ios - UITableView 内存泄漏

Question

解决方案

只需阅读@Kjuly的答案即可

非常感谢

问题

我将 tableView 与部分一起使用，每个部分有 4 行，第一行必须显示来 self 使用的网站的图像 HJCache类来缓存图像并避免泄漏/内存问题。

现在，这段代码运行良好，当我快速滚动时它不会泄漏或造成内存问题

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    //UITableViewCell *cell=nil;

    if (indexPath.row == 0) {
    static NSString *CellIdentifier = @"Cell";
    HJManagedImageV* mi;
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];


        mi = [[HJManagedImageV alloc] initWithFrame:CGRectMake(0,0,cell.frame.size.width, 310)];
        mi.tag = 999;

        [cell addSubview:mi];

    } else {
        mi = (HJManagedImageV*)[cell viewWithTag:999];
        [mi clear];

    }



    if (indexPath.row == 0) {

        mi.image = [UIImage imageNamed:@"placeholder"];

    mi.url = [NSURL URLWithString:[pictures objectAtIndex:indexPath.section]];

    [objMan manage:mi];
        UITapGestureRecognizer *tapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(likeTappedDouble:)];
        tapped.numberOfTapsRequired = 2;

        [mi setUserInteractionEnabled:YES];
        [mi addGestureRecognizer:tapped];



    }

        return cell;

    }
}

但是，当我尝试配置其他行时，它会泄漏，并且在滚动应用程序时会出现内存问题并且速度非常慢。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    //UITableViewCell *cell=nil;

    if (indexPath.row == 0) {
    static NSString *CellIdentifier = @"Cell";
    HJManagedImageV* mi;
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];


        mi = [[HJManagedImageV alloc] initWithFrame:CGRectMake(0,0,cell.frame.size.width, 310)];
        mi.tag = 999;

        [cell addSubview:mi];

    } else {
        mi = (HJManagedImageV*)[cell viewWithTag:999];
        [mi clear];

    }



    if (indexPath.row == 0) {

        mi.image = [UIImage imageNamed:@"placeholder"];

    mi.url = [NSURL URLWithString:[pictures objectAtIndex:indexPath.section]];

    [objMan manage:mi];


        UITapGestureRecognizer *tapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(likeTappedDouble:)];
        tapped.numberOfTapsRequired = 2;

        [mi setUserInteractionEnabled:YES];
        [mi addGestureRecognizer:tapped];



    }

        return cell;

    }



    static NSString *CellIdentifier = @"CellS";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];



    if (indexPath.row == 1) {
        // configure row 1
    }
        if (indexPath.row == 2) {
            // configure row 2
        }

    // etc for the others ..

    return cell;
}

问题出在哪里，谢谢..

更新

这段代码效果不佳，它在滚动时将 subview 添加到其他行

 static NSString *CellIdentifier = @"CellS";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
     cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;

        if (indexPath.row == 1) {
            UIImage* likesimage = [UIImage imageNamed:@"likespic"];
            CGRect frameimg = CGRectMake(7, 5, likesimage.size.width, likesimage.size.height);
            likesbutton = [[UIButton alloc] initWithFrame:frameimg];
            [likesbutton setBackgroundImage:likesimage forState:UIControlStateNormal];
            likesbutton.backgroundColor = [UIColor clearColor];
            [cell addSubview:likesbutton];

            label3 = [[UILabel alloc] initWithFrame:CGRectMake(20, 2, 100, 20)];
            label3.textColor = [UIColor colorWithRed:61.0/255.0 green:113.0/255.0 blue:154.0/255.0 alpha:1.0];
            label3.backgroundColor = [UIColor clearColor];
            label3.font = [UIFont fontWithName:@"Helvetica-Bold" size:12];
            label3.adjustsFontSizeToFitWidth = YES;

            [cell addSubview:label3];



        }

    }

Answer 1

对于其他单元格，您需要重复使用该单元格:

static NSString *CellIdentifier = @"CellS";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
  cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}

---

编辑更新的问题:

您需要了解“单元重用”的工作原理。至于你更新的代码，它说只有第一行需要像图像这样的 subview ，对吗？因此，您需要将其添加到 if (cell == nil){} 代码段之外，如下面的代码:

static NSString *CellIdentifier = @"CellS";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
  cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
  cell.selectionStyle = UITableViewCellSelectionStyleNone;
}

if (indexPath.row == 1) {
  UIImage* likesimage = [UIImage imageNamed:@"likespic"];
  CGRect frameimg = CGRectMake(7, 5, likesimage.size.width, likesimage.size.height);
  likesbutton = [[UIButton alloc] initWithFrame:frameimg];
  [likesbutton setBackgroundImage:likesimage forState:UIControlStateNormal];
  likesbutton.backgroundColor = [UIColor clearColor];
  [cell addSubview:likesbutton];

  label3 = [[UILabel alloc] initWithFrame:CGRectMake(20, 2, 100, 20)];
  label3.textColor = [UIColor colorWithRed:61.0/255.0 green:113.0/255.0 blue:154.0/255.0 alpha:1.0];
  label3.backgroundColor = [UIColor clearColor];
  label3.font = [UIFont fontWithName:@"Helvetica-Bold" size:12];
  label3.adjustsFontSizeToFitWidth = YES;

  [cell addSubview:label3];
}

注意:最好像对第 0 行所做的那样创建一个新的单元格实例，因为它只需要创建一次。