CSC 222: Object-Oriented Programming. Fall 2015

Transcription

1 CSC 222: Object-Oriented Programming Fall 2015 Object-oriented design OO design review objects, cohesion, loose coupling, polymorphism, Model-View-Controller (MVC) pattern netbeans IDE create/edit/run a project, advanced features GUIBuilder, Swing GUI toolkit 1 Object-oriented development OO design is the dominant approach to large-scale software development developing cohesive (& loosely coupled) software objects allows for 1. independent teams to contribute 2. independent testing & debugging 3. easier code reuse polymorphism via interfaces allows for 1. independent development (interface serves as contract) 2. generic code that can work on entire hierarchies of classes polymorphism via inheritance allows for 1. code reuse (can extend existing code without direct access) 2. generic code that can work on entire hierarchies of classes 2 1

2 BlueJ à netbeans BlueJ is an Interactive Development Environment (IDE) designed for novice programmers simple to use visual interface makes class vs. object distinction clear can directly manipulate objects & call methods using mouse clicks can also write and execute statements in the Code Pad however, it is somewhat limiting to experienced programmers netbeans is a popular, industry-strength IDE for developing software free & open-source multi-platform (Mac, Windows, Linux) multi-language (Java, PHP, C/C++, ) has an integrated GUI builder download from netbeans.org 3 Create a project 4 2

3 Select location & project name 5 Adding a file to the project 6 3

4 Select location & file/class name 7 Can then edit the default file 8 4

5 Completing a project each class in the project is its own file one class must have a public static void main method when you run the project, this main method is executed 9 Editor features code completion when type OBJECT., see list of method options Source menu Format will try to indent selected lines consistently Shift Left / Shift Right will manually indent selected lines Toggle Comment comments/uncomments selected lines Refactor Rename can change a class/variable/method name throughout the project Run Build Main Project compile all classes in the project Run Main Project execute the main method note: can also right-click on a file and select Run File 10 5

6 example: Magic 8-ball create a new project named Magic use the default option to create a default main class named TerminalUI download the Die.java class into the src folder of this project define a new class named Magic8Ball has a 3-sided Die object as a field has a getanswer method that takes a String as input (a question) and returns one of 3 possible answers at random: "Definitely", "No way", or "Outlook hazy" define a new class named TerminalUI, in the main method prompt the user for a question call getanswer and display the answer 11 MVC pattern model-view-controller is a software pattern used to develop reusable, modular software goal: isolate the application-specific logic from the user interface allows for independent testing & development, easy updates for this example: the model consists of the logic of the application Die & Magic8Ball the view is the Java terminal window the controller is the TerminalUI class with its text-based input/output by separating the logic from the interface, it makes it possible to plug in a different interface, e.g., a Graphical User Interface (GUI) 12 6

7 GUIBuilder netbeans has an integrated GUI builder built-in can create a (Swing) GUI using a drag-and-drop interface 13 Naming the GUI class 14 7

8 GUI design view 15 Build interface drag GUI elements from the Palette onto the Design Frame can arrange, resize, alter Properties of the elements in particular, right click and change names of elements to be meaningful (e.g., questionarea, answerbutton, answerbox) 16 8

9 Associate events with elements right click on element, select the event you want to handle 17 Source view click on the Source button to see the generated code 18 9

10 Completing the GUI add the Controller code to the GUI class here, Magic8Ball object is a field, initialized in constructor code for I/O & method call are entered into the event-handler method 19 Wumpus GUI we could similarly define a GUI for Hunt the Wumpus Model: CaveContents + Cave + CaveMaze (note: no I/O in these classes) View: window with text area (for output) and buttons (for input) Controller: JFrame that connects GUI elements with CaveMaze model 20 10