android - 从 url 下载不同类型的文件

Question

我想下载不同类型的文件，并且有可能像这样的链接

https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcRpDmM-KiKgR-wcFtJnXUYVua-2409t5z7pjqski5wQ9pYZfOJG7nklFnc

我不知道文件名、类型和任何描述。那么如何获取这些信息。所以我将该文件名设为默认值？

谢谢你。

Answer 1

您必须使用异步任务来下载文件

调用它

String Your_Url = "https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcRpDmM-KiKgR-wcFtJnXUYVua-2409t5z7pjqski5wQ9pYZfOJG7nklFnc";

new downloadProcess(Your_Url, Your_Context).execute();



 public downLoadProcess(String Url , Context context)
            {
                context.Url = Url ;
            }

            @Override
            protected void onPreExecute()
            {
                super.onPreExecute();

            }

            @Override
            protected void onPostExecute(ArrayList<String> result) 
            {
                super.onPostExecute(result);
            }


            @Override
            protected ArrayList<String> doInBackground(Void... Params) 
            {
                ArrayList<String> Data = new ArrayList<String>();
                boolean flag = false;
                URL url;
                URLConnection conn;
                int fileSize, lastSlash;
                String fileName, path = null;
                BufferedInputStream inStream;
                BufferedOutputStream outStream;
                File outFile;
                FileOutputStream fileStream;

                WebServiceMethods objWSMethod = new WebServiceMethods(); 

                String downloadUrl = Url ;

                try
                {
                    url = new URL(downloadUrl);
                    conn = url.openConnection();
                    conn.setUseCaches(false);
                    fileSize = conn.getContentLength();

                    // get the filename
                    lastSlash = url.toString().lastIndexOf('/');
                    fileName = "file.bin";
                    if(lastSlash >=0)
                    {
                        fileName = url.toString().substring(lastSlash + 1);
                    }
                    if(fileName.equals(""))
                    {
                        fileName = "file.bin";
                    }

                    int DOWNLOAD_BUFFER_SIZE = fileSize;

                    // start download
                    inStream = new BufferedInputStream(conn.getInputStream());
                    path = Environment.getExternalStorageDirectory().toString() ;
                    File file = new File(path + "/Download");
                    file.mkdir();

                    path = Environment.getExternalStorageDirectory() + "/Download/" + fileName;
                    outFile = new File(path);
                    fileStream = new FileOutputStream(outFile);
                    outStream = new BufferedOutputStream(fileStream, DOWNLOAD_BUFFER_SIZE);
                    byte[] data = new byte[DOWNLOAD_BUFFER_SIZE];
                    int bytesRead = 0, totalRead = 0;
                    while((bytesRead = inStream.read(data, 0, data.length)) >= 0)
                    {
                        if(Check_your_Internet_is_on?)
                        {
                            outStream.write(data, 0, bytesRead);

                            totalRead += bytesRead;

                            flag = true;
                        }
                        else
                        {
                            flag = outFile.delete();
                            flag = false;
                        }
                    }

                    outStream.close();
                    fileStream.close();
                    inStream.close();

                }
                catch(MalformedURLException e)
                {

                }
                catch(FileNotFoundException e)
                {
                }
                catch(Exception e)
                {
                    }
                return Data;    
            }

        }

希望它会帮助你..！