This document discusses different methods for data storage in Android applications, including: 1. Accessing files from the raw resource folder or external storage for static files. 2. Using shared preferences to store key-value pairs for default values or UI state. 3. Accessing a local SQLite database with a helper DAO class to perform CRUD operations like inserting, selecting, updating, and deleting rows of data. The exercises provide examples of updating a sample project to load and store contact data using these different storage methods.

1. Android Programming
Lesson 7
Data Storage
NGUYEN The Linh

2. Android Programming
Contents
1 Accessing Files
2 Using Preferences
3 Accessing Local Database
4 Exercise 7
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3. Android Programming
Data Storage
Accessing Files
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4. Android Programming
Accessing Files
 Including Static Files as Resources
 If your application requires external file resources, you can include
them in your distribution package by placing them in the res/raw
folder of your project hierarchy.
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5. Android Programming
Accessing Files
 Including Static Files as Resources (etc.)
 Adding raw files to your resources hierarchy is an excellent
alternative for large, preexisting data sources (such as
dictionaries) where it’s not desirable (or even possible) to convert
them into an Android database.
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6. Android Programming
Accessing Files
 Accessing File from SDCard
 Permission
• <uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 SDCard Path
• Environment.getExternalStorageDirectory().getAbsolutePath()
 Check a file is exists or not
• /sdcard/contacts.xml
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7. Android Programming
Accessing Files
 Accessing File from SDCard(etc. )
 Check a file is exists or not
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8. Android Programming
Accessing Files
 Accessing File from SDCard(etc. )
 Create New File
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9. Android Programming
Accessing Files
 Accessing File from SDCard(etc. )
 Delete File
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10. Android Programming
Accessing Files
 Example 7.1
 Update Exercise 6 project:
• Data will be loaded from /raw/contacts.xml
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11. Android Programming
Accessing Files
 Example 7.2
 Update Exercise 6 project:
• Data will be stored in SDCard
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12. Android Programming
Data Storage
Shared Preferences
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13. Android Programming
Shared Preference
 Using SharedPreferences, you can create named maps
of key/value pairs within your application that can be
shared between application components running in
the same Context.
 Shared Preferences support the primitive types
Boolean, string, float, long, and integer, making them
an ideal way to quickly store default values, class
instance variables, the current UI state, and user
preferences.
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14. Android Programming
Shared Preference
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15. Android Programming
Shared Preference
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16. Android Programming
Shared Preference
 Example 7.3
 Update Example 7.2 project:
• Prompt engaged users to rate your app
in the Google Play
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17. Android Programming
Data Storage
Accessing Local Database
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18. Android Programming
Accessing Local Database
 Install a Firefox Add-on: SQLite manager
 https://addons.mozilla.org/vi/firefox/addon/sqlite-manager/
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19. Android Programming
Accessing Local Database
 Create Helper class
 It’s good practice to create a helper class to simplify your
database interactions.
 BaseDAO class will be provided
 Add database file (demo.sqlite) to assets folder
 Open BaseDAO class and change DB_NAME = “demo.sqlite”
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20. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Check and create DB
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21. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Add new row
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22. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Add new row
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23. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Select rows
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24. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Delete a row
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25. Android Programming
Accessing Local Database
 Using the BaseDAO class
 Update a row
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26. Android Programming
Exercise 7
 Update Exercise 6 project:
 Data will be stored in SQLite database
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27. Android Programming