java - 使用 ProgressDialog 下载文件，取消下载 (Android)

Question

下载文件时，我向用户显示此对话框，有取消按钮

    protected Dialog onCreateDialog(int id) {
    switch (id) {
    case DIALOG_DOWNLOAD_PROGRESS:
        mProgressDialog = new ProgressDialog(this);
        mProgressDialog.setMessage("Downloading ..");
        mProgressDialog.setButton(DialogInterface.BUTTON_NEGATIVE,
                "Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        mProgressDialog.setCancelable(false);
        mProgressDialog.show();
        return mProgressDialog;
    default:
        return null;
    }
}

<小时/>

我的下载代码是:

protected String doInBackground(String... aurl) {
        int count;

        try {

            URL url = new URL(aurl[0]);
            URLConnection conexion = url.openConnection();
            conexion.connect();

            int lenghtOfFile = conexion.getContentLength();
            Log.d("ANDRO_ASYNC", "Lenght of file: " + lenghtOfFile);

            InputStream input = new BufferedInputStream(url.openStream());
            OutputStream output = new FileOutputStream(sunDir.getPath()
                    + musicFileName);
            byte data[] = new byte[1024];
            long total = 0;
            while ((count = input.read(data)) != -1) {
                total += count;
                publishProgress("" + (int) ((total * 100) / lenghtOfFile));
                output.write(data, 0, count);
            }

            output.flush();
            output.close();
            input.close();

        } catch (Exception e) {
        }
        return null;

    }

<小时/>

我的问题是:

• 当在文件下载对话框中按下取消按钮时，不要取消
• 如果文件下载完成，我想当用户按下取消按钮时
  或者不完全删除文件

Answer 1

when press cancel button on dialog file downloading don't cancel

您将需要使用AsyncTask.cancel()要取消取消按钮上的 AsyncTask，请单击:

   public static boolean downloadstatus=true;
    mProgressDialog.setButton(DialogInterface.BUTTON_NEGATIVE,
                    "Cancel", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            your_AsyncTask.cancel(true);  //<<<<<
                             downloadstatus=false;
                            dialog.cancel();
                        }
                    });

I want to when user press cancel button if file downloaded complete or not delete file exactly

您需要检查 AsyncTask 是否在 doInBackground 内运行或取消，以停止文件下载:

    while ((count = input.read(data)) != -1) {
       if(!your_AsyncTask.isCancelled() &&  downloadstatus !=false){
        total += count;
        publishProgress("" + (int) ((total * 100) / lenghtOfFile));
        output.write(data, 0, count);
       }
      else{
             // free all resources here
            break;
        }
    }