ios - 自定义 UITableViewCell 元素不仅仅出现在 iPad 上

Question

我在 iPad 上运行我的应用程序时遇到了以下问题。我的自定义第一行 UITableViewCell 的 UI 元素没有出现。我正在手动分配和定位这些元素，因此问题与使用错误的 xib 无关。我已经上传了在 iPhone 6 上运行完全相同代码的结果。与 iPad 2 .请注意第一行单元格在 iPad 上是空的，但在 iPhone 6 上正确地包含两个 UITextField 元素和 UIButton

经过一些实验后，我现在知道是什么导致了这个问题，但我不知道为什么。这是我对 tableView:cellForRowAtIndexPath:

的实现

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *summonerCellIdentifier = @"summonerCellIdentifier";
    static NSString *footerCellIdentifier = @"footerCellIdentifier";
    static NSString *headerCellIdentifier = @"headerCellIdentifier";

    UITableViewCell *cell;
    if (indexPath.row == 0) {
        // header view 1
        cell = [tableView dequeueReusableCellWithIdentifier:headerCellIdentifier];
        if (cell == nil) {
            cell = [UITableViewCell new];
        }
        cell.backgroundColor = [UIColor LHBeigeLight];
        cell.selectionStyle = UITableViewCellSelectionStyleNone;

        self.summonerName = [[UITextField alloc] initWithFrame:CGRectMake(0,30,200,40)];
        [self.summonerName setCenter:CGPointMake(self.view.center.x, self.summonerName.center.y)];
        [self.summonerName setBackgroundColor:[UIColor whiteColor]];
        [self.summonerName setLeftViewMode:UITextFieldViewModeAlways];
        [self.summonerName setLeftView:[[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)]];
        [self.summonerName setPlaceholder:@"Summoner Name"];
        [self.summonerName setKeyboardType:UIKeyboardTypeEmailAddress];
        [self.summonerName setAutocapitalizationType:UITextAutocapitalizationTypeNone];
        [self.summonerName setAutocorrectionType:UITextAutocorrectionTypeNo];
        // [self.summonerName setAutoresizingMask:(UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin)];
        [cell.contentView addSubview:self.summonerName];

        self.summonerRegion = [[UITextField alloc] initWithFrame:CGRectMake(0,80,200,40)];
        [self.summonerRegion setCenter:CGPointMake(self.view.center.x, self.summonerRegion.center.y)];
        [self.summonerRegion setBackgroundColor:[UIColor whiteColor]];
        [self.summonerRegion setLeftViewMode:UITextFieldViewModeAlways];
        [self.summonerRegion setLeftView:[[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)]];
        [self.summonerRegion setPlaceholder:@"Summoner Region"];
        [self.summonerRegion setKeyboardType:UIKeyboardTypeEmailAddress];
        [self.summonerRegion setAutocapitalizationType:UITextAutocapitalizationTypeNone];
        [self.summonerRegion setAutocorrectionType:UITextAutocorrectionTypeNo];
        // [self.summonerRegion setAutoresizingMask:(UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin)];
        [cell.contentView addSubview:self.summonerRegion];

        self.searchButton = [[UIButton alloc]initWithFrame:CGRectMake(0,130,200,40)];
        [self.searchButton setCenter:CGPointMake(self.view.center.x, self.searchButton.center.y)];
        [self.searchButton setTitle:@"Search" forState:UIControlStateNormal];
        [self.searchButton.titleLabel setTextColor:[UIColor whiteColor]];
        [self.searchButton setBackgroundImage: [AppDelegate imageFromColor:[UIColor LHGoldColor]] forState:UIControlStateNormal];
        [self.searchButton setBackgroundImage: [AppDelegate imageFromColor:[UIColor LHGoldLightColor]] forState:UIControlStateHighlighted];
        [self.searchButton setBackgroundImage: [AppDelegate imageFromColor:[UIColor LHGoldLightColor]] forState:UIControlStateSelected];
        [self.searchButton setContentEdgeInsets:UIEdgeInsetsMake(5, 15, 5, 15)];
        [self.searchButton addTarget:self action:@selector(search:) forControlEvents:UIControlEventTouchUpInside];
        // [self.searchButton setAutoresizingMask:(UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin)];
        [cell.contentView addSubview:self.searchButton];

        _pickerView = [[UIPickerView alloc] init];
        [self.summonerName setDelegate:self];
        [self.summonerRegion setInputView:_pickerView];
        [self.summonerRegion setDelegate:self];

        // Initialize Data
        _pickerData = @[@"NA", @"EUW", @"EUNE", @"BR", @"KR", @"LAN", @"LAS", @"OCE", @"RU", @"TR"];

        // Connect data
        _pickerView.dataSource = self;
        _pickerView.delegate = self;
        _pickerView.showsSelectionIndicator = YES;

        [self.summonerRegion setText:[_pickerData objectAtIndex:0]];
    } else if (indexPath.row == (recentSearchesArray.count+1)) {
        // footer view 1
        cell = [tableView dequeueReusableCellWithIdentifier:footerCellIdentifier];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:footerCellIdentifier];
        }
        cell.frame = CGRectMake(0, 0, self.recentSearchesTable.frame.size.width, 140);
        cell.backgroundColor = [UIColor LHRedColor];
        cell.textLabel.textColor = [UIColor LHBeigeLight];
        cell.textLabel.text = @"Follow Us On Twitter";
        cell.detailTextLabel.textColor = [UIColor LHBeigeLight];
        cell.detailTextLabel.text = @"for app updates and events!";
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
    } else if (indexPath.row == (recentSearchesArray.count+2)) {
        // footer view 2
        cell = [tableView dequeueReusableCellWithIdentifier:footerCellIdentifier];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:footerCellIdentifier];
        }
        cell.frame = CGRectMake(0, 0, self.recentSearchesTable.frame.size.width, 140);
        cell.textLabel.textColor = [UIColor LHBeigeLight];
        cell.backgroundColor = [UIColor LHGreenColor];
        cell.textLabel.text = @"Battlefy Tournaments";
        cell.detailTextLabel.textColor = [UIColor LHBeigeLight];
        cell.detailTextLabel.text = @"Check out our community tournaments!";
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
    } else {
        // regular cell
        Summoner *summoner = [recentSearchesArray objectAtIndex:indexPath.row-1];

        cell = [tableView dequeueReusableCellWithIdentifier:summonerCellIdentifier];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:summonerCellIdentifier];
        }
        cell.textLabel.text = summoner.summonerName;
        cell.detailTextLabel.text = [summoner.summonerRegion uppercaseString];
        cell.backgroundColor = [UIColor whiteColor];
        cell.selectionStyle = UITableViewCellSelectionStyleDefault;
    }
    return cell;
}

我在第一个单元格中注释掉了破坏我的自定义 View 的三行，并取消了格式设置。无论出于何种原因，如果我设置左右灵活的自动调整大小蒙版，单元格元素就会在 iPad 版本上消失。我使用这些 UIViewAutoresizing 掩码来处理旋转(通过使元素在第一个单元格中水平居中)。

有人知道为什么会这样吗？如果我设置这个 0 索引 UITableViewCell 的方式是不好的做法，或者如果我的代码有其他问题，请告诉我!

---

编辑:更多信息。这是 tableView:heightForRowAtIndexPath: 的样子:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    if (indexPath.row == 0) {
        return 200;
    } else if (indexPath.row >= recentSearchesArray.count + 1) {
        return 130;
    } else {
        return 44;
    }
}

这些是 iPhone 6 的 po [self.view recursiveDescription] 的输出:

(lldb) po [self.view recursiveDescription]
<UIView: 0x7ff3e156d290; frame = (0 0; 320 568); autoresize = W+H; layer = <CALayer: 0x7ff3e156d360>>
   | <UITableView: 0x7ff3e1858e00; frame = (0 0; 320 568); clipsToBounds = YES; autoresize = RM+BM; gestureRecognizers = <NSArray: 0x7ff3e156ad60>; layer = <CALayer: 0x7ff3e1568610>; contentOffset: {0, 0}; contentSize: {320, 0}>
   |    | <UITableViewWrapperView: 0x7ff3e156bbf0; frame = (0 0; 320 568); gestureRecognizers = <NSArray: 0x7ff3e156c660>; layer = <CALayer: 0x7ff3e156c160>; contentOffset: {0, 0}; contentSize: {320, 568}>
   |    | <UIImageView: 0x7ff3e15698b0; frame = (0 565.5; 320 2.5); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x7ff3e15294a0>>
   |    | <UIImageView: 0x7ff3e156a5d0; frame = (317.5 561; 2.5 7); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0x7ff3e156a5b0>>

对于 iPad 2:

(lldb) po [self.view recursiveDescription]
<UIView: 0x7869a230; frame = (0 0; 320 568); autoresize = W+H; layer = <CALayer: 0x786a2b20>>
   | <UITableView: 0x78907600; frame = (0 0; 320 568); clipsToBounds = YES; autoresize = RM+BM; gestureRecognizers = <NSArray: 0x78690b00>; layer = <CALayer: 0x786a62c0>; contentOffset: {0, 0}; contentSize: {320, 0}>
   |    | <UITableViewWrapperView: 0x786a9470; frame = (0 0; 320 568); gestureRecognizers = <NSArray: 0x786a8290>; layer = <CALayer: 0x7866ab40>; contentOffset: {0, 0}; contentSize: {320, 568}>
   |    | <UIImageView: 0x786a9160; frame = (0 565; 320 3); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0x7866a750>>
   |    | <UIImageView: 0x78679fe0; frame = (317 561; 3 7); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0x78671490>>

---

编辑 2:为最佳实践添加了出列代码

---

编辑 3:根据 Brian 的建议切换到更好的单元格初始化函数 [UITableViewCell new]; 并将 subview 添加到内容 View 而不是单元格本身。仍然没有运气。

---

编辑 4 修复: 最后我不得不切换到使用自定义 UITableViewCell 子类并直接在 .xib 中执行所有约束以修复此问题。我不确定根本原因是什么，但如果您仍想重现它，您可能只需将测试应用程序中的每个单元格都设为我为 0 索引创建的单元格即可。

---

编辑 5 FIXED X 2: 我用上面的代码找到了原始问题的解决方案。您可以在这里查看 https://stackoverflow.com/a/28185714/740474

Answer 1

又回过头来看问题，终于找到了真凶。我试图将 subview 在单元格内水平居中，所以调用了这样的东西:

[self.summonerName setCenter:CGPointMake(self.view.center.x, self.summonerName.center.y)];

无论出于何种原因，self.view.center.x 在 iPad 上的评估结果完全出乎意料，并将内容 View 定位在屏幕外。我真正应该做的(以及解决上述代码问题的方法)是基于单元格中心而不是 super View 中心设置 subview 中心，如下所示:

[self.summonerName setCenter:CGPointMake(cell.center.x, self.summonerName.center.y)];

为了向任何好奇的人进行演示，我创建了一个绝对准系统的示例项目来说明这个问题，您可以在此处查看: https://github.com/oseparovic/ipaduitableviewbug