最近的週末，一時無聊也用起了手機裏的愛奇藝App追劇，每次都是把視頻先緩存到本地習慣有的快進播放。突然好奇，想試試App的離線下載功能怎麼實現。想到以前在github上看到的daimajia做的一個專注動畫視頻的App（https://github.com/daimajia/AnimeTaste）的實現，想借鑑借鑑思路。本文的實習是在daimajia的下載模塊的基礎上實現愛奇藝的視頻下載效果,增加對下載的暫停、斷點下載功能和對下載使用功能的優化等。下面來說說視頻緩存的實現：
先看看愛奇藝的下載效果（沒有找到合適的gif製作軟件，下面截圖貼出圖片）：
以下是我的實現下載模塊效果圖：
看完效果圖，以下來談談關於下載模塊的實現要點：
1. 對現在任務的監聽，通過觀察者模式實現對下載頁和通知欄的同時監聽；
2. 手機應用的內存大小有限，通過線程池來限制下載的線程個數（節約系統資源）；
3. Http協議和文件的讀出位置重定向，保證了對斷點下載的支持；
下面我們來分析觀察者模式的實現，首選我們通過類圖說明：
我們的實現裏有三個觀察者，MissionListenerForAdapter觀察者對應下載詳情頁（DownloadActivity），MissionListenerForNotification觀察者對應通知欄，MissionSaver觀察者對應數據庫下載記錄。我們看下載任務Mission的代碼如下：
public class Mission implements Runnable {
public static int ID = 0;
private final int MissionID;
private String Uri;
private String SaveDir;
private String SaveName;
protected long mDownloaded;
protected long mFileSize;
private String mOriginFilename;
private String mExtension;
private String mShowName;
private long mPreviousNotifyTime;
private int mProgressNotifyInterval = 1;
private TimeUnit mTimeUnit = TimeUnit.SECONDS;
private long mLastSecondDownloadTime = 0;
private long mLastSecondDownload = 0;
private int mPreviousPercentage = -1;
protected long mStartTime;
protected long mEndTime;
public enum RESULT_STATUS {
STILL_DOWNLOADING, SUCCESS, FAILED
}
private RESULT_STATUS mResultStatus = RESULT_STATUS.STILL_DOWNLOADING;
private boolean isContinuing = false;
private boolean isDone = false;
private boolean isPaused = false;
private boolean isSuccess = false;
private boolean isCanceled = false;
private final Object o = new Object();
private List<MissionListener<Mission>> missionListeners;
private HashMap<String, Object> extras;
public Mission(String uri, String saveDir,long downloadedNum,long fileSize) {
MissionID = ID++;
Uri = uri;
SaveDir = saveDir;
this.mFileSize = fileSize;
mStartTime = System.currentTimeMillis();
mPreviousNotifyTime = mStartTime;
setOriginFileName(FileUtil.getFileName(uri));
setExtension(FileUtil.getFileExtension(uri));
SaveName = getOriginFileName() + "." + getExtension();
missionListeners = new ArrayList<MissionListener<Mission>>();
extras = new HashMap<String, Object>();
mDownloaded = downloadedNum;
}
public Mission(String uri, String saveDir, String saveFileName) {
this(uri, saveDir,0,0);
SaveName = getSafeFilename(saveFileName);
}
public Mission(String uri,String saveDir,String saveFileName,long downloadedNum,long fileSize){
this(uri,saveDir,downloadedNum,fileSize);
SaveName = getSafeFilename(saveFileName);
}
public Mission(String uri, String saveDir, String saveFilename,
String showName) {
this(uri, saveDir, saveFilename);
this.mShowName = showName;
}
//註冊回調接口
public void addMissionListener(MissionListener<Mission> listener) {
missionListeners.add(listener);
}
public void removeMissionListener(MissionListener<Mission> listener) {
missionListeners.remove(listener);
}
public void setProgressNotificateInterval(TimeUnit unit, int interval) {
mTimeUnit = unit;
mProgressNotifyInterval = interval;
}
@Override
public void run() {
notifyStart();
InputStream in = null;
RandomAccessFile fos = null;
HttpURLConnection httpURLConnection = null;
try {
httpURLConnection = (HttpURLConnection) new URL(Uri)
.openConnection();
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setRequestProperty("Range", "bytes=" + mDownloaded+"-");
//當文件沒有開始下載，記錄文件大小
if(mFileSize <= 0)
setFileSize(httpURLConnection.getContentLength());
in = httpURLConnection.getInputStream();
File accessFile = getSafeFile(getSaveDir(), getSaveName());
fos = new RandomAccessFile(accessFile, "rw");
fos.seek(mDownloaded);
byte data[] = new byte[1024];
int count;
notifyMetaDataReady();
while (!isCanceled() && (count = in.read(data, 0, 1024)) != -1) {
fos.write(data, 0, count);
mDownloaded += count;
notifyPercentageChange();
notifySpeedChange();
checkPaused();
}
if (isCanceled == false) {
notifyPercentageChange();
notifySuccess();
} else {
notifyCancel();
}
} catch (Exception e) {
notifyError(e);
} finally {
try {
if (in != null)
in.close();
if (fos != null)
fos.close();
} catch (IOException e) {
notifyError(e);
}
notifyFinish();
}
}
protected FileOutputStream getSafeOutputStream(String directory,
String filename) {
String filepath;
if (directory.lastIndexOf(File.separator) != directory.length() - 1) {
directory += File.separator;
}
File dir = new File(directory);
dir.mkdirs();
filepath = directory + filename;
File file = new File(filepath);
try {
file.createNewFile();
return new FileOutputStream(file.getCanonicalFile().toString());
} catch (Exception e) {
e.printStackTrace();
throw new Error("Can not get an valid output stream");
}
}
protected File getSafeFile(String directory, String filename) {
String filepath;
if (directory.lastIndexOf(File.separator) != directory.length() - 1) {
directory += File.separator;
}
File dir = new File(directory);
dir.mkdirs();
filepath = directory + filename;
File file = new File(filepath);
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
throw new Error("Can not Create A New File");
}
return file;
}
protected String getSafeFilename(String name) {
return name.replaceAll("[\\\\|\\/|\\:|\\*|\\?|\\\"|\\<|\\>|\\|]", "-");
}
protected void checkPaused() {
synchronized (o) {
while (isPaused) {
try {
notifyPause();
o.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public void pause() {
if (isPaused() || isDone())
return;
isPaused = true;
}
public void resume() {
if (!isPaused() || isDone()) {
return;
}
synchronized (o) {
isPaused = false;
o.notifyAll();
}
notifyResume();
}
public void cancel() {
isCanceled = true;
if (isPaused()) {
resume();
}
}
//通知進度改變
protected final void notifyPercentageChange() {
if (missionListeners != null && missionListeners.size() != 0) {
int currentPercentage = getPercentage();
if (mPreviousPercentage != currentPercentage) {
for (MissionListener<Mission> l : missionListeners) {
l.onPercentageChange(this);
}
mPreviousPercentage = currentPercentage;
}
}
}
//通知下載速度更新
protected final void notifySpeedChange() {
if (missionListeners != null && missionListeners.size() != 0) {
long currentNotifyTime = System.currentTimeMillis();
long notifyDuration = currentNotifyTime - mPreviousNotifyTime;
long spend = mTimeUnit.convert(notifyDuration,
TimeUnit.MILLISECONDS);
if (spend >= mProgressNotifyInterval) {
mPreviousNotifyTime = currentNotifyTime;
for (MissionListener<Mission> l : missionListeners) {
l.onSpeedChange(this);
}
}
long speedRecordDuration = currentNotifyTime
- mLastSecondDownloadTime;
if (TimeUnit.MILLISECONDS.toSeconds(speedRecordDuration) >= 1) {
mLastSecondDownloadTime = currentNotifyTime;
mLastSecondDownload = getDownloaded();
}
}
}
protected final void notifyAdd() {
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onAddMission(this);
}
}
}
protected final void notifyStart() {
isContinuing = true;
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onStart(this);
}
}
}
protected final void notifyPause() {
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onPause(this);
}
}
}
protected final void notifyResume() {
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onResume(this);
}
}
}
protected final void notifyCancel() {
isContinuing = false; //取消被通知到的時候，isContinuing爲fasle
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onCancel(this);
}
}
}
protected final void notifyMetaDataReady() {
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onMetaDataPrepared(this);
}
}
}
protected final void notifySuccess() {
mResultStatus = RESULT_STATUS.SUCCESS;
isDone = true;
isSuccess = true;
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onSuccess(this);
}
}
}
protected final void notifyError(Exception e) {
mResultStatus = RESULT_STATUS.FAILED;
isDone = true;
isSuccess = false;
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onError(this, e);
}
}
}
protected final void notifyFinish() {
isContinuing = false;
mEndTime = System.currentTimeMillis();
if (missionListeners != null && missionListeners.size() != 0) {
for (MissionListener<Mission> l : missionListeners) {
l.onFinish(this);
}
}
}
public String getUri() {
return Uri;
}
public String getSaveDir() {
return SaveDir;
}
public String getSaveName() {
return SaveName;
}
public long getDownloaded() {
return mDownloaded;
}
public long getFilesize() {
return mFileSize;
}
protected void setFileSize(int size) {
mFileSize = size;
}
public long getTimeSpend() {
if (mEndTime != 0) {
return mEndTime - mStartTime;
} else {
return System.currentTimeMillis() - mStartTime;
}
}
public String getAverageReadableSpeed() {
return FileUtil.getReadableSpeed(getDownloaded(), getTimeSpend(),
TimeUnit.MILLISECONDS);
}
public String getAccurateReadableSpeed() {
return FileUtil.getReadableSize(getDownloaded() - mLastSecondDownload,
false) + "/s";
}
public int getPercentage() {
if (mFileSize == 0) {
return 0;
} else {
return (int) (mDownloaded * 100.0f / mFileSize);
}
}
public String getAccurateReadableSize() {
return FileUtil.getReadableSize(getDownloaded());
}
public String getReadableSize() {
return FileUtil.getReadableSize(getFilesize());
}
public String getReadablePercentage() {
StringBuilder builder = new StringBuilder();
builder.append(getPercentage());
builder.append("%");
return builder.toString();
}
public void setOriginFileName(String name) {
mOriginFilename = name;
}
public String getOriginFileName() {
return mOriginFilename;
}
public void setExtension(String extension) {
mExtension = extension;
}
public String getExtension() {
return mExtension;
}
public String getShowName() {
if (mShowName == null || mShowName.length() == 0) {
return getSaveName();
} else {
return mShowName;
}
}
public int getMissionID() {
return MissionID;
}
public boolean isDownloading() {
return isContinuing;
}
public boolean isDone() {
return isDone;
}
public boolean isSuccess() {
return isSuccess;
}
public boolean isPaused() {
return isPaused;
}
public void setCanceled(boolean isCanceled){
this.isCanceled = isCanceled;
}
public boolean isCanceled() {
return isCanceled;
}
public RESULT_STATUS getResultStatus() {
return mResultStatus;
}
public void addExtraInformation(String key, Object value) {
extras.put(key, value);
}
public void removeExtraInformation(String key) {
extras.remove(key);
}
public Object getExtraInformation(String key) {
return extras.get(key);
}
public interface MissionListener<T extends Mission> {
public void onAddMission(T mission);
public void onStart(T mission);
public void onMetaDataPrepared(T mission);
public void onPercentageChange(T mission);
public void onSpeedChange(T mission);
public void onError(T mission, Exception e);
public void onSuccess(T mission);
public void onFinish(T mission);
public void onPause(T mission);
public void onResume(T mission);
public void onCancel(T mission);
}
}
通過代碼我們知道，Mission實現的Runnable接口，下載任務運行時候，開始通知註冊下載任務的觀察者們。
我們選擇MissionSaver觀察者的實習來分析：
public class MissionSaver implements Mission.MissionListener<Mission>{
private DownloadDetail getDownloadDetail(Mission mission){
Object obj = mission.getExtraInformation(mission.getUri());
DownloadDetail detail = null;
if(obj!=null)
detail = (DownloadDetail)obj;
return detail;
}
private void save(Mission mission){
DownloadDetail detail = getDownloadDetail(mission);
if(detail!=null){
DownloadRecord.save(detail,mission);
}
}
private void delete(Mission mission){
DownloadDetail detail = getDownloadDetail(mission);
if(detail!=null){
DownloadRecord.deleteOne(detail);
}
}
@Override
public void onStart(Mission mission) {
save(mission);
}
@Override
public void onMetaDataPrepared(Mission mission) {
}
@Override
public void onPercentageChange(Mission mission) {
}
@Override
public void onSpeedChange(Mission mission) {
}
@Override
public void onError(Mission mission, Exception e) {
save(mission);
}
@Override
public void onSuccess(Mission mission) {
save(mission);
}
@Override
public void onFinish(Mission mission) {
}
@Override
public void onPause(Mission mission) {
}
@Override
public void onResume(Mission mission) {
}
/*
* 此處的onCancel，目的是暫停下載任務退出當前線程，並不是取消下載，此時下載進度會被保存起來
*/
@Override
public void onCancel(Mission mission) {
save(mission);
}
@Override
public void onAddMission(Mission mission) {
}
}
public class DownloadManager {
private final String TAG = "DownLoadManager";
private static int MAX_MISSION_COUNT = 5; //設置線程池最大線程個數
private static DownloadManager Instance;
protected ThreadPoolExecutor mExecutorService;
protected HashMap<Integer,Mission> mMissionBook;
public static synchronized DownloadManager getInstance(){
if(Instance == null || Instance.mExecutorService.isShutdown()){
Instance = new DownloadManager();
}
return Instance;
}
private DownloadManager(){
mMissionBook = new HashMap<Integer, Mission>();
mExecutorService = new ThreadPoolExecutor(MAX_MISSION_COUNT,MAX_MISSION_COUNT,15,TimeUnit.SECONDS,
new LinkedBlockingDeque<Runnable>()); //實例化線程池
}
public boolean containMission(int missionID){
return mMissionBook.containsKey(missionID);
}
public void addMission(Mission mission){
mMissionBook.put(mission.getMissionID(), mission);
mission.notifyAdd();
}
public void executeMission(Mission mission){
if(mission.isCanceled())
mission.setCanceled(false);
mExecutorService.execute(mission);
}
public void pauseMission(int missionID){
if(mMissionBook.containsKey(missionID)){
mMissionBook.get(missionID).pause();
}
}
public void resumeMission(int missionID){
if(mMissionBook.containsKey(missionID)){
mMissionBook.get(missionID).resume();
}
}
public void cancelMission(int missionID){
if(mMissionBook.containsKey(missionID)){
mMissionBook.get(missionID).cancel();
}
}
/*
* 停止所有任務
*/
public void surrenderMissions(){
for(Map.Entry<Integer, Mission> mission : mMissionBook.entrySet()){
mission.getValue().cancel();
mMissionBook.get(mission).cancel();
}
}
public static void setMaxMissionCount(int count){
if(Instance == null && count > 0)
MAX_MISSION_COUNT = count;
else
throw new IllegalStateException("Can not change max mission count after getInstance been called");
}
}public class DownloadHelper {
private Context mContext;
private DownloadServiceBinder mDownloadServiceBinder;
private Boolean isConnected = false;
private Object o = new Object();
public DownloadHelper(Context context) {
mContext = context;
}
private ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
mDownloadServiceBinder = (DownloadService.DownloadServiceBinder) service;
synchronized (o) {
isConnected = true;
o.notify();//當DownloadService連接上，通知下載線程繼續
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
isConnected = false;
}
};
public void startDownload(final DownloadDetail detail) {
final DownloadRecord record = new Select().from(DownloadRecord.class)
.where("DownloadId = ? ", detail.VideoId).executeSingle();
if (record != null) {
if (record.Status == DownloadRecord.STATUS.SUCCESS) {
new AlertDialog.Builder(mContext)
.setTitle(R.string.tip)
.setMessage(R.string.redownload_tips)
.setPositiveButton(R.string.yes,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
File file = new File(record.SaveDir
+ record.SaveFileName);
if (file.exists() && file.isFile()) {
file.delete();
}
safeDownload(detail);
}
})
.setNegativeButton(R.string.no,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
dialog.dismiss();
}
}).create().show();
} else if (record.Status == DownloadRecord.STATUS.PAUSE) { // 繼續上次下載
safeDownload(record);
} else {
safeDownload(detail);
}
} else { // 新建下載
safeDownload(detail);
}
}
private void safeDownload(final DownloadRecord record) {
if (NetworkUtils.isNetworkAvailable(mContext)) {
if (NetworkUtils.isWifiConnected(mContext)) {
download(record);
} else {
new AlertDialog.Builder(mContext)
.setTitle(R.string.tip)
.setMessage(R.string.no_wifi_download)
.setPositiveButton(R.string.yes,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
download(record);
}
}).setNegativeButton(R.string.no, null)
.create().show();
}
} else {
Toast.makeText(mContext, R.string.no_network, Toast.LENGTH_LONG)
.show();
}
}
private void safeDownload(final DownloadDetail detail) {
if (NetworkUtils.isNetworkAvailable(mContext)) {
if (NetworkUtils.isWifiConnected(mContext)) {
download(detail);
} else {
new AlertDialog.Builder(mContext)
.setTitle(R.string.tip)
.setMessage(R.string.no_wifi_download)
.setPositiveButton(R.string.yes,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
download(detail);
}
}).setNegativeButton(R.string.no, null)
.create().show();
}
} else {
Toast.makeText(mContext, R.string.no_network, Toast.LENGTH_LONG)
.show();
}
}
/*
* 下載任務線程重新開始執行
*/
public void download(final Mission mission) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
mDownloadServiceBinder.continueDownload(mission);
}
}.start();
}
public void download(final DownloadRecord record) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
File file = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
Mission mission = new Mission(record.DownloadUrl,
file.getAbsolutePath() + "/Download/", record.FileName
+ "." + record.Extension, record.DownloadedSize,record.FileSize);
mission.addExtraInformation(mission.getUri(),
DownloadRecord.getDownloadDetail(record));
mDownloadServiceBinder.startDownload(mission);
}
}.start();
}
/*
* 將未完成的下載記錄添加到下載任務列表，並讓下載任務開始執行
*/
public void AddDownload(final DownloadRecord record) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
File file = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
Mission mission = new Mission(record.DownloadUrl,
file.getAbsolutePath() + "/Download/", record.FileName
+ "." + record.Extension, record.DownloadedSize,record.FileSize);
mission.addExtraInformation(mission.getUri(),
DownloadRecord.getDownloadDetail(record));
mDownloadServiceBinder.startDownload(mission);
}
}.start();
}
/*
* 將未完成的下載記錄添加到下載任務列表
*/
public void addDownloadMission(final List<DownloadRecord> records) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
File file = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
file.mkdirs();
for (DownloadRecord record : records) {
Mission mission = new Mission(record.DownloadUrl,
file.getAbsolutePath() + "/Download/",
record.FileName + "." + record.Extension,
record.DownloadedSize,record.FileSize);
mission.addExtraInformation(mission.getUri(),
DownloadRecord.getDownloadDetail(record));
mDownloadServiceBinder.AddDownload(mission);
}
}
}.start();
}
/*
* 將未完成的下載記錄添加到下載任務列表
*/
public void addDownloadMission(final DownloadRecord record) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
File file = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
file.mkdirs();
Mission mission = new Mission(record.DownloadUrl,
file.getAbsolutePath() + "/Download/", record.FileName
+ "." + record.Extension, record.DownloadedSize,record.FileSize);
mission.addExtraInformation(mission.getUri(),
DownloadRecord.getDownloadDetail(record));
mDownloadServiceBinder.AddDownload(mission);
}
}.start();
}
private void download(final DownloadDetail detail) {
new Thread() {
@Override
public void run() {
super.run();
if (!isDownloadServiceRunning()) {
mContext.startService(new Intent(mContext,
DownloadService.class));
}
if (mDownloadServiceBinder == null || isConnected == false) {
mContext.bindService(new Intent(mContext,
DownloadService.class), connection,
Context.BIND_AUTO_CREATE);
synchronized (o) {
while (!isConnected) {
try {
o.wait();//當DownloadService還未連接，下載線程被通知等待
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
File file = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
file.mkdirs();
Mission mission = new Mission(detail.DownloadUrl,
file.getAbsolutePath() + "/Download/", detail.FileName
+ "." + detail.Extension);
mission.addExtraInformation(mission.getUri(), detail);
mDownloadServiceBinder.startDownload(mission);
}
}.start();
}
/*
* 判斷下載服務是否在運行
*/
private boolean isDownloadServiceRunning() {
ActivityManager manager = (ActivityManager) mContext
.getSystemService(Context.ACTIVITY_SERVICE);
for (ActivityManager.RunningServiceInfo service : manager
.getRunningServices(Integer.MAX_VALUE)) {
if (DownloadService.class.getName().equals(
service.service.getClassName())) {
return true;
}
}
return false;
}
public void unbindDownloadService() {
if (isDownloadServiceRunning() && isConnected && connection != null) {
mContext.unbindService(connection);
}
}
}轉載請註明出處：http://blog.csdn.net/johnnyz1234/article/details/44280479