2

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:

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()
            }
        }
    })
}

However no file is created in the phone.

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:

package main
import "os"
func main(){
    os.Create("zzz.txt")
}

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.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.

saurabh
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Kyle
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1 Answers1

3

To write to a file your app needs some form of permission.

If you don't have one create an AndroidManifest.xml. You can see the content of the file gomobile automatically create for you using the -v flag. (gomobile build -v)

Add the following line between <manifest> and </manifest> tags.

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Build the app again. Make sure gomobile is using your manifest file using the -v flag. I was able to create the file by os.Create("/sdcard/zzz.txt"). I also needed this for debugging so I didn't mind writing to a specific location, namely my sdcard. Of course in your phone the location may change.

Additionally, If you just want some logs you can install Android Debug Bridge and use adb logcat. To filter out the logs from your Go app adb logcat | grep "I/GoLog" would work.

Aruna Herath
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  • A few comments for people who is looking for solution: – Kyle Nov 20 '15 at 19:39
  • http://stackoverflow.com/questions/3593420/is-there-a-way-to-get-the-source-code-from-an-apk-file – Kyle Nov 20 '15 at 19:39
  • Step 3 of that solution can extract xml files. After finish modification put the modified xml under the same directory of the .go file(s) and compile as usual, gomobile will compile with the new xml file together. – Kyle Nov 20 '15 at 19:40