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![A simple list
• ListView
– Contains a list
– android:id=“@android:id/list”
• Elements of the list
– android.R.layout.simple_list_item_1
• Static
– May use String[]
• Dynamic
– Use ArrayList<String>
16](https://image.slidesharecdn.com/mdad4new-211115080058/85/MDAD-4-Lists-adapters-and-recycling-16-320.jpg)
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More from Alexandru Radovici
MDAD 4 - Lists, adapters and recycling
- 1. Android Lists, adapters andrecycling
- 2. Bibliography 1. Wallace Jackson,Android Apps for Absolute Beginners, Apress, 2017 2. Hello Views, http://developer.android.com/guide/tutorials/vi ews/index.html 3. Android Application Fundamentals, http://developer.android.com/guide/topics/fun damentals.html 2
- 3. Contents • MVC • Lists –Model – Adaptor • List Elements – Simple – from XML • ListActvity • Optimization – Recycling – Tags – Cache • GridView 3
- 4. Model View Controller •Pattern • Splits – UI – Program – Data storage • Advantages – Programing with components – Easier to maintain • Disadvantages – May be slow 4
- 5. MVC Empirical Database (Model) Display(View) Program logic (Controller) 5
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- 7. Specific Activities • ListActivity –Specially for a list – May have other components – List ID • android:id=“@android:id/list” • Special functions – onListItemClick (…) – setListAdapter (…) 7
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- 9. ListView • A verticalcontainer – Similar with ScrollView – Optimized for movement • Identical components – Each row – Almost true ;) • Adapter’s role – Creates these components • Events – setOnItemClickListener (…) – setOnItemLongClickListener (…) 9
- 10. Adapter • Part ofView • Specifies the way of display – Adapts the data – Modifies the View 10
- 11. ListView Adapter • Predefined –ArrayAdapter • User defined – Implementation of ListAdapter – Extend BaseAdapter 11
- 12. Usage of ArrayAdapter(XML) • Example – Static list 12
- 13. Usage of ArrayAdapter(Java) • Example – Static List 13
- 14. Usage of ArrayAdapter(XML) • Example – Dynamic List 14
- 15. Usage of ArrayAdapter(Java) 15
- 16. A simple list •ListView – Contains a list – android:id=“@android:id/list” • Elements of the list – android.R.layout.simple_list_item_1 • Static – May use String[] • Dynamic – Use ArrayList<String> 16
- 17. The List withcomplex elements • Elements – Components • EditView • ImageView • Container • Adapter custom-made – Implement ListAdapter – Extend BaseAdapter 17
- 18. Extend BaseAdapter • ViewgetView (int position, View convertView, ViewGroup list) • int getCount () • Object getItem (int position) • long getItemId (int position) • int getViewTypeCount () • int getItemViewType (int position) 18
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- 24. Recycling • Objects reusage •Avoid object creation – new is bad for memory! • Use – Buffers – Lists 24
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- 27. Different types ofelements? int getViewTypeCount () int getItemViewType (int position) 27
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- 29. Tags (for View) •void setTag (Object tag) • Object getTag () 29
- 30. Efficient using Tag Utilizareatag-ului 30
- 31. GridView • Identical withListView – Extend BaseAdapater 31
- 32. The new RecyclerView •A new way of building lists – Uses several layouts • Not just a LinearLayout – The developer has to use recycling and tagging • Extend RecyclerView.Adapter – onCreateViewHolder() • Inflate the view – onBindViewHolder() • Set the View’s data – getItemCount() 32
- 33. Conclusions • Lists – Linearcontainers – Contain components • Including containers • ListActivity – Activity with special functions for list • Adapter – Formats the data from the model for the list – Simple – Custom made – Recycling of elements • Elements – Described in XML 33
- 34. Keywords • MVC • Adaptor •Classes – ListActivity – ListView – GridView – View – ArrayAdapter – BaseAdapter – ArrayList • Interfaces – ListAdapter • Recycling • Tags 34
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