View Controllers (second part) Content taken from book: “iPhone SDK Development” by Bill Dudney and Chris Adamson

Running Application From last lecture

Creating the New View Controller In Xcode, select the Classes group, Ctrl+click the group, and choose Add > New File from the pop- up menu. In the wizard that pops up, choose the “UIViewController subclass” item in the iPhone OS > Cocoa Touch Classes group. Don’t select the “With XIB for user interface” checkbox, because we will be creating our interface shortly. Click Next, and name the class MovieEditorViewController.

Adding outlets/actions to new UI UI with three text fields and one button Add the outlets and actions that we will need to interact properly with the UI to our header file The text fields will allow the user to edit the title, box-office gross, and summary, respectively, and the button will signal the user is done with the edits.

MovieEditorViewController.h Add a declaration at the top inside angle brackets for the UITextFieldDelegate protocol. That tells the compiler that this class intends to implement all required methods from that protocol. – Make sure to save the file so Interface Builder will know about the new outlets and actions we’ve added.

MovieEditorViewController.m Add the import of Movie.h Add statement for each of the properties that were declared in the MovieEditorViewController.h file. – Now we need to implement the viewWillAppear: method to place the values from the Movie object into the text fields.

viewWillAppear: method In MovieEditorViewController.m In the done method, we dismiss the current modal view controller with a call to the dismissModalViewControllerAnimated:

UITextFieldDelegate protocol We will make our view controller the delegate of all the text fields so we can capture the input via the UITextFieldDelegate protocol. We need to implement two methods of the UITextFieldDelegate protocol. – textFieldShouldReturn: – textFieldDidEndEditing:

textFieldShouldReturn: The textFieldShouldReturn: method is called by the text field when the user presses the Return button on the keyboard. This is the perfect spot for us to resign first responder status for the field (which in turn will cause the keyboard to animate out) by calling resignFirstResponder.

textFieldDidEndEditing: The textFieldDidEndEditing: method is called when the text field resigns its first responder status. This method is a great spot to capture the data that the user typed into the field. – We take the values from the fields and place those values into the movie object.

Building the new UI Now we need to add a new nib file to the project In Xcode, Ctrl+click the Resources group, choose Add > New File, click iPhone OS > User Interface, and then choose the View XIB item. Click Next, name the file MovieEditorViewController.xib, and then click Finish. Open MovieEditorViewController.xib in IB by double-clicking it.

Modify the new nib Modify the new nib so that it becomes the user interface for our MovieEditorViewController Change the class of the File’s Owner Select this object, and open the Identity inspector with D-4. Change the Class field to MovieEditorViewController.

UI and its connections Now that IB knows about our outlets and actions, we need to create the UI and make the connections. Open the view by double- clicking it. Create UI Make the connections

Connections Inspector This is what our Connections inspector should look like:

Configuring the Text Field Tap in a text region -> a keyboard Text field becomes the first responder We want the correct keyboard to show up, and we want it to be properly configured

Text Filed Attributes Here the text field is configured to capitalize words and take the defaults for correction, type, and appearance. The Return key is set to Done

MovieEditorViewController We have both view controllers and the user interface set up to display the movie as well as edit the movie. However, we have no way of getting to the second view where the user can edit the movie data.

Making the MovieEditorViewController 1.Add an outlet to MovieViewController for the instance of MovieEditorViewController we are going to create. 2.Update MovieViewController ’s edit method to modally display the MovieEditorViewController. 3.Create an instance of MovieEditorViewController in MovieViewController ’s nib file, and make the connection from the outlet.

Adding Outlet In MovieViewController.h add an outlet named editingViewController to the MovieEditorViewController Make sure to add the forward declaration:

Updating the edit method In MovieViewController.m Don’t forget to add the import statement to the implementation file for the MovieEditorViewController.h and statements for each property.

The Editing View Controller in IB Open the MovieViewController.xib file. We need to add a view controller to this nib file. From the Library, drag a view controller into the document window.

Still editing View Controller in IB We need to change the class of this view controller to MovieEditorViewController. Select the new view controller, open the Identity inspector, and change Class to MovieEditorViewController. Next we need to set the nib filename for this view controller, so open the Attributes inspector with D-1, and type MovieEditorViewController into the NIB Name field.

Connecting outlet to new view controller All that remains is to make the connection from the File’s Owner’s editingViewController outlet to the new view controller. Now hit Build and Go to see your work in the simulator.

The View Controller’s View When the view controller is asked for its view; if it’s not there, the view controller checks to see whether its nib file is set. If so, then the view controller loads that nib file, passing self in as the File’s Owner.

Our View Controller’s View And since we set the view property in our MovieEditorViewController.xib file, the view gets set. Here’s the basic picture of what happens once the view is requested but not found: