<![CDATA[Students with multiple academic activities often have difficulty organizing class schedules, which results in missed sessions, incorrect room information, and overlapping course entries. Existing student scheduling applications mainly provide schedule recording and reminders, and studies that combine automatic conflict validation with offline local storage remain limited. This study aims to design and evaluate an offline Android-based academic scheduling system with an automated schedule conflict detection mechanism and a class reminder mechanism. The system was developed using the Waterfall model, which consists of requirement analysis, system design, implementation, testing, and evaluation. It uses a three-layer architecture, Create, Read, Update, and Delete (CRUD) operations on a persistent SQLite database, a conflict validation query that compares the day and time range of a new entry with stored schedules, and reminders scheduled through Android's AlarmManager. Black-box functional testing with four scenarios showed that all scenarios passed: valid schedules were saved, invalid time input was rejected, overlapping schedules were blocked with a warning, and reminder alarms were registered in the Android system to trigger a local notification 15 minutes before class. These results indicate that the proposed system prevents scheduling input errors without requiring an internet connection. The system provides a practical basis for student time management, and future work should include user acceptance testing, cloud synchronization, and schedule export.]]>
