我试图写一个简单的应用程序得到更新。为此,我需要一个简单的函数,可以下载文件并在ProgressDialog中显示当前进度。我知道如何做的ProgressDialog,但我不确定如何显示当前的进度,以及如何下载文件放在第一位。
当前回答
private class DownloadTask extends AsyncTask<String, Integer, String> {
private PowerManager.WakeLock mWakeLock;
String onlinePathBundle, onlinePathMusic, offlinePathBundle, offlinePathMusic;
CircleProgressBar progressBar;
RelativeLayout rl_progress;
ImageView btn_download;
TextView tv_progress;
public DownloadTask(String onlinePathBundle, String onlinePathMusic, String offlinePathBundle, String offlinePathMusic, CircleProgressBar progressBar, RelativeLayout rl_progress, ImageView btn_download,
TextView tv_progress) {
this.offlinePathBundle = offlinePathBundle;
this.offlinePathMusic = offlinePathMusic;
this.progressBar = progressBar;
this.rl_progress = rl_progress;
this.btn_download = btn_download;
this.tv_progress = tv_progress;
this.onlinePathBundle = onlinePathBundle;
this.onlinePathMusic = onlinePathMusic;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
progressBar.setMax(100);
rl_progress.setVisibility(View.VISIBLE);
btn_download.setVisibility(View.GONE);
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, getClass().getName());
mWakeLock.acquire();
}
@Override
protected String doInBackground(String... sUrl) {
String firstResult = downTask(onlinePathBundle, 1, offlinePathBundle);
String seondResult = downTask(onlinePathMusic, 2, offlinePathMusic);
if (firstResult != null) {
Toast.makeText(SplashActivity.this, "Download error: " + firstResult, Toast.LENGTH_LONG).show();
return firstResult;
} else {
return seondResult;
}
}
@Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
progressBar.setProgress(progress[0]);
tv_progress.setText(progress[0] + "%");
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
rl_progress.setVisibility(View.GONE);
btn_download.setVisibility(View.VISIBLE);
if (result != null) {
Toast.makeText(SplashActivity.this, "Download error: " + result, Toast.LENGTH_LONG).show();
} else {
rl_progress.setVisibility(View.GONE);
btn_download.setVisibility(View.GONE);
}
}
public String downTask(String onlineNewPath, int numberOfTask, String offlineNewPath) {
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
try {
URL url = new URL(onlineNewPath);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
// expect HTTP 200 OK, so we don't mistakenly save error report
// instead of the file
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return "Server returned HTTP " + connection.getResponseCode()
+ " " + connection.getResponseMessage();
}
// this will be useful to display download percentage
// might be -1: server did not report the length
int fileLength = connection.getContentLength();
// download the file
input = connection.getInputStream();
output = new FileOutputStream(offlineNewPath);
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
// allow canceling with back button
if (isCancelled()) {
input.close();
return null;
}
total += count;
// publishing the progress....
if (fileLength > 0) {// only if total length is known
if (numberOfTask == 1) {
publishProgress((int) (total * 50 / fileLength));
} else if (numberOfTask == 2) {
publishProgress(((int) (total * 50 / fileLength)) + 50);
}
}
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
} finally {
try {
if (output != null)
output.close();
if (input != null)
input.close();
} catch (IOException ignored) {
}
if (connection != null)
connection.disconnect();
}
return null;
}
}
其他回答
我正在为我现在使用的其他解决方案添加另一个答案,因为Android查询太大了,无法保持健康。所以我搬到了这个https://github.com/amitshekhariitbhu/Fast-Android-Networking。
AndroidNetworking.download(url,dirPath,fileName).build()
.setDownloadProgressListener(new DownloadProgressListener() {
public void onProgress(long bytesDownloaded, long totalBytes) {
bar.setMax((int) totalBytes);
bar.setProgress((int) bytesDownloaded);
}
}).startDownload(new DownloadListener() {
public void onDownloadComplete() {
...
}
public void onError(ANError error) {
...
}
});
您可以使用LiveData和协程观察下载管理器的进度,参见下面的要点
https://gist.github.com/FhdAlotaibi/678eb1f4fa94475daf74ac491874fc0e
data class DownloadItem(val bytesDownloadedSoFar: Long = -1, val totalSizeBytes: Long = -1, val status: Int)
class DownloadProgressLiveData(private val application: Application, private val requestId: Long) : LiveData<DownloadItem>(), CoroutineScope {
private val downloadManager by lazy {
application.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
}
private val job = Job()
override val coroutineContext: CoroutineContext
get() = Dispatchers.IO + job
override fun onActive() {
super.onActive()
launch {
while (isActive) {
val query = DownloadManager.Query().setFilterById(requestId)
val cursor = downloadManager.query(query)
if (cursor.moveToFirst()) {
val status = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS))
Timber.d("Status $status")
when (status) {
DownloadManager.STATUS_SUCCESSFUL,
DownloadManager.STATUS_PENDING,
DownloadManager.STATUS_FAILED,
DownloadManager.STATUS_PAUSED -> postValue(DownloadItem(status = status))
else -> {
val bytesDownloadedSoFar = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR))
val totalSizeBytes = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES))
postValue(DownloadItem(bytesDownloadedSoFar.toLong(), totalSizeBytes.toLong(), status))
}
}
if (status == DownloadManager.STATUS_SUCCESSFUL || status == DownloadManager.STATUS_FAILED)
cancel()
} else {
postValue(DownloadItem(status = DownloadManager.STATUS_FAILED))
cancel()
}
cursor.close()
delay(300)
}
}
}
override fun onInactive() {
super.onInactive()
job.cancel()
}
}
我个人的建议是使用进度对话框并在执行前进行构建,或者在OnPreExecute()上初始化,如果你使用进度对话框的水平风格的进度条,则经常发布进度。剩下的部分是优化doInBackground的算法。
我推荐你使用我的Project Netroid,它是基于Volley的。我添加了一些功能,如多事件回调,文件下载管理。这可能会有帮助。
权限
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
使用HttpURLConnection
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.app.Dialog;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.Window;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
public class DownloadFileUseHttpURLConnection extends Activity {
ProgressBar pb;
Dialog dialog;
int downloadedSize = 0;
int totalSize = 0;
TextView cur_val;
String dwnload_file_path =
"http://coderzheaven.com/sample_folder/sample_file.png";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button b = (Button) findViewById(R.id.b1);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
showProgress(dwnload_file_path);
new Thread(new Runnable() {
public void run() {
downloadFile();
}
}).start();
}
});
}
void downloadFile(){
try {
URL url = new URL(dwnload_file_path);
HttpURLConnection urlConnection = (HttpURLConnection)
url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
//connect
urlConnection.connect();
//set the path where we want to save the file
File SDCardRoot = Environment.getExternalStorageDirectory();
//create a new file, to save the downloaded file
File file = new File(SDCardRoot,"downloaded_file.png");
FileOutputStream fileOutput = new FileOutputStream(file);
//Stream used for reading the data from the internet
InputStream inputStream = urlConnection.getInputStream();
//this is the total size of the file which we are downloading
totalSize = urlConnection.getContentLength();
runOnUiThread(new Runnable() {
public void run() {
pb.setMax(totalSize);
}
});
//create a buffer...
byte[] buffer = new byte[1024];
int bufferLength = 0;
while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
fileOutput.write(buffer, 0, bufferLength);
downloadedSize += bufferLength;
// update the progressbar //
runOnUiThread(new Runnable() {
public void run() {
pb.setProgress(downloadedSize);
float per = ((float)downloadedSize/totalSize) *
100;
cur_val.setText("Downloaded " + downloadedSize +
"KB / " + totalSize + "KB (" + (int)per + "%)" );
}
});
}
//close the output stream when complete //
fileOutput.close();
runOnUiThread(new Runnable() {
public void run() {
// pb.dismiss(); // if you want close it..
}
});
} catch (final MalformedURLException e) {
showError("Error : MalformedURLException " + e);
e.printStackTrace();
} catch (final IOException e) {
showError("Error : IOException " + e);
e.printStackTrace();
}
catch (final Exception e) {
showError("Error : Please check your internet connection " +
e);
}
}
void showError(final String err){
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(DownloadFileDemo1.this, err,
Toast.LENGTH_LONG).show();
}
});
}
void showProgress(String file_path){
dialog = new Dialog(DownloadFileDemo1.this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.myprogressdialog);
dialog.setTitle("Download Progress");
TextView text = (TextView) dialog.findViewById(R.id.tv1);
text.setText("Downloading file from ... " + file_path);
cur_val = (TextView) dialog.findViewById(R.id.cur_pg_tv);
cur_val.setText("Starting download...");
dialog.show();
pb = (ProgressBar)dialog.findViewById(R.id.progress_bar);
pb.setProgress(0);
pb.setProgressDrawable(
getResources().getDrawable(R.drawable.green_progress));
}
}
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