Question

我使用tableView，手动缓存单元格，但是当我滚动时，我得到一点滞后。这是我的代码：

    func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
{


    var realRow = indexPath.row / 2
    if indexPath.row / 2 > self.SUGGESTED_USERS_RATE && suggestedUsers.count > 0
    {
        --realRow
    }
    if indexPath.row / 2 > self.SUGGESTED_RADIOS_RATE && suggestedRadioStations.count > 0
    {
        --realRow
    }

    if indexPath.row % 2 == 1
    {
        return self.CELL_MARGIN
    }
    else if indexPath.row / 2 == self.SUGGESTED_USERS_RATE && suggestedUsers.count > 0
    {
        return self.SUGGESTED_USERS_CELL_HEIGHT
    }
    else if indexPath.row / 2 == self.SUGGESTED_RADIOS_RATE && suggestedRadioStations.count > 0
    {
        return self.SUGGESTED_USERS_CELL_HEIGHT
    }
    else
    {
        return self.CELLS_HEIGHT[realRow]//[indexPath.row / 2 - indexPath.row / (self.SUGGESTED_USERS_RATE * 2 + 2)]
    }

//让row = indexPath.row / 2

}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
    var realRow = indexPath.row / 2

    if indexPath.row / 2 > self.SUGGESTED_USERS_RATE && suggestedUsers.count > 0
    {
        --realRow
    }
    if indexPath.row / 2 > self.SUGGESTED_RADIOS_RATE && suggestedRadioStations.count > 0
    {
        --realRow
    }




    if indexPath.row % 2 == 1
    {
        let cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "")
        cell.backgroundColor = UIColor.grayColor().colorWithAlphaComponent(0.3)

        cell.selectionStyle = .None

        addSeperatorsToView(cell.contentView, width: self.bounds.width,
            height: self.CELL_MARGIN, up: true, down: true, left: false, right: false)

        return cell
    }
    else if indexPath.row / 2 == self.SUGGESTED_RADIOS_RATE && suggestedRadioStations.count > 0
    {
        let cell = SuggestedUsersCell(width: self.bounds.width, height: self.SUGGESTED_USERS_CELL_HEIGHT, radios: suggestedRadioStations.prefix(5) + [])
        return cell
    }
    else if indexPath.row / 2 == self.SUGGESTED_USERS_RATE && suggestedUsers.count > 0
    {
        let cell = SuggestedUsersCell(width: self.bounds.width, height: self.SUGGESTED_USERS_CELL_HEIGHT, users: suggestedUsers.prefix(5)  + [])
        return cell
    }
    else
    {
        var cell : ActivityTableViewCell

        if let myCell = self.cells_cache[realRow]
        {
            cell = myCell
        }
        else
        {
            let activity = self.actevetiesArr[realRow]

            cell = ActivityTableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: self.CELL_ID,
                height: self.CELLS_HEIGHT[realRow],
                width: self.bounds.width, activity: activity ,
                index : realRow  ,
                delegate : self)

            self.cells_cache[realRow] = cell

        }



        cell.userInteractionEnabled = true
        cell.selectionStyle = .None

        return cell
    }
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
    var count = self.actevetiesArr.count * 2

    if self.actevetiesArr.count > self.SUGGESTED_USERS_RATE
    {
        count = count + 2
    }
    if self.actevetiesArr.count > self.SUGGESTED_RADIOS_RATE
    {
        count = count + 2
    }

    if self.actevetiesArr.count < max(self.SUGGESTED_USERS_RATE , self.SUGGESTED_RADIOS_RATE)
    {
        count += 2
        self.SUGGESTED_RADIOS_RATE = 1
        self.SUGGESTED_USERS_RATE = 0
    }
    else
    {
        self.SUGGESTED_USERS_RATE = SUGGESTED_USERS_INDEX
        self.SUGGESTED_RADIOS_RATE = SUGGESTED_RADIOS_INDEX
    }

    if suggestedRadioStations.count == 0
    {
        count -= 2
    }

    if suggestedUsers.count == 0
    {
        count -= 2
    }

    return count//(self.actevetiesArr.count + (self.actevetiesArr.count 
}

有什么问题??！，我没有在cellForRowAtIndexPath中做大量的代码。注意：cell_cache是一个字典==＆gt; [Int：ActivityTableViewCell

Answer 1

问题是你没有使用惯用法 - 即你应该使用可重复使用的单元格。

Answer 2

添加此

func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return  44;
}

或者您可以添加

self.tableView. estimatedRowHeight = 44.0

中的

viewDidLoad

让我知道它是否有效

Answer 3

尝试用户可重复使用的单元格。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    CustomCell *cell = (CustomCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
       cell = (CustomCell *) [[[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:self options:nil] objectAtIndex:0];
       cell.selectionStyle = UITableViewCellSelectionStyleNone;
    }
    return cell;
}

滚动时UITableView滞后

3 个答案: