Question

I am creating an app that involves reading data from text files that are in the Assets folder. For each file, it stores the data in a separate ArrayList. The files are read in one after another in the onCreate() method of the activity. All of the text files combined total 1.8 MB and on the emulator it currently takes 12 seconds for the activity to load. The app does not crash on the emulator (it just takes approx 12 seconds).

I have read about asynchronous threads, but I have never had a need for them in the past. I was planning on having some sort of message or progress bar to notify the user that the activity is in fact loading and has not crashed.

So my question is: even though the app does not crash when loading the activity, should I still put the reading of the files on an asynchronous or different thread? If so, how would I go about doing it properly? (I have never done it before.)

Here is sample code with the reading of the text files:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_name);

    populateArrayLists();

}

public void populateArrayLists() {
    BufferedReader br = null;
    try {
        br = new BufferedReader(new InputStreamReader(getAssets().open(
                "text1.txt")));
        String text;
        while ((word = br.readLine()) != null) {
            ArrayList1.add(text);
        }                           
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            br.close(); // stop reading
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }


    br = null;
    try {
        br = new BufferedReader(new InputStreamReader(getAssets().open(
                "text2.txt")));

    // the same process is duplicated for 1-15
    // it may not be the best or most efficient way but it works

Any help would be appreciated.

Answer 1

Yes, you’ll need a background thread for this. The Loader api may be your easiest bet.

This will allow you at least display a notice and offer some content while the files load. Maybe even load them and incrementally displaying the data, if that’s what you’re doing.

Edit: Loaders are a 3.0 feature available in the compatibility library. If you’re not willing to add the dependency, you can always fall back to AsyncTask, in which case you could take a look at this.