具有自动布局的自定义单元格的动态高度

Question

我尝试使用自动布局构建不同的自定义单元格，但我总是得到默认高度 44。为了更好地理解：

GTBlockView 是我所有自定义单元格的超类，它是一个 UITableViewCell！ 这适用于 iOS 7 和 iOS 8，所以我不能使用新的自动功能... 我永远不知道单元格应该有多高，因为我从我的服务器获取数据！所以重要的是，一切都是动态的！

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return [self heightForBasicCellAtIndexPath:indexPath];
}


- (CGFloat)heightForBasicCellAtIndexPath:(NSIndexPath *)indexPath {

static GTBlockView *sizingCell = nil;
static dispatch_once_t onceToken;

dispatch_once(&onceToken, ^{
    sizingCell = [self.tableView dequeueReusableCellWithIdentifier:CellIdentifier];
});

sizingCell = [self configureBasicCell:sizingCell atIndexPath:indexPath];

return [self calculateHeightForConfiguredSizingCell:sizingCell];
}


- (CGFloat)calculateHeightForConfiguredSizingCell:(GTBlockView *)sizingCell
{
    sizingCell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(self.tableView.bounds), 0.0f);
    [sizingCell.contentView setNeedsLayout];
    [sizingCell.contentView layoutIfNeeded];

    CGSize size = [sizingCell systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    NSLog(@"HÖHE: %f",size.height);

    return size.height;

}



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


- (GTBlockView *)basicCellAtIndexPath:(NSIndexPath *)indexPath {

GTBlockView *cell = [self.tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

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

[self configureBasicCell:cell atIndexPath:indexPath];
return cell;
}


- (GTBlockView*)configureBasicCell:(GTBlockView *)cellBlock atIndexPath:(NSIndexPath *)indexPath {

GFBlock *block = [self.node.blocks objectAtIndex:indexPath.row];

cellBlock = [[GTAppController sharedInstance] createInterfaceForBlock:block];

return cellBlock;
}

这是 Cell 的重要方法：

- (GTBlockView *)createInterfaceForBlock:(GFBlock *)block {

NSString* className = [self.interfacesDict objectForKey:NSStringFromBlockType(block.blockTypeId)];

Class c = nil;


if (className == nil)
{
    c = [GTGenericBlockView class];

} else {
    //Generate the specific Custom Cell Class
    c = NSClassFromString(className);
}

GTBlockView* instance = [(GTBlockView *)[c alloc] initWithBlock:block];


return instance;
}

在这里，我使用约束调用我的自定义单元之一：

- (id)initWithBlock:(GFBlock *)block {
self = [super initWithBlock:block];

if (self) {
        self.backgroundColor = GTDefaultBackgroundColor;

        self.button = [[UIButton alloc]init];
        self.button.translatesAutoresizingMaskIntoConstraints = NO;

        [self.contentView addSubview:self.button];
}

return self;

}


- (void)updateConstraints
{

if (!self.didSetupConstraints)
{
// 1. Create a dictionary of views
NSDictionary *viewsDictionary = @{@"buttonView":self.button};
NSDictionary *metrics = @{@"vSpacing":@0, @"hSpacing":@0};

// 3. Define the buttonView Position
NSArray *constraint_POS_V_SV = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[buttonView]"
                                                                       options:0
                                                                       metrics:metrics
                                                                         views:viewsDictionary];


NSArray *constraint_POS_H_SV = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-10-[buttonView]-10-|"
                                                                       options:0
                                                                       metrics:metrics
                                                                         views:viewsDictionary];


[self.contentView addConstraints:constraint_POS_V_SV];
[self.contentView addConstraints:constraint_POS_H_SV];

    NSArray *constraint_V = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[buttonView(==100)]"
                                                                options:0
                                                                metrics:nil
                                                                  views:viewsDictionary];
[self.button addConstraints:constraint_V];

   self.didSetupConstraints = YES;
}
[super updateConstraints];

}

但就像我上面说的，我总是得到默认高度，但在这种情况下它应该是 100.0f....

Answer 1

在 viewDidLoad 中添加这个

tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 101