自定义tableview移动

关于tableview的移动，apple提供了官方的做法，但是无法做扩展，生成的cell往往不符合实际需求，所以这里提供自定义移动操作：

//为tableview添加对应的手势来模拟移动手势。
UILongPressGestureRecognizer* longPressGesture=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(handlerLongPress:)];
longPressGesture.minimumPressDuration=0.5;
[_sortTableView addGestureRecognizer:longPressGesture];


-(void)handlerLongPress:(UILongPressGestureRecognizer*)sender{
    switch (sender.state) {
        case UIGestureRecognizerStateBegan:
            [self handlerLongPressBegan:sender];
            break;

        case UIGestureRecognizerStateChanged:
            [self handlerLongPressChanged:sender];
            break;
        case UIGestureRecognizerStateCancelled:
            [self handlerLongPressEnded:sender];
            break;
        case UIGestureRecognizerStateEnded:
            [self handlerLongPressEnded:sender];
            break;
        default:
            break;
    }
}

-(void)handlerLongPressBegan:(UILongPressGestureRecognizer*)longPressGesture{
    //手势识别开始阶段获取对应的触碰位置.
    CGPoint location=[longPressGesture locationInView:_sortTableView];
    NSIndexPath* indexPath=[_sortTableView indexPathForRowAtPoint:location];

    //判断触碰位置是否为tableview的某一行
    if(indexPath){
          //_sourceIndexPath为属性变量用于保存初始被移动的cell的位置。
        _sourceIndexPath=indexPath;
        //获取cell
        QTShortcutsListenSortTableCell* cell=[_sortTableView cellForRowAtIndexPath:indexPath];
        //对cell进行截图并保存到属性变量
        _snapshot=[cell resizableSnapshotViewFromRect:CGRectMake(0, 0, cell.frame.size.width, 50) afterScreenUpdates:NO withCapInsets:UIEdgeInsetsZero];
        //得到初始位置的cell的中心。然后隐藏cell，并将截图放到cell对应的位置，用此截图来假装一个cell来拖动。
        CGPoint center=cell.center;
        [_sortTableView addSubview:_snapshot];
        center.y=location.y;
        _snapshot.center=center;
        _snapshot.transform=CGAffineTransformMakeScale(1, 1);
        _snapshot.alpha=1;
        _snapshot.backgroundColor=cell.backgroundColor;
        cell.backgroundColor=[UIColor clearColor];
        cell.hidden=true;

    }
}

-(void)handlerLongPressChanged:(UILongPressGestureRecognizer*)longPressGesture{
    //当手势改变的时候，获取所处的位置，然后一步步交换截图以及对应的cell和相对应的数据。
    CGPoint location=[longPressGesture locationInView:_sortTableView];
    NSIndexPath* indexPath=[_sortTableView indexPathForRowAtPoint:location];
    CGPoint center=_snapshot.center;
    center.y=location.y;
    _snapshot.center=center;

    if(indexPath&&![indexPath isEqual:_sourceIndexPath]){
        //这里的_sortModelArr对应着数据模型数组
        QTShortcutsListenSortModel* modelToMove=_sortModelArr[_sourceIndexPath.row];
        [_sortModelArr removeObjectAtIndex:_sourceIndexPath.row];
        [_sortModelArr insertObject:modelToMove atIndex:indexPath.row];
        [_sortTableView moveRowAtIndexPath:_sourceIndexPath toIndexPath:indexPath];
        _sourceIndexPath=indexPath;
    }
}

-(void)handlerLongPressEnded:(UILongPressGestureRecognizer*)longPressGesture{
    QTShortcutsListenSortTableCell* cell=[_sortTableView cellForRowAtIndexPath:_sourceIndexPath];
    //手势结束以后，将截图置为nil，将原来的cell展示出来。
    [UIView animateWithDuration:0.25 animations:^{
        _snapshot.center=cell.center;
        _snapshot.transform=CGAffineTransformIdentity;
        _snapshot.alpha=0;
        cell.backgroundColor=_snapshot.backgroundColor;
        cell.hidden=false;
    } completion:^(BOOL finished) {
        [_snapshot removeFromSuperview];
        _snapshot=nil;
    }];
    _sourceIndexPath=nil;
}