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

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License

The source code is released under:
Apache License
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Java Source Code

/*
 * Copyright 2014 Roy Clarkson/* ww w . ja  va2s. 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.Fragment;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.ContextMenu;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.TextView;

import com.royclarkson.springagram.model.ItemResource;

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 Fragment} that displays a list of {@link ItemResource}s
 *
 * @author Roy Clarkson
 */
public class PhotoListFragment extends Fragment implements AbsListView.OnItemClickListener {

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

  private static final String ARG_PHOTO_LIST_URL = "photos_url";

  private String photosUrl;

  private PhotoListFragmentListener photoListFragmentListener;

  private AbsListView listView;

  private ListAdapter listAdapter;


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

  public static PhotoListFragment newInstance(String photosUrl) {
    PhotoListFragment fragment = new PhotoListFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PHOTO_LIST_URL, photosUrl);
    fragment.setArguments(args);
    return fragment;
  }


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

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
      this.photosUrl = getArguments().getString(ARG_PHOTO_LIST_URL);
    }
    fetchPhotoList();
  }

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
               Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_photo, container, false);
    this.listView = (AbsListView) view.findViewById(android.R.id.list);
    this.listView.setOnItemClickListener(this);
    registerForContextMenu(this.listView);
    return view;
  }

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

  /**
   * The default content for this Fragment has a TextView that is shown when
   * the list is empty. If you would like to change the text, call this method
   * to supply the text it should use.
   */
  public void setEmptyText(CharSequence emptyText) {
    View emptyView = listView.getEmptyView();

    if (emptyText instanceof TextView) {
      ((TextView) emptyView).setText(emptyText);
    }
  }

  @Override
  public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
      this.photoListFragmentListener = (PhotoListFragmentListener) activity;
    } catch (ClassCastException e) {
      throw new ClassCastException(activity.toString()
          + " must implement OnPhotoSelectedListener");
    }
  }

  @Override
  public void onDetach() {
    super.onDetach();
    this.photoListFragmentListener = 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.photo_list_context_menu, menu);
  }

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


  //***************************************
  // OnItemClickListener methods
  //***************************************

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    if (null != this.photoListFragmentListener) {
      this.photoListFragmentListener.onPhotoSelected(position);
    }
  }


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

  public interface PhotoListFragmentListener {

    public void onDownloadPhotosComplete(List<ItemResource> photos);

    public void onPhotoSelected(int position);

    public ItemResource getPhotoByPosition(int position);

    public void onDeletePhotoByPosition(int position);

    public void onPhotoAddToGallerySelected(int position);

    public void onNetworkError(String message);

  }


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

  public void fetchPhotoList() {
    new DownloadPhotosTask().execute(this.photosUrl);
  }

  private void refreshPhotoList(Resources resources) {
    if (resources != null) {
      List<ItemResource> photos = new ArrayList<ItemResource>(resources.getContent());
      if (null != this.photoListFragmentListener) {
        this.photoListFragmentListener.onDownloadPhotosComplete(photos);
      }
      listAdapter = new PhotoListAdapter(getActivity(), photos);
      listView.setAdapter(listAdapter);
    }
  }

  private void deletePhoto(int position) {
    ItemResource itemResource = this.photoListFragmentListener.getPhotoByPosition(position);
    new DeletePhotoTask().execute(itemResource.getLink(ItemResource.REL_SELF).getHref());
    this.photoListFragmentListener.onDeletePhotoByPosition(position);
    ((PhotoListAdapter) listAdapter).notifyDataSetChanged();
  }

  private void addToGallery(int position) {
    this.photoListFragmentListener.onPhotoAddToGallerySelected(position);
  }


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

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

    private Exception exception;

    @Override
    protected Resources doInBackground(String... params) {
      try {
        final String url = params[0];
        ParameterizedTypeReference<Resources<ItemResource>> typeRef =
            new ParameterizedTypeReference<Resources<ItemResource>>() { };
        RestTemplate restTemplate = RestUtils.getInstance();
        ResponseEntity<Resources<ItemResource>> responseEntity = restTemplate.exchange(url, HttpMethod.GET,
            RestUtils.getRequestEntity(), typeRef);
        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) {
        photoListFragmentListener.onNetworkError(this.exception.getMessage());
      } else {
        refreshPhotoList(resources);
      }
    }

  }

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

    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) {
        photoListFragmentListener.onNetworkError(this.exception.getMessage());
      }
    }

  }

}
Java Source Code List
