Using threads to apply UI changes in android

Question

I ran into a problem and need some help. I want to remove some user's files after a button click and also show the files removing progress (in progressbar) and also show some Fancy UI. First i changed the layout after button click and hide some elements and visible the others. after that i called methods to remove files. The problem is that i can not see any UI changes and system hangs until all user file removed and after that based on my scenario it go to another activity. I've google around and found that i should use thread or UI thread but exactly don't know how. Here is my code :

new Thread() {
    public void run() {
        try {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    ProgressBar spinner;
                    spinner = (ProgressBar) findViewById(R.id.progressBar);
                    listview.setVisibility(View.GONE);
                    spinner.setVisibility(View.VISIBLE);
                    preresult.setVisibility(View.VISIBLE);
                    resulttxt.setVisibility(View.VISIBLE);
                    wv.setVisibility(View.VISIBLE);
                    btnClear.setVisibility(View.GONE);
                    wv.loadUrl("file:///android_asset/rocket.gif");
                    resulttxt.setText("");
                }
            });
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}.start();

Thread b = new Thread() {
    @Override
    public void run() {
        Long TotalJunk = 0L;
        for (Apps social : checkedSocial) {
            if (social.getName() == "Telegram") {
                preresult.setText("Calculating Files :");
                resulttxt.setText("Telegram");
                preresult.setText("Removing Files...");
                clearMediashistory(social.path);
                TotalJunk = TotalJunk + social.junksize;
            }
                                           }
        SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = pref.edit();
        editor.putString("FreeUp", formatSize(TotalJunk));
        //commits your edits
        editor.commit();
    }
};
b.start();

What is wrong with my code. Is there any better method to do that?

Answer 1

Try

new AsyncTask<String, String, String> () {

    @Override
    protected void onPreExecute() {
        //show loader if requried
    }

    @Override
    protected String doInBackground(String... params) {

        Long TotalJunk = 0L;
        for (Apps social : checkedSocial) {
            if (social.getName() == "Telegram") {
                preresult.setText("Calculating Files :");
                resulttxt.setText("Telegram");
                preresult.setText("Removing Files...");
                clearMediashistory(social.path);
                TotalJunk = TotalJunk + social.junksize;
            }
        }
        SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = pref.edit();
        editor.putString("FreeUp", formatSize(TotalJunk));
        //commits your edits
        editor.commit();
    }

    @Override
    protected void onPostExecute(String result){

        ProgressBar spinner;
        spinner = (ProgressBar) findViewById(R.id.progressBar);
        listview.setVisibility(View.GONE);
        spinner.setVisibility(View.VISIBLE);
        preresult.setVisibility(View.VISIBLE);
        resulttxt.setVisibility(View.VISIBLE);
        wv.setVisibility(View.VISIBLE);
        btnClear.setVisibility(View.GONE);
        wv.loadUrl("file:///android_asset/rocket.gif");
        resulttxt.setText("");
    }

}.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTER);

Answer 2

Use AsyncTask instead of Thread https://developer.android.com/reference/android/os/AsyncTask.html

Android AsyncTask example and explanation