How can I add a directory tree to a tableview?

I'm not sure how its called. Is there a default element for this or do I have to make it from scratch?

UITableViewController

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    return 2;
}

- (NSInteger)tableView:(nonnull UITableView *)tableView
 numberOfRowsInSection:(NSInteger)section {
    
    if (section == 0) {
        
        return 2;
        
    } else {
        
        return 1;
    }
}

- (nonnull UITableViewCell *)tableView:(nonnull UITableView *)tableView
                 cellForRowAtIndexPath:(nonnull NSIndexPath *)indexPath {
    
    UITableViewCell *cellView = [tableView dequeueReusableCellWithIdentifier:@"cell"];
    
    if (!cellView) {
        
        cellView = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                          reuseIdentifier:@"cell"];
    }
    
    return cellView;
}

CodePudding user response：

There is no "built-in tree view" type of UI component, but you can do this with the cell's .indentationLevel and .indentationWidth properties.

Here is a very simple example:

struct IndentDataStruct {
    var level: Int = 0
    var title: String = ""
}
class TreeTableViewController: UITableViewController {

    var myData: [IndentDataStruct] = []
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        var ids: IndentDataStruct!
        
        ids = IndentDataStruct(level: 0, title: "Favorites")
        myData.append(ids)
        
        for i in 1...2 {
            ids = IndentDataStruct(level: 1, title: "Favorite \(i)")
            myData.append(ids)
        }
        
        ids = IndentDataStruct(level: 0, title: "Bookmarks")
        myData.append(ids)
        
        for i in 1...3 {
            ids = IndentDataStruct(level: 1, title: "Bookmark \(i)")
            myData.append(ids)
        }
        
        ids = IndentDataStruct(level: 0, title: "Others")
        myData.append(ids)
        
        for i in 1...2 {
            ids = IndentDataStruct(level: 1, title: "Other \(i)")
            myData.append(ids)
            for j in 1...2 {
                ids = IndentDataStruct(level: 2, title: "Other Sub \(i) - \(j)")
                myData.append(ids)
            }
        }

        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "defaultCell")

    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return myData.count
    }
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let c = tableView.dequeueReusableCell(withIdentifier: "defaultCell", for: indexPath)
        let d = myData[indexPath.row]
        c.textLabel?.text = d.title
        c.indentationLevel = d.level
        // just to show different indent widths...
        c.indentationWidth = d.level == 2 ? 32 : 16
        return c
    }
    
}

and the output is:

Note that the example uses default UITableViewCell class, which handles the indentation automatically.

If you are using a custom cell, you need to adjust that yourself.

Assuming you're constraining the cell's elements to the cell's contentView.layoutMarginsGuide (which you should be doing), you'll want to implement:

override func layoutSubviews() {
    super.layoutSubviews()
    contentView.layoutMargins.left = CGFloat(indentationLevel) * indentationWidth
}