The following tutorial is intended to get anyone up to speed developing iOS and Android apps using Forge.
We're working hard to make Forge the simplest way to make mobile apps. We hope you'll find our guides easy to follow - but if you get stuck at any point, just drop us a line at email@example.com. We'd love to help!
This guide will take you through building your first mobile app with Forge. We recommend reading Getting Started first to set up your environment.
Goal: Set up development environment
Forge can be used to generate both iOS and Android apps from a single codebase. You can follow the subsequent tutorial with either (or both).
If you have a Mac we recommend you get started with the iOS Simulator. With Windows or Linux, the Android emulator or device is likely to be the simplest. Of course you can also work with the Android emulator on a Mac. Or an iOS device on any development machine but that requires that you have an iOS developer account and additional setup:
To build and run iOS apps, you can use a Mac, Windows or Linux computer. However, to use the iOS simulator, a Mac is required.
To use the iOS Simulator on a Mac, you need to install Xcode. You can download Xcode from https://developer.apple.com/xcode/. When this is installed, start XCode and click 'Preferences' from the XCode menu to check the iOS Simulator and command-line tools are listed as installed under components. If not, you may install it from that window.
Note: You do not need to install the Xcode command-line tools just to use the iOS Simulator, but it is required for when you come to package for distribution. So we recommend you install it at the same time that you setup Xcode.
Important: The location of an important utility,
aapt, moved in Android SDK version 22. The Trigger.io platform handles this from v1.4.48 onwards. If you see "File not found" errors when building for Android, it's recommended you update to this platform version or later.
In order to build your app for Android there is a minimum requirement of
having Java installed. The
java command should be installed and
made available on your path.
In order to run the app, you'll need a USB attached phone with debug drivers installed or an active Android emulator device. We recommend connecting an Android device rather than using the emulator since the emulator can be very slow resulting in a slower build / test cycle.
If you do wish to use the emulator then you can setup the Android SDK location by clicking on your app from the project page, then clicking on 'Tools' in the sidebar.
At the command-line, use the
--android.sdk flag when using
forge run android to point to your Android SDK location and run your
own emulator AVD. All automatic installation procedures will prompt
before making any changes to your system.
Important: There is a bug in the Android 2.3 emulator that will render your apps unusable - this is not a Trigger.io issue but if you manage your own Android AVD you should use an Android 2.2, 3 or 4+ AVD.
Goal: To see your iOS and Android apps running
You can build and test your app using either the toolkit or the command-line.
If you run a new app straight after you've created it, you will see our default 'Hello World' app appear:
From the project page, simply click on the app name you wish to build.
You can then click the appropriate button to build and run the app for Android or iOS. You will see the full traceback in the console as the commands are run so you can see progress and any warnings.
If you make subsequent code changes that you want to build and test on the same platform, just click 'Run again' at the bottom of the console view in the app run page. To see more information from the app, check the "Show debug" box.
Note: If you are running the app for Android using the emulator, and an AVD (Android Virtual Device) is not already started when you click the run link, it can take a long time to startup. It will be faster on subsequent runs, but in general we recommend that you develop with an Android device for a faster build / test cycle.
At the command-line you must use two commands
forge build and
forge run to build and test an app. See Getting started with the command-line tools for the
location of the
forge executable for your platform.
To build your app:
forge build iosor
forge build androidto create your iOS and Android apps.
src/config.jsonconfiguration file changes the entire app needs to be rebuilt.
developmentdirectory and you should see
To test your app on iOS:
forge run ios
To test your app on Android:
forge run android
Goal: Adding static content
srcdirectory created inside your app directory. This is where all of your app files should be placed
srcdirectory should contain a
config.jsonfile which holds all of the configuration settings for the app. You can also edit this configuration from inside the Toolkit: click on "App" in the sidebar
src/index.html in your favorite text editor
You will see the HTML for a default "Hello World" app: you can use this as a starting point for your real app.
Note: Forge looks for index.html as the entry point of your application. This file must be present and the name cannot be changed.
Let's add some dynamic functionality next and re-build:
Replace the contents of the
body element in
<p>Hello World, this is HTML!</p>
Edit the file
js/main.js and change its contents to:
Rebuild and re-run the application: you should see your "Hello World" message in the app.
Look at the command prompt/terminal running the code and you should see your "Hello World" log message.
Important: Now that you know how to use logging it is highly encouraged to use it frequently for debugging purposes.
You can always contact us at firstname.lastname@example.org, or ask a question on our tag on StackOverflow
Next you could try our Weather App tutorial.
Or if you're comfortable with the tooling and want to do something more advanced check out the recipes section in these docs.