显示下载进度条

Question

在我的应用程序中，我使用executor服务从url下载文件。现在我想添加一个水平进度条来显示下载进度。但我要面对错误。我如何在此代码中添加进度条，而不使用异步任务?

private class ExecutorServiceDownload implements Runnable {
private String url;
public ExecutorServiceDownload(String url) {
this.url = url;
}
@Override
public void run() {
dlFile(url);
}
private String dlFile(String surl) {

try {
// I added progressbar here and it didn't download anything 

InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
URL url = new URL(surl);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK)
return "Server returned HTTP " + connection.getResponseCode() + " " + connection.getResponseMessage();
input = connection.getInputStream();
String title = URLUtil.guessFileName(String.valueOf(url), null, null);
output = new FileOutputStream(Environment.getExternalStorageDirectory().toString() + "/test_files" + "/" + title);
int contentLength = connection.getContentLength();
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
total += count;
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
}
return null;
}
}

Answer 1

使用此代码下载执行器服务:

in onCreate:

ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreat`enter code here`e(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = findViewById(R.id.progressbar);

downloading();

使用executor服务下载文件:

private void downloading() {
progressBar.setVisibility(View.VISIBLE);

ExecutorService executor = Executors.newSingleThreadScheduledExecutor();
Handler handler = new Handler(Looper.getMainLooper());
executor.execute(new Runnable() {
int count;
@Override
public void run() {
//Background work here
try {
// put your url.this is sample url.
URL url = new URL("http://techslides.com/demos/sample-videos/small.mp4");
URLConnection conection = url.openConnection();
conection.connect();

int lenghtOfFile = conection.getContentLength();
// download the file
InputStream input = conection.getInputStream();
//catalogfile is your destenition folder
OutputStream output = new FileOutputStream(catalogfile + "video.mp4");

byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....

publishProgress(Integer.valueOf("" + (int) ((total * 100) / lenghtOfFile)));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();

handler.post(new Runnable() {
@Override
public void run() {
//UI Thread work here
progressBar.setVisibility(View.GONE);
}
});
} catch (Exception e) {
}
}
});

}

更新progressbar

private void publishProgress(Integer... progress) {
progressBar.setProgress(progress[0]);
}

和水平进度条使用:

<ProgressBar
android:max="100"
style="?android:attr/progressBarStyleHorizontal"
android:visibility="invisible"
android:id="@+id/progressbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"