Writing to text file in Java

Question

I have an app in need of (probably a glance from) a seasoned Java pro. The engine works perfectly, but I cannot save data to a text file; moreover, I have to tether my tablet, uninstall the old app, copy the apk, and reinstall every time I debug file operations because I cannot write to disk in the emulator.

I added:

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

to the manifest outside of the application tag as well as tried numerous write-to-file methods. The exception is either (depending on the current attempt) eacces or file does not exist. I have also Googled all day to find the solution. Does anybody have any idea?

// this is a canned method that should presumably work
 private void writeStringToTextFile(String s, String f){
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath());
dir.mkdirs();
File file = new File(dir, f);
try{
    FileOutputStream f1 = new FileOutputStream(file,false); //True = Append to file, false = Overwrite
    PrintStream p = new PrintStream(f1);
    p.print(s);
    p.close();
    f1.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}   }


// this is the save method
// it has been modified a little less than a million times today
// some lines may be unnecessary because I have tried several approaches
  public void saveSystem(View view){
          String s="";
          String FILENAME = "data/data/TopExpertAndroid/" + fileName;
          FileOutputStream f;
          File file = new File(FILENAME);
          if(!(file.exists())){
             try{
                 file.createNewFile();} 
             catch(Exception e){
                showSplash(e.getMessage() + e.getCause(), "OK");
                return;}}
          try{
              getFile();
              if(fileName.equals("")){}
              else{
                   f = openFileOutput(FILENAME, Context.MODE_PRIVATE);
                   for(int temp=0; temp<50; temp++){
                       for(int loop=0; loop<50; loop++){
                           s += topExpert.nodeBank[temp][loop].activationResponse + "\n";
                           s += topExpert.nodeBank[temp][loop].display + "\n";
                           s += topExpert.nodeBank[temp][loop].falseLink + "\n";
                           s += topExpert.nodeBank[temp][loop].identifier + "\n";
                           if(topExpert.nodeBank[temp][loop].isTop){
                              s += "true";}
                           else{
                                s += "false";}
                           s += "\n" + topExpert.nodeBank[temp][loop].trueLink + "\n";}}
                           writeStringToTextFile(s,FILENAME);
              }}
          catch(Exception e){
                showSplash(e.getMessage() + e.getCause(), "OK");}}

Answer 1

The FILENAME variable probably is missing a / at the beginning:

String FILENAME = "/data/data/TopExpertAndroid/" + fileName;

And you should probably use getDataDirectory or getExternalStorageDirectory instead...

But what you say about not being able to write to the disk of the emulator seems pretty weird...?