2015_08_09.md

Objectives

• Make an object conform to a protocol
• What are the pros and cons of open source?

Think Piece

http://www.ted.com/talks/angela_lee_duckworth_the_key_to_success_grit?language=en

Protocols

http://rypress.com/tutorials/objective-c/protocols
https://developer.apple.com/library/ios/documentation/General/Conceptual/DevPedia-CocoaCore/Protocol.html#//apple_ref/doc/uid/TP40008195-CH45-SW1

Delegation

https://developer.apple.com/library/ios/documentation/General/Conceptual/DevPedia-CocoaCore/Delegation.html

Exercises

UIAlertView
http://code.tutsplus.com/tutorials/ios-sdk-working-with-uialertview-and-uialertviewdelegate--mobile-3159

• In viewDidLoad, create and show a UIAlertView.
• Make sure your view controller conforms to the UIAlertViewDelegate protocol
• Implement some UIAlertViewDelegate methods with NSLogs

UIAlertViewController
As of iOS 8, Apple introduced a new way to handle alerts, UIAlertController.

• Create another alert using UIAlertController Notice that there is no delegate for UIAlertController. What are some pros a cons to the new approach?

UITextField

• Add a UITextField to your storyboard.
• Drag from your UITextField int your code, creating a property in your view controller.
• In viewDidLoad, set the delegate property of the UITextField to self (the view controller)
• Make sure that your view controller class *conforms to the UITextField (<UITextFieldDelegate)
• Which method would you use to disable editing of the UITextField?
• Add a UISwitch. Only allow editing when the UISwitch is set to on.
• Implement the textFieldDidEndEditing method. What do you need to do to trigger this method (hint: first responder)?

UIPickerView https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIPickerViewDelegate_Protocol/index.html
https://developer.apple.com/library/ios/documentation/iPhone/Reference/UIPickerViewDataSource_Protocol/index.html#//apple_ref/occ/intf/UIPickerViewDataSource

• Add a UIPickerView to your storyboard.
• Drag from your UIPickerView into your code, creating a property in your view controller.
• In viewDidLoad, set the delegate property of the UIPickerView to be self (the view controller)
• In viewDidLoad, set the dataSource property to be self (the view controller)
• Make sure that your view controller class *conforms to the UIPickerViewDelegate protocol and the UIPickerViewDataSource protocol. (<UIPickerViewDelegate, UIPickerViewDataSource>)
• Implement the required methods to render and interact with the UIPickerView
• Fun ensues

Roll your own

• Create a UINavigationController with a UITableViewController as its root view controller.
• Create a new class called CQColorTableViewController (subclass of UITableViewController) and change the UITableViewController in the storyboard to CQColorTableViewController.
• In CQColorTableViewController.m add @property (nonatomic) NSMutableArray *colors;
• Implement the UITableViewDataSource methods so that there is 1 section and there is a row for every item in your array.
• Head back into the storyboard.
• In the UINavigationBar of the UINavigationController, add a + to the top right.
• Add a modal segue from the + button to a new UIViewController
• Make a new class called CQColorPickerViewController and change your new UIViewController to a CQColorPickerViewController
• In your CQColorPickerViewController add 6 buttons. Make the button titles the names of some colors. List of colors

• Create an action for when a user taps on one of the buttons (drag from storyboard to view controller).
• In your new method, add code to dismiss the modal view controller
• Create a new Objective-C file. Make sure you choose protocol from the drop down. Name it CQColorPickerViewControllerDelegate

• In CQColorPickerViewControllerDelegate.h, in between @protocol and @end, add one method:
  - (void)colorPickerViewController:(CQColorPickerViewController *)viewController didPickColor:(UIColor *)color;

• Head over to CQColorPickerViewController.h. Create a new property: @property (nonatomic, weak) id<CQColorPickerViewControllerDelegate>delegate;. This is creating a property of type id called delegate. The stuff in the <> is saying that this object must conform to the CQColorPickerViewViewControllerDelegate.

• In CQColorTableViewController.m, import CQColorPickerViewControllerDelegate. Make CQColorTableViewController conform to the CQColorPickerViewControllerDelegate protocol and implement the one method that we created, colorPickerViewController:didPickColor: