package com.meg7.soas.ui.fragment;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.widget.SwipeRefreshLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;
import com.meg7.soas.R;
import com.meg7.soas.data.Photo;
import com.meg7.soas.data.Photos;
import com.meg7.soas.ui.adapter.BaseEndlessScrollListener;
import com.meg7.soas.ui.adapter.PhotosAdapter;
import org.apache.http.HttpStatus;
/**
* A list fragment representing a list of Photos. 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 PhotoDetailFragment}.
* <p/>
* Activities containing this fragment MUST implement the {@link Callbacks}
* interface.
*/
public class PhotosListFragment extends SwipeRefreshListFragment {
public static final String TAG = PhotosListFragment.class.getSimpleName();
/**
* 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;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public static interface Callbacks {
/**
* Force refresh, reload first page.
*/
public void refresh();
/**
* Callback for when next page can be loaded.
*
* @return Returns true if there are more pages to be loaded.
*/
public void requestNextPage();
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(View view, Photo photo);
}
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public PhotosListFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Set divider to nothing but keep its height.
getListView().setDividerHeight(0);
// Set empty view.
View emptyView = LayoutInflater.from(getActivity()).inflate(R.layout.list_empty_view, null);
getListView().setEmptyView(emptyView);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
}
}
/**
* Create new or or append to {@link PhotosAdapter} newly requested photos. It also shows retry
* layout in case of failure.
*
* @param statusCode Response code {@link HttpStatus}
* @param photos Photos to add or append to the adapter.
*/
public void setPhotos(int statusCode, Photos photos) {
if (statusCode == HttpStatus.SC_OK && photos != null) {
PhotosAdapter adapter = (PhotosAdapter) getListAdapter();
if (adapter == null) {
adapter = new PhotosAdapter(getActivity(), photos.photos, photos.count);
setListAdapter(adapter);
// Attach listener to handle "swipe to refresh" gesture, SwipeRefreshLayout invokes
// onRefresh method, same method should be called in response to the Refresh action
// from the action bar.
setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
// Execute the background task to refresh page.
mCallbacks.refresh();
}
});
// Attach listener to handle requesting new pages.
getListView().setOnScrollListener(new BaseEndlessScrollListener() {
@Override
public void onLoadMore(int page, int totalItemsCount) {
// Triggered only when new data needs to be appended to the list
// Add whatever code is needed to append new items to your AdapterView
mCallbacks.requestNextPage();
}
});
} else {
adapter.clear();
adapter.addAll(photos.photos);
// Stop the refreshing indicator.
setRefreshing(false);
}
} else {
// TODO :: Show retry layout.
Toast.makeText(getActivity(), "Oops! " + statusCode, Toast.LENGTH_SHORT).show();
// Stop the refreshing indicator.
setRefreshing(false);
}
}
/**
* Append to {@link PhotosAdapter} newly requested photos. It could also show an indication of failure.
*
* @param statusCode Response code {@link HttpStatus}
* @param photos Photos to append to the adapter.
*/
public void appendPhotos(int statusCode, Photos photos) {
if (statusCode == HttpStatus.SC_OK && photos != null) {
PhotosAdapter adapter = (PhotosAdapter) getListAdapter();
// Adapter should not be NULL at this point.
adapter.addAll(photos.photos);
} else {
// TODO :: Update error message!
Toast.makeText(getActivity(), "Oops! Could not load next page, " + statusCode, Toast.LENGTH_SHORT).show();
}
}
@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();
mCallbacks = null;
}
@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(view, ((PhotosAdapter) getListAdapter()).getItem(position));
}
@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);
}
}
/**
* 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;
}
}