Flashcard Learning App with Spaced Repetition

Re-reading notes feels productive and fails reliably: memory research since Ebbinghaus shows recall decays exponentially unless reviews are spaced at increasing intervals. Spaced-repetition software exploits this — each card reappears just before it would be forgotten — and it is the standard study tool behind medical and language exams worldwide. This project implements that idea as an Android app with an original, explainable scheduler: every card carries an ease factor, an interval and a due date; grading Again resets the interval and lowers ease, Hard keeps it short, Easy multiplies the interval out. The daily queue is simply every card due today, ordered by overdue-ness. Because the interval math is implemented from first principles and documented rule by rule, the student can walk an examiner through exactly why a card is due when it is.

1. The student creates decks and adds question-answer cards for the topics to revise.
2. Each day the app queues every card whose due date has arrived, ordered by how overdue it is.
3. The study session shows the question; the student recalls, taps to reveal the answer, and grades honestly.
4. The scheduler updates the card: Again collapses the interval and lowers ease, Hard keeps it short, Easy stretches it out.
5. The card's new due date is stored; mastered cards disappear for days or weeks while weak cards return tomorrow.
6. Statistics aggregate the review log into recall rates, streaks and per-deck retention for the stats section.

Tech stack:

• Android (Kotlin or Java) with Android SDK
• SQLite via Room for local storage
• SM-2-family scheduling algorithm (original implementation)
• Material Design components

• [Deck and card management] Create, edit, delete and organize decks — Java OOP concepts, DBMS viva questions, OS scheduling, vocabulary — with per-deck card counts.
• [Study sessions with self-grading] Read the question, tap to reveal the answer, then grade recall as Again (<1 day), Hard (3 days) or Easy (7 days).
• [SM-2-inspired scheduler] Each grade updates the card's ease factor and interval deterministically; the next due date is written back to the database.
• [Due-card queues] The app shows exactly how many cards are due and queues them by overdue-ness, with session progress tracking.
• [Retention statistics] Recall rate, reviews per month, cards mastered, average daily study time and per-deck 30-day retention.
• [Study streaks and heatmap] Consecutive study days and a weekly activity heatmap keep the habit visible.
• [Fully offline scheduling] All interval math runs on-device; studying never needs a network connection.

• Complete Android app source code (decks, study session, scheduler, stats)
• Scheduler documentation with rule-by-rule interval examples
• Sample decks (Java OOP, DBMS viva, OS scheduling, vocabulary) for demonstration
• Setup guide (build, install, usage walkthrough)
• Project report PDF (background, forgetting curve, scheduler design, methodology)
• PPT presentation for final review
• Viva Q&A preparation document (Android, SQLite, spaced-repetition theory)

• Recall grading is self-reported; the scheduler is only as honest as the student's grading.
• The SM-2-family scheduler is a well-known heuristic, not a personalized memory model — intervals are approximate by design.
• Card quality determines effectiveness; poorly written cards (vague questions) produce poor retention regardless of scheduling.
• There is no cloud sync or shared-deck marketplace in this build; decks live on one device.
• Image and audio cards are not implemented; cards are text-based.