Android写文件什么都不做

Question

I have a program where I want to save what the user entered for use in later runs. I am currently trying to save it to a text file. I can run the program fine and everything seems to work, but at the end I check the file and its untouched. Here is the code:

public void onClick(View v) 
    {
        LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.activity_tax_popup, (ViewGroup) findViewById(R.id.taxWindow), false);

        String filename = "tax.txt";
        boolean isEnabled = layout.findViewById(R.id.taxBox).isEnabled();
        String enable = String.valueOf(isEnabled);
        String taxPercent = layout.findViewById(R.id.enterTax).toString();
        FileOutputStream fos;

        try 
        {
            fos = openFileOutput(filename, Context.MODE_PRIVATE);
            fos.write(enable.getBytes());
            fos.write(taxPercent.getBytes());
            fos.close();
        } 
        catch (Exception e) 
            {e.printStackTrace();}

        pw.dismiss();       
    }

How can I change it to write to a file? Also if anyone knows a better way to save data between runs I'm open to suggestions.

Answer 1

There's a beautiful little thing called shared preferences for this exact thing :)

Here is an example from the Android Developer Guide :

public class Calc extends Activity {
public static final String PREFS_NAME = "MyPrefsFile";

@Override
protected void onCreate(Bundle state){
   super.onCreate(state);
   . . .

   // Restore preferences
   SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
   boolean silent = settings.getBoolean("silentMode", false);
   setSilent(silent);
}

@Override
protected void onStop(){
   super.onStop();

  // We need an Editor object to make preference changes.
  // All objects are from android.context.Context
  SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
  SharedPreferences.Editor editor = settings.edit();
  editor.putBoolean("silentMode", mSilentMode);

  // Commit the edits!
  editor.commit();
}
}

You can (and probably will), of course, do more than just putBoolean - I find myself using putString("HEY THERE"); much more often.

I hope this helps. Good luck :)