如何从对话框中取消文件下载
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【中文标题】如何从对话框中取消文件下载【英文标题】：How to cancel file downloading from a dialog 【发布时间】：2018-05-26 18:59:51 【问题描述】：当用户下载文件时，我会向用户显示一个包含取消按钮的对话框。
我的问题是当用户按下对话框文件上的取消按钮时，下载过程不会被取消。
我希望当用户按下取消按钮时文件下载是否完成，我必须删除。 请向任何人解释我该怎么做。
代码：
public class DownloadTask
private static final String TAG = "Download Task";
private Context context;
private String downloadUrl = "", downloadFileName = "";
private ProgressDialog progressDialog;
public DownloadTask(Context context, String downloadUrl)
this.context = context;
this.downloadUrl = downloadUrl;
downloadFileName = downloadUrl.substring(downloadUrl.lastIndexOf( '/' ),downloadUrl.length());
Log.e(TAG, downloadFileName);
//Start Downloading Task
new DownloadingTask().execute();
private class DownloadingTask extends AsyncTask<Void, Integer, Void>
File apkStorage = null;
File outputFile = null;
@Override
protected void onPreExecute()
super.onPreExecute();
progressDialog = new ProgressDialog(bookejtemaeat.this);
progressDialog.setMessage("يتم تحميل الملف مرة واحدة يرجى الانتظار ......");
progressDialog.setIndeterminate(true);
progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progressDialog.setCancelable(false);
progressDialog.setProgress(0);
progressDialog.setCanceledOnTouchOutside(false) ;
progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Cancel", new DialogInterface.OnClickListener()
@Override
public void onClick(DialogInterface dialog, int which)
DownloadingTask.this.cancel(true);
dialog.dismiss();
);
progressDialog.show();
@Override
protected Void doInBackground(Void... arg0)
try
URL url = new URL(downloadUrl);//Create Download URL
HttpURLConnection c = (HttpURLConnection) url.openConnection();//Open Url Connection
c.setRequestMethod("GET");//Set Request Method to "GET" since we are grtting data
c.connect();//connect the URL Connection
final int fileLength = c.getContentLength();
Log.e(TAG, "fileLength " + fileLength);
if (c.getResponseCode() != HttpURLConnection.HTTP_OK)
Log.e(TAG, "Server returned HTTP " + c.getResponseCode()
+ " " + c.getResponseMessage());
//Get File if SD card is present
if (new CheckForSDCard().isSDCardPresent())
apkStorage = getApplicationContext().getDir(
"NKDROID FILES",Context.MODE_PRIVATE);
else
Toast.makeText(context, "Tidak ada SD Card.", Toast.LENGTH_SHORT).show();
//If File is not present create directory
if (!apkStorage.exists())
apkStorage.mkdir();
Log.e(TAG, "Directory Created.");
outputFile = new File(apkStorage, downloadFileName);//Create Output file in Main File
//Create New File if not present
if (!outputFile.exists())
outputFile.createNewFile();
Log.e(TAG, "File Created");
FileOutputStream fos = new FileOutputStream(outputFile);//Get OutputStream for NewFile Location
InputStream is = c.getInputStream();//Get InputStream for connection
byte[] buffer = new byte[1024];//Set buffer type
int len1 = 0;//init length
long total = 0;
while ((len1 = is.read(buffer)) != -1)
total += len1;
final long total_tmp = total;
Log.e(TAG, "progressDialog " + (total*100/fileLength));
publishProgress((int) (total * 100 / fileLength));
runOnUiThread(new Runnable()
@Override
public void run()
progressDialog.setProgress((int) (total_tmp*100/fileLength));
);
fos.write(buffer, 0, len1);//Write new file
//Close all connection after doing task
fos.close();
is.close();
catch (Exception e)
//Read exception if something went wrong
e.printStackTrace();
outputFile = null;
Log.e(TAG, "Download Error Exception " + e.getMessage());
return null;
【问题讨论】：
【参考方案1】：只需在您的类中添加一个布尔值即可让您控制 while 循环。喜欢
while (continueDownload&& (len1 = is.read(buffer)) != -1)
让这项工作像
yourDwnloadTask.setContinueDownload(false);
并处理您的输出文件
if (!continueDownload && outputFile.exists())
try
outputFile.delete();
catch (Exception e)
e.printStackTrace();
如果你问我完整的代码。
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class DownloadTask
private static final String TAG = "Download Task";
private Context context;
private String downloadUrl = "", downloadFileName = "";
private ProgressDialog progressDialog;
private boolean continueDownload = true;
public void setContinueDownload(boolean continueDownload)
this.continueDownload = continueDownload;
public DownloadTask(Context context, String downloadUrl)
this.context = context;
this.downloadUrl = downloadUrl;
downloadFileName = downloadUrl.substring(downloadUrl.lastIndexOf('/'), downloadUrl.length());
continueDownload = true;
Log.e(TAG, downloadFileName);
//Start Downloading Task
new DownloadingTask().execute();
private class DownloadingTask extends AsyncTask<Void, Integer, Void>
File apkStorage = null;
File outputFile = null;
@Override
protected void onPreExecute()
super.onPreExecute();
progressDialog = new ProgressDialog(bookejtemaeat.this);
progressDialog.setMessage("يتم تحميل الملف مرة واحدة يرجى الانتظار ......");
progressDialog.setIndeterminate(true);
progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progressDialog.setCancelable(false);
progressDialog.setProgress(0);
progressDialog.setCanceledOnTouchOutside(false);
progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Cancel", new DialogInterface.OnClickListener()
@Override
public void onClick(DialogInterface dialog, int which)
DownloadingTask.this.cancel(true);
dialog.dismiss();
);
progressDialog.show();
@Override
protected Void doInBackground(Void... arg0)
try
URL url = new URL(downloadUrl);//Create Download URL
HttpURLConnection c = (HttpURLConnection) url.openConnection();//Open Url Connection
c.setRequestMethod("GET");//Set Request Method to "GET" since we are grtting data
c.connect();//connect the URL Connection
final int fileLength = c.getContentLength();
Log.e(TAG, "fileLength " + fileLength);
if (c.getResponseCode() != HttpURLConnection.HTTP_OK)
Log.e(TAG, "Server returned HTTP " + c.getResponseCode()
+ " " + c.getResponseMessage());
//Get File if SD card is present
if (new CheckForSDCard().isSDCardPresent())
apkStorage = getApplicationContext().getDir(
"NKDROID FILES", Context.MODE_PRIVATE);
else
Toast.makeText(context, "Tidak ada SD Card.", Toast.LENGTH_SHORT).show();
//If File is not present create directory
if (!apkStorage.exists())
apkStorage.mkdir();
Log.e(TAG, "Directory Created.");
outputFile = new File(apkStorage, downloadFileName);//Create Output file in Main File
//Create New File if not present
if (!outputFile.exists())
outputFile.createNewFile();
Log.e(TAG, "File Created");
FileOutputStream fos = new FileOutputStream(outputFile);//Get OutputStream for NewFile Location
InputStream is = c.getInputStream();//Get InputStream for connection
byte[] buffer = new byte[1024];//Set buffer type
int len1 = 0;//init length
long total = 0;
while (continueDownload && (len1 = is.read(buffer)) != -1)
total += len1;
final long total_tmp = total;
Log.e(TAG, "progressDialog " + (total * 100 / fileLength));
publishProgress((int) (total * 100 / fileLength));
runOnUiThread(new Runnable()
@Override
public void run()
progressDialog.setProgress((int) (total_tmp * 100 / fileLength));
);
fos.write(buffer, 0, len1);//Write new file
if (!continueDownload && outputFile.exists())
try
outputFile.delete();
catch (Exception e)
e.printStackTrace();
//Close all connection after doing task
fos.close();
is.close();
catch (Exception e)
//Read exception if something went wrong
e.printStackTrace();
outputFile = null;
Log.e(TAG, "Download Error Exception " + e.getMessage());
return null;
【讨论】：
感谢您的回复，但我在哪里添加 DownloadingTask.setContinueDownload(false); 你应该选择你需要停止下载的地方。以上是关于如何从对话框中取消文件下载的主要内容，如果未能解决你的问题，请参考以下文章