ImageDetailActivity.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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.gmail.charleszq.picorner.ui;

import java.util.HashSet;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;

import android.app.ActionBar;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

import com.gmail.charleszq.picorner.BuildConfig;
import com.gmail.charleszq.picorner.R;
import com.gmail.charleszq.picorner.dp.IPhotosProvider;
import com.gmail.charleszq.picorner.model.MediaObject;
import com.gmail.charleszq.picorner.utils.IConstants;
import com.nostra13.universalimageloader.core.ImageLoader;

public class ImageDetailActivity extends FragmentActivity implements
		OnClickListener {
	private static final String				TAG						= ImageDetailActivity.class
																			.getSimpleName();
	public static final String				LARGE_IMAGE_POSITION	= "extra_image";				//$NON-NLS-1$
	public static final String				DP_KEY					= "data.provider";				//$NON-NLS-1$
	public static final String				OFFLINE_COMMAND_KEY		= "is.command.support.offline"; //$NON-NLS-1$

	/**
	 * The intent key to say if we need to start the slide show.
	 */
	public static final String				SLIDE_SHOW_KEY			= "start.slide.show";			//$NON-NLS-1$

	/**
	 * The key to save intent value to indicate whether we show the action bar
	 * by default
	 */
	public static final String				SHOW_ACTION_BAR_KEY		= "show.action.bar";			//$NON-NLS-1$

	private ImagePagerAdapter				mAdapter;
	private ImageLoader						mImageFetcher;
	private ViewPager						mPager;

	private Set<IActionBarVisibleListener>	mActionBarListeners;

	IPhotosProvider							mPhotosProvider;

	/**
	 * the marker to say if the current command is offline enabled.
	 */
	boolean									mIsOfflineEnabled		= false;

	private Timer							mTimer;
	private Handler							mHandler				= new Handler();

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.image_detail_pager);

		// The ImageFetcher takes care of loading images into our ImageView
		// children asynchronously
		mImageFetcher = ImageLoader.getInstance();

		// is offline enabled
		String isOfflineEnabledString = getIntent().getStringExtra(
				OFFLINE_COMMAND_KEY);
		if (isOfflineEnabledString != null) {
			mIsOfflineEnabled = Boolean.parseBoolean(isOfflineEnabledString);
		}

		// Set up ViewPager and backing adapter
		mPhotosProvider = (IPhotosProvider) getIntent().getExtras()
				.getSerializable(DP_KEY);
		mAdapter = new ImagePagerAdapter(mPhotosProvider,
				getSupportFragmentManager(), mPhotosProvider.getCurrentSize(),
				mIsOfflineEnabled);
		mPager = (ViewPager) findViewById(R.id.pager);
		mPager.setAdapter(mAdapter);
		mPager.setPageMargin((int) getResources().getDimension(
				R.dimen.image_detail_pager_margin));
		mPager.setOffscreenPageLimit(2);

		// Set up activity to go full screen
		getWindow().addFlags(LayoutParams.FLAG_FULLSCREEN);

		final ActionBar actionBar = getActionBar();

		// Hide title text and set home as up
		actionBar.setDisplayHomeAsUpEnabled(true);
		// actionBar.setDisplayShowTitleEnabled(false);

		// Hide and show the ActionBar as the visibility changes
		mPager.setOnSystemUiVisibilityChangeListener(new View.OnSystemUiVisibilityChangeListener() {
			@Override
			public void onSystemUiVisibilityChange(int vis) {
				boolean shown = true;
				if ((vis & View.SYSTEM_UI_FLAG_LOW_PROFILE) != 0) {
					actionBar.hide();
					shown = false;
				} else {
					actionBar.show();
				}

				if (mActionBarListeners != null) {
					for (IActionBarVisibleListener lis : mActionBarListeners) {
						lis.onActionBarShown(shown);
					}
				}

			}
		});

		// Start low profile mode and hide ActionBar
		boolean showActionBar = getIntent().getBooleanExtra(
				SHOW_ACTION_BAR_KEY, true);
		if (!showActionBar) {
			mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE);
			actionBar.hide();
		}

		// Set the current item based on the extra passed in to this activity
		final int extraCurrentItem = getIntent().getIntExtra(
				LARGE_IMAGE_POSITION, -1);
		if (extraCurrentItem != -1) {
			mPager.setCurrentItem(extraCurrentItem);
		}
		boolean startSlide = getIntent().getBooleanExtra(SLIDE_SHOW_KEY, false);
		if (startSlide) {
			startSlideShow(1);
		}
	}

	/**
	 * If slide show command comes directly from the offline menu item, set the 'delay' to the same as
	 * the interval, otherwise, it means the command comes from this activity itself, then just delay for
	 * 2 seconds.
	 * @param delay
	 */
	void startSlideShow(int delay) {
		SharedPreferences sp = this.getSharedPreferences(IConstants.DEF_PREF_NAME, Context.MODE_APPEND);
		int interval = Integer.parseInt(sp.getString(IConstants.PREF_SLIDE_SHOW_INTERVAL, IConstants.DEF_SLIDE_SHOW_INTERVAL));
		
		getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
		mTimer = new Timer();
		mTimer.scheduleAtFixedRate(new TimerTask() {
			@Override
			public void run() {
				mHandler.post(new Runnable() {
					@Override
					public void run() {
						int currentPosition = mPager.getCurrentItem();
						currentPosition++;
						if (currentPosition >= mAdapter.getCount())
							currentPosition = 0;
						mPager.setCurrentItem(currentPosition);
					}
				});
			}
		}, delay == 1 ? interval : 2000, interval);
		mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE);
		getActionBar().hide();
		if (BuildConfig.DEBUG)
			Log.d(TAG, "slide show starts..."); //$NON-NLS-1$
	}

	/**
	 * Called by the ViewPager child fragments to load images via the one
	 * ImageFetcher
	 */
	public ImageLoader getImageFetcher() {
		return mImageFetcher;
	}

	/**
	 * The main adapter that backs the ViewPager. A subclass of
	 * FragmentStatePagerAdapter as there could be a large number of items in
	 * the ViewPager and we don't want to retain them all in memory at once but
	 * create/destroy them on the fly.
	 */
	private class ImagePagerAdapter extends FragmentStatePagerAdapter {
		private final int		mSize;
		private IPhotosProvider	mProvider;
		private boolean			mIsOfflineEnabled	= false;

		public ImagePagerAdapter(IPhotosProvider provider, FragmentManager fm,
				int size, boolean offlineEnabled) {
			super(fm);
			mSize = size;
			this.mProvider = provider;
			this.mIsOfflineEnabled = offlineEnabled;
		}

		@Override
		public int getCount() {
			return mSize;
		}

		@Override
		public Fragment getItem(int position) {
			MediaObject obj = mProvider.getMediaObject(position);
			ImageDetailFragment frg = ImageDetailFragment.newInstance(
					obj.getLargeUrl() == null ? obj.getThumbUrl() : obj
							.getLargeUrl(), mProvider, position,
					mIsOfflineEnabled);
			return frg;
		}
	}

	/**
	 * Set on the ImageView in the ViewPager children fragments, to
	 * enable/disable low profile mode when the ImageView is touched.
	 */
	@Override
	public void onClick(View v) {
		final int vis = mPager.getSystemUiVisibility();
		if ((vis & View.SYSTEM_UI_FLAG_LOW_PROFILE) != 0) {
			mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE);
		} else {
			mPager.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE);
		}
		if (mTimer != null) {
			mTimer.cancel();
			if (BuildConfig.DEBUG)
				Log.d(TAG, "slide show stoped..."); //$NON-NLS-1$
		}
		getWindow().clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
	}

	void addActionBarListener(IActionBarVisibleListener lis) {
		if (mActionBarListeners == null) {
			mActionBarListeners = new HashSet<IActionBarVisibleListener>();
		}
		mActionBarListeners.add(lis);
	}

	void removeActionBarListener(IActionBarVisibleListener lis) {
		if (mActionBarListeners != null) {
			mActionBarListeners.remove(lis);
		}
	}

	/**
	 * @author charles(charleszq@gmail.com)
	 * 
	 */
	static interface IActionBarVisibleListener {
		void onActionBarShown(boolean show);
	}
}