iphone - UITableView 滚动缓慢，内存泄漏问题

Question

我有一个 UITableView 和一个 UITableCell 子类。每个表格单元格都有两个 scrollviews，每个 ScrollView 旋转一个动态数量的标签，这些标签是在我的表格单元格实现中创建的。我的滚动性能很差，我相信这是内存泄漏造成的。我正在引用此 stackoverflow 正确答案来解决我的问题:cellForRowAtIndexPath memory management .

我不知道如何调整我的代码，这样我就不必在每次创建标签时都分配内存。

ViewController.m

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Custom Cell";

cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}


NSDictionary *dictionary = [parseDataArray objectAtIndex: indexPath.row];

NSArray *popularLinkTitleArray = [dictionary objectForKey:@"popularLinkTitleArray"];
NSString *soundCloudLink = [dictionary objectForKey:@"soundCloudLink"];
NSArray *soundCloudTrackTitleArray = [dictionary objectForKey:@"soundCloudTrackTitleArray"];


cell.artistNameLabel.text = artistName;

[cell createPopularLinkLabels: popularLinkTitleArray];

return cell;
}

CustomCell.m

- (void)layoutScrollLabelsForPopularLinkScrollView: (float)arrayCount
{
UIView *view = nil;
NSArray *subviews = [popularLinkScrollView subviews];

// reposition all image subviews in a horizontal serial fashion
CGFloat curXLoc = 0;
for (view in subviews)
{
    if ([view isKindOfClass:[UILabel class]] && view.tag >= 0)
    {
        CGRect frame = view.frame;
        frame.origin = CGPointMake(curXLoc, 0);
        view.frame = frame;

        curXLoc += (kScrollObjWidth);
    }
}

[popularLinkScrollView setContentSize:CGSizeMake((arrayCount * kScrollObjWidth),    [popularLinkScrollView bounds].size.height)];

}

-(void) createPopularLinkLabels:(NSArray *) popularLinkTitleArray
{

popularLinkScrollView.clipsToBounds = YES;

kScrollObjHeight = popularLinkScrollView.frame.size.height;
kScrollObjWidth = popularLinkScrollView.frame.size.width;

for (UIView* subView in popularLinkScrollView.subviews)
    [subView removeFromSuperview];

NSUInteger i;
    for (i = 0; i < popularLinkTitleArray.count; i++)
    {
        NSString *string = [NSString stringWithFormat:@"%@", [popularLinkTitleArray objectAtIndex: i]];
        UILabel *label = [[UILabel alloc] init];
        label.text = [NSString stringWithFormat:@"%@", string];
        label.backgroundColor = [UIColor clearColor];
        label.numberOfLines = 5;
        [label setFont:[UIFont fontWithName:@"Calibri" size:18]];

        // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
        CGRect rect = label.frame;
        rect.size.height = kScrollObjHeight;
        rect.size.width = kScrollObjWidth;
        label.frame = rect;
        label.tag = i;  // tag our images for later use when we place them in serial fashion
        [popularLinkScrollView addSubview:label];
    }

[self layoutScrollLabelsForPopularLinkScrollView:popularLinkTitleArray.count];

}

Answer 1

您在使用 ARC 吗？如果没有，你应该自动释放到

cell = [[[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]

单元格对象被重用，每次更改内容时不需要重新添加 subview 。只需更改数据并根据需要更新标签框。

如果您有明显不同的单元格，请考虑使用单独的自定义单元格类。您需要为 reuseIdentifier 使用单独的值。

还可以考虑不创建自定义单元格，而只是将元素添加到标准 UITableViewCell。 Read this about styling a cell .