CODEWITHSUNDEEP
androidjson
user3796978
user3796978

Reputation: 91

Load more data dynamically in a listview in android

i'm doing an android application. I retrive data with GSON and display 10 elements each time i do a request. My problem is that i don't know how to add the new elements, to the elements before, in the bottom of the list. I use onScroll,so when i reach at the end of the list with 10 elements ,i make a request on the server. I'm trying to integrate some libraries from github ,but it doesn't work. Here is my code: First is my method that populate the main list:

  public void popullateMainList(final String url,final long expirationTime) {
    //requestData(MAIN_LIST_URL);


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

     ProgressBar  pb = (ProgressBar)findViewById(R.id.progressBar);

        @Override
        protected void onPreExecute() {
                pb.setVisibility(View.VISIBLE);
                  }

        @Override
        protected Void doInBackground(Void... voids) {
            try {

            elements = new Elements(url, expirationTime);

            } catch (Exception e) {
                e.printStackTrace();
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(final Void result) {

            pb.setVisibility(View.GONE);

            updateDisplay();
            mainElementAdapter.notifyDataSetChanged();
        }
    }.execute();
}

And the method updateDisplay has the following code:

protected void updateDisplay() {
    eList = (ListView) findViewById(R.id.mainView);
    mainElementAdapter = new ElementListAdapter(this, elements.getElements());

  //  mainElementAdapter.add(elements.getElements());

    footerView = ((LayoutInflater)     this.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.loading_footer, null, false);
    eList.addFooterView(footerView);
    eList.setAdapter(mainElementAdapter);
    eList.removeFooterView(footerView);
    eList.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {
            if (scrollState == SCROLL_STATE_IDLE) {
                if (eList.getLastVisiblePosition() >= eList.getCount() - visibleThreshold) {
                    currentPage++;
                    actualUrl = Constants.MAIN_LIST_URL + "?pageNumber=" + currentPage;
                    popullateMainList(actualUrl,1);

                }

            }}
        public boolean canChildScrollUp() {
            //your condition to check scrollview reached at top while scrolling
            if (swipeLayout.getScrollY() == 0.0)
                return true;
            else
                return false;
        }
        @Override
        public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalItemCount)
            {
            if (firstVisibleItem == 0)
                swipeLayout.setEnabled(true);
            else
                swipeLayout.setEnabled(false);
        }
    });
}

I hope that anybody help me. Thank you in advance!

Upvotes: 0

Views: 125

Answers (1)

Stanislav
Stanislav

Reputation: 405

Try save old.

when you use 

elements = new Elements(url, expirationTime);

you override your Elements object and when you use

mainElementAdapter = new ElementListAdapter(this, elements.getElements());

you override your old data in adapter

added new method in your class Elemets

something like that

if(elements == null) {
    elements = new Elements(url, expirationTime);
} else {
    elements.add(new Elements(url, expirationTime).getElements());
}

Upvotes: 1

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