Android通过startService实现文件批量下载

package com.ispring.startservicedemo;

import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class DownloadService extends Service {
  //存储所有的startId
  private List allStartIdList = new ArrayList<>();
  //存储已经下载完成的startId
  private List finishedStartIdList = new ArrayList<>();

  private Handler handler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
      if(msg.what == 1){
        String tip = (String)msg.obj;
        Toast.makeText(DownloadService.this, tip, Toast.LENGTH_LONG).show();
      }
    }
  };

  class DownloadThread extends Thread {

    //对应的intent的startId信息
    private int startId = 0;

    //要下载的文章名称
    private String blogName = null;

    //要下载的文章地址
    private String blogUrl = null;

    public DownloadThread(int startId, String name, String url){
      this.startId = startId;
      this.blogName = name;
      this.blogUrl = url;
    }

    @Override
    public void run() {
      HttpURLConnection cOnn= null;
      InputStream is = null;
      try{
        //下载指定的文件
        URL url = new URL(this.blogUrl);
        cOnn= (HttpURLConnection)url.openConnection();
        if(conn != null){
          //我们在此处得到所下载文章的输入流，可以将其以文件的形式写入到存储卡上面或
          //将其读取出文本显示在App中
          is = conn.getInputStream();
        }
      }catch (MalformedURLException e){
        e.printStackTrace();
      }catch (IOException e){
        e.printStackTrace();
      }finally {
        if(conn != null){
          conn.disconnect();
        }
      }

      finishedStartIdList.add(startId);

      if(finishedStartIdList.containsAll(allStartIdList)){
        String tip = "全部下载完成, 数量" + finishedStartIdList.size();
        Message msg = handler.obtainMessage(1);
        msg.obj = tip;
        handler.sendMessage(msg);
      }

      Log.i("DemoLog", "stopSelf(" + startId + ")");
      stopSelf(startId);
    }
  }

  @Override
  public void onCreate() {
    super.onCreate();
    Log.i("DemoLog", "DownloadService -> onCreate");
  }

  @Override
  public int onStartCommand(Intent intent, int flags, int startId) {
    allStartIdList.add(startId);
    String name = intent.getStringExtra("name");
    String url = intent.getStringExtra("url");
    Log.i("DemoLog", "DownloadService -> onStartCommand, startId: " + startId + ", name: " + name);
    DownloadThread downloadThread = new DownloadThread(startId, name, url);
    downloadThread.start();
    return START_REDELIVER_INTENT;
  }

  @Override
  public IBinder onBind(Intent intent) {
    return null;
  }

  @Override
  public void onDestroy() {
    super.onDestroy();
    Log.i("DemoLog", "DownloadService -> onDestroy");
  }
}

package com.ispring.startservicedemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;


public class DownloadActivity extends Activity implements Button.OnClickListener {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_download);
  }

  @Override
  public void onClick(View v) {
    List list = new ArrayList<>();
    list.add("Android中startService基本使用方法概述;https://www.jb51.net/article/76470.htm");
    list.add("Android登陆界面实现清除输入框内容和震动效果;https://www.jb51.net/article/76328.htm");

    Iterator iterator = list.iterator();

    while (iterator.hasNext()){
      String str = (String)iterator.next();
      String[] splits = str.split(";");
      String name = splits[0];
      String url = splits[1];
      Intent intent = new Intent(this, DownloadService.class);
      intent.putExtra("name", name);
      intent.putExtra("url", url);
      startService(intent);
    }
  }
}