Question

当尝试从笔尖加载自定义UITableViewCell时，只有在主故事板中的原型单元格上设置了reuseIdentifier，我才能让单元格出现。如果将其设置为空白，我会收到来自xcode的警告，但代码运行正常。我在其他几个控制器中有类似的代码，但是这是唯一一个提出这个问题的控制器。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = @"AssetsTableCell";
AssetsTableCell *assetTableCell = (AssetsTableCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];

int rightIndex = (indexPath.row * 4);
int rightMiddleIndex = (indexPath.row * 4) + 1;
int leftMiddleIndex = (indexPath.row * 4) + 2;
int leftIndex = (indexPath.row * 4) + 3;

if (assetTableCell == nil) {
    NSArray *topLevelObjects;
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"AssetsTableCell_iPhone" owner:nil options:nil];
        assetTableCell = (AssetsTableCell *)[topLevelObjects objectAtIndex:0];
        [assetTableCell setDelegate:self];

    }

    // Need to collect the badge details in groups of 4.    
    @try {
        NSArray *rowArray = [NSArray arrayWithObjects:[remoteContainers objectAtIndex:rightIndex], 
                                                      [remoteContainers objectAtIndex:rightMiddleIndex], 
                                                      [remoteContainers objectAtIndex:leftMiddleIndex],
                                                      [remoteContainers objectAtIndex:leftIndex], 
                                                      nil];

        NSDictionary *cellData = [NSDictionary dictionaryWithObjectsAndKeys:
                                  [rowArray objectAtIndex:0], @"LEFT_CONTAINER", 
                                  [rowArray objectAtIndex:1], @"LEFT_MIDDLE_CONTAINER", 
                                  [rowArray objectAtIndex:2], @"RIGHT_MIDDLE_CONTAINER", 
                                  [rowArray objectAtIndex:3], @"RIGHT_CONTAINER", nil];
        [assetTableCell populateCellData:cellData];
    }
    @catch (NSException *exception) {
        DLog(@"Exceeds boundary of remoteContainers array by %d.", ([remoteContainers count] % 4));
        int remainder = [remoteContainers count] % 4;

        switch (remainder) {
            case 1: {
                // Check to see the number of remaining containers left in the rest of the array. This dictates the way the final row must be constructed.
                if ([remoteContainers objectAtIndex:currentStartRangeIndex]) {
                    NSDictionary *cellData = [NSDictionary dictionaryWithObjectsAndKeys:[remoteContainers objectAtIndex:rightIndex], @"LEFT_CONTAINER", @"EMPTY_CELL", @"LEFT_MIDDLE_CONTAINER", @"EMPTY_CELL", @"RIGHT_MIDDLE_CONTAINER", @"EMPTY_CELL", @"RIGHT_CONTAINER", nil];
                    [assetTableCell populateCellData:cellData];                
                }                       
            }
                break;
            case 2: {
                // There are two elements at the end of the array.
                NSDictionary *cellData = [NSDictionary dictionaryWithObjectsAndKeys:[remoteContainers objectAtIndex:rightIndex], @"LEFT_CONTAINER", [remoteContainers objectAtIndex:rightMiddleIndex], @"LEFT_MIDDLE_CONTAINER", @"EMPTY_CELL", @"RIGHT_MIDDLE_CONTAINER", @"EMPTY_CELL", @"RIGHT_CONTAINER", nil];
                [assetTableCell populateCellData:cellData];
            }
                break;
            case 3: {
                // There are three elements at the end of the array.                    
                NSDictionary *cellData = [NSDictionary dictionaryWithObjectsAndKeys:[remoteContainers objectAtIndex:rightIndex], @"LEFT_CONTAINER", [remoteContainers objectAtIndex:rightMiddleIndex], @"LEFT_MIDDLE_CONTAINER", [remoteContainers objectAtIndex:leftMiddleIndex], @"RIGHT_MIDDLE_CONTAINER", @"EMPTY_CELL", @"RIGHT_CONTAINER", nil];
                [assetTableCell populateCellData:cellData];                    
            }
                break;
            default: {
                DLog(@"Thought the array had more elements, however was unable to determine the number of elements remaining in array.");

            }
                break;
        }
    }
}
return assetTableCell;

}

Answer 1

看起来您只在tableView无法为您出列单元格的情况下配置每个单元格。首先，您的单元重用可能因此而被破坏。这是一个问题。

然后在故事板的情况下，如果单元标识符设置正确，那么[tableview dequeueReusableCellWithIdentifier：]将始终为您返回一个单元格。所以assetTableCell不会是零，即使是第一次。

目前还不清楚你的所有逻辑是什么，但是在assetTableCell不为零的情况下，你需要能够正确设置你的单元格的内容。（或者因为单元格正在被回收，或者因为单元格来自故事板缓存）

在故事板上设置reuseIdentifier会导致不显示自定义UITableViewCell

1 个答案: