app/doc.go

// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

/*
Package app lets you write portable all-Go apps for Android and iOS.

There are typically two ways to use Go on Android and iOS. The first
is to write a Go library and use `gomobile bind` to generate language
bindings for Java and Objective-C. Building a library does not
require the app package. The `gomobile bind` command produces output
that you can include in an Android Studio or Xcode project. For more
on language bindings, see https://golang.org/x/mobile/cmd/gobind.

The second way is to write an app entirely in Go. The APIs are limited
to those that are portable between both Android and iOS, in particular
OpenGL, audio, and other Android NDK-like APIs. An all-Go app should
use this app package to initialze the app, manage its lifecycle, and
receive events.

Building apps

Apps written entirely in Go have a main function, and can be built
with `gomobile build`, which directly produces runnable output for
Android and iOS.

The gomobile tool can get installed with go get. For details, see
https://golang.org/x/mobile/cmd/gomobile.

Event processing in Native Apps

The Go runtime is initialized on Android when NativeActivity
onCreate is called, and on iOS when the process starts. In both
cases, Go init functions run before the app lifecycle has started.

An app is expected to call the Main function in main.main. When the
function exits, the app exits.

	package main

	import (
		"log"

		"golang.org/x/mobile/app"
	)

	func main() {
		app.Main(func(a app.App) {
			for e := range a.Events() {
				switch e := event.Filter(e).(type) {
				case event.Lifecycle:
					// ...
				case event.Draw:
					log.Print("Call OpenGL here.")
					a.EndDraw()
				}
			}
		})
	}

For details on the event model, see https://golang.org/x/mobile/event.
*/
package app // import "golang.org/x/mobile/app"