- Creating a Shared App Group
- Creating the iOS Application
- Coding the Apple Watch App
- Using a Framework to Contain Repetitive Code
- Summary
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Creating the iOS Application
Now let's write the code for the iOS application:
First we'll populate the View window in the Main.Storyboard file with the following views (see Figure 6):
- Label
- Picker
Figure 6 Populating the View window in the containing iOS app. (The list of city names is just a placeholder.)
Create an outlet for the Picker view by using the drag-and-drop method (via the Show Editor window). This action will create the statement shown in bold below in the ViewController.swift file:
import UIKit class ViewController: UIViewController { @IBOutlet weak var pickerCountries: UIPickerView! override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically // from a nib. } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }Add the following statements in bold to the ViewController.swift file to populate the Picker view with a list of countries. When a country is selected, the value of the country will be saved using the NSUserDefaults class:
import UIKit class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate { @IBOutlet weak var pickerCountries: UIPickerView! //---replace "group.net.learn2develop.articles.sharingdata" // with the string that you have created earlier--- var defaults = NSUserDefaults( suiteName: "group.net.learn2develop.articles.sharingdata") var countries: [String]! override func viewDidLoad() { super.viewDidLoad() countries = ["Singapore", "Norway", "Japan", "Thailand", "Hong Kong"] self.pickerCountries.delegate = self self.pickerCountries.dataSource = self } func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int { return 1 } func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int { return countries.count } func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! { return countries[row] } //---read a value from the setting, given a key--- func readSettingValue(key:String) -> String? { return defaults?.objectForKey(key) as? String } //---save a setting value, given the key--- func saveSettingValue(key:String, value:String) { defaults?.setObject(value, forKey: key) defaults?.synchronize() } //---when the user selects a country--- func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) { saveSettingValue("country", value: countries[row]) } //---when the view appears--- override func viewDidAppear(animated: Bool) { if let countrysSelected = self.readSettingValue("country") { //---set the picker to display the previously // selected country--- self.pickerCountries.selectRow( find(countries, countrysSelected)!, inComponent: 0, animated: true) } } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }Select the SharingData scheme at the top of Xcode and run the application on the iPhone Simulator. Select a country as shown in Figure 7.
Figure 7 Selecting a country from the Picker view.
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