1. Chapter 5:
MVC Architecture
Chapter 5

2. We will … Learn MVC software architecture
Describe MVC-based solution for ball shooting
Examine Expendability of MVC solutions
Develop software library support for MVC framework: UWBGL
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3. In a nutshell … So far … This chapter: Programming model: event driven
GUI API: elements and event registrations
Graphics API: GHC initialization and drawing with RC
This chapter:
MVC Architecture: consolidate all of the above!
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4. The MVC Architecture
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5. Model-View-Controller
Application state
The persistent variables
View
Draws the application state
Graphics API support
Controller
Accepts input from user to change the model
GUI API support
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6. Model of Ball shooting program
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7. Model: Application State: Support: All persistent variables
State Inquiries
State Changes
Timer event support (Simulation update)
State Visualization
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8. View of Ball shooting program
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9. Controller of Ball shooting program
ViewController: is our Camera!
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10. Expanding Ball shooting program
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11. Implement 2 views …
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12. Notes on MVC … Simplicity: Portability: Expendability:
Model: usually most complex
MVC: allow design of Model to be independent from user interaction and from drawing
Portability:
E.g., Change of controller ports Model to a different GUI platform
Expendability:
As we have seen: adding new view/controller pairs is straightforward
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13. MVC: component interactions
User change application state:
Via controllers
Application changes its own state
Via timer events
All controllers and views must present consistent state
GUI element must be correct: e.g., slider bar reflecting the falling hero ball position
Drawing must be update to date
Classic MVC architecture
Elaborate protocol to ensure all states are consistent …
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14. MVC with real-time simulation …
Every 25 milliseconds: timer fires!
Application state likely to change
MUST redraw all views!!
During Timer event … ALWAYS
Poll/update all controllers
Update Application state
Update all views
Simple update protocol
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15. 2-View ball shooting component interaction
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16. Inter-Ball Collision
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