Required build assets

This guide covers the required build assets when packaging your app for delivery as a binary package with AppGyver Composer.

You can access the Build Service via the Launch tab in the global toolbar.

iOS assets

App icon

The app icon is shown on the device's home screen, in different parts of iOS and in App Store.

You can read more about app icons in Apple's App Icon documentation.

Launch screen

The launch screen (sometimes called splashscreen) is a full-screen image that appears immediately when your app starts up. It is Apple's intention that the launch screen helps make your app feel fast and responsive. As such, it should represent static parts of your app's initial UI, so that when the app actually launches, the transition will be seamless. That said, many apps show a logo or similar on the launch screen.

Composer only supports static PNG images for the launch screen. This means a separate image is required for all supported screen sizes.

You can read more about the launch screen and view a list of required screen sizes in Apple's Launch Screen documentation.

Android assets

Keystore file

The keystore file is used to securely and uniquely sign your app binary, so that e.g. other apps can't pretend to be an update for your app. For example, submitting an update to Google Play requires that the new app binary has been signed with the same keystore file as the original build.

To generate a keystore file, the easiest way is to use the Java keytool – run the following command in your Terminal or Command Prompt (replacing my-app-name appropriately).

keytool -genkey -v -keystore my-app-name.keystore -alias my-app-name -keyalg RSA -keysize 2048 -validity 10000

You then need to input a password required to use the keystore. The owner, city etc. data are not necessary, but you can fill them in if you want. You ca enter a separate password for the alias, but that's not necessary either. In Composer on the Keystore tab, you have the following fields:

  • Keystore file – your my-app-name.keystore file is uploaded here

  • Keystore password – enter the password you gave when generating the keystore

  • Keystore alias – enter the keystore alias (my-app-name in the above example)

  • Keystore alias password – unless you set a separate alias password, this is the same as Keystore password