使用Android Eclipse下载文件时遇到困难

Question

我正在努力制作一个简单的应用程序来下载互联网文件这里我的代码我从另一个问题编辑了一点，但每当我运行我的应用程序时，我仍然没有响应错误，任何人都可以向我展示更正甚至不同的方式?

    package com.example.downloading;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import org.apache.http.util.ByteArrayBuffer;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.os.ResultReceiver;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.IntentService;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
public class MainActivity extends Activity {
    Button startBtn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startBtn = (Button)findViewById(R.id.download_button);
        startBtn.setOnClickListener(new OnClickListener(){
            public void onClick(View v) {
                String url = "my stuff";
                DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
                request.setDescription("descrition");
                request.setTitle("title");
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                    request.allowScanningByMediaScanner();
                    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                }
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "etc.mp3");

                DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
                manager.enqueue(request);
            }
        });
    }
}

Answer 1

public void DownLoadTheMusic(){
        try {
            URL url = new URL("http://www.tagsinfosoft.com/android/shelf/Shelf_Cam.mp3");
            HttpURLConnection c = (HttpURLConnection) url.openConnection();
            c.setRequestMethod("GET");
            c.setDoOutput(true);
            c.connect();
            String PATH = Environment.getExternalStorageDirectory() + "/download/";
            File file = new File(PATH);
            file.mkdirs();
            File outputFile = new File(file, "Shelf_Cam.mp3");
            FileOutputStream fos = new FileOutputStream(outputFile);
            InputStream is = c.getInputStream();
            byte[] buffer = new byte[1024];
            int len1 = 0;
            while ((len1 = is.read(buffer)) != -1) {
                fos.write(buffer, 0, len1);
            }
            fos.close();
            is.close();

        } catch (IOException e) {
            Toast.makeText(getApplicationContext(), "Update error!", Toast.LENGTH_LONG).show();
        }
    }  

call this in a Asynctask


    public class downloadMusic extends AsyncTask<Integer, Integer, Integer>
        {

            @Override
            protected Integer doInBackground(Integer... params) {
                // TODO Auto-generated method stub
                try {
                    DownLoadTheMusic();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                return null;
            }
            @Override
            protected void onPostExecute(Integer result) {
                // TODO Auto-generated method stub
                super.onPostExecute(result);
                Context context=shelf.this;
                pd.dismiss();
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory() + "/download/" + "Shelf_Cam.mp3")), "application/vnd.android.package-archive");
                startActivity(intent);  
            }
            @Override
            protected void onPreExecute() {
                // TODO Auto-generated method stub
                super.onPreExecute();
                pd=ProgressDialog.show(shelf.this,"Updating","Please wait....." );
            }
        }