SharedPreferences

The “Save Game” of Android Development, Explored & Visualized

Storing small bits of data shouldn’t require a full database. SharedPreferences allows you to persist key-value pairs easily. Whether it’s a user’s high score or a “Dark Mode” toggle, this API has been the backbone of Android persistence for years.

Try the Simulator

Click the buttons to see the UI update instantly, then watch apply() write the data to the Disk Storage in the background.

Android UI

Current Counter

Disk Storage (.xml)
high_score: Empty

Step-by-Step Implementation

Ready to build it? Follow these two files to create your own persistent high-score app.

XML res/layout/activity_main.xml

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    android:padding="24dp">

    <TextView
        android:id="@+id/scoreDisplay"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="High Score: 0"
        android:textSize="32sp"
        android:textStyle="bold" />

    <EditText
        android:id="@+id/scoreInput"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Enter new score"
        android:inputType="number"
        android:layout_marginTop="20dp" />

    <Button
        android:id="@+id/saveButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Save with apply()" />

</LinearLayout>

JAVA MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static final String KEY_SCORE = "high_score";
    private SharedPreferences sharedPref;
    private TextView scoreDisplay;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        scoreDisplay = findViewById(R.id.scoreDisplay);
        EditText scoreInput = findViewById(R.id.scoreInput);
        Button saveButton = findViewById(R.id.saveButton);

        // Initialize: getPreferences is tied to this Activity only
        sharedPref = getPreferences(Context.MODE_PRIVATE);

        // 1. Read existing value
        int currentScore = sharedPref.getInt(KEY_SCORE, 0);
        scoreDisplay.setText("High Score: " + currentScore);

        // 2. Write new value
        saveButton.setOnClickListener(v -> {
            int newScore = Integer.parseInt(scoreInput.getText().toString());
            
            SharedPreferences.Editor editor = sharedPref.edit();
            editor.putInt(KEY_SCORE, newScore);
            editor.apply(); // Background save

            scoreDisplay.setText("High Score: " + newScore);
        });
    }
}

🗄️ Working with Multiple Files

Sometimes, putting everything in one file is messy. If your app has “User Profile” data and separate “Game Settings,” you can create multiple named files using getSharedPreferences().

Android App Private Storage

📄

user_data.xml

“user_name”: “Alex”
“is_logged”: true

📄

settings.xml

“dark_mode”: false
“notifs”: true

Each file is isolated and managed by a unique Name.

Implementation Example (Java)

// 1. Access the 'User' file
SharedPreferences userPrefs = getSharedPreferences("user_data", Context.MODE_PRIVATE);

// 2. Access the 'Settings' file
SharedPreferences settingsPrefs = getSharedPreferences("settings", Context.MODE_PRIVATE);

// Writing to the User file specifically
userPrefs.edit().putString("user_name", "Alex").apply();

// Reading from the Settings file specifically
boolean isDark = settingsPrefs.getBoolean("dark_mode", false);

Best Practice: Always use Context.MODE_PRIVATE. Other modes like MODE_WORLD_READABLE are deprecated and will throw a SecurityException on modern Android versions (7.0+).

Example Project Code: