Question

我一直试图让这个教程dynamic-cell-height在ios8中工作好几天，但无法弄清楚发生了什么。它适用于iPhone上的ios7，适用于ios7和ios7。在iPAD上的ios8，但它不适用于ios8上的任何iphone。

我认为问题在于如何以及何时在单元格内创建标签。

我在控制器中有以下代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.dbManager = [[DBManager alloc] initWithDatabaseFilename:@"tomhaisdb.sql"];

    [self loadData];

}

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [self deselectAllRows];
}

-(void)deselectAllRows{
    for (NSIndexPath * indexPath in [self.tableView indexPathsForSelectedRows]) {
        [self.tableView deselectRowAtIndexPath:indexPath animated:NO];
    }
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void)loadData {
    NSString *query = @"select * from favourites";

    if (self.favourites != nil) {
        self.favourites = nil;
    }

    self.favourites = [[NSArray alloc] initWithArray:[self.dbManager loadDataFromDB:query]];

   /* [self reloadDataWithCompletions:^{
         self.tableView.backgroundColor = [UIColor colorWithRed:28.0f/255.0f green:30.0f/255.0f blue:35.0f/255.0f alpha:1];
    }];*/
    [self reloadTableViewContent];
}

- (void)reloadTableViewContent {
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.tableView reloadData];
        [self.tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:NO];
    });
}

/*-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
    return 1;
}*/

#pragma mark - UITableViewDataSource

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    NSLog(@"Number of rows: %d", self.favourites.count);
    return self.favourites.count;
}


-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    return [self basicCellAtIndexPath:indexPath];
}

-(favouritedCell *)basicCellAtIndexPath:(NSIndexPath *)indexPath {
    favouritedCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"favouriteCell" forIndexPath:indexPath];
    [self configureBasicCell:cell atIndexPath:indexPath];
    return cell;
}

-(void)configureBasicCell:(favouritedCell *)cell atIndexPath:(NSIndexPath *)indexPath{
    NSInteger indexOfTomhaisText = [self.dbManager.arrColumnNames indexOfObject:@"tomhaisText"];
    NSString *tomhaisText = [[self.favourites objectAtIndex:indexPath.row] objectAtIndex:indexOfTomhaisText];
    [self setTomhaisForCell:cell item:tomhaisText];
    [self setAnswerForCell:cell item:tomhaisText]; // change this later
}

-(void)setTomhaisForCell:(favouritedCell *)cell item:(NSString *)item{
    [cell.favouriteText setText:item];
}

-(void)setAnswerForCell:(favouritedCell *)cell item:(NSString *)item{
    [cell.answer setText:item];
}

#pragma mark - UITableViewDelegate

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
   /* if ([[[UIDevice currentDevice]systemVersion]floatValue] >= 8.0) {
        return UITableViewAutomaticDimension;
    }
    else{*/
        return [self heightForFavouriteCellAtIndexPath:indexPath];
    /*}*/

}

-(CGFloat)heightForFavouriteCellAtIndexPath:(NSIndexPath *)indexPath{
    static favouritedCell *sizingCell = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sizingCell = [self.tableView dequeueReusableCellWithIdentifier:@"favouriteCell"];
    });

    [self configureBasicCell:sizingCell atIndexPath:indexPath];
    return [self calculateHeightForConfiguredSizingCell:sizingCell];
}

-(CGFloat)calculateHeightForConfiguredSizingCell:(UITableViewCell *)sizingCell{
    sizingCell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(self.tableView.frame), CGRectGetHeight(sizingCell.bounds));
    NSLog(@"Bounds before Layout %@", NSStringFromCGRect(sizingCell.bounds));
     NSLog(@"Content View before Layout %@", NSStringFromCGRect(sizingCell.contentView.bounds));
    [sizingCell setNeedsLayout];
    [sizingCell layoutIfNeeded];

    CGSize size = [sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    NSLog(@"Bounds after layout %@", NSStringFromCGRect(sizingCell.bounds));
    NSLog(@"Content View before Layout %@", NSStringFromCGRect(sizingCell.contentView.bounds));
    return size.height + 1.0f;
}

-(CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath{
    return 155.0f;
}

在自定义标签中，单元格使用我有以下内容：

    @implementation favouriteLabel

- (void)setBounds:(CGRect)bounds {
    [super setBounds:bounds];

    // If this is a multiline label, need to make sure
    // preferredMaxLayoutWidth always matches the frame width
    // (i.e. orientation change can mess this up)

    if (self.numberOfLines == 0 && bounds.size.width != self.preferredMaxLayoutWidth) {
        self.preferredMaxLayoutWidth = self.bounds.size.width;
        NSLog(@"Label Bounds before update constraints %@", NSStringFromCGRect(self.bounds));
        [self setNeedsUpdateConstraints];
        NSLog(@"Label Bounds after update constraints %@", NSStringFromCGRect(self.bounds));
    }
}

@end

我认为我的问题在于创建标签时的原因是因为在ios 7中我输出如下：

2015-06-01 20:07:10.563 Facts[63322:607] Label Bounds before update constraints {{0, 0}, {216, 2}}
2015-06-01 20:07:10.563 Facts[63322:607] Label Bounds after update constraints {{0, 0}, {216, 2}}
2015-06-01 20:07:10.563 Facts[63322:607] Label Bounds before update constraints {{0, 0}, {217, 40}}
2015-06-01 20:07:10.563 Facts[63322:607] Label Bounds after update constraints {{0, 0}, {217, 40}}
>2015-06-01 20:07:10.564 Facts[63322:607] Bounds after layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.564 Facts[63322:607] Content View before Layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.564 Facts[63322:607] Bounds before Layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.564 Facts[63322:607] Content View before Layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.565 Facts[63322:607] Bounds after layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.565 Facts[63322:607] Content View before Layout {{0, 0}, {256, 82}}
2015-06-01 20:07:10.569 Facts[63322:607] Label Bounds before update constraints {{0, 0}, {216, 74.5}}
2015-06-01 20:07:10.569 Facts[63322:607] Label Bounds after update constraints {{0, 0}, {216, 74.5}}
2015-06-01 20:07:10.569 Facts[63322:607] Label Bounds before update constraints {{0, 0}, {217, 40}}
2015-06-01 20:07:10.570 Facts[63322:607] Label Bounds after update constraints {{0, 0}, {217, 40}}

但是在ios8中，输出是不同的。

2015-06-01 20:18:06.049 Facts[63396:81689795] Bounds before Layout {{0, 0}, {256, 44}}
2015-06-01 20:18:06.049 Facts[63396:81689795] Content View before Layout {{0, 0}, {320, 44}}
2015-06-01 20:18:06.131 Facts[63396:81689795] Label Bounds before update constraints {{0, 0}, {216, 0}}
2015-06-01 20:18:06.131 Facts[63396:81689795] Label Bounds after update constraints {{0, 0}, {216, 0}}
2015-06-01 20:18:06.131 Facts[63396:81689795] Label Bounds before update constraints {{0, 0}, {217, 4.5}}
2015-06-01 20:18:06.131 Facts[63396:81689795] Label Bounds after update constraints {{0, 0}, {217, 4.5}}

在ios7中，首先创建标签，然后创建单元格边界，然后再次调整标签大小。但是在ios8中我们首先看到内容视图输出，然后我们才看到标签的输出。

对不起，我无法解释它。这对我来说有点神秘，ios如何制作它的表格，所以我真的很难理解为什么它在ios7而不是在ios8中工作

最值得赞赏的任何帮助。我已经在这里写了这个问题：Dynamic Cell Height autolayout IOS但我想我在这个问题上投了一个关于自动布局的红色鲱鱼。

Answer 1

“答案”标签错误地放置了框架。由于没有为anyXany安装标签，因此在Interface Builder中没有显示警告。

由于约束不等于预期高度，因此停止了Auto Layout正确解决iOS 8的单元格高度。

快速解决方法是勾选anyXany的已安装框。您将看到警告显示。选择答案标签，选择编辑器 - >自动布局问题 - >更新框架，您就可以了！

<强>更新

标签最初出现而不需要重新加载的原因是因为打了anyXany框。 Apple看到安装了约束，初始高度正确无需重新加载或滚动。

如果未勾选此框，则在布局过程中添加约束的时间太晚，以使标签具有正确的初始高度。

我建议安装单元格标签（适用于任何规模的类别），因为单元格的限制不会发生变化，具体取决于特征。

（虽然tableView约束确实发生了变化，但单元格的约束不应该是有条件的。如果是一个单元格，它将始终具有相同的约束，无论大小等级如何。）

UITableView中的动态单元格高度，带AutoLayout

1 个答案: