Android UI not updating

Question

I am currently creating a program that recursively searches through the SD card of the videos on an android phone, and then produces as hash for each of the videos.

Everything works fine, but when I try and create a progress bar, the progress bar doesn't update, until the end.

So essentially progress bar's progress appears to go from 0 to the max, but I can tell from log output that values are being sent to the progress bar to update it, the progress bar just isn't upating.

My code is below:

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        progress = (ProgressBar) findViewById(R.id.progressBar1);
        text = (TextView) findViewById(R.id.tv1);
        Button btnStart = (Button) findViewById(R.id.btnStart);

        btnStart.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {

                recursiveVideoFinder(new File("/sdcard"));
                String strDB3File = getFilesDir().getPath()
                        + "/VideoHashes.db3";
                sql3 = SQLiteDatabase.openDatabase(strDB3File, null,
                        SQLiteDatabase.CREATE_IF_NECESSARY);
                try {
                    String mysql = "CREATE TABLE videohashes (id INTEGER  NOT NULL PRIMARY KEY AUTOINCREMENT, path TEXT NOT NULL, hash TEXT NOT NULL, date TEXT NOT NULL, size INTEGER)";
                    sql3.execSQL(mysql);
                } catch (SQLiteException e) {
                    // TODO: handle exception
                }

                progress.setProgress(0);
                progress.setMax(myFiles.size());

                for (String path : myFiles) {
                    try {
                        String hash = getMD5Checksum(path);
                        ContentValues myInsertData = new ContentValues();
                        myInsertData.put("path", path);
                        myInsertData.put("hash", hash);
                        Date date = new Date();
                        myInsertData.put("date", dateFormat.format(date));
                        myInsertData.put("size", getFileSize(path));
                        sql3.insert("videohashes", null, myInsertData);
                        currVid++;
                        updateProgress();
                        Log.i("Progress", "CurrVid:" + currVid + "  Max:"
                                + progress.getMax());
                        text.append(currVid + " ");

                    } catch (Exception e) {
                        Log.i("File", "File not Found");
                    }
                }

                Cursor cur = sql3.query("videohashes", null, null, null, null,
                        null, null);
                cur.moveToFirst();
                while (!cur.isAfterLast()) {
                    /*
                     * ((TextView) findViewById(R.id.tv1)).append("\n" +
                     * cur.getString(1) + "\n" + cur.getString(2) + "\n" +
                     * cur.getString(3) + "\n" + cur.getString(4) + "\n");
                     */
                    cur.moveToNext();
                }
                cur.close();
            }
        });

    }

    public long getFileSize(String path) {
        File file = new File(path);
        return file.length();

    }

    private void recursiveVideoFinder(File _dir) {

        File[] files = _dir.listFiles();
        if (files == null) {
            return;
        }

        for (File currentFile : files) {
            if (currentFile.isDirectory()) {
                    recursiveVideoFinder(currentFile);
                continue;
            } else {
                for (String aEnd : getResources().getStringArray(
                        R.array.VideoExtensions)) {
                    if (currentFile.getName().endsWith(aEnd)) {

                        Log.d("PS:", currentFile.getPath().toString());

                        String videoFileName = currentFile.getPath().toString();
                        myFiles.add(videoFileName);

                    }
                }

            }
        }
    }

    // Code based off this example:
    // http://stackoverflow.com/questions/304268/getting-a-files-md5-checksum-in-java
    public static byte[] createCheckSum(String filename) throws Exception {
        InputStream fis = new FileInputStream(filename);

        byte[] buffer = new byte[1024];
        MessageDigest complete = MessageDigest.getInstance("MD5");
        int numRead;

        do {
            numRead = fis.read(buffer);
            if (numRead > 0) {
                complete.update(buffer, 0, numRead);
            }
        } while (numRead != -1);

        fis.close();
        // Return MD5 Hash
        return complete.digest();
    }

    public String getMD5Checksum(String filename) throws Exception {
        byte[] b = createCheckSum(filename);
        String result = "";

        for (int i = 0; i < b.length; i++) {
            result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
        }
        return result;
    }

    public void updateProgress() {
        progress.setProgress(currVid);
        progress.invalidate();
        Log.i("Updating", "Updating Progress Bar");
    }
}

Answer 1

Put your updating task by overriding onResume(). Start a new timer thread there and keep calling your function. When you click back, finish that thread too by saying timer.cancel(). SO whenever you go that activity, only then the timer starts and exits on hitting back. Check this for more info

Answer 2

Why do you keep all the processing code in Onclick(). That is not a good approach. Create an AsyncTask and use publishProgress to update your progressbar.