[Android] Data Storage
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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.
[Android] Data Storage
- 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 2
- 3. Android Programming Data Storage Accessing Files 3
- 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. 4
- 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. 5
- 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 6
- 7. Android Programming Accessing Files Accessing File from SDCard(etc. ) Check a file is exists or not 7
- 8. Android Programming Accessing Files Accessing File from SDCard(etc. ) Create New File 8
- 9. Android Programming Accessing Files Accessing File from SDCard(etc. ) Delete File 9
- 10. Android Programming Accessing Files Example 7.1 Update Exercise 6 project: • Data will be loaded from /raw/contacts.xml 10
- 11. Android Programming Accessing Files Example 7.2 Update Exercise 6 project: • Data will be stored in SDCard 11
- 12. Android Programming Data Storage Shared Preferences 12
- 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. 13
- 16. Android Programming Shared Preference Example 7.3 Update Example 7.2 project: • Prompt engaged users to rate your app in the Google Play 16
- 17. Android Programming Data Storage Accessing Local Database 17
- 18. Android Programming Accessing Local Database Install a Firefox Add-on: SQLite manager https://addons.mozilla.org/vi/firefox/addon/sqlite-manager/ 18
- 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” 19
- 20. Android Programming Accessing Local Database Using the BaseDAO class Check and create DB 20
- 21. Android Programming Accessing Local Database Using the BaseDAO class Add new row 21
- 22. Android Programming Accessing Local Database Using the BaseDAO class Add new row 22
- 23. Android Programming Accessing Local Database Using the BaseDAO class Select rows 23
- 24. Android Programming Accessing Local Database Using the BaseDAO class Delete a row 24
- 25. Android Programming Accessing Local Database Using the BaseDAO class Update a row 25
- 26. Android Programming Exercise 7 Update Exercise 6 project: Data will be stored in SQLite database 26