How does it work with AutoLayout?

[jianghaoyuan2007]

When I using this library set a variable height of cell, what's the best way?

for example:

• (CGFloat)heightWithItem:(MultilineTextItem *)item tableViewManager:(RETableViewManager *)tableViewManager;

[sebastianludwig]

I'm assuming you're using custom designed cells?

I just had good success by basically following this guide and looking at the mentioned example project. I've used IB to set to constraints though.

The key points are to implement layoutSubviews of your custom cell class like this

- (void)layoutSubviews
{
    [super layoutSubviews];

    [self.contentView setNeedsLayout];
    [self.contentView layoutIfNeeded];

    self.body.preferredMaxLayoutWidth = CGRectGetWidth(self.body.frame);
}

Register your VC as RETableViewManagerDelegate, keep a reference to an offscreen cell obtained with heightCalculationCell = [tableView dequeueReusableCellWithIdentifier:@"TwoLineItem"]; and implement

- (CGFloat)tableView:(UITableView *)tv heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    heightCalculationCell.header.text = @"heading";
    heightCalculationCell.body.text = content[indexPath.row];

    [heightCalculationCell updateConstraints];

    heightCalculationCell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(tv.bounds), CGRectGetHeight(heightCalculationCell.bounds));

    [heightCalculationCell layoutSubviews];

    CGFloat height = [heightCalculationCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    return height + 1;
}

@romaonthego it would be nice to get the reference to the item passed into the delegate, to be able to react to properties like the accessoryType. What's your opinion about a tableView:heightForRowAtIndexPath:forItem: delegate method which is called instead of tableView:heightForRowAtIndexPath if implemented?

[sebastianludwig]

I just found out that is possible with implementing the class method +heightWithItem:tableViewManager:.

static TwoLineCell *heightCalculationCell = nil;

@implementation TwoLineCell

+ (CGFloat)heightWithItem:(TwoLineItem *)item tableViewManager:(RETableViewManager *)tableViewManager
{
    if (!heightCalculationCell) {
        heightCalculationCell = [tableViewManager.tableView dequeueReusableCellWithIdentifier:@"TwoLineItem"];
    }

    heightCalculationCell.item = item;
    [heightCalculationCell cellWillAppear];
    [heightCalculationCell layoutSubviews];
    [heightCalculationCell updateConstraints];

    heightCalculationCell.bounds = CGRectMake(0.0f, 0.0f, CGRectGetWidth(tableViewManager.tableView.bounds), CGRectGetHeight(heightCalculationCell.bounds));

    [heightCalculationCell layoutSubviews];

    CGFloat height = [heightCalculationCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;

    return height + 1;
}

[sebastianludwig]

However, to implement row height caching, the heightWithItem solution is not sufficient and we're back to tableView:heightForRowAtIndexPath:forItem:. Fancy a PR @romaonthego?

[wayne798]

@sebastianludwig I tried your code, but failed, I create the cell with pure code not xib. Can you give more code segment?

[sebastianludwig]

@wayne798 can you elaborate on "failed"? What exactly is the problem? Can you provide a demo project showcasing your issue?

[wayne798]

@sebastianludwig Aha,I resolved it , I changed "heightCalculationCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;" to "heightCalculationCell systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;" , then it worked well. I googled "systemLayoutSizeFittingSize" , there are some issues like me. I use Xcode8.1 ans iOS10.2