How to check if a FileInputStream is "full"

Question

I'm trying to write a file on users mobile following this example

Storage Options [data-storage]

I want to create that file the first time users run my app.

After the first time users run my app, I want FIRST read the file, and THEN write something in it (if i need).

Following the example above i'm using FileInputStream stream= openFileInput(FILENAME),

Is there a way to know if the file i put in FileInputStream exists by checking the fIleInpuStream itself?

see http://stackoverflow.com/questions/8867334/check-if-a-file-exists-before-calling-openfileinput — njzk2, Jan 14 '13 at 16:56
i would say that if you can read from it, you can safely assume it exists, but you couldn't open it if it didn't exist, meaning you'd have to catch a FileNotFoundException — njzk2, Jan 14 '13 at 16:58
on the side note, why don't you use preferences to store your application specific data? It is a standard way of "remembering" application information rather than using a file in SD card. Also what happens, when the user changes/removes his sd card? Your application will think that it is getting launched for the first time. Is it what you are expecting? — Durairaj Packirisamy, Jan 14 '13 at 17:05
@DurairajP : openFileInput open a private file for this context. It is not on the SDCard (as it is private). It uses the internal storage, as the Storage Options article states. — njzk2, Jan 15 '13 at 09:08

score 1 · Answer 1 · answered Jan 15 '13 at 09:11

Thank everybody for your help. Maybe the best way to do what i want to do was suggested by @Durairaj P.

I used Preferences.

But i'm still wondering if it's suitable and appropriate for what i want to do. I want to keep track of the points that users earn while playing my game; when users re-open my app, i have to show all the points they earned since they installed my app. I'm just wondering if Preferences are suitable and appropriatefor this, or if i should use something else.

Anyway i post my code, it might help someone

public class managePreferences{
Context context;    

    managePreferences(Context context){
        this.context = context;
    }


    public String readPreference(String fieldName, String defaultValue){    
        SharedPreferences prefs = context.getSharedPreferences("MY_PREFERENCES", Context.MODE_PRIVATE);
        String value = prefs.getString(fieldName, defaultValue);
        return value ;
    }


    public void writePreference(String fieldName, String value){
        SharedPreferences prefs = context.getSharedPreferences("MY_PREFERENCES", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(fieldName, value);
        editor.commit();

    }

}

score -1 · Answer 2 · answered Jan 14 '13 at 17:00

-1

I would use

context.fileList();

and test if my file is somewhere. (quickest way is to make a List of it and use contains()) :

Arrays.asList(context.fileList()).contains(FILENAME);

answered Jan 14 '13 at 17:00

njzk2

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thanks for the downvote, someone. care to elaborate as to why the error is wrong? – njzk2 Jan 15 '13 at 09:04

How to check if a FileInputStream is "full"

2 Answers2