51CTO HarmonyOS Developer Community

Aug 5, 2026 · Mobile Development

Building HarmonyOS Interactive Cards: Pomodoro Timer Widget with FormKit

This tutorial walks through building a HarmonyOS interactive desktop widget using FormKit, covering configuration, UI with @LocalStorageProp, FormExtensionAbility lifecycle, event handling via postCardAction, state machine design, and real-world pitfalls like formId extraction and background execution limits.