beginning ios6 development ch03 handlling basic interaction
TRANSCRIPT
The Model-View-Controller Paradigm
• Model-View-Controller (MVC) is a very logical way of dividing the code that makes up a GUI-based application.
• The MVC pattern divides all functionality into three distinct categories:– Model: The classes that hold your application’s data.– View: Made up of the windows, controls, and other
elements that the user can see and interact with.– Controller: The code that binds together the model
and view. It contains the application logic that decides how to handle the user’s inputs.
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Looking at the View Controller
• The Button Fun folder should contain four source code files (the ones that end in .h or .m) and a single nib file.
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Looking at the View Controller
• The controller class called BIDViewController is responsible for managing our application’s view.
• contents of the BIDViewController header file:
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Outlets and Actions
• A controller class can refer to objects in a nib file by using a special kind of property called an outlet.
• interface objects in nib file can be set up to trigger special methods in controller class. These special methods are known as action methods.
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Outlets
• Outlets are special Objective-C class properties that are declared using the keyword IBOutlet.
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Actions
• Actions are methods that are declared with a special return type, IBAction, which tells Interface Builder that this method can be triggered by a control in a nib file.
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Buttons and Action Method
1) Object library
2) Round Rect Button.(Drag)
3) View (Drop)
4) Edit the button’s title.
5) Show the Assistant Editor.
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Buttons and Action Method
6) Control-dragging to source code
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Buttons and Action Method
7) Connection: Action, Name: buttonPressed, Press connect.
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Buttons and Action Method
8) Header file should now look like this:
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Buttons and Action Method
9) Impelementation file added a method stub
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Action Method
Take the title of the button
Put the title in a string
Equal the string to the label
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Application Delegate
• Objects that take responsibility for doing certain tasks on behalf of another object.
• Every iOS application has one, and only one.
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