Question

I’m trying to save and load a String to/from the internal storage in a way that allows the user to exit the app, even shut down the phone, but still access this String whenever the app is used.

When I exit the app it and re-enter, it will not load the String I stored previously. I need it to load the previous String even if I reboot the phone. Here is what I have so far:

EditText sharedData;
TextView dataResults;
FileOutputStream fos;
String FILENAME = "InternalString";

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sharedpreferences);
    setupVariables();
}

private void setupVariables() {
    // TODO Auto-generated method stub
    sharedData = (EditText) findViewById(R.id.editText_SharedPrefs);
    dataResults = (TextView) findViewById(R.id.textView_LoadSharedPrefs);
    Button save = (Button) findViewById(R.id.button_save);
    Button load = (Button) findViewById(R.id.button_load);
    save.setOnClickListener(this);
    load.setOnClickListener(this);
    try {
        fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
        fos.close();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    switch (v.getId()) {
    case R.id.button_save:
        String data = sharedData.getText().toString();
        try {
            fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
            fos.write(data.getBytes());
            fos.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        break;
    case R.id.button_load:
        String collected = null;
        FileInputStream fis = null;
        try {
            fis = openFileInput(FILENAME);
            byte[] dataArray = new byte[fis.available()];
            while(fis.read(dataArray) != -1){
                collected = new String(dataArray);
            }
            dataResults.setText(collected);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                fis.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        break;
    }
}

Answer 1

Depending on what sort of “string” you’re using you should use SharedPreferences rather than write files… unless it’s a lot of data.

getSharedPreferences(getPackageName() , MODE_PRIVATE).edit().putString("myString").commit();

That will persist through phone powercycles. It will get lost if you uninstall the app however (which is probably a good thing).

Here’s the Android doc for all the various data saving possibilities open to you…

Saving Stuff On Android