我有一些线程可以打开进度对话框并下载文件。当线程下载文件时，它会更新进度条。但是如果进度对话框被隐藏，线程会创建一个通知并在通知中更新进度条。我想做这个：当用户点击通知时，Android 会打开 Activity 并显示进度对话框。我怎样才能做到这一点？
这是我下载文件的方法：
public void downloadAction(int id) {
if(id<0 || id>data.length) { IO.showNotify(MusicActivity.this, getResources().getStringArray(R.array.errors)[4]); return; }
final int itemId = id;
AsyncTask<Void, Integer, Boolean> downloadTask = new AsyncTask<Void, Integer, Boolean>() {
ProgressDialog progressDialog = new ProgressDialog(MusicActivity.this);
String error = null;
int nId = -1;
int progressPercent = 0;
boolean notificated = false;
int urlFileLength;
String FILE_NAME = fileName(data.getName(itemId));
@Override
protected void onPreExecute() {
progressDialog.setTitle(data.getName(itemId));
progressDialog.setIndeterminate(false);
progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progressDialog.setCancelable(true);
progressDialog.setOnCancelListener(new OnCancelListener() {
public void onCancel(DialogInterface dialog) {
cancel(true);
}
});
progressDialog.setButton(Dialog.BUTTON_POSITIVE, getResources().getString(R.string.hide), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
progressDialog.hide();
}
});
progressDialog.setButton(Dialog.BUTTON_NEGATIVE, getResources().getString(R.string.cancel), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
if(progressDialog.isShowing()) { cancel(true); progressDialog.dismiss();}
}
});
progressDialog.show();
progressDialog.setProgressNumberFormat("");
}
@Override
protected Boolean doInBackground(Void... params) {
int localFileLength, len;
int fullProgress = 0;
byte[] bytes = new byte[1024];
File rootDir = new File(PATH);
if(!rootDir.isDirectory()) rootDir.mkdir();
try {
URLConnection urlConnection = new URL(data.getUrl(itemId)).openConnection();
urlConnection.setConnectTimeout(20000);
urlConnection.setReadTimeout(60000);
localFileLength = (int) new File(FILE_NAME).length();
urlFileLength = urlConnection.getContentLength();
if (urlFileLength == 169 || urlFileLength == 0 || urlFileLength == -1) {
error = getResources().getStringArray(R.array.errors)[5];
return false;
}
if (urlFileLength == localFileLength) {
error = getResources().getString(R.string.file_exist);
return false;
} else {
publishProgress(0, urlFileLength);
InputStream in = urlConnection.getInputStream();
OutputStream out = new FileOutputStream(FILE_NAME);
while((len=in.read(bytes))!=-1) {
if(!isCancelled()) {
out.write(bytes, 0, len);
fullProgress += len;
publishProgress(fullProgress);
} else {
new File(FILE_NAME).delete();
error = getResources().getString(R.string.stopped);
return false;
}
}
}
} catch (MalformedURLException e) {
new File(FILE_NAME).delete();
error = getResources().getStringArray(R.array.errors)[2];
} catch (IOException e) {
new File(FILE_NAME).delete();
error = getResources().getStringArray(R.array.errors)[3];
}
return true;
}
@Override
protected void onProgressUpdate(Integer ... progress) {
int tmp;
if (progress.length==2) {
progressDialog.setProgress(progress[0]);
progressDialog.setMax(progress[1]);
} else if(progress.length==1) {
if(!progressDialog.isShowing()) {
if(!notificated) {
nId = NotificationUtils.getInstace(MusicActivity.this).createDownloadNotification(data.getName(itemId));
notificated = true;
} else {
tmp = (int) (progress[0]/(urlFileLength*0.01));
if(progressPercent!=tmp) {
progressPercent = tmp;
NotificationUtils.getInstace(MusicActivity.this).updateProgress(nId, progressPercent);
}
}
} else {
progressDialog.setProgress(progress[0]);
}
}
}
@Override
protected void onPostExecute(Boolean result) {
if(result==true && error == null) {
if(progressDialog.isShowing()) {
IO.showNotify(MusicActivity.this, getResources().getString(R.string.downloaded) + " " + PATH);
progressDialog.dismiss();
} else if (nId!=-1) {
NotificationUtils.getInstace(MusicActivity.this).cancelNotification(nId);
NotificationUtils.getInstace(MusicActivity.this).createMessageNotification(data.getName(itemId) + " " + getResources().getString(R.string.finished));
}
} else {
if(progressDialog.isShowing()) {
IO.showNotify(MusicActivity.this, error);
progressDialog.dismiss();
} else if (nId!=-1){
NotificationUtils.getInstace(MusicActivity.this).cancelNotification(nId);
NotificationUtils.getInstace(MusicActivity.this).createMessageNotification(getResources().getString(R.string.error) + "! " + error);
}
}
}
@Override
protected void onCancelled() {
IO.showNotify(MusicActivity.this, getResources().getString(R.string.stopped));
}
};
if(downloadTask.getStatus().equals(AsyncTask.Status.PENDING) || downloadTask.getStatus().equals(AsyncTask.Status.FINISHED))
downloadTask.execute();
}
这是创建通知的两种方法：
public int createDownloadNotification(String fileName) {
String text = context.getString(R.string.notification_downloading).concat(" ").concat(fileName);
RemoteViews contentView = createProgressNotification(text, text);
contentView.setImageViewResource(R.id.notification_download_layout_image, android.R.drawable.stat_sys_download);
return lastId++;
}
private RemoteViews createProgressNotification(String text, String topMessage) {
Notification notification = new Notification(android.R.drawable.stat_sys_download, topMessage, System.currentTimeMillis());
RemoteViews contentView = new RemoteViews(context.getPackageName(), R.layout.notification_download_layout);
contentView.setProgressBar(R.id.notification_download_layout_progressbar, 100, 0, false);
contentView.setTextViewText(R.id.notification_download_layout_title, text);
notification.contentView = contentView;
notification.flags = Notification.FLAG_NO_CLEAR | Notification.FLAG_ONGOING_EVENT | Notification.FLAG_ONLY_ALERT_ONCE;
Intent notificationIntent = new Intent(context, NotificationUtils.class);
PendingIntent contentIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
notification.contentIntent = contentIntent;
manager.notify(lastId, notification);
notifications.put(lastId, notification);
return contentView;
}
请帮帮我...