Present dictionary in several NSTableviews - macos

Question

I'm a beginner to cocoa and I've been trying to make a simple app for Mac using swift programming language, but I'm stuck and can't find a solution.
I want to present a data from dictionary in two or more tableViews, where the first table will show key, and the second table will show value.
For example, I have a dictionary
var worldDict:NSDictionary = ["Africa":["Egypt", "Togo"],"Europe": ["Austria", "Spain"]]
I can present all continents in the first table, but I can't find out how to make second table to display countries from continent I choose in the first table.
My ViewController is a DataSource and Delegate for both tables.
extension ViewController: NSTableViewDataSource {
func numberOfRowsInTableView(tableView: NSTableView) -> Int {
if tableView == continentTable {
return self.worldDict.valueForKey("Continent")!.count
} else if tableView == countryTable {
return self.worldDict.valueForKey("Continent")!.allKeys.count
}
return 0
}
func tableView(tableView: NSTableView, viewForTableColumn tableColumn: NSTableColumn?, row: Int) -> NSView? {
var cell = tableView.makeViewWithIdentifier(tableColumn!.identifier, owner: self) as! NSTableCellView
if tableView == self.continentTable {
let continent: AnyObject? = wordlDict.valueForKey("Continent")
var keys = continent!.allKeys
cell.textField?.stringValue = keys[row] as! String
} else if tableView == self.countryTable {
var countriesOfContinent: AnyObject? = worldDict.valueForKey("Continent")?.valueForKey("Africa")!
cell.textField?.stringValue = countriesOfContinent?.allKeys[row] as! String
}
return cell
}
}
Here I present data from dictionary in tables, but separately, and can't figure out how to make them work together.
Also I know how to get the number of row that has been selected
extension ViewController: NSTableViewDelegate {
func tableViewSelectionDidChange(notification: NSNotification) {
let continentSelected = rowSelected()
}}
func rowSelected() -> Int? {
let selectedRow = self.continentTable.selectedRow
if selectedRow >= 0 && selectedRow < self.worldDict.valueForKey("Continent")!.count {
return selectedRow
}
return nil
}

Answer 1

Part of the problem is that you're relying on the ordering of the keys returned by allKeys() to be reliable, which it's not. You need to keep a separate array of continents. It can basically be a copy of whatever allKeys() returned on one occasion, but you should not keep calling allKeys() each time.
In numberOfRowsInTableView(), for the countries table, you want to return the number of countries in the selected continent:
} else if tableView == countryTable {
if let selectedContinentRow = rowSelected() {
let selectedContinent = continentsArray[selectedContinentRow]
return self.worldDict[selectedContinent].count
}
return 0
}
For tableView(_:viewForTableColumn:row:), you want to return an element from the selected continent's array of countries:
} else if tableView == self.countryTable {
if let selectedContinentRow = rowSelected() {
let selectedContinent = continentsArray[selectedContinentRow]
return self.worldDict[selectedContinent][row]
}
}
Also, whenever the selected continent changes, you need to tell the countries table to reload its data:
func tableViewSelectionDidChange(notification: NSNotification) {
// ... whatever else ...
let tableView = notification.object as! NSTableView
if tableView == continentTable {
countryTable.reloadData()
}
}