There are essentially two ways to deliver an application on Android: as a client-side application (developed using the Android SDK and installed on user devices in an APK) or as a web application (developed using web standards and accessed through a web browser—there's nothing to install on user devices).
If you chose to provide a web-based app for Android-powered devices, you can rest
assured that major web browsers for Android (and the
allow you to specify viewport and style properties that make your web pages appear at the proper
size and scale on all screen configurations.
To start developing web pages for Android-powered devices, see the following documents: