Managing Multiple Views and Segues

1. Managing Multiple Viewsand Segues FA 172 Intro to Mobile App Development

2. Multiple Views • Recall the RiddleApp the class created on the first day of classes • Used a navigation controller, multiple views, and segues • For today, we will learn to manage multiple views and pass data (objects) between views

3. Product inventory app • Three projects • ProductInvAppPrototype • Focus on user interface • ProductTest • Focus on testing an existing product class • ProductInvApp • Create the final app

4. ProductInvAppPrototype • Create a single view project with three buttons • Embed in a navigation controller • Select the view controller, thenNavigator -> Embed In -> Navigation Controller • Add one view controller to the storyboard with a label and an image view • Set label text to some product name (e.g., “Apple”) • Get an image file from the web representing the product (e.g., apple.jpeg), then drag onto“Supporting Files” section • Select the ImageView control, set the image file name

5. ProductInvAppPrototype • Make two more copies of the view controller (that contains a label and an image) • Update these two copies so the three views represent different products (e.g., apple, orange and pomelo) • Control-drag from each button to a view controller to create the corresponding segues • Select “push” • Build and execute

7. ProductTest • Create a single-view application with a single button • Add an action connection • Test code will be placedin the corresponding method • Download the Product class (Product.h and Product.m) • Three properties: name, imgFileName, and stockLevel(the first two are of type NSString* the third is an int) • An initWith… method that initializes the properties • Methods to increase/decrease stockLevel:-(void)acceptDelivery:(int) qty-(void) releaseStock:(int) qty • Test the Product class (test code provided in website)

8. ProductInventoryApp • Follow instructions posted on the course website • Summary • Two view controllers (controlled by a navigation controller), one for the main interface, the other for the product • Product class must be included in the project • Three products created by main view controller • Detail/product view controller has its display based on a product object

9. ProductInventoryApp: main view • No properties defined in ViewController.h file • No outlet connections • No action connections (button click functionality handled through the segues) • Three product variables declared outside of the methods within the ViewController.m file (these could have been properties but there is no reason to have the data available as properties) • Product objects created within viewDidload method (initialization code executed when view appears) • prepareForSegue method checks which button was pressed (which segue was used) and then sets the appropriate product to be set by the second view

10. ProductInventoryApp: product view • Separate class (with superclassUIViewController) needs to be created and associated to this view controller • Properties defined in .h file • outlet connections for all controls (except buttons) • One product object (to be set by the main view, but used by this view for display) • Action connections (for the add and remove buttons) • viewDidload contains code (in .m file) that displays details of the product object • Code for the add/remove actions • Retrieve data from the text field and convert to int • Call methods to increase/decrease stock on the product object • Redisplay stock level

11. ProductInventoryApp