iphone - UITableView 正在加载每个单元格

Question

UITableview 应该只加载第一次可见的单元格，对吗？我的表格 View 最初加载每个单元格，这会大大减慢速度。我正在使用大约 1000 行。仅希望它在必要时加载单元格(例如用户向下滚动)。有人知道为什么要这样做吗？

Answer 1

我知道每个单元格最初都会调用 cellForRowAtIndexPath 。单元格的高度为 89。

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

static NSString *CellIdentifier = @"Cell";
UILabel *textName               = nil;
UIImageView* image              = nil;
unsigned int        DATA_TAG    = 1001;
unsigned int        IMG_TAG     = 1002;

//  Retrieve a cell is Available
cell = [aTableView dequeueReusableCellWithIdentifier:CellIdentifier];

//  Check if no new cell was available
if (cell == nil) 
{
    cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];

    //  Set the Accessory Data
    textName = [[[UILabel alloc]initWithFrame:CGRectMake(cell.frame.origin.x, 80, cell.frame.size.width, 20)]autorelease];
    textName.tag                    = DATA_TAG;
    textName.textAlignment          = UITextAlignmentCenter;
    textName.backgroundColor        = [UIColor clearColor];
    textName.highlightedTextColor   = [UIColor colorWithRed:1.0 green:1.0 blue:0.9 alpha:1.0];
    textName.textColor              = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0];
    textName.lineBreakMode          = UILineBreakModeWordWrap;

    [cell.contentView addSubview:textName];

    //Set the Image Data
    image = [[[UIImageView alloc]initWithFrame:CGRectMake(cell.frame.origin.x, cell.frame.origin.y, cell.frame.size.width, 80)]autorelease];
    image.tag = IMG_TAG;
    image.contentMode= UIViewContentModeScaleAspectFit;
    [cell.contentView addSubview:image];

}

Accessory* acc= [[AccessoryManager sharedManager].currentList objectAtIndex:indexPath.row];
if(acc == nil)
    return cell;


textName= (UILabel*)[cell.contentView viewWithTag:DATA_TAG];
textName.text= acc.accessoryName;


image= (UIImageView*)[cell.contentView viewWithTag:IMG_TAG];
[image setImage:acc.accessoryImage];    
return cell;
}