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我正在关注 a tutorial to download files using the Retrofit library .
我的应用程序的用户界面有几个不同的按钮,它们使用上述方法下载不同的文件。问题是当有人在按下第一个按钮后按下另一个按钮时,它会排队并在第一个按钮完成后开始。我希望它立即同时开始。
这是 DownloadService
的代码:
public class DownloadService extends IntentService {
public DownloadService() {
super("Download Service");
}
private int totalFileSize;
private NotificationCompat.Builder notificationBuilder;
private NotificationManager notificationManager;
@Override
protected void onHandleIntent(Intent intent) {
MyApp x = (MyApp)getApplicationContext();
notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationBuilder = new NotificationCompat.Builder(this)
.setSmallIcon(R.drawable.ic_file_download_deep_orange_a400_18dp)
.setContentTitle("Downloading")
.setContentText("Please wait...")
.setAutoCancel(true);
notificationManager.notify(x.ID, notificationBuilder.build());
Log.i("Paras", "onHandleIntent: " + x.filename + x.url);
initDownload(x.filename,x.url,x.ID);
}
private void initDownload(String filename, String url, int id) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://dl.dropboxusercontent.com/")
.build();
RequestInterface.RetrofitInterface retrofitInterface = retrofit.create(RequestInterface.RetrofitInterface.class);
Call<ResponseBody> request = retrofitInterface.downloadFile(url);
try {
downloadFile(request.execute().body(),filename,id);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
private void downloadFile(ResponseBody body, String filename,int id) throws IOException {
int count;
byte data[] = new byte[1024 * 4];
long fileSize = body.contentLength();
InputStream bis = new BufferedInputStream(body.byteStream(), 1024 * 8);
File outputFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), filename);
OutputStream output = new FileOutputStream(outputFile);
long total = 0;
long startTime = System.currentTimeMillis();
int timeCount = 1;
while ((count = bis.read(data)) != -1) {
total += count;
totalFileSize = (int) (fileSize / (Math.pow(1, 2))) / 1000;
double current = Math.round(total / (Math.pow(1, 2))) / 1000;
int progress = (int) ((total * 100) / fileSize);
long currentTime = System.currentTimeMillis() - startTime;
Download download = new Download();
download.setTotalFileSize(totalFileSize);
if (currentTime > 1000 * timeCount) {
download.setCurrentFileSize((int) current);
download.setProgress(progress);
sendNotification(download,id);
timeCount++;
}
output.write(data, 0, count);
}
onDownloadComplete(filename,id);
output.flush();
output.close();
bis.close();
}
private void sendNotification(Download download, int id) {
sendIntent(download);
notificationBuilder.setProgress(100, download.getProgress(), false);
notificationBuilder.setContentText("Downloading file " + download.getCurrentFileSize() + "/" + totalFileSize + " KB");
notificationManager.notify(id, notificationBuilder.build());
}
private void sendIntent(Download download) {
Intent intent = new Intent(subject.MESSAGE_PROGRESS);
intent.putExtra("download", download);
LocalBroadcastManager.getInstance(DownloadService.this).sendBroadcast(intent);
}
private void onDownloadComplete(String filename,int id) {
try {
Download download = new Download();
download.setProgress(100);
sendIntent(download);
notificationManager.cancel(id);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText("Tap to open");
notificationManager.notify(id, notificationBuilder.build());
String path1 = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + filename;
File file = new File(path1);
Uri uri_path = Uri.fromFile(file);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension
(MimeTypeMap.getFileExtensionFromUrl(path1));
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setType(mimeType);
intent.setDataAndType(uri_path, mimeType);
PendingIntent pIntent = PendingIntent.getActivity(this, (int) System.currentTimeMillis(), intent, 0);
String string = filename;
notificationBuilder
.setContentIntent(pIntent)
.setAutoCancel(true)
.setContentTitle(string + " Downloaded");
Log.i("Paras", "onDownloadComplete: " + string);
notificationManager.notify(id, notificationBuilder.build());
} catch (Exception ex) {
}
}
@Override
public void onTaskRemoved(Intent rootIntent) {
}
}
然后我阅读了有关 IntentService
和 Service
类的内容。 Service
类是否允许同时下载?我试过这样的事情:
public class DownloadService extends Service {
public DownloadService() {
super();
}
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
MyApp x = (MyApp)getApplicationContext();
notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationBuilder = new NotificationCompat.Builder(getBaseContext())
.setSmallIcon(R.drawable.ic_file_download_deep_orange_a400_18dp)
.setContentTitle("Downloading")
.setContentText("Please wait...")
.setAutoCancel(true);
notificationManager.notify(x.ID, notificationBuilder.build());
Log.i("Paras", "onHandleIntent: " + x.filename + x.url);
initDownload(x.filename,x.url,x.ID);
}
}
@Override
public void onCreate() {
// Start up the thread running the service. Note that we create a
// separate thread because the service normally runs in the process's
// main thread, which we don't want to block. We also make it
// background priority so CPU-intensive work will not disrupt our UI.
HandlerThread thread = new HandlerThread("ServiceStartArguments", Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the HandlerThread's Looper and use it for our Handler
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// For each start request, send a message to start a job and deliver the
// start ID so we know which request we're stopping when we finish the job
MyApp x = (MyApp)getApplicationContext();
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;
msg.obj= intent.putExtra("ID",x.ID);
mServiceHandler.sendMessage(msg);
// If we get killed, after returning from here, restart
return START_STICKY;
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
private int totalFileSize;
private NotificationCompat.Builder notificationBuilder;
private NotificationManager notificationManager;
private void initDownload(String filename, String url, int id) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://dl.dropboxusercontent.com/")
.build();
RequestInterface.RetrofitInterface retrofitInterface = retrofit.create(RequestInterface.RetrofitInterface.class);
Call<ResponseBody> request = retrofitInterface.downloadFile(url);
try {
downloadFile(request.execute().body(),filename,id);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
private void downloadFile(ResponseBody body, String filename,int id) throws IOException {
int count;
byte data[] = new byte[1024 * 4];
long fileSize = body.contentLength();
InputStream bis = new BufferedInputStream(body.byteStream(), 1024 * 8);
File outputFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), filename);
OutputStream output = new FileOutputStream(outputFile);
long total = 0;
long startTime = System.currentTimeMillis();
int timeCount = 1;
while ((count = bis.read(data)) != -1) {
total += count;
totalFileSize = (int) (fileSize / (Math.pow(1, 2))) / 1000;
double current = Math.round(total / (Math.pow(1, 2))) / 1000;
int progress = (int) ((total * 100) / fileSize);
long currentTime = System.currentTimeMillis() - startTime;
Download download = new Download();
download.setTotalFileSize(totalFileSize);
if (currentTime > 1000 * timeCount) {
download.setCurrentFileSize((int) current);
download.setProgress(progress);
sendNotification(download,id);
timeCount++;
}
output.write(data, 0, count);
}
onDownloadComplete(filename,id);
output.flush();
output.close();
bis.close();
}
private void sendNotification(Download download, int id) {
sendIntent(download);
notificationBuilder.setProgress(100, download.getProgress(), false);
notificationBuilder.setContentText("Downloading file " + download.getCurrentFileSize() + "/" + totalFileSize + " KB");
notificationManager.notify(id, notificationBuilder.build());
}
private void sendIntent(Download download) {
Intent intent = new Intent(subject.MESSAGE_PROGRESS);
intent.putExtra("download", download);
LocalBroadcastManager.getInstance(DownloadService.this).sendBroadcast(intent);
}
private void onDownloadComplete(String filename,int id) {
try {
Download download = new Download();
download.setProgress(100);
sendIntent(download);
notificationManager.cancel(id);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText("Tap to open");
notificationManager.notify(id, notificationBuilder.build());
String path1 = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + filename;
File file = new File(path1);
Uri uri_path = Uri.fromFile(file);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension
(MimeTypeMap.getFileExtensionFromUrl(path1));
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setType(mimeType);
intent.setDataAndType(uri_path, mimeType);
PendingIntent pIntent = PendingIntent.getActivity(this, (int) System.currentTimeMillis(), intent, 0);
String string = filename;
notificationBuilder
.setContentIntent(pIntent)
.setAutoCancel(true)
.setContentTitle(string + " Downloaded");
Log.i("Paras", "onDownloadComplete: " + string);
notificationManager.notify(id, notificationBuilder.build());
} catch (Exception ex) {
}
}
@Override
public void onTaskRemoved(Intent rootIntent) {
}
}
但是没有用。任何线索我应该做什么?如果需要,我准备好提供更多详细信息。
编辑 1: DownloadService 在函数“startDownload”上运行,该函数由各种按钮执行。正如您在第二个代码中看到的,类扩展服务。有一个线程处理所有这些按钮点击。如果您查看评论,建议我对所有这些点击使用服务和不同的线程。现在我如何以编程方式创建这么多线程。有将近 40 个按钮使用了 DownloadService。
最佳答案
感谢@Lxu,我让它工作了。所以IntentService
的意思是一次做一个任务,不能同时做多个任务。我们应该改用 Service
。它允许同时执行多个任务。我们可以在 Service
中创建多个线程,它们将同时执行。通过将 onCreate()
的所有代码放到 onStartCommand()
中,我的问题得到了解决。当服务第一次被调用时,onCreate()
被调用,之后无论调用多少次都不再调用。在每次服务调用时,都会执行 onStartCommand()
,每次都会创建新线程。就是这样。
完整代码如下:
public class DownloadService extends Service {
public DownloadService() {
super();
}
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
int id1;
int id2;
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
MyApp x = (MyApp)getApplicationContext();
notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationBuilder = new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.drawable.ic_file_download_deep_orange_a400_18dp)
.setContentTitle("Downloading")
.setContentText("Please wait...")
.setAutoCancel(true);
notificationManager.notify(x.ID, notificationBuilder.build());
Log.i("Paras", "onHandleIntent: " + x.filename + x.url + " " + x.ID);
initDownload(x.filename,x.url,x.ID);
}
}
@Override
public void onCreate() {
// Get the HandlerThread's Looper and use it for our Handler
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// For each start request, send a message to start a job and deliver the
// start ID so we know which request we're stopping when we finish the job
HandlerThread thread = new HandlerThread("ServiceStartArguments", Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
MyApp x = (MyApp)getApplicationContext();
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;
mServiceHandler.sendMessage(msg);
// If we get killed, after returning from here, restart
return START_STICKY;
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
private int totalFileSize;
private NotificationCompat.Builder notificationBuilder;
private NotificationManager notificationManager;
private void initDownload(String filename, String url, int id) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://dl.dropboxusercontent.com/")
.build();
RequestInterface.RetrofitInterface retrofitInterface = retrofit.create(RequestInterface.RetrofitInterface.class);
Call<ResponseBody> request = retrofitInterface.downloadFile(url);
try {
downloadFile(request.execute().body(),filename,id);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
private void downloadFile(ResponseBody body, String filename,int id) throws IOException {
int count;
byte data[] = new byte[1024 * 4];
long fileSize = body.contentLength();
InputStream bis = new BufferedInputStream(body.byteStream(), 1024 * 8);
File outputFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), filename);
OutputStream output = new FileOutputStream(outputFile);
long total = 0;
long startTime = System.currentTimeMillis();
int timeCount = 1;
while ((count = bis.read(data)) != -1) {
total += count;
totalFileSize = (int) (fileSize / (Math.pow(1, 2))) / 1000;
double current = Math.round(total / (Math.pow(1, 2))) / 1000;
int progress = (int) ((total * 100) / fileSize);
long currentTime = System.currentTimeMillis() - startTime;
Download download = new Download();
download.setTotalFileSize(totalFileSize);
if (currentTime > 1000 * timeCount) {
download.setCurrentFileSize((int) current);
download.setProgress(progress);
sendNotification(download,id);
timeCount++;
}
output.write(data, 0, count);
}
onDownloadComplete(filename,id);
output.flush();
output.close();
bis.close();
}
private void sendNotification(Download download, int id) {
sendIntent(download,id);
notificationBuilder.setProgress(100, download.getProgress(), false)
.setContentTitle("Downloading");
notificationBuilder.setContentText("Downloading file " + download.getCurrentFileSize() + "/" + totalFileSize + " KB");
notificationManager.notify(id, notificationBuilder.build());
}
private void sendIntent(Download download, int id) {
Intent intent = new Intent(subject.MESSAGE_PROGRESS);
intent.putExtra("download", download);
LocalBroadcastManager.getInstance(DownloadService.this).sendBroadcast(intent);
}
private void onDownloadComplete(String filename,int id) {
try {
Download download = new Download();
download.setProgress(100);
sendIntent(download,id);
notificationManager.cancel(id);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText("Tap to open");
notificationManager.notify(id, notificationBuilder.build());
String path1 = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/" + filename;
File file = new File(path1);
Uri uri_path = Uri.fromFile(file);
String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension
(MimeTypeMap.getFileExtensionFromUrl(path1));
Intent intent = new Intent(android.content.Intent.ACTION_VIEW);
intent.setType(mimeType);
intent.setDataAndType(uri_path, mimeType);
PendingIntent pIntent = PendingIntent.getActivity(this,(int) System.currentTimeMillis(), intent, 0);
String string = filename;
notificationBuilder
.setContentIntent(pIntent)
.setAutoCancel(true)
.setContentTitle(string + " Downloaded");
Log.i("Paras", "onDownloadComplete: " + string);
notificationManager.notify(id, notificationBuilder.build());
}catch (Exception ex){
}
}
@Override
public void onTaskRemoved(Intent rootIntent) {
}
}
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