Android Open Source - spring-a-gram-android Gallery List Fragment

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright 2014 Roy Clarkson//from  w  ww .jav  a2 s .c  om
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.royclarkson.springagram;

import android.app.Activity;
import android.app.ListFragment;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;

import com.royclarkson.springagram.model.GalleryResource;

import org.springframework.core.ParameterizedTypeReference;
import org.springframework.hateoas.Resources;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.ResourceAccessException;
import org.springframework.web.client.RestTemplate;

import java.util.ArrayList;
import java.util.List;

/**
 * {@link ListFragment} that displays a list of {@link GalleryResource}s
 *
 * @author Roy Clarkson
 */
public class GalleryListFragment extends ListFragment {

  public static final String TAG = GalleryListFragment.class.getSimpleName();

  private static final String ARG_GALLERIES_LIST_URL = "galleries_url";

  private String galleriesUrl;

  private GalleryListFragmentListener galleryListFragmentListener;


  public GalleryListFragment() {
    // Required empty public constructor
  }

  public static GalleryListFragment newInstance(String galleriesUrl) {
    GalleryListFragment fragment = new GalleryListFragment();
    Bundle args = new Bundle();
    args.putString(ARG_GALLERIES_LIST_URL, galleriesUrl);
    fragment.setArguments(args);
    return fragment;
  }


  //***************************************
  // Fragment methods
  //***************************************

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
      this.galleriesUrl = getArguments().getString(ARG_GALLERIES_LIST_URL);
    }
    fetchGalleryList();
  }

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

  @Override
  public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    setRetainInstance(true);
  }

  @Override
  public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
      galleryListFragmentListener = (GalleryListFragmentListener) activity;
    } catch (ClassCastException e) {
      throw new ClassCastException(activity.toString()
          + " must implement OnGalleryFragmentInteractionListener");
    }
  }

  @Override
  public void onDetach() {
    super.onDetach();
    galleryListFragmentListener = null;
  }

  @Override
  public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = new MenuInflater(this.getActivity());
    inflater.inflate(R.menu.gallery_list_context_menu, menu);
  }

  @Override
  public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    switch (item.getItemId()) {
      case R.id.action_delete:
        deleteGallery(info.position);
        return true;
      default:
        return super.onContextItemSelected(item);
    }
  }


  //***************************************
  // ListFragment methods
  //***************************************

  @Override
  public void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    if (null != this.galleryListFragmentListener) {
      this.galleryListFragmentListener.onGallerySelected(position);
    }
  }


  //***************************************
  // Private methods
  //***************************************

  public void fetchGalleryList() {
    new DownloadGalleriesTask().execute(this.galleriesUrl);
  }

  private void refreshGalleryList(Resources resources) {
    if (resources != null) {
      List<GalleryResource> galleries = new ArrayList<GalleryResource>(resources.getContent());
      if (null != this.galleryListFragmentListener) {
        this.galleryListFragmentListener.onDownloadGalleriesComplete(galleries);
      }
      ListAdapter listAdapter = new GalleryListAdapter(getActivity(), galleries);
      setListAdapter(listAdapter);
    }
  }

  private void deleteGallery(int position) {
    GalleryResource galleryResource = this.galleryListFragmentListener.getGalleryByPosition(position);
    new DeleteGalleryTask().execute(galleryResource.getLink("self").getHref());
    this.galleryListFragmentListener.onDeleteGalleryByPosition(position);
    ((GalleryListAdapter) getListAdapter()).notifyDataSetChanged();
  }


  // ***************************************
  // Listener interface
  // ***************************************

  public interface GalleryListFragmentListener {

    public void onDownloadGalleriesComplete(List<GalleryResource> galleries);

    public void onGallerySelected(int position);

    public GalleryResource getGalleryByPosition(int position);

    public void onDeleteGalleryByPosition(int position);

    public void onNetworkError(String message);

  }


  // ***************************************
  // Private classes
  // ***************************************

  private class DownloadGalleriesTask extends AsyncTask<String, Void, Resources> {

    Exception exception;

    @Override
    protected Resources doInBackground(String... params) {
      try {
        final String url = params[0];
        RestTemplate restTemplate = RestUtils.getInstance();
        ResponseEntity<Resources<GalleryResource>> responseEntity = restTemplate.exchange(url, HttpMethod.GET,
            RestUtils.getRequestEntity(),
            new ParameterizedTypeReference<Resources<GalleryResource>>() {
            });
        return responseEntity.getBody();
      } catch (Exception e) {
        this.exception = e;
        Log.e(TAG, e.getMessage(), e);
        return null;
      }
    }

    @Override
    protected void onPostExecute(Resources resources) {
      if (this.exception != null && this.exception instanceof ResourceAccessException) {
        galleryListFragmentListener.onNetworkError(this.exception.getMessage());
      } else {
        refreshGalleryList(resources);
      }
    }

  }

  private class DeleteGalleryTask extends AsyncTask<String, Void, Void> {

    private Exception exception;

    @Override
    protected Void doInBackground(String... params) {
      try {
        final String url = params[0];
        RestTemplate restTemplate = RestUtils.getInstance();
        restTemplate.delete(url);
      } catch (Exception e) {
        this.exception = e;
        Log.e(TAG, e.getMessage(), e);
      }
      return null;
    }

    @Override
    protected void onPostExecute(Void v) {
      if (this.exception != null && this.exception instanceof ResourceAccessException) {
        galleryListFragmentListener.onNetworkError(this.exception.getMessage());
      }
    }

  }

}

Java Source Code List

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