51CTO HarmonyOS Developer Community

Jun 30, 2026 · Frontend Development

HarmonyOS Timer Deep Dive: 4 Real-World Scenarios with Production Code

This article implements four timer scenarios — countdown, stopwatch, Pomodoro, and alarm — in HarmonyOS ArkUI, explaining design choices like setInterval vs Date.now() for precision, state machines for phase transitions, and lifecycle cleanup to avoid memory leaks.