Java tutorial
package com.example.damerap_ver1; /* Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. The ASF licenses this file to you 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. */ import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.net.URLEncoder; import java.util.HashMap; import java.util.Map; import javax.xml.parsers.FactoryConfigurationError; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.app.Activity; import android.app.AlertDialog; import android.app.AlertDialog.Builder; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.graphics.Color; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.net.Uri; import android.net.wifi.WifiManager; import android.os.AsyncTask; import android.os.Bundle; import android.os.PowerManager; import android.os.PowerManager.WakeLock; import android.telephony.TelephonyManager; import android.util.Log; import android.util.TypedValue; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.WindowManager; import android.widget.LinearLayout; import android.widget.LinearLayout.LayoutParams; import android.widget.MediaController; import android.widget.ProgressBar; import android.widget.RelativeLayout; import android.widget.TextView; import android.widget.VideoView; /** * <p>Activity that will play a video from YouTube. A specific video or the latest video in a YouTube playlist * can be specified in the intent used to invoke this activity. The data of the intent can be set to a * specific video by using an Intent data URL of the form:</p> * * <pre> * ytv://videoid * </pre> * * <p>where <pre>videoid</pre> is the ID of the YouTube video to be played.</p> * * <p>If the user wishes to play the latest video in a YouTube playlist, the Intent data URL should be of the * form:</p> * * <pre> * ytpl://playlistid * </pre> * * <p>where <pre>playlistid</pre> is the ID of the YouTube playlist from which the latest video is to be played.</p> * * <p>Code used to invoke this intent should look something like the following:</p> * * <pre> * Intent lVideoIntent = new Intent(null, Uri.parse("ytpl://"+YOUTUBE_PLAYLIST_ID), this, IntroVideoActivity.class); * startActivity(lVideoIntent); * </pre> * * <p>There are several messages that are displayed to the user during various phases of the video load process. If * you wish to supply text other than the default english messages (e.g., internationalization, etc.), you can pass * the text to be used via the Intent's extended data. The messages that can be customized include: * * <ul> * <li>com.keyes.video.msg.init - activity is initializing.</li> * <li>com.keyes.video.msg.detect - detecting the bandwidth available to download video.</li> * <li>com.keyes.video.msg.playlist - getting latest video from playlist.</li> * <li>com.keyes.video.msg.token - retrieving token from YouTube.</li> * <li>com.keyes.video.msg.loband - buffering low-bandwidth.</li> * <li>com.keyes.video.msg.hiband - buffering hi-bandwidth.</li> * <li>com.keyes.video.msg.error.title - dialog title displayed if anything goes wrong.</li> * <li>com.keyes.video.msg.error.msg - message displayed if anything goes wrong.</li> * </ul> * * <p>For example:</p> * * <pre> * Intent lVideoIntent = new Intent(null, Uri.parse("ytpl://"+YOUTUBE_PLAYLIST_ID), this, IntroVideoActivity.class); * lVideoIntent.putExtra("com.keyes.video.msg.init", getString("str_video_intro")); * lVideoIntent.putExtra("com.keyes.video.msg.detect", getString("str_video_detecting_bandwidth")); * ... * startActivity(lVideoIntent); * </pre> * * @author David Keyes * */ public class IntroVideoActivity extends Activity { public static final String SCHEME_YOUTUBE_VIDEO = "ytv"; public static final String SCHEME_YOUTUBE_PLAYLIST = "ytpl"; private static final String YOUTUBE_VIDEO_INFORMATION_URL = "http://www.youtube.com/get_video_info?&video_id="; private static final String YOUTUBE_PLAYLIST_ATOM_FEED_URL = "http://gdata.youtube.com/feeds/api/playlists/"; private static final String TAG_WAKELOCK = "introVideo"; protected ProgressBar mProgressBar; protected TextView mProgressMessage; protected VideoView mVideoView; public final static String MSG_INIT = "com.keyes.video.msg.init"; protected String mMsgInit = "Initializing"; public final static String MSG_DETECT = "com.keyes.video.msg.detect"; protected String mMsgDetect = "Detecting Bandwidth"; public final static String MSG_PLAYLIST = "com.keyes.video.msg.playlist"; protected String mMsgPlaylist = "Determining Latest Video in YouTube Playlist"; public final static String MSG_TOKEN = "com.keyes.video.msg.token"; protected String mMsgToken = "Retrieving YouTube Video Token"; public final static String MSG_LO_BAND = "com.keyes.video.msg.loband"; protected String mMsgLowBand = "Buffering Low-bandwidth Video"; public final static String MSG_HI_BAND = "com.keyes.video.msg.hiband"; protected String mMsgHiBand = "Buffering High-bandwidth Video"; public final static String MSG_ERROR_TITLE = "com.keyes.video.msg.error.title"; protected String mMsgErrorTitle = "Communications Error"; public final static String MSG_ERROR_MSG = "com.keyes.video.msg.error.msg"; protected String mMsgError = "An error occurred during the retrieval of the video. This could be due to network issues or YouTube protocols. Please try again later."; /** Background task on which all of the interaction with YouTube is done */ protected QueryYouTubeTask mQueryYouTubeTask; /** The wake lock that keeps the screen on while video is playing */ protected WakeLock mWakeLock; @Override protected void onCreate(Bundle pSavedInstanceState) { super.onCreate(pSavedInstanceState); this.requestWindowFeature(Window.FEATURE_NO_TITLE); this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); // create the layout of the view setupView(); // determine the messages to be displayed as the view loads the video extractMessages(); // grab a wake-lock so that the video can play without the screen being turned off PowerManager lPwrMgr = (PowerManager) getSystemService(POWER_SERVICE); mWakeLock = lPwrMgr.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, TAG_WAKELOCK); mWakeLock.acquire(); mProgressMessage.setText(mMsgInit); // extract the playlist or video id from the intent that started this video Uri lVideoIdUri = this.getIntent().getData(); if (lVideoIdUri == null) { Log.i(this.getClass().getSimpleName(), "No video ID was specified in the intent. Closing video activity."); finish(); } String lVideoSchemeStr = lVideoIdUri.getScheme(); String lVideoIdStr = lVideoIdUri.getEncodedSchemeSpecificPart(); if (lVideoIdStr == null) { Log.i(this.getClass().getSimpleName(), "No video ID was specified in the intent. Closing video activity."); finish(); } if (lVideoIdStr.startsWith("//")) { if (lVideoIdStr.length() > 2) { lVideoIdStr = lVideoIdStr.substring(2); } else { Log.i(this.getClass().getSimpleName(), "No video ID was specified in the intent. Closing video activity."); finish(); } } /////////////////// // extract either a video id or a playlist id, depending on the uri scheme YouTubeId lYouTubeId = null; if (lVideoSchemeStr != null && lVideoSchemeStr.equalsIgnoreCase(SCHEME_YOUTUBE_PLAYLIST)) { lYouTubeId = new PlaylistId(lVideoIdStr); } else if (lVideoSchemeStr != null && lVideoSchemeStr.equalsIgnoreCase(SCHEME_YOUTUBE_VIDEO)) { lYouTubeId = new VideoId(lVideoIdStr); } if (lYouTubeId == null) { Log.i(this.getClass().getSimpleName(), "Unable to extract video ID from the intent. Closing video activity."); finish(); } mQueryYouTubeTask = (QueryYouTubeTask) new QueryYouTubeTask().execute(lYouTubeId); } /** * Determine the messages to display during video load and initialization. */ private void extractMessages() { Intent lInvokingIntent = getIntent(); String lMsgInit = lInvokingIntent.getStringExtra(MSG_INIT); if (lMsgInit != null) { mMsgInit = lMsgInit; } String lMsgDetect = lInvokingIntent.getStringExtra(MSG_DETECT); if (lMsgDetect != null) { mMsgDetect = lMsgDetect; } String lMsgPlaylist = lInvokingIntent.getStringExtra(MSG_PLAYLIST); if (lMsgPlaylist != null) { mMsgPlaylist = lMsgPlaylist; } String lMsgToken = lInvokingIntent.getStringExtra(MSG_TOKEN); if (lMsgToken != null) { mMsgToken = lMsgToken; } String lMsgLoBand = lInvokingIntent.getStringExtra(MSG_LO_BAND); if (lMsgLoBand != null) { mMsgLowBand = lMsgLoBand; } String lMsgHiBand = lInvokingIntent.getStringExtra(MSG_HI_BAND); if (lMsgHiBand != null) { mMsgHiBand = lMsgHiBand; } String lMsgErrTitle = lInvokingIntent.getStringExtra(MSG_ERROR_TITLE); if (lMsgErrTitle != null) { mMsgErrorTitle = lMsgErrTitle; } String lMsgErrMsg = lInvokingIntent.getStringExtra(MSG_ERROR_MSG); if (lMsgErrMsg != null) { mMsgError = lMsgErrMsg; } } /** * Create the view in which the video will be rendered. */ private void setupView() { LinearLayout lLinLayout = new LinearLayout(this); lLinLayout.setId(1); lLinLayout.setOrientation(LinearLayout.VERTICAL); lLinLayout.setGravity(Gravity.CENTER); lLinLayout.setBackgroundColor(Color.BLACK); LayoutParams lLinLayoutParms = new LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT); lLinLayout.setLayoutParams(lLinLayoutParms); this.setContentView(lLinLayout); RelativeLayout lRelLayout = new RelativeLayout(this); lRelLayout.setId(2); lRelLayout.setGravity(Gravity.CENTER); lRelLayout.setBackgroundColor(Color.BLACK); android.widget.RelativeLayout.LayoutParams lRelLayoutParms = new android.widget.RelativeLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT); lRelLayout.setLayoutParams(lRelLayoutParms); lLinLayout.addView(lRelLayout); mVideoView = new VideoView(this); mVideoView.setId(3); android.widget.RelativeLayout.LayoutParams lVidViewLayoutParams = new android.widget.RelativeLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); lVidViewLayoutParams.addRule(RelativeLayout.CENTER_IN_PARENT); mVideoView.setLayoutParams(lVidViewLayoutParams); lRelLayout.addView(mVideoView); mProgressBar = new ProgressBar(this); mProgressBar.setId(4); android.widget.RelativeLayout.LayoutParams lProgressBarLayoutParms = new android.widget.RelativeLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); lProgressBarLayoutParms.addRule(RelativeLayout.CENTER_IN_PARENT); mProgressBar.setLayoutParams(lProgressBarLayoutParms); lRelLayout.addView(mProgressBar); mProgressMessage = new TextView(this); mProgressMessage.setId(5); android.widget.RelativeLayout.LayoutParams lProgressMsgLayoutParms = new android.widget.RelativeLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); lProgressMsgLayoutParms.addRule(RelativeLayout.CENTER_HORIZONTAL); lProgressMsgLayoutParms.addRule(RelativeLayout.BELOW, 4); mProgressMessage.setLayoutParams(lProgressMsgLayoutParms); mProgressMessage.setTextColor(Color.LTGRAY); mProgressMessage.setTextSize(TypedValue.COMPLEX_UNIT_PT, 8); mProgressMessage.setText("..."); lRelLayout.addView(mProgressMessage); } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); // release wake-lock if (mWakeLock != null) { mWakeLock.release(); } this.mQueryYouTubeTask = null; this.mVideoView = null; } public void updateProgress(String pProgressMsg) { try { mProgressMessage.setText(pProgressMsg); } catch (Exception e) { Log.e(this.getClass().getSimpleName(), "Error updating video status!", e); } } private class ProgressUpdateInfo { public String mMsg; public ProgressUpdateInfo(String pMsg) { mMsg = pMsg; } } /** * Task to figure out details by calling out to YouTube GData API. We only use public methods that * don't require authentication. * */ private class QueryYouTubeTask extends AsyncTask<YouTubeId, ProgressUpdateInfo, Uri> { private boolean mShowedError = false; @Override protected Uri doInBackground(YouTubeId... pParams) { String lUriStr = null; String lYouTubeFmtQuality = "17"; // 3gpp medium quality, which should be fast enough to view over EDGE connection String lYouTubeVideoId = null; if (isCancelled()) return null; try { publishProgress(new ProgressUpdateInfo(mMsgDetect)); WifiManager lWifiManager = (WifiManager) IntroVideoActivity.this .getSystemService(Context.WIFI_SERVICE); TelephonyManager lTelephonyManager = (TelephonyManager) IntroVideoActivity.this .getSystemService(Context.TELEPHONY_SERVICE); //////////////////////////// // if we have a fast connection (wifi or 3g), then we'll get a high quality YouTube video if ((lWifiManager.isWifiEnabled() && lWifiManager.getConnectionInfo() != null && lWifiManager.getConnectionInfo().getIpAddress() != 0) || (lTelephonyManager.getNetworkType() == TelephonyManager.NETWORK_TYPE_UMTS && lTelephonyManager.getDataState() == TelephonyManager.DATA_CONNECTED)) { lYouTubeFmtQuality = "18"; } /////////////////////////////////// // if the intent is to show a playlist, get the latest video id from the playlist, otherwise the video // id was explicitly declared. if (pParams[0] instanceof PlaylistId) { publishProgress(new ProgressUpdateInfo(mMsgPlaylist)); lYouTubeVideoId = queryLatestPlaylistVideo((PlaylistId) pParams[0]); } else if (pParams[0] instanceof VideoId) { lYouTubeVideoId = pParams[0].getId(); } publishProgress(new ProgressUpdateInfo(mMsgToken)); if (isCancelled()) return null; //////////////////////////////////// // calculate the actual URL of the video, encoded with proper YouTube token lUriStr = calculateYouTubeUrl(lYouTubeFmtQuality, lYouTubeVideoId); if (isCancelled()) return null; if (lYouTubeFmtQuality.equals("17")) { publishProgress(new ProgressUpdateInfo(mMsgLowBand)); } else { publishProgress(new ProgressUpdateInfo(mMsgHiBand)); } } catch (Exception e) { Log.e(this.getClass().getSimpleName(), "Error occurred while retrieving information from YouTube.", e); } if (lUriStr != null) { return Uri.parse(lUriStr); } else { return null; } } /** * Calculate the YouTube URL to load the video. Includes retrieving a token that YouTube * requires to play the video. * * @param pYouTubeFmtQuality quality of the video. 17=low, 18=high * @param pYouTubeVideoId the id of the video * @return the url string that will retrieve the video * @throws IOException * @throws ClientProtocolException * @throws UnsupportedEncodingException */ private String calculateYouTubeUrl(String pYouTubeFmtQuality, String pYouTubeVideoId) throws IOException, ClientProtocolException, UnsupportedEncodingException { String lUriStr; HttpClient lClient = new DefaultHttpClient(); HttpGet lGetMethod = new HttpGet(YOUTUBE_VIDEO_INFORMATION_URL + pYouTubeVideoId); HttpResponse lResp = null; lResp = lClient.execute(lGetMethod); ByteArrayOutputStream lBOS = new ByteArrayOutputStream(); String lInfoStr = null; lResp.getEntity().writeTo(lBOS); lInfoStr = new String(lBOS.toString("UTF-8")); String[] lArgs = lInfoStr.split("&"); Map<String, String> lArgMap = new HashMap<String, String>(); for (int i = 0; i < lArgs.length; i++) { String[] lArgValStrArr = lArgs[i].split("="); if (lArgValStrArr != null) { if (lArgValStrArr.length >= 2) { lArgMap.put(lArgValStrArr[0], URLDecoder.decode(lArgValStrArr[1])); } } } String lTokenStr = URLDecoder.decode(lArgMap.get("token")); lUriStr = "http://www.youtube.com/get_video?video_id=" + pYouTubeVideoId + "&t=" + URLEncoder.encode(lTokenStr) + "&fmt=" + pYouTubeFmtQuality; return lUriStr; } /** * Retrieve the latest video in the specified playlist. * @param pPlaylistId the id of the playlist for which to retrieve the latest video id * @return the video id of the latest video, null if something goes wrong * @throws IOException * @throws ClientProtocolException * @throws FactoryConfigurationError */ private String queryLatestPlaylistVideo(PlaylistId pPlaylistId) throws IOException, ClientProtocolException, FactoryConfigurationError { String lVideoId = null; HttpClient lClient = new DefaultHttpClient(); HttpGet lGetMethod = new HttpGet( YOUTUBE_PLAYLIST_ATOM_FEED_URL + pPlaylistId.getId() + "?v=2&max-results=50&alt=json"); HttpResponse lResp = null; if (isCancelled()) return null; lResp = lClient.execute(lGetMethod); ByteArrayOutputStream lBOS = new ByteArrayOutputStream(); String lInfoStr = null; JSONObject lYouTubeResponse = null; try { lResp.getEntity().writeTo(lBOS); lInfoStr = lBOS.toString("UTF-8"); lYouTubeResponse = new JSONObject(lInfoStr); JSONArray lEntryArr = lYouTubeResponse.getJSONObject("feed").getJSONArray("entry"); JSONArray lLinkArr = lEntryArr.getJSONObject(lEntryArr.length() - 1).getJSONArray("link"); for (int i = 0; i < lLinkArr.length(); i++) { JSONObject lLinkObj = lLinkArr.getJSONObject(i); ; String lRelVal = lLinkObj.optString("rel", null); if (lRelVal != null && lRelVal.equals("alternate")) { String lUriStr = lLinkObj.optString("href", null); Uri lVideoUri = Uri.parse(lUriStr); lVideoId = lVideoUri.getQueryParameter("v"); break; } } } catch (IllegalStateException e) { Log.i(getClass().getSimpleName(), "Error retrieving content from YouTube", e); } catch (IOException e) { Log.i(getClass().getSimpleName(), "Error retrieving content from YouTube", e); } catch (JSONException e) { Log.i(getClass().getSimpleName(), "Error retrieving content from YouTube", e); } return lVideoId; } @Override protected void onPostExecute(Uri pResult) { super.onPostExecute(pResult); try { if (isCancelled()) return; if (pResult == null) { throw new RuntimeException("Invalid NULL Url."); } mVideoView.setVideoURI(pResult); if (isCancelled()) return; // TODO: add listeners for finish of video mVideoView.setOnCompletionListener(new OnCompletionListener() { @Override public void onCompletion(MediaPlayer pMp) { if (isCancelled()) return; IntroVideoActivity.this.finish(); } }); if (isCancelled()) return; final MediaController lMediaController = new MediaController(IntroVideoActivity.this); mVideoView.setMediaController(lMediaController); lMediaController.show(0); mVideoView.setKeepScreenOn(true); mVideoView.setOnPreparedListener(new MediaPlayer.OnPreparedListener() { @Override public void onPrepared(MediaPlayer pMp) { if (isCancelled()) return; IntroVideoActivity.this.mProgressBar.setVisibility(View.GONE); IntroVideoActivity.this.mProgressMessage.setVisibility(View.GONE); } }); if (isCancelled()) return; mVideoView.requestFocus(); mVideoView.start(); } catch (Exception e) { Log.e(this.getClass().getSimpleName(), "Error playing video!", e); if (!mShowedError) { showErrorAlert(); } } } private void showErrorAlert() { Builder lBuilder = new AlertDialog.Builder(IntroVideoActivity.this); lBuilder.setTitle(mMsgErrorTitle); lBuilder.setCancelable(false); lBuilder.setMessage(mMsgError); lBuilder.setPositiveButton(getResources().getString(R.string.ok), new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface pDialog, int pWhich) { IntroVideoActivity.this.finish(); } }); AlertDialog lDialog = lBuilder.create(); lDialog.show(); } @Override protected void onProgressUpdate(ProgressUpdateInfo... pValues) { super.onProgressUpdate(pValues); IntroVideoActivity.this.updateProgress(pValues[0].mMsg); } } public abstract class YouTubeId { protected String mId; public YouTubeId(String pId) { mId = pId; } public String getId() { return mId; } } public class VideoId extends YouTubeId { public VideoId(String pId) { super(pId); } } public class PlaylistId extends YouTubeId { public PlaylistId(String pId) { super(pId); } } }