title: Golang: Gomobile app cannot generate files
body: <p>Does anyone use gomobile app before and have successfully create files in phones? I tried the following code on Galaxy S4 with Android 4.4.2:</p>
  
  <pre><code>package main
  import (
      "golang.org/x/mobile/app"
      "golang.org/x/mobile/event/lifecycle"
      "golang.org/x/mobile/event/paint"
      "os"
  )
  func main() {
      os.Create("zzz.txt")
      app.Main(func(a app.App) {
          for e := range a.Events() {
              switch e := a.Filter(e).(type) {
              case lifecycle.Event:
                  _=e
              case paint.Event:
                  a.Publish()
              }
          }
      })
  }
  </code></pre>
  
  <p>However no file is created in the phone.</p>
  
  <p>I also tried an app called "AnGoIde" which allow us to write Go and compile directly in Android, and the following code is able to create the "zzz.txt" file:</p>
  
  <pre><code>package main
  import "os"
  func main(){
      os.Create("zzz.txt")
  }
  </code></pre>
  
  <p>Eventually I would like to save all errors in a file so I can see what cause my apps to crash, and AnGoIde doesn't support many packages so I cannot use it for my tests. Does anyone successfully generated files with gomobile apps before?</p>
  
  <p>p.s. I tried to specify the directory to "/storage/emulated/0/Go/" which is the same place I store the apk file but doesn't work.</p>