CURATED SOURCE EXAMPLE

Offline notes · data layer

Explore a parameterized SQLite helper for a local-first notes app.

IntermediateJavaSQLite

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A closer look at the code.

Choose a file to explore. Copy it into your own project when you’re ready.

NotesDb.java

package com.example.notes;
import android.content.Context;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class NotesDb extends SQLiteOpenHelper {
    public NotesDb(Context context) { super(context, "notes.db", null, 1); }
    @Override public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE notes (id INTEGER PRIMARY KEY, title TEXT NOT NULL)");
    }
    @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Add non-destructive migrations when the schema changes.
    }
    public long add(String title) {
        ContentValues values = new ContentValues();
        values.put("title", title);
        return getWritableDatabase().insertOrThrow("notes", null, values);
    }
    public int count() {
        try (Cursor cursor = getReadableDatabase().rawQuery("SELECT COUNT(*) FROM notes", null)) {
            return cursor.moveToFirst() ? cursor.getInt(0) : 0;
        }
    }
}

Setup & requirements

Create a Java-based Empty Views Activity in Android Studio with an installed Android SDK.
Keep the Gradle files generated by your installed Android Studio version. These snippets do not prescribe an AGP version.
Add NotesDb.java, adapt its package name, and invoke its operations from a background executor.
Build and run locally. Review lifecycle behavior and test your changes.

What to explore

SQLiteOpenHelper and schema creation
Bound inserts and cursor cleanup
Small, readable files you can adapt

Related reading

Read the companion guide

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package com.example.notes; import android.content.Context; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class NotesDb extends SQLiteOpenHelper { public NotesDb(Context context) { super(context, "notes.db", null, 1); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE notes (id INTEGER PRIMARY KEY, title TEXT NOT NULL)"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // Add non-destructive migrations when the schema changes. } public long add(String title) { ContentValues values = new ContentValues(); values.put("title", title); return getWritableDatabase().insertOrThrow("notes", null, values); } public int count() { try (Cursor cursor = getReadableDatabase().rawQuery("SELECT COUNT(*) FROM notes", null)) { return cursor.moveToFirst() ? cursor.getInt(0) : 0; } } }

Setup & requirements

Create a Java-based Empty Views Activity in Android Studio with an installed Android SDK.

Keep the Gradle files generated by your installed Android Studio version. These snippets do not prescribe an AGP version.

Add NotesDb.java, adapt its package name, and invoke its operations from a background executor.

Build and run locally. Review lifecycle behavior and test your changes.