在内部存储设备上创建，读取和保存文件（Android）

Question

I'm creating a little game in Android, now I want to use a file as a savegame. On Start it checks if there is already a savegame, if not, it should create it. If there is a savegame it should read it. And when you close the app/turn your phone off/etc. it should save it. To code this, i googled a bit and found something, but it seems that it doesn't work, but I don't know why. Here are the relevant snippets of my class:

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    setContentView(R.layout.activity_main);

    FileStart();


}

public void FileStart() {

    File external = getFilesDir();
    String path = external.getPath();
    File file = new File(path + "inv.txt");

    if(file.exists()) {
        //read files
        try {
            BufferedReader in = new BufferedReader(new FileReader(file));
            String result = in.readLine();
            String[] resultSplit = result.split("|");
            fruits = Integer.parseInt(resultSplit[0]);
            milk = Integer.parseInt(resultSplit[1]);
            sugar = Integer.parseInt(resultSplit[2]);
            wheat = Integer.parseInt(resultSplit[3]);
            cake = Integer.parseInt(resultSplit[4]);

            in.close();

            TextView tView = new TextView(this);
            tView=(TextView)findViewById(R.id.textView1); 
            tView.setText(fruits + " x Fruits");
            tView=(TextView)findViewById(R.id.textView3); 
            tView.setText(milk + " x Milk");
            tView=(TextView)findViewById(R.id.textView4); 
            tView.setText(sugar + " x Sugar");
            tView=(TextView)findViewById(R.id.textView5); 
            tView.setText(wheat + " x Wheat");

            tView=(TextView)findViewById(R.id.textView9); 
            tView.setText(cake + " Cakes");

        } catch (Exception e) {
            e.printStackTrace();
        } 
    } else {
        try {
            file.createNewFile();
            FileWriter filewriter = new FileWriter(file);
            BufferedWriter out = new BufferedWriter(filewriter);
            out.write("0|0|0|0|0");
            out.flush();
            out.close();
            filewriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }



}

@Override
protected void onPause () {
    super.onPause();  // Always call the superclass method first
    //save game progress
    File external = getFilesDir();
    String path = external.getPath();
    File file = new File(path + "inv.txt");
    try {
        FileWriter filewriter = new FileWriter(file);
        BufferedWriter out = new BufferedWriter(filewriter);
        String toWrite = fruits + "|" + milk + "|" + "|" + sugar + "|" + wheat + "|" + cake;
        out.write(toWrite);
        out.flush();
        out.close();
        filewriter.close();

    } catch (IOException e) {
        e.printStackTrace();
    }
}

Answer 1

Use the following code to create a directory:

boolean success = (new File(getApplicationContext().getFilesDir()+"/YourFolderName")).mkdir(); 
        if (!success){
            Log.w("directory not created", "directory not created");
        }