列表9",@"列表10",@"列表11",@"列表12"]mutableCopy];    myTableView = [[UITableView alloc]initWithFrame:self.view.frame];    myTableView.delegate = self;    myTableView.dataSource = self;    [self.view addSubview:myTableView];        UILongPressGestureRecognizer *gesture = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPressHandler:)];    [myTableView addGestureRecognizer:gesture];}-(void)longPressHandler:(id)sender{    UILongPressGestureRecognizer *gesture = (UILongPressGestureRecognizer*)sender;    CGPoint location = [gesture locationInView:myTableView];    NSIndexPath *indexPath = [myTableView indexPathForRowAtPoint:location];//根据长按的点获取indexPath    static UIView *snapshot = nil;//截图    static NSIndexPath  *sourceIndexPath = nil;//根据手指的位置获取行    switch (gesture.state) {        case UIGestureRecognizerStateBegan://长按时触发        {            NSLog(@"UIGestureRecognizerStateBegan");            sourceIndexPath = indexPath;            UITableViewCell *cellView = [myTableView cellForRowAtIndexPath:sourceIndexPath];            //获取截图            snapshot = [self customSnapshoFromView:cellView];            [self.view addSubview:snapshot];            __block CGPoint center = cellView.center;            snapshot.center = center;            snapshot.alpha = 0.0;            [myTableView addSubview:snapshot];            [UIView animateWithDuration:0.25 animations:^{                                // 给截图指定位置                center.y = location.y;                snapshot.center = center;                snapshot.transform = CGAffineTransformMakeScale(1.05, 1.05);                snapshot.alpha = 0.98;                cellView.alpha = 0.0;                            } completion:^(BOOL finished) {                                cellView.hidden = YES;                            }];            break;        }            case UIGestureRecognizerStateChanged://移动        {            NSLog(@"UIGestureRecognizerStateChanged");            //改变截图的位置            CGPoint center = snapshot.center;            center.y = location.y;            snapshot.center = center;            //更新列表            if (indexPath&&![indexPath isEqual:sourceIndexPath]) {                [dataArray exchangeObjectAtIndex:indexPath.row withObjectAtIndex:sourceIndexPath.row];                [myTableView moveRowAtIndexPath:sourceIndexPath toIndexPath:indexPath];                sourceIndexPath = indexPath;            }            break;        }        default://松开时移除截图        {            NSLog(@"default");            UITableViewCell *cell = [myTableView cellForRowAtIndexPath:sourceIndexPath];            cell.hidden = NO;            cell.alpha = 0.0;                        [UIView animateWithDuration:0.25 animations:^{                                snapshot.center = cell.center;                snapshot.transform = CGAffineTransformIdentity;                snapshot.alpha = 0.0;                cell.alpha = 1.0;                            } completion:^(BOOL finished) {                                sourceIndexPath = nil;                [snapshot removeFromSuperview];                snapshot = nil;                            }];            break;        }    }}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {    return [dataArray count];}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{    static NSString *kIdentifier = @"Cell Identifier";    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:kIdentifier];    if (!cell) {        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:kIdentifier];    }    cell.textLabel.text = [dataArray objectAtIndex:indexPath.row];    return cell;}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (UIView *)customSnapshoFromView:(UIView *)inputView {        UIView *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;}@end