StoryFragment.java

package com.airlocksoftware.hackernews.fragment;

import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
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.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.airlocksoftware.hackernews.R;
import com.airlocksoftware.hackernews.activity.MainActivity;
import com.airlocksoftware.hackernews.adapter.StoryAdapter;
import com.airlocksoftware.hackernews.data.AppData;
import com.airlocksoftware.hackernews.interfaces.SharePopupInterface;
import com.airlocksoftware.hackernews.interfaces.TabletLayout;
import com.airlocksoftware.hackernews.loader.StoryLoader;
import com.airlocksoftware.hackernews.model.*;
import com.airlocksoftware.hackernews.parser.StoryParser.StoryResponse;
import com.airlocksoftware.hackernews.view.SharePopup;
import com.airlocksoftware.holo.actionbar.ActionBarButton;
import com.airlocksoftware.holo.actionbar.ActionBarButton.Priority;
import com.airlocksoftware.holo.actionbar.interfaces.ActionBarClient;
import com.airlocksoftware.holo.actionbar.interfaces.ActionBarController;
import com.airlocksoftware.holo.image.IconView;
import com.airlocksoftware.holo.utils.Utils;
import com.airlocksoftware.holo.utils.ViewUtils;
import com.crashlytics.android.Crashlytics;

import com.airlocksoftware.hackernews.R;

public class StoryFragment extends Fragment implements ActionBarClient, LoaderManager.LoaderCallbacks<StoryResponse> {

	// State
	private StoryAdapter mAdapter;
	private Page mPage = Page.FRONT;
	private Request mRequest = Request.NEW;
	private Result mLastResult = Result.EMPTY;
	private boolean mIsLoading = false;
	private boolean mShouldRestoreListState;

	// Activity interfaces
	TabletLayout mTabletLayout = null;
	StoryFragment.Callbacks mCallbacks = null;

	// Views
	View mError, mLoading;
	private ListView mList;
	private ActionBarButton mRefreshButton;
	private View mMoreButton;
	private TextView mMoreButtonText;
	private IconView mMoreIcon;

	// Listeners
	private OnClickListener mMoreListener = new OnClickListener() {
		@Override
		public void onClick(View v) {
			mRequest = Request.MORE;

			// change more link text & icon
			mMoreButtonText.setText(getActivity().getString(R.string.loading_));
			mMoreIcon.setVisibility(View.GONE);

			getLoaderManager().restartLoader(0, null, StoryFragment.this);
		}
	};

	private OnClickListener mRefreshListener = new OnClickListener() {
		@Override
		public void onClick(View v) {
			mRequest = Request.REFRESH;
			getLoaderManager().restartLoader(0, null, StoryFragment.this);
		}
	};
	
	// Constants
	public static final String PAGE = StoryFragment.class.getSimpleName() + ".page";
	@SuppressWarnings("unused")
	private static final String TAG = StoryFragment.class.getSimpleName();

	// Constructors
	public StoryFragment() {
		// default empty constructor
	}

	// Fragment Lifecycle
	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		
		// get StoryFragment.Callbacks
		if (activity instanceof StoryFragment.Callbacks) {
			mCallbacks = (Callbacks) activity;
		} else {
			throw new RuntimeException(
					"The activity StoryFragment attached to is required to implement the StoryFragment.Callbacks interface.");
		}

		// get TabletLayoutInterface
		if (activity instanceof TabletLayout) {
			mTabletLayout = (TabletLayout) activity;
		} else {
			throw new RuntimeException(
					"The activity StoryFragment attached to is required to implement the TabletLayoutInterface interface.");
		}
	}

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		// start loading if this Fragment is part of the layout
		if (mCallbacks.storyFragmentIsInLayout()) {
			getLoaderManager().initLoader(0, null, this);
		}

		// Default Crashlytics custom keys
		Crashlytics.setString("StoryFragment :: mPage", mPage.toString());
	}

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

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

		if (!mCallbacks.storyFragmentIsInLayout()) {
			// if this Fragment is no longer part of the layout, return early
			return;
		}
		
		findViews();
		setupMoreButton();
		setupAdapter();

		// if in tablet layout, change background & cache color hint of the list to a different color
		if (mTabletLayout.isTabletLayout()) {
			setupTabletBackgroundColors();
		}

		// restoring saved state
		if (savedInstanceState != null) {
			mPage = ((Page) savedInstanceState.getSerializable(PAGE));
			mAdapter.onRestoreInstanceState(savedInstanceState);
		}

		Crashlytics.setString("StoryFragment :: mPage", mPage == null ? "" : mPage.toString());

		mShouldRestoreListState = true;

		refreshContentVisibility();
	}

	@Override
	public void onPause() {
        /* Save list state to shared prefs (since we kill the activity when we switch to the comments list) */
        FragmentActivity fragActivity = getActivity();

        // Make sure we're not going to nullPointerException
        if (fragActivity != null) {
            AppData actData = new AppData(fragActivity);

            if (mList != null)  {
                actData.saveStoryListPosition(mList.getFirstVisiblePosition());
            } else {
                Log.d(TAG, "mList is null! Story position NOT saved!");
            }
        }

        super.onPause();
    }

	@SuppressWarnings("deprecation")
	private void setupTabletBackgroundColors() {
		Resources res = getActivity().getResources();

		// bg
		int tabletBgResId = Utils.getThemedResourceId(getActivity(), R.attr.bgStorylistTablet);
		Drawable tabletBg = res.getDrawable(tabletBgResId);
		ViewUtils.fixDrawableRepeat(tabletBg);

		mList.setBackgroundDrawable(tabletBg);
		mError.setBackgroundDrawable(tabletBg);
		mLoading.setBackgroundDrawable(tabletBg);

		// cache color hint
		int cacheColorHintResId = Utils.getThemedResourceId(getActivity(), R.attr.cacheColorHintStorylistTablet);
		mList.setCacheColorHint(res.getColor(cacheColorHintResId));
	}

	private void setupAdapter() {
		SharePopup popup = ((SharePopupInterface) getActivity()).getSharePopup();
		mAdapter = new StoryAdapter(getActivity(), mList, popup, mCallbacks, mTabletLayout);
		mList.setAdapter(mAdapter);
	}

	/** inflate & add the more button **/
	private void setupMoreButton() {
		LayoutInflater inflater = getActivity().getLayoutInflater();
		mMoreButton = inflater.inflate(R.layout.vw_more_link, mList, false);
		mMoreButton.setOnClickListener(mMoreListener);
		mMoreButton.setVisibility(View.GONE);
		mMoreButtonText = (TextView) mMoreButton.findViewById(R.id.txt_more);
		mMoreIcon = (IconView) mMoreButton.findViewById(R.id.icv_more);
		mList.addFooterView(mMoreButton, null, false);
	}

	private void findViews() {
		// have to make sure we're finding views inside of stories container (fixes bug where StoryFragment &
		// CommentsFragment would confused each other's views when they're part of the same activity)
		View container = getActivity().findViewById(R.id.cnt_stories);

		mLoading = container.findViewById(R.id.cnt_loading);
		mError = container.findViewById(R.id.cnt_error);
		mError.findViewById(R.id.btn_error)
					.setOnClickListener(mRefreshListener);

		ViewUtils.fixBackgroundRepeat(mError);
		ViewUtils.fixBackgroundRepeat(mLoading);

		mList = (ListView) container.findViewById(android.R.id.list);
		mList.setItemsCanFocus(true);
	}

	@Override
	public void onSaveInstanceState(Bundle outState) {
		/* Save to bundle */
		if (!mCallbacks.storyFragmentIsInLayout()) return;
		outState.putSerializable(PAGE, mPage);
		outState = mAdapter.onSaveInstanceState(outState);
		super.onSaveInstanceState(outState);

	}

	// Loader interface
	@Override
	public Loader<StoryResponse> onCreateLoader(int id, Bundle args) {
		mIsLoading = true;
		refreshContentVisibility();
		return new StoryLoader(getActivity(), mPage, mRequest);
	}

	@Override
	public void onLoadFinished(Loader<StoryResponse> loader, StoryResponse response) {

		// if this Fragment is no longer part of the layout, return early
		if (!mCallbacks.storyFragmentIsInLayout()) {
			return;
		}

		// Variable for showing Toasts
		Toast msg;

		// if NULL_RESPONSE, make a toast! Cheers! Drink responsibly; return early.
		if (response == null || response.isNull()) {
			msg = Toast.makeText(getActivity(), getActivity().getString(R.string.error_no_page), Toast.LENGTH_SHORT);
			msg.show();
			return;
		}

		mIsLoading = false;
		mLastResult = response.result;

		switch (mLastResult) {

		case SUCCESS: // first page
			mAdapter.clear();
			mAdapter.addAll(response.stories);
			break;

		case MORE: // new data from web
			mAdapter.addAll(response.stories);
			break;

		case FNID_EXPIRED: // the link was expired - refresh the page
			msg = Toast.makeText(getActivity(), getActivity().getString(R.string.link_expired), Toast.LENGTH_SHORT);
			msg.show();

			// start loader with refresh request
			mRequest = Request.REFRESH;
			getLoaderManager().restartLoader(0, null, this);
			break;

		case FAILURE: // Show error message
			msg = Toast.makeText(getActivity(), getActivity().getString(R.string.problem_downloading_content), Toast.LENGTH_SHORT);
			msg.show();
			break;

		default:
			break;
		}

		mAdapter.setActiveStory(mCallbacks.getActiveStory());
		showMoreLink();
		checkForExpiredCache(response);
		refreshContentVisibility();

		if(mShouldRestoreListState) {
			mShouldRestoreListState = false;
			int listPosition = new AppData(getActivity()).getStoryListPosition();
			mList.setSelectionFromTop(listPosition, 0);
		}
	}

	private void checkForExpiredCache(StoryResponse response) {
		if (response.timestamp != null && response.timestamp.time > Comment.JAN_1_2012
				&& System.currentTimeMillis() - response.timestamp.time > Comment.CACHE_EXPIRATION) {
			// still display cached values, but need to start refresh
			mRequest = Request.REFRESH;
			getLoaderManager().restartLoader(0, null, this);
		}
	}

	private void showMoreLink() {
		mMoreButtonText.setText(getActivity().getString(R.string.load_more));
		mMoreIcon.setVisibility(View.VISIBLE);
		mMoreButton.setVisibility(View.VISIBLE);
	}

	@Override
	public void onLoaderReset(Loader<StoryResponse> loader) {
		// no implementation necessary
	}

	// ActionBar interface
	@Override
	public void setupActionBar(Context context, ActionBarController controller) {
		if (mRefreshButton == null) {
			mRefreshButton = new ActionBarButton(context);
			mRefreshButton.text(context.getString(R.string.refresh_stories))
										.icon(R.drawable.ic_action_refresh)
										.priority(Priority.HIGH)
										.onClick(mRefreshListener);
		}
		controller.addButton(mRefreshButton);
	}

	@Override
	public void cleanupActionBar(Context context, ActionBarController controller) {
		controller.removeButton(mRefreshButton);
	}

	public void setPage(Page page) {
		mPage = page;
		Crashlytics.setString("StoryFragment :: mPage", mPage.toString());
	}

	public StoryAdapter getStoryAdapter() {
		return mAdapter;
	}

	/** Determines which view (List, Error, or Loading) show be visible. **/
	private void refreshContentVisibility() {
		// can't refresh visibility until / unless all views are created
		if (mAdapter == null || mList == null || mError == null || mLoading == null) return;

		boolean errorVis = mLastResult == Result.FAILURE && mAdapter.getCount() < 1 && !mIsLoading;
		boolean loadingVis = mIsLoading && mAdapter.getCount() < 1 && !errorVis;
		boolean listVis = !(errorVis || loadingVis);

		mRefreshButton.icon(errorVis ? R.drawable.ic_action_refresh_error : R.drawable.ic_action_refresh);
		mRefreshButton.showProgress(mIsLoading);

		mList.setVisibility(ViewUtils.boolToVis(listVis));
		mError.setVisibility(ViewUtils.boolToVis(errorVis));
		mLoading.setVisibility(ViewUtils.boolToVis(loadingVis));
	}

	// Static creator method
	public static StoryFragment newInstance(Page page) {
		StoryFragment fragment = new StoryFragment();
		fragment.setPage(page);
		return fragment;
	}

	// Callbacks
	/** To be implemented by any Activity containing this Fragment. Notifies when this fragment receives new data. **/
	public interface Callbacks {
		/**
		 * Called when the User has clicked on a Story in the ListView (called by StoryAdapter).
		 **/
		public void showCommentsForStory(Story story, MainActivity.CommentsTab initalTab);

		/** Called by StoryFragment.onLoadFinished to make sure this Fragment's StoryAdapter has the active story **/
		public Story getActiveStory();

		/**
		 * Allows the StoryFragment to check if it is part of the layout in MainActivity after being recreated on
		 * orientation change.
		 * If it is not in layout, it's method's should return early.
		 **/
		public boolean storyFragmentIsInLayout();
	}

}