Android Open Source - TymyApp Discussion List Fragment

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License

The source code is released under:

GNU General Public License

Java Source Code

package cz.tymy.api.tymyapp;
/*from  ww w  . j av  a 2s .  c  o m*/
import android.app.Activity;
import android.os.*;
import android.support.v4.app.ListFragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.Loader;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

import java.io.IOException;
import java.util.zip.Inflater;

import cz.tymy.api.tymyapp.apimodel.ApiDs;
import cz.tymy.api.tymyapp.apimodel.ApiException;
import cz.tymy.api.tymyapp.apireaders.ApiReader;

/**
 * A list fragment representing a list of Discussions. This fragment
 * also supports tablet devices by allowing list items to be given an
 * 'activated' state upon selection. This helps indicate which item is
 * currently being viewed in a {@link DiscussionDetailFragment}.
 * <p>
 * Activities containing this fragment MUST implement the {@link Callbacks}
 * interface.
 */
public class DiscussionListFragment extends ListFragment
        implements LoaderManager.LoaderCallbacks<String>  {

    /**
     * The serialization (saved instance state) Bundle key representing the
     * activated item position. Only used on tablets.
     */
    private static final String STATE_ACTIVATED_POSITION = "activated_position";

    /**
     * The fragment's current callback object, which is notified of list item
     * clicks.
     */
    private Callbacks mCallbacks = sDummyCallbacks;

    /**
     * The current activated item position. Only used on tablets.
     */
    private int mActivatedPosition = ListView.INVALID_POSITION;

    /**
     * Adapter for Discussion List
     */
    private DiscussionAdapter mDSesAdapter;

    /**
     * Application state singleton
     */
    private TymyApplication appState;

    /**
     * Fragment View
     */
    private View mView;


    /**
     * A callback interface that all activities containing this fragment must
     * implement. This mechanism allows activities to be notified of item
     * selections.
     */
    public interface Callbacks {
        /**
         * Callback for when an item has been selected.
         */
        public void onItemSelected(String id);
    }

    /**
     * A dummy implementation of the {@link Callbacks} interface that does
     * nothing. Used only when this fragment is not attached to an activity.
     */
    private static Callbacks sDummyCallbacks = new Callbacks() {
        @Override
        public void onItemSelected(String id) {
        }
    };

    /**
     * Mandatory empty constructor for the fragment manager to instantiate the
     * fragment (e.g. upon screen orientation changes).
     */
    public DiscussionListFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Application state singleton
        appState = (TymyApplication) this.getActivity().getApplication();

        // Restore the previously serialized activated item position.
        if (savedInstanceState != null
                && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
            setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
        }
        Bundle args = new Bundle();
        args.putString(ApiLoader.CMD, ApiLoader.CMD_DS_LIST);
        args.putString(ApiLoader.USER, appState.getUser());
        args.putString(ApiLoader.PASS, appState.getPass());
        args.putString(ApiLoader.SITE_URL, appState.getUrl());
        getLoaderManager().initLoader(0, args, this);

        mDSesAdapter = new DiscussionAdapter(getActivity(), R.layout.row_ds_layout);
        setListAdapter(mDSesAdapter);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mView = inflater.inflate(R.layout.fragment_discussion_list, container, false);
        return mView;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // Activities containing this fragment must implement its callbacks.
        if (!(activity instanceof Callbacks)) {
            throw new IllegalStateException("Activity must implement fragment's callbacks.");
        }

        mCallbacks = (Callbacks) activity;
    }

    @Override
    public void onDetach() {
        super.onDetach();

        // Reset the active callbacks interface to the dummy implementation.
        mCallbacks = sDummyCallbacks;
    }

    @Override
    public void onListItemClick(ListView listView, View view, int position, long id) {
        super.onListItemClick(listView, view, position, id);

        // Notify the active callbacks interface (the activity, if the
        // fragment is attached to one) that an item has been selected.
        mCallbacks.onItemSelected(String.valueOf(mDSesAdapter.getItem(position).getId()));
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mActivatedPosition != ListView.INVALID_POSITION) {
            // Serialize and persist the activated item position.
            outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
        }
    }

    /**
     * Set Custom Empty text
     * @param text
     */
    @Override
    public void setEmptyText(CharSequence text) {
        LayoutInflater inflater = getActivity().getLayoutInflater();
        TextView empty = (TextView) mView.findViewById(android.R.id.empty);
        disableProgessBar();
        empty.setText(text);
    }

    private void disableProgessBar() {
        ProgressBar progress = (ProgressBar) mView.findViewById(R.id.progress_bar);
        progress.setVisibility(View.GONE);
    }


    /**
     * Turns on activate-on-click mode. When this mode is on, list items will be
     * given the 'activated' state when touched.
     */
    public void setActivateOnItemClick(boolean activateOnItemClick) {
        // When setting CHOICE_MODE_SINGLE, ListView will automatically
        // give items the 'activated' state when touched.
        getListView().setChoiceMode(activateOnItemClick
                ? ListView.CHOICE_MODE_SINGLE
                : ListView.CHOICE_MODE_NONE);
    }

    private void setActivatedPosition(int position) {
        if (position == ListView.INVALID_POSITION) {
            getListView().setItemChecked(mActivatedPosition, false);
        } else {
            getListView().setItemChecked(position, true);
        }

        mActivatedPosition = position;
    }

    /*
    * LoaderCallbacks implementation
    */
    @Override
    public Loader<String> onCreateLoader(int i, Bundle args) {
        Log.v(DiscussionListActivity.TAG, "onCreateLoader");
        return new ApiLoader(getActivity(), args);
    }

    @Override
    public void onLoadFinished(Loader<String> stringLoader, String results) {
        if (results != null ) {
            Log.v(DiscussionListActivity.TAG, results);
            ApiReader ar = new ApiReader();
            mDSesAdapter.clear();
            try {
                mDSesAdapter.addAll(ar.readApiDSesList(results));
                disableProgessBar();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (ApiException e) {
                this.setEmptyText("Error: " + e.getMessage() + "\n" +
                        appState.getUser()  + " @ "+ appState.getUrl());
            }
        }
    }

    @Override
    public void onLoaderReset(Loader<String> stringLoader) {
    }
}

Java Source Code List

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