实施进度条文件下载在Android中 [英] Implement Progress Bar for File Download in Android
本文介绍了实施进度条文件下载在Android中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我是新来的Android开发。
我已经写了下面的code下载的视频文件 因特网。它工作正常。现在，我想在附加进度条 下载process.I试图继承AsyncTask的写内部doInBackground（）方法下载code。但是，不知何故，我不明白。
有人可以请帮我修改此code来实现这一目标？
包sample.android.download;
进口java.io.BufferedInputStream中;
进口的java.io.File;
进口java.io.FileOutputStream中;
进口java.io.IOException异常;
进口的java.io.InputStream;
进口的java.net.URL;
进口java.net.URLConnection中;
进口org.apache.http.util.ByteArrayBuffer;
进口android.app.Activity;
进口android.content.Intent;
进口android.net.Uri;
进口android.os.Bundle;
进口android.os.Environment;
进口android.util.Log;
进口android.widget.TextView;
公共类涓嬭浇延伸活动{
私人TextView的电视;
私人字符串videoURL =http://mysite-name.com/videos/videofile_name.mp4;
私人字符串文件名=my_video.mp4;
/ **第一次创建活动时调用。 * /
@覆盖
公共无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.main）;
电视=（TextView中）findViewById（R.id.TextView01）;
如果（checkExternalMedia（）==真）{
DownloadFromUrl（videoURL，文件名）;
tv.append（\ñ\ nDownload完成！）;
}
其他 {
tv.append（\ñ\ nExternal媒体不是可读/写）;
}
}
/ **方法来检查是否外部媒体提供可写的。 * /
私人布尔checkExternalMedia（）{
布尔mExternalStorageAvailable = FALSE;
布尔mExternalStorageWriteable = FALSE;
布尔统计;
字符串状态= Environment.getExternalStorageState（）;
如果（Environment.MEDIA_MOUNTED.equals（州））{
//可读写的介质
mExternalStorageAvailable = mExternalStorageWriteable = TRUE;
STAT = TRUE;
}
否则，如果（Environment.MEDIA_MOUNTED_READ_ONLY.equals（州））{
//只能读取媒体
mExternalStorageAvailable = TRUE;
mExternalStorageWriteable = FALSE;
STAT = FALSE;
} 其他 {
//无法读取或写入
mExternalStorageAvailable = mExternalStorageWriteable = FALSE;
STAT = FALSE;
}
tv.append（\ñ\ nExternal媒体：可读=+ mExternalStorageAvailable +可写=+ mExternalStorageWriteable）;
返回统计;
}
/ **方法从网络到SD卡中下载的外部文件。 * /
公共无效DownloadFromUrl（字符串videoURL，字符串文件名）{
尝试 {
文件根= android.os.Environment.getExternalStorageDirectory（）;
tv.append（\ nExternal文件系统的根：+根）;
文件DIR =新的文件（root.getAbsolutePath（）+/视频）;
//dir.mkdirs（）;
网址URL =新的URL（videoURL）; //你可以在这里写任何链接
档案文件=新的文件（目录，文件名）;
长的startTime = System.currentTimeMillis的（）;
Log.d（ImageManager，下载开始时）;
Log.d（ImageManager，下载网址：+网址）;
Log.d（ImageManager，已下载文件的名称：+文件名）;
/ *打开到URL的连接。 * /
URLConnection的UCON = url.openConnection（）;
/ *
*定义InputStreams从URLConnection的阅读。
* /
InputStream的是= ucon.getInputStream（）;
的BufferedInputStream双=新的BufferedInputStream（是）;
/ *
*读取字节的缓冲区，直到有没有更多阅读（-1）。
* /
ByteArrayBuffer BAF =新ByteArrayBuffer（5000）;
INT电流= 0;
而（（电流= bis.read（））！= - 1）{
baf.append（（字节）电流）;
}
/ *读取转换为字符串的字节数。 * /
FileOutputStream中FOS =新的FileOutputStream（文件）;
fos.write（baf.toByteArray（））;
fos.flush（）;
fos.close（）;
Log.d（ImageManager，下载准备在+（（System.currentTimeMillis的（） - 的startTime）/ 1000）+秒）;
}赶上（IOException异常E）{
Log.d（ImageManager，错误：+ E）;
}
sendBroadcast（新意图（Intent.ACTION_MEDIA_MOUNTED，Uri.parse（文件：//+ Environment.getExternalStorageDirectory（））））;
}
}
解决方案
查看：
http://developer.android.com/guide/topics/ui/ dialogs.html
请参阅上第二个线程中创建一个进度条的例子。
I am new to Android Development.
I've written the following code to download a video file from the internet. It works fine. Now I want to attach a progress bar during the download process.I tried to subclass AsyncTask and write the download code inside doInBackground() method. But, somehow I can't figure it out.
Can somebody please help me modify this code to accomplish that?
package sample.android.download;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import org.apache.http.util.ByteArrayBuffer;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.widget.TextView;
public class DownloadDemo extends Activity {
private TextView tv;
private String videoURL = "http://mysite-name.com/videos/videofile_name.mp4";
private String fileName = "my_video.mp4";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = (TextView) findViewById(R.id.TextView01);
if(checkExternalMedia()==true) {
DownloadFromUrl(videoURL,fileName);
tv.append("\n\nDownload Complete!");
}
else {
tv.append("\n\nExternal Media is NOT readable/writable");
}
}
/** Method to check whether external media available and writable. */
private boolean checkExternalMedia(){
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
boolean stat;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// Can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
stat = true;
}
else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// Can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
stat = false;
} else {
// Can't read or write
mExternalStorageAvailable = mExternalStorageWriteable = false;
stat = false;
}
tv.append("\n\nExternal Media: readable="+mExternalStorageAvailable+ "writable="+mExternalStorageWriteable);
return stat;
}
/** Method to download an external file from the network to the SD card. */
public void DownloadFromUrl(String videoURL, String fileName) {
try {
File root = android.os.Environment.getExternalStorageDirectory();
tv.append("\nExternal file system root: "+root);
File dir = new File (root.getAbsolutePath() + "/video");
//dir.mkdirs();
URL url = new URL(videoURL); //you can write here any link
File file = new File(dir, fileName);
long startTime = System.currentTimeMillis();
Log.d("ImageManager", "download begining");
Log.d("ImageManager", "download url:" + url);
Log.d("ImageManager", "downloaded file name:" + fileName);
/* Open a connection to that URL. */
URLConnection ucon = url.openConnection();
/*
* Define InputStreams to read from the URLConnection.
*/
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
/*
* Read bytes to the Buffer until there is nothing more to read(-1).
*/
ByteArrayBuffer baf = new ByteArrayBuffer(5000);
int current = 0;
while ((current = bis.read()) != -1) {
baf.append((byte) current);
}
/* Convert the Bytes read to a String. */
FileOutputStream fos = new FileOutputStream(file);
fos.write(baf.toByteArray());
fos.flush();
fos.close();
Log.d("ImageManager", "download ready in" + ((System.currentTimeMillis() - startTime) / 1000) + " sec");
} catch (IOException e) {
Log.d("ImageManager", "Error: " + e);
}
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://"+ Environment.getExternalStorageDirectory())));
}
}
解决方案
Check:
http://developer.android.com/guide/topics/ui/dialogs.html
See the example on creating a progress bar within a second thread.
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