Saving data on Android : File Storage vs SQLite Database vs Shared Preferences

Saving Data on Android

Android provides several options for saving data, each with its own advantages and disadvantages. The three most common methods are:

• File Storage
• SQLite Database
• Shared Preferences

File Storage

File storage involves saving data in plain text files, which can be read and written using standard Java I/O classes.

Advantages

• Simple and easy to understand
• Suitable for storing small amounts of data
• No need for a database or other external libraries

Disadvantages

• Not suitable for large amounts of data
• Difficult to manage and maintain
• No built-in support for querying or searching data

Example

// Write data to a file
FileOutputStream fos = openFileOutput("mydata.txt", MODE_PRIVATE);
fos.write("This is some data".getBytes());
fos.close();

// Read data from a file
FileInputStream fis = openFileInput("mydata.txt");
byte[] data = new byte[fis.available()];
fis.read(data);
fis.close();
String text = new String(data);

SQLite Database

SQLite is a lightweight embedded database that is built into Android. It provides a structured way to store and manage data.

Advantages

• Efficient for storing and retrieving large amounts of data
• Supports querying and searching data
• Built-in support for data integrity and consistency

Disadvantages

Example

// Create a database and table
SQLiteDatabase db = openOrCreateDatabase("mydb", MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS mytable (id INTEGER PRIMARY KEY, name TEXT)");

// Insert data into the database
ContentValues values = new ContentValues();
values.put("name", "John Doe");
db.insert("mytable", null, values);

// Query data from the database
Cursor cursor = db.query("mytable", null, null, null, null, null, null);
while (cursor.moveToNext()) {
String name = cursor.getString(cursor.getColumnIndex("name"));
}
cursor.close();
db.close();

Shared Preferences

Shared Preferences is a simple mechanism for storing key-value pairs of data.

Advantages

• Easy to use for storing small amounts of settings and preferences
• Data is automatically saved and restored

Disadvantages

• Not suitable for large amounts of data
• Limited data types supported (strings, integers, floats, booleans, long)
• No support for querying or searching data

Example

// Save a preference
SharedPreferences prefs = getSharedPreferences("myprefs", MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("username", "john.doe");
editor.apply();

// Retrieve a preference
String username = prefs.getString("username", "");

Comparison

Conclusion

The best method for saving data depends on the specific requirements of your application. For small amounts of data, File Storage or Shared Preferences may be sufficient. For large amounts of structured data, SQLite Database is the preferred option.