github.com/c-darwin/mobile@v0.0.0-20160313183840-ff625c46f7c9/example/network/main.go (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin linux
     6  
     7  // An app that paints green if golang.org is reachable when the app first
     8  // starts, or red otherwise.
     9  //
    10  // In order to access the network from the Android app, its AndroidManifest.xml
    11  // file must include the permission to access the network.
    12  //
    13  //   http://developer.android.com/guide/topics/manifest/manifest-intro.html#perms
    14  //
    15  // The gomobile tool auto-generates a default AndroidManifest file by default
    16  // unless the package directory contains the AndroidManifest.xml. Users can
    17  // customize app behavior, such as permissions and app name, by providing
    18  // the AndroidManifest file. This is irrelevent to iOS.
    19  //
    20  // Note: This demo is an early preview of Go 1.5. In order to build this
    21  // program as an Android APK using the gomobile tool.
    22  //
    23  // See http://godoc.org/github.com/c-darwin/mobile/cmd/gomobile to install gomobile.
    24  //
    25  // Get the network example and use gomobile to build or install it on your device.
    26  //
    27  //   $ go get -d github.com/c-darwin/mobile/example/network
    28  //   $ gomobile build github.com/c-darwin/mobile/example/network # will build an APK
    29  //
    30  //   # plug your Android device to your computer or start an Android emulator.
    31  //   # if you have adb installed on your machine, use gomobile install to
    32  //   # build and deploy the APK to an Android target.
    33  //   $ gomobile install github.com/c-darwin/mobile/example/network
    34  //
    35  // Switch to your device or emulator to start the network application from
    36  // the launcher.
    37  // You can also run the application on your desktop by running the command
    38  // below. (Note: It currently doesn't work on Windows.)
    39  //   $ go install github.com/c-darwin/mobile/example/network && network
    40  package main
    41  
    42  import (
    43  	"net/http"
    44  
    45  	"github.com/c-darwin/mobile/app"
    46  	"github.com/c-darwin/mobile/event/paint"
    47  	"github.com/c-darwin/mobile/event/size"
    48  	"github.com/c-darwin/mobile/exp/app/debug"
    49  	"github.com/c-darwin/mobile/gl"
    50  )
    51  
    52  func main() {
    53  	// checkNetwork runs only once when the app first loads.
    54  	go checkNetwork()
    55  
    56  	app.Main(func(a app.App) {
    57  		var sz size.Event
    58  		for e := range a.Events() {
    59  			switch e := app.Filter(e).(type) {
    60  			case size.Event:
    61  				sz = e
    62  			case paint.Event:
    63  				onDraw(sz)
    64  				a.EndPaint(e)
    65  			}
    66  		}
    67  	})
    68  }
    69  
    70  var (
    71  	determined = make(chan struct{})
    72  	ok         = false
    73  )
    74  
    75  func checkNetwork() {
    76  	defer close(determined)
    77  
    78  	_, err := http.Get("http://golang.org/")
    79  	if err != nil {
    80  		return
    81  	}
    82  	ok = true
    83  }
    84  
    85  func onDraw(sz size.Event) {
    86  	select {
    87  	case <-determined:
    88  		if ok {
    89  			gl.ClearColor(0, 1, 0, 1)
    90  		} else {
    91  			gl.ClearColor(1, 0, 0, 1)
    92  		}
    93  	default:
    94  		gl.ClearColor(0, 0, 0, 1)
    95  	}
    96  	gl.Clear(gl.COLOR_BUFFER_BIT)
    97  
    98  	debug.DrawFPS(sz)
    99  }