这是我的代码。当我点击下载按钮时，它会下载两次。如何停止第二次下载？请帮我防止第二次下载。 这是我的按钮点击监听器：
downloadPackage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
downloadPackage.setEnabled(false);
SharedPreferences.Editor editor = getSharedPreferences("SETID", MODE_PRIVATE).edit();
editor.putInt("setId", setId);
editor.commit();
Intent intent = new Intent(ReadingListeningTestActivity.this, DownloadService.class);
startService(intent);
}
});
public class DownloadService extends Service {
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
private NotificationManager notificationManager;
private NotificationCompat.Builder notificationBuilder;
private int totalFileSize;
SharedPreferences prefs;
private boolean isDownloading = false;
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
prefs = getSharedPreferences("SETID", MODE_PRIVATE);
int setId = prefs.getInt("setId", 0);
Log.d("SEtID", setId + "");
if (isDownloading) {
return;
} else {
Log.d("Download", "isDownloading: " + isDownloading);
isDownloading = true;
initDownload(setId);
}
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}
private void initDownload(int setId) {
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... voids) {
notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationBuilder = new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.mipmap.ic_launcher)
.setContentTitle(data.getTitle())
.setContentText("Downloading File")
.setAutoCancel(true);
notificationManager.notify(0, notificationBuilder.build());
downloadFileTest("test.zip");
return null;
}
}.execute();
}
private void downloadFileTest(String uri) {
int count;
InputStream stream = null;
OutputStream output = null;
HttpURLConnection connection = null;
String fileName = packageName(uri);
try {
URL url = new URL(Application.BASE_URL + uri);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return;
}
byte data[] = new byte[4096];
long fileSize = connection.getContentLength();
stream = new BufferedInputStream(connection.getInputStream());
File outputFile = getCacheDir(fileName + ".part");
output = new FileOutputStream(outputFile);
try {
long total = 0;
long startTime = System.currentTimeMillis();
int timeCount = 1;
while ((count = stream.read(data)) != -1) {
total += count;
totalFileSize = (int) (fileSize / (Math.pow(1024, 2)));
double current = Math.round(total / (Math.pow(1021, 2)));
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);
timeCount++;
}
output.write(data, 0, count);
}
} catch (IOException e) {
isDownloading = false;
prefs.edit().clear().commit();
outputFile.delete();
onErrorDownload("Internet Connection Problem Retry Download");
} finally {
isDownloading = false;
prefs.edit().clear().commit();
File originalName = getCacheDir(fileName);
if (originalName.exists()) {
outputFile.delete();
throw new IOException("file exists");
}
boolean success = outputFile.renameTo(originalName);
if (success) {
if (connection != null)
connection.disconnect();
onDownloadComplete();
output.flush();
output.close();
stream.close();
}
}
} catch (IOException e) {
isDownloading = false;
prefs.edit().clear().commit();
Log.d("Test", "Main");
if (e.getMessage().equals("file exists"))
onErrorDownload("Package Already Exists");
else
onErrorDownload("Internet Connection Problem Retry Download");
}
}
private void onDownloadComplete() {
Download download = new Download();
download.setProgress(100);
sendIntent(download);
notificationManager.cancel(0);
notificationBuilder.setOngoing(false);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText("File Downloaded");
notificationManager.notify(0, notificationBuilder.build());
}
private void onErrorDownload(String message) {
Download download = new Download();
download.setProgress(download.getProgress());
sendIntent(download);
notificationManager.cancel(0);
notificationBuilder.setOngoing(false);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText(message);
notificationManager.notify(0, notificationBuilder.build());
}
private void sendNotification(Download download) {
sendIntent(download);
notificationBuilder.setProgress(100, download.getProgress(), false);
notificationBuilder.setOngoing(true);
notificationBuilder.setContentText("Downloading Progress " + download.getProgress() + "%" + " /100%");
notificationManager.notify(0, notificationBuilder.build());
}
private void sendIntent(Download download) {
Intent intent = new Intent(ReadingListeningTestActivity.MESSAGE_PROGRESS);
intent.putExtra("download", download);
LocalBroadcastManager.getInstance(DownloadService.this).sendBroadcast(intent);
}
private String packageName(String uri) {
String[] parts = uri.split("/");
return parts[parts.length - 1];
}
public File getCacheDir(String packageName) {
File cache = null;
File external = getApplication().getExternalCacheDir();
if (external != null && external.exists()) {
cache = external;
} else {
cache = getApplication().getCacheDir();
}
File file = new File(cache, packageName);
return file;
}
}