Question

I have an application that creates a configuration file and a log file. I stored these in the external storage, but when I try it in my android emulator it doesn’t work because the external storage isn’t writable. If this happens, where should I store the files?

This is my code:

private void createConfigurationFile(){
    File ssConfigDirectory = 
        new File(Environment.getExternalStorageDirectory()+"/MyApp/config/");
    File file = new File(ssConfigDirectory, mUsername+".cfg");

    if(!file.exists()){
        try{
            String state = Environment.getExternalStorageState();
            if (!Environment.MEDIA_MOUNTED.equals(state)){
                ssConfigDirectory = new File("PATH_WHERE_I_SHOULD_STORE_IT");
            }
            File ssLogDirectory = new File(ssConfigDirectory+"/SweetSyncal/log/");
            ssLogDirectory.mkdirs();                
            ssConfigDirectory.mkdirs();

            File outputFile = new File(ssConfigDirectory, mUsername+".cfg");                
            FileOutputStream fOut = new FileOutputStream(outputFile);
            OutputStreamWriter osw = new OutputStreamWriter(fOut); 

            writeFile(osw);
            osw.flush();
            osw.close();
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

Answer 1

If the file isn’t too big you can save it in the device’s Internal Storage.

To access the Internal Storage you can use the following method:

FileOutputStream openFileOutput (String name, int mode)

(You need an instance of Context to use it)

Example:

String FILENAME = "hello_file";
String string = "hello world!";

FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();

As to why the code you provided is not working then there are two possibilities:

1. You forgot to add the required permission (WRITE_EXTERNAL_STORAGE).
2. You’r emulator doesn’t have an SD card enabled. Assuming you are using Eclipse you can enabled it in the AVD Manager. Just edit your AVD instance and type in the size of the SD card in the appropriate field. You should also add a hardware feature called SD Card Support and set it to TRUE.

There is a great article in the official Developer Guide which will tell you everything you need to know about storage in Android.

You can read it HERE