6

这是我的服务代码：

public class DownloadService extends Service {
    LocalBroadcastManager mLocalBroadcastManager;
    ArrayList<DownloadAsyncTask> dat = new ArrayList<DownloadAsyncTask>();
    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public void onStart( Intent intent, int startId ) {
          super.onStart( intent, startId );
          Log.d("service","DownloadService started");
    }
    public void startDownload(String url, String fname, ProgressBar pBar){
        int dID = dat.size();
        Log.d("status","dat length:"+dID);
        dat.add( new DownloadAsyncTask(url,fname,pBar));
        dat.get(dID).execute();
    }

    public void cancelDownload(String fname){
        for(DownloadAsyncTask da: dat){
            if(da.getName().equals(fname)){
                da.cancel(true);
            }
        }
    }

    public DownloadAsyncTask getDownloadByName(String fname){
        for(DownloadAsyncTask da: dat){
            if(da.getName().equals(fname)){
                return da;
            }
        }
        return null;
    }
    public ArrayList<DownloadAsyncTask> getAllDownloads(){
        return dat;
    }
    public class DownloadAsyncTask extends AsyncTask<String, Integer, String>{
        ProgressBar progressBar;
        File sdCard = Environment.getExternalStorageDirectory();
        File dir = new File (sdCard.getAbsolutePath() + "/com.ms.rightel.store/");
        int percentage = 0;
        static final int DOWNLOAD_STATUS_FINISHED = 1;
        static final int DOWNLOAD_STATUS_RUNNING = 0;
        static final int DOWNLOAD_STATUS_FAILED = -1;
        static final int DOWNLOAD_STATUS_PAUSED = 2;
        int status = DOWNLOAD_STATUS_RUNNING;
        double fileSize = 0;
        String downloadUrl,fileName;

        public DownloadAsyncTask(String url, String fname, ProgressBar pBar){
            downloadUrl = url;
            fileName = fname;
            progressBar = pBar;
        }
        public String getName(){
            return fileName;
        }
        public void replaceProgressBar(ProgressBar pBar){
            progressBar = pBar;
        }

        private boolean checkDirs(){
            if(!dir.exists()){
                return dir.mkdirs();
            }
            return true;
        }
        public int getDownloadStatus(){
            return status;
        }
        private long isIncomplete(){
            File from = new File(dir,fileName+"-incomplete");
            if(from.exists()){
                Log.d("status","download is incomplete, filesize:" + from.length());
                return from.length();
            }
            return 0;
        }

        @Override
        protected String doInBackground(String... params) {
                //fileName = downloadUrl.substring(downloadUrl.lastIndexOf("/")+1);
                if(!checkDirs()){
                    return "Making directories failed!";
                }
                try {
                    byte[] buffer = new byte[500];
                    int bufferLength = 0;
                    double downloadedSize = 0;
                    URL url = new URL(downloadUrl);
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                    urlConnection.setRequestMethod("GET");
                    urlConnection.setConnectTimeout(10000);
                    urlConnection.setReadTimeout(10000);
                    //Log.d("status","ReadTimeOut: "+urlConnection.getReadTimeout() + "ConnectTimeOut: "+urlConnection.getConnectTimeout());
                    long downloaded = isIncomplete();
                    if(downloaded > 0){
                        urlConnection.setRequestProperty("Range", "bytes="+(downloaded)+"-");
                        downloadedSize = downloaded;
                        fileSize = downloaded;
                    }
                    urlConnection.setDoOutput(true);
                    urlConnection.connect();
                    fileSize += urlConnection.getContentLength();
                    FileOutputStream fos = new FileOutputStream(new File(dir,fileName+"-incomplete"),true);
                    InputStream inputStream = urlConnection.getInputStream();
                    while ( (bufferLength = inputStream.read(buffer)) > 0 ) 
                    {
                        if(isCancelled()){
                            break;
                        }
                        fos.write(buffer, 0, bufferLength);
                        downloadedSize += bufferLength;
                        percentage = (int) ((downloadedSize / fileSize) * 100);
                        publishProgress(percentage);
                        //Log.d("status","downloading: " + downloadedSize+"/"+fileSize+" ("+percentage+"%)");
                    }
                    fos.close();
                    urlConnection.disconnect();
                } catch (Exception e) {
                    Log.e("Download Failed","Error: " + e.getMessage());
                    return "Download failed";
                }
                if(isCancelled()){
                    return "Download cancelled";
                }
            return "Download complete";
        }
        @Override
        protected void onProgressUpdate(Integer... values){
            super.onProgressUpdate(values[0]);
            if(progressBar != null){
                progressBar.setProgress(values[0]);
            }else{
                Log.w("status", "ProgressBar is null, please supply one!");
            }
        }

        @Override
        protected void onPreExecute(){
            mLocalBroadcastManager.sendBroadcast(new Intent("org.test.download.DOWNLOAD_STARTED"));
        }

        @Override
        protected void onPostExecute(String str){
            if(str.equals("Download complete")){
                File from = new File(dir,fileName+"-incomplete");
                File to = new File(dir,fileName);
                from.renameTo(to);
                mLocalBroadcastManager.sendBroadcast(new Intent("org.test.download.DOWNLOAD_FINISHED"));
            }
            if(str.equals("Download failed")){
                mLocalBroadcastManager.sendBroadcast(new Intent("org.test.download.DOWNLOAD_FAILED"));
            }
        }

        @Override
        protected void onCancelled(){
            mLocalBroadcastManager.sendBroadcast(new Intent("org.test.download.DOWNLOAD_CANCELLED"));
        }

    }

}

我正在使用此服务来管理多个下载。现在我需要在不同的活动中访问这个服务对象，以便能够添加到下载或获取当前正在运行的下载列表。我怎样才能做到这一点？

4

2 回答 2

6

好吧，我是通过使用单音来完成的。我在类中添加了一个静态变量，由null. 然后在onStart方法内部，我将类的当前实例分配给这个静态变量，然后使用静态方法返回实际对象。

private static DownloadService self = null;
public static DownloadService getServiceObject(){
    return self;
}
@Override
public void onStart( Intent intent, int startId ) {
   super.onStart( intent, startId );
   self = this;
}
于 2012-06-24T18:59:13.810 回答
1

你可以将数据从活动传递到您的服务：

Intent myIntent = new Intent(MainActivity.this, DownloadService.class);
Bundle bundle = new Bundle();
bundle.putCharSequence("extraData", "DATA YOU WANT TO SEND SERVICE");
myIntent.putExtras(bundle);
pendingIntent = PendingIntent.getService(MainActivity.this, 0, myIntent, 0);

并在下载服务

public void onStart(Intent intent, int startId) {
 // TODO Auto-generated method stub
 super.onStart(intent, startId);

 Bundle bundle = intent.getExtras();
 data = (String) bundle.getCharSequence("extraData");
 smsTextToSend = (String) bundle.getCharSequence("extraSmsText");
 ...
}

以及在服务和活动之间进行通信的另一个选项使用自定义广播接收器

请参阅此示例以使用 BroadcastReceiver 在服务和 Activity 之间进行通信：

服务和活动之间的通信

于 2012-06-24T13:41:50.153 回答