我现在要做的是从包含大约875个文件的URL循环下载pdf。
我已经通过使用Asynctask并更新进度中的进度对话框也完成了一切工作正常，但我遇到的问题是当用户点击我的DOWNLOAD IN BACKGROUND按钮时，下载仍在继续我想再次重新开放这项活动。但是显示给用户的文件的进度和名称不再显示。
我知道当我们开始新的活动时，它会忽略我们上一个Asynctask的后台运行过程，那么我们怎么能解决这个问题呢？ （对不起我的英语，这是我第一次通过StackOverflow）
我的代码示例：
class DownloadFileFromURL extends AsyncTask<ArrayList<LawDocument>,Integer, String> {
private boolean running = true;
Exception error;
@Override
protected void onPreExecute() {
super.onPreExecute();
if(haveNetworkConnection()){
showDialog(progress_bar_type);
}else {
running = false;
showdailog();
}
}
@Override
protected void onCancelled() {
super.onCancelled();
running = false;
}
@Override
protected String doInBackground(ArrayList<LawDocument>[] f_url) {
ArrayList<LawDocument> passed = f_url[0]; //get passed arraylist
System.out.println("Data::" + passed.size());
int count;
InputStream input = null;
OutputStream output = null;
while(!isCancelled()) {
try {
for (int i = 0; i < passed.size(); i++) {
File file = getBaseContext().getFileStreamPath(passed.get(i).getActualFilename());
if (file.exists()){
countfile+=1;
pDialog.setMessage(" Exist / "+ConstantClass.filecount);
}else{
Log.d("checkFilecount" + i, "fileName: " + passed.get(i).getFileName());
String filename = passed.get(i).getFileName().substring(passed.get(i).getFileName().lastIndexOf("/") + 1);
Log.d("checkFile", "name: " + filename);
URL url = new URL(passed.get(i).getFileName());
System.out.println("Data::" + passed.get(i).getFileName());
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
input = new BufferedInputStream(url.openStream(), 8192);
//input = new BufferedInputStream(url.openStream(), 20000);
System.out.println("Data::" + passed.get(i).getFileName());
System.out.println("Data::" + filename);
// Output stream to write file
output = new FileOutputStream(getApplicationContext().getFilesDir() + "/" + filename);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress((int) ((total * 100) / lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
countfile+=1;
runOnUiThread(new Runnable() {
@Override
public void run() {
pDialog.setMessage(countfile+" / "+ConstantClass.filecount);
}
});
}
}
} catch (Throwable t) {
Log.e("AsyncTask", "OMGCrash", t);
// maybe throw it again
Toast.makeText(DownloadLoading.this,"There is a problem",Toast.LENGTH_SHORT).show();
throw new RuntimeException(t);
} finally {
if (output != null) {
try {
output.flush();
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (input != null) {
try {
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
return null;
}
/**
* Updating progress bar
*/
protected void onProgressUpdate(Integer... progress) {
// setting progress percentage
pDialog.setProgress(progress[0]);
}
/**
* After completing background task Dismiss the progress dialog
**/
@Override
protected void onPostExecute(String file_url) {
// dismiss the dialog after the file was downloaded
//dismissDialog(progress_bar_type);
if (error !=null){
Toast.makeText(DownloadLoading.this, error.getMessage(),
Toast.LENGTH_SHORT).show();
}else if(!running){
Log.d("Faild","Download fail connection");
}else{
Toast.makeText(DownloadLoading.this, "Success", Toast.LENGTH_SHORT).show();
}
}
}
} }
答案 0 :(得分：0)
我想最佳解决方案是将服务与 BroadCast
一起使用这意味着你所有的下载服务
让我们说
public class DowloadService extends Service {
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Bundle extras = intent.getExtras();
your_data = extras.get() // just example
for (int i = 0; i < passed.size(); i++) {
File file = getBaseContext().getFileStreamPath(passed.get(i).getActualFilename());
if (file.exists()){
countfile+=1;
pDialog.setMessage(" Exist / "+ConstantClass.filecount);
}else{
Log.d("checkFilecount" + i, "fileName: " + passed.get(i).getFileName());
String filename = passed.get(i).getFileName().substring(passed.get(i).getFileName().lastIndexOf("/") + 1);
Log.d("checkFile", "name: " + filename);
URL url = new URL(passed.get(i).getFileName());
System.out.println("Data::" + passed.get(i).getFileName());
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
input = new BufferedInputStream(url.openStream(), 8192);
//input = new BufferedInputStream(url.openStream(), 20000);
System.out.println("Data::" + passed.get(i).getFileName());
System.out.println("Data::" + filename);
// Output stream to write file
output = new FileOutputStream(getApplicationContext().getFilesDir() + "/" + filename);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress((int) ((total * 100) / lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
countfile+=1;
// send broadcast with data you want
ntent.putExtra("dataType",dataType);
intent.putExtra("getAccuracy",gpsSignal);
LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(intent);
}
});
return START_NOT_STICKY;
}
}
然后在您的activiy Setup Local BroadCast中获取数据发送
private class BroadCastLocal extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent) {
if (Constrains.PEDOMETERBROADCAST.equalsIgnoreCase(intent.getAction()))
{
int dataType = intent.getIntExtra("dataType",-1);
}
}
现在，只要用户开始/结束您的活动，该过程就不会生效