These slides are part of the Android Development Course which I taught to 10 students, while participating in the IP Workshop Summer School 2011. http://www.scoaladevara.info/2011/?page_id=39

1. Android
Model View Controller, Observer,
liste, adaptoare si reciclare
Vlad PETRE
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1 Scoala de Vara IP Workshop 2011 – Calimanesti Valcea

2. Model View Controller (I)
• Architectural Pattern
• Separa
– Interfata grafica
– Programul in sine
– Stocarea datelor
• Avantaje
– Programare pe componente
– Usor de intretinut
• Dezavantaje
– Poate fi lent
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3. Model View Controller (II)
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4. Model View Controller (III)
• Linie continua – asociere directa
• Linie intrerupta – asociere indirecta (ex: Observer)
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5. Model View Controller (IV)
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6. Observer (I)
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7. Observer (II)
• Design Pattern
• Separa
– Obiectul observat
– Observator
• Avantaje
– Programare pe componente
– Usor de intretinut
– Schema generalizata
• Dezavantaje
– Poate fi lent
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8. Observer – Exemplu (I)
Abonarea la Gmail
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9. Observer – Exemplu (II)
Notificarea
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10. ListActivity
• Activitate specializata pentru o
lista
• Poate contine si alte componente
• ID-ul listei:
– android:id=“@android:id/list”
• Metode speciale:
– onListItemClick(…)
– setListAdapter(…)
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11. Adaptor
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12. ListView
• Container vertical
• Optimizat pentru miscare
• Implicit, avem componente
identice pe fiecare rand
• Rolul adaptorului:
– Genereaza aceste componente
• Evenimente:
– setOnItemClickListener(…)
– setOnItemLongClickListener(…)
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13. Adaptor
• Poate fi predefinit:
– ArrayAdapter
• Sau customizat de programator:
– Prin implementarea ListAdapter
– Extinderea BaseAdapter
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14. Varianta statica cu ArrayAdapter (I)
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15. Varianta statica cu ArrayAdapter (II)
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16. Varianta dinamica cu ArrayAdapter (I)
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17. Varianta dinamica cu ArrayAdapter (II)
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18. Concluzii implementare cu
ArrayAdapter
• ListView
– Contine o lista
– android:id=“@android:id/list”
• Elementele listei
– android.R.layout.simple_list_item_1
• Static
– Putem utiliza String[]
• Dinamic
– Putem utiliza ArrayList<String>
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19. Sa incercam ceva mai complex 
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20. Liste cu elemente complexe
• Elementele sunt componente de tip container, ce
pot contine:
– TextView
– ImageView
–…
• Adaptor custom-made
– Prin implementarea ListAdapter
– Extinderea BaseAapter
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21. Extinderea BaseAdapter (I)
• public View getView
(int position, View convertView, ViewGroup list);
• public int getCount ();
• public Object getItem(int position) ;
• public long getItemId(int position);
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22. BaseAdapter (II)
Extinderea
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23. Extinderea BaseAdapter (III)
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24. Extinderea BaseAdapter (IV)
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25. BaseAdapter (V)
Extinderea
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26. BaseAdapter (VI)
Extinderea
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27. Reciclare
• Reutilizarea Obiectelor
• Evitarea crearii de obiecte
– new is bad for memory!
• Utilizam
– buffere
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28. Optimizare (I)
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29. Optimizare (II)
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30. Optimizare (III)
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31. Tag-uri (pentru View)
• public void setTag(Object tag);
• public Object getTag();
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32. Eficient folosind Tag
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33. Referinte
• http://pdm.ipworkshop.ro
• http://en.wikipedia.org/wiki/Model%E2%80%93view%E2
• http://developer.android.com/guide/tutorials/views/hel
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34. Întrebări?
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