Preparations for Development

This document is intended for novices at developing OpenHarmony applications. By building a simple application with page navigation (as shown below), you will better understand the project directory and the typical OpenHarmony application development process.

Before you begin, there are two basic concepts that will help you better understand OpenHarmony: UI framework and application model.

Basic Concepts

UI Framework

OpenHarmony provides a UI development framework, known as ArkUI. ArkUI provides a full range of capabilities you may need for application UI development, ranging from components to layout calculation, animation, UI interaction, and rendering capabilities.

ArkUI comes with two development paradigms: ArkTS-based declarative development paradigm (declarative development paradigm for short) and JavaScript-compatible web-like development paradigm (web-like development paradigm for short). You can choose whichever development paradigm that aligns with your practice.

Development Paradigm	Programming Language	UI Update Mode	Applicable To	Intended Audience
Declarative development paradigm	ArkTS	Data-driven	Applications involving technological sophistication and teamwork	Mobile application and system application developers
Web-like development paradigm	JavaScript	Data-driven	Applications with simple UIs and service widgets	Frontend web developers

For more details, see About This Kit.

Application Model

The application model abstracts the capabilities required by an application and provides components and mechanisms required for running the application. By adhering to a unified model, you can streamline application development, making it more efficient and straightforward. For details, see Elements of the Application Model.

Along its evolution, OpenHarmony has provided two application models:

• Stage model: This model is supported since API version 9. It is recommended. In this model, classes such as AbilityStage and WindowStage are provided as the stage of application components and windows. That's why it is named stage model. For details about development based on the stage model, see Stage Model Development Overview. The examples in this topic are all based on the stage model.

• Feature Ability (FA) model: This model is supported since API version 7. It is no longer recommended. For details about development based on the FA model, see FA Model Development Overview.

For details about the differences between the FA model and stage model, see Application Models.

To help you better understand the preceding basic concepts and application development process, Quick Start walks you through an example of building your first ArkTS application with two pages in the stage model.

Tool Preparation

Install the latest version of DevEco Studio.

When you finish tool preparation and basic concept learning, you can set out to build your first ArkTS application in the stage model.