UITableViewCell重用良好的做法

Question

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


    static NSString *CellIdentifier = @"NotificationViewCell";
    CardViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if(cell==nil){

        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CardViewCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];


        cell.contentView.backgroundColor=[UIColor clearColor];
        [ModelClass addSublayer:cell.contentView];


        cell.cellbg.layer.cornerRadius = 8;
        cell.cellbg.layer.masksToBounds = YES;

         cell.cellbg.layer.borderWidth = 1;
         cell.cellbg.layer.borderColor = [[UIColor grayColor] CGColor];


        cell.logoImage.layer.cornerRadius = 8;
        cell.logoImage.layer.masksToBounds = YES;

        cell.logoImage.layer.borderWidth = 1;
        cell.logoImage.layer.borderColor = [[UIColor grayColor] CGColor];



        Merchant *merchantList= [self.cardListArr objectAtIndex:indexPath.row];

        cell.nameLab.text=merchantList.name;

        NSLog(@"merchantList.myloyalty.points=%@",merchantList.myloyalty.points);
    //    NSLog(@"memberNO=%@",merchantList.myloyalty.memberNO);
        cell.integralLab.text=[NSString stringWithFormat:NSLocalizedString(@"points_dot", @"") ,[merchantList.myloyalty.points intValue]];


        cell.cardNumberLab.text=[NSString stringWithFormat:@"%@%@",NSLocalizedString(@"ID", nil), merchantList.myloyalty.memberNO];



        if(![ModelClass isBlankString:merchantList.introPic])
        {
              NSLog(@"merchantList.introPic=%@",merchantList.introPic);

            [cell.logoImage setImageUrl:merchantList.introPic];


        }
    }

    return cell;

}

1. 我想使用上面的代码重用UITableViewCell,我不知道它是否正确,我想得到一些建议.

2. 你可以看到我使用的代码if(cell == nil),我想知道我应该编写什么代码if(cell!= nil)(if(cell == nil)else {我应该做什么可以改善单元重用})

3. 如果每个单元格都有相同的视图,但有不同的高度,例如imageview有时是20或40等等,如何处理这种情况.

Answer 1

1.这是不正确的,因为你的单元格被重用了,当它被创建时,它就不会进入if-statement,所以,if-statement你只需要初始化单元格,你应该在外面编写setText和setImage这个 if-statement.

如 :

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


    static NSString *CellIdentifier = @"NotificationViewCell";
    CardViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if(cell==nil){

        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CardViewCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];


        cell.contentView.backgroundColor=[UIColor clearColor];
        [ModelClass addSublayer:cell.contentView];


        cell.cellbg.layer.cornerRadius = 8;
        cell.cellbg.layer.masksToBounds = YES;

         cell.cellbg.layer.borderWidth = 1;
         cell.cellbg.layer.borderColor = [[UIColor grayColor] CGColor];


        cell.logoImage.layer.cornerRadius = 8;
        cell.logoImage.layer.masksToBounds = YES;

        cell.logoImage.layer.borderWidth = 1;
        cell.logoImage.layer.borderColor = [[UIColor grayColor] CGColor];

        }

        Merchant *merchantList= [self.cardListArr objectAtIndex:indexPath.row];

        cell.nameLab.text=merchantList.name;

        NSLog(@"merchantList.myloyalty.points=%@",merchantList.myloyalty.points);
    //    NSLog(@"memberNO=%@",merchantList.myloyalty.memberNO);
        cell.integralLab.text=[NSString stringWithFormat:NSLocalizedString(@"points_dot", @"") ,[merchantList.myloyalty.points intValue]];


        cell.cardNumberLab.text=[NSString stringWithFormat:@"%@%@",NSLocalizedString(@"ID", nil), merchantList.myloyalty.memberNO];



        if(![ModelClass isBlankString:merchantList.introPic])
        {
              NSLog(@"merchantList.introPic=%@",merchantList.introPic);

            [cell.logoImage setImageUrl:merchantList.introPic];


        }


        return cell;

    }

2大多数人的代码如下:

if(cell==nil)
{
    //init code
}

// setting code

3.如果要设置单元格高度,则无法编码 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

你应该在dataSource的方法中编码: - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

像这样的代码:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (index.row % 2)
        return 20.0f;
    return 40.0f;
}