表格查看单元格高度

Question

I have multiple cells in my table view; eg Cat Cell, Dog Cell, Chicken Cell. In the Cat Cell I have two views: a graphs view and an images view.

If the graphs view is hidden and the images view is visible, then I want to set my cell height to 200, and 350 in the opposite case.

How would I achieve that? I am registering my nib file in the heightForRowAt delegate method of the table view and I have tried different things to no avail. These are the two views in my cell:

@property (weak, nonatomic) IBOutlet UIView *imagesView;
@property (weak, nonatomic) IBOutlet UIView *graphView;

...and this is my heightForRowAt method:

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{

    TrainingImageCell *cell = (TrainingImageCell*)[self.tableView dequeueReusableCellWithIdentifier:@"TrainingImageCell"];
    if (cell.isGraphViewOnTop == YES) {
        return 350;
    }
    else {
        return 200;
    }
    return 200;
}

Answer 1

Instead of initiating a new cell, you need to access the one what is already in the tableView .

Instead of

TrainingImageCell *cell = (TrainingImageCell*)[self.tableView dequeueReusableCellWithIdentifier:@"TrainingImageCell"];

Do

TrainingImageCell *currentCell = (TrainingImageCell*)[tableView cellForRowAtIndexPath:indexPath];

And than take a look on the property.

EDIT: Looking at the lengthy discussion we have, here is a very reliable example for an approach you could use in Swift .

import UIKit

class RightAlignedCell: UITableViewCell {
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var subLabel: UILabel!
    // Your boolean property you would like to map
    var randomBool: Bool = false
}

class RightAlignedTableViewController: UIViewController {
    // This is just an example for the dataSource, you should have this somewhere already
    lazy var dataSource: [Bool] = {
        var dataSource: [Bool] = []
        for index in 0..<10 {
            dataSource.append(index % 2 == 0)
        }
        return dataSource
    }() 

    @IBOutlet weak var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        tableView.reloadData()
    }
}

extension RightAlignedTableViewController: UITableViewDelegate {}

extension RightAlignedTableViewController: UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 10
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        // Take a look in the !!!dataSource!!!, what is value for isHidden
        let isHidden = self.dataSource[indexPath.row]
        // return the right height
        return isHidden ? 60 : 100
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell: RightAlignedCell = tableView.dequeueReusableCell(withIdentifier: "RightAlignedCell", for: indexPath) as! RightAlignedCell
        cell.titleLabel.text = "Something"
        cell.subLabel.text = "Nothing"
        cell.randomBool = self.dataSource[indexPath.row]

        return cell
    }
}

Answer 2

Why are registering nib file in heightForRowAt. You are registering new cell hence cannot access the existing cell. If you want it working in your style instead of registering new cell in height for row at IndexPath you can access existing cell using indexPath as

TrainingImageCell *currentCell = (TrainingImageCell*)[tableView cellForRowAtIndexPath:indexPath];

and access check property.

 -(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
 TrainingImageCell *currentCell = (TrainingImageCell*)[tableView cellForRowAtIndexPath:indexPath];
  if (cell.isGraphViewOnTop == YES) {
  return 350;
  }
return 200;
}

Answer 3

If you dequeueReusableCellWithIdentifier you just get a new cell, it will not have any data to check if isGraphViewOnTop

My advice will be to return UITableViewAutomaticDimension and set cell views with constants, so when the element is hidden, a cell will have a smaller size.