Android Studio 下载视频到本地

最近在研究视频下载到本地的问题,像爱奇艺,腾讯视频,迅雷看看等等一些视频播放器,如果在一个播放器里面视频下载到一半用户退出App之后,再次登录从头开始,那么就太可悲了,所以在做视频音频类的项目时,要实现的一个功能就是断点续传,就是将用户下载的视频或者音频等以字节流的形式存入数据库,下次用户再次下载时,将继续上次数据库的接着下载,这样用户体验就会很好,也大大节省了成本.

好了废话不多说,开始今天的正题.

一、先上效果图

二、使用GreenDao我们需要导入依赖

1.以下在项目gradle依赖中添加

compile 'org.greenrobot:greendao:3.2.2'//依赖 在最后一行插入
apply plugin: 'org.greenrobot.greendao' //greenDao在第二行插入
greendao {//在依赖导入汇总添加一个自动添加数据库表名的配置依赖
 schemaVersion 1 //数据库版本号
 daoPackage 'com.example.greendaodemo.database' //设置时生成代码的目录
 targetGenDir 'src/main/java' //设置DaoMaster、DaoSession、Dao目录
}

2.以下在工程gradle依赖中添加

classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'

3.既然我们要联网下载,读写权限肯定不能忘记了

<uses-permission android:name="android.permission.INTERNET"/>
 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
 <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" /> 

三、当然还要有实体类写入实体类后,build下make project一下,让他自动生成GreenDao的三个类

import org.greenrobot.greendao.annotation.Entity;
import org.greenrobot.greendao.annotation.Id;
import org.greenrobot.greendao.annotation.Generated;
/**
 * author:Created by ZhangPengFei.
 * Email: 1271396448@qq.com
 * data: 2018/1/18
 */
@Entity
public class User {
 @Id
 private Long id;
 private Integer thread_id;
 private Integer start_pos;
 private Integer end_pos;
 private Integer compelete_size;
 private String url;
 @Generated(hash = 2041931179)
 public User(Long id, Integer thread_id, Integer start_pos, Integer end_pos,
   Integer compelete_size, String url) {
  this.id = id;
  this.thread_id = thread_id;
  this.start_pos = start_pos;
  this.end_pos = end_pos;
  this.compelete_size = compelete_size;
  this.url = url;
 }
 @Generated(hash = 586692638)
 public User() {
 }
 public Long getId() {
  return this.id;
 }
 public void setId(Long id) {
  this.id = id;
 }
 public Integer getThread_id() {
  return this.thread_id;
 }
 public void setThread_id(Integer thread_id) {
  this.thread_id = thread_id;
 }
 public Integer getStart_pos() {
  return this.start_pos;
 }
 public void setStart_pos(Integer start_pos) {
  this.start_pos = start_pos;
 }
 public Integer getEnd_pos() {
  return this.end_pos;
 }
 public void setEnd_pos(Integer end_pos) {
  this.end_pos = end_pos;
 }
 public Integer getCompelete_size() {
  return this.compelete_size;
 }
 public void setCompelete_size(Integer compelete_size) {
  this.compelete_size = compelete_size;
 }
 public String getUrl() {
  return this.url;
 }
 public void setUrl(String url) {
  this.url = url;
 }
} 

四、本人使用了单例模式,所以在全局配置里初始化了数据库的操作

import android.app.Application;
import com.example.greendaodemo.database.DaoMaster;
import com.example.greendaodemo.database.DaoSession;
import com.example.greendaodemo.database.UserDao;
/**
 * author:Created by ZhangPengFei.
 * Email: 1271396448@qq.com
 * data: 2018/1/18
 */
public class App extends Application {
 public static UserDao userDao;
 @Override
 public void onCreate() {
  super.onCreate();
  DaoMaster.DevOpenHelper devOpenHelper = new DaoMaster.DevOpenHelper(this, "zpf.db", null);
  DaoMaster daoMaster = new DaoMaster(devOpenHelper.getWritableDb());
  DaoSession daoSession = daoMaster.newSession();
  userDao = daoSession.getUserDao();
 }
} 

五、因为我们是多线程,所以写一个保存每个线程下载信息的类

public class DownLoadInfo {
 /**
  * 保存每个下载线程下载信息类
  *
  */
 private int threadId;// 下载器id
 private int startPos;// 开始点
 private int endPos;// 结束点
 private int compeleteSize;// 完成度
 private String url;// 下载文件的URL地址
 public DownLoadInfo(int threadId, int startPos, int endPos,
      int compeleteSize, String url) {
  this.threadId = threadId;
  this.startPos = startPos;
  this.endPos = endPos;
  this.compeleteSize = compeleteSize;
  this.url = url;
 }
 public DownLoadInfo() {
 }
 public String getUrl() {
  return url;
 }
 public void setUrl(String url) {
  this.url = url;
 }
 public int getThreadId() {
  return threadId;
 }
 public void setThreadId(int threadId) {
  this.threadId = threadId;
 }
 public int getStartPos() {
  return startPos;
 }
 public void setStartPos(int startPos) {
  this.startPos = startPos;
 }
 public int getEndPos() {
  return endPos;
 }
 public void setEndPos(int endPos) {
  this.endPos = endPos;
 }
 public int getCompeleteSize() {
  return compeleteSize;
 }
 public void setCompeleteSize(int compeleteSize) {
  this.compeleteSize = compeleteSize;
 }
 @Override
 public String toString() {
  return "DownloadInfo [threadId=" + threadId + ", startPos=" + startPos
    + ", endPos=" + endPos + ", compeleteSize=" + compeleteSize
    + "]";
 }
} 

六、写一个用来记录的类,修改,添加和下载完清空数据库的操作

import android.util.Log;
import com.example.greendaodemo.database.UserDao;
import java.util.ArrayList;
import java.util.List;
import static com.bwie.mtd.App.userDao;
/**
 * author:Created by ZhangPengFei.
 * Email: 1271396448@qq.com
 * data: 2018/1/18
 */
public class DownLoadSqlTool {
 /**
  * 创建下载的具体信息
  */
 public void insertInfos(List<DownLoadInfo> infos) {
  for (DownLoadInfo info : infos) {
   User user = new User(null, info.getThreadId(), info.getStartPos(), info.getEndPos(), info.getCompeleteSize(), info.getUrl());
   userDao.insert(user);
  }
 }
 /**
  * 得到下载具体信息
  */
 public List<DownLoadInfo> getInfos(String urlstr) {
  List<DownLoadInfo> list = new ArrayList<DownLoadInfo>();
  List<User> list1 = userDao.queryBuilder().where(UserDao.Properties.Url.eq(urlstr)).build().list();
  for (User user : list1) {
   DownLoadInfo infoss = new DownLoadInfo(
     user.getThread_id(), user.getStart_pos(), user.getEnd_pos(),
     user.getCompelete_size(), user.getUrl());
   Log.d("main-----", infoss.toString());
   list.add(infoss);
  }
  return list;
 }
 /**
  * 更新数据库中的下载信息
  */
 public void updataInfos(int threadId, int compeleteSize, String urlstr) {
  User user = userDao.queryBuilder()
    .where(UserDao.Properties.Thread_id.eq(threadId), UserDao.Properties.Url.eq(urlstr)).build().unique();
  user.setCompelete_size(compeleteSize);
  userDao.update(user);
 }
 /**
  * 下载完成后删除数据库中的数据
  */
 public void delete(String url) {
  userDao.deleteAll();
 }
} 

七、多线程下载的实践类

import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import java.io.File;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
/**
 * author:Created by ZhangPengFei.
 * Email: 1271396448@qq.com
 * data: 2018/1/18
 */
public class DownloadHttpTool {
 /**
  * 利用Http协议进行多线程下载具体实践类
  */
 private static final String TAG = DownloadHttpTool.class.getSimpleName();
 private int threadCount;//线程数量
 private String urlstr;//URL地址
 private Context mContext;
 private Handler mHandler;
 private List<DownLoadInfo> downloadInfos;//保存下载信息的类
 private String localPath;//目录
 private String fileName;//文件名
 private int fileSize;
 private DownLoadSqlTool sqlTool;//文件信息保存的数据库操作类
 private enum Download_State {
  Downloading, Pause, Ready;//利用枚举表示下载的三种状态
 }
 private Download_State state = Download_State.Ready;//当前下载状态
 private int globalCompelete = 0;//所有线程下载的总数
 public DownloadHttpTool(int threadCount, String urlString,
       String localPath, String fileName, Context context, Handler handler) {
  super();
  this.threadCount = threadCount;
  this.urlstr = urlString;
  this.localPath = localPath;
  this.mContext = context;
  this.mHandler = handler;
  this.fileName = fileName;
  sqlTool = new DownLoadSqlTool();
 }
 //在开始下载之前需要调用ready方法进行配置
 public void ready() {
  Log.w(TAG, "ready");
  globalCompelete = 0;
  downloadInfos = sqlTool.getInfos(urlstr);
  if (downloadInfos.size() == 0) {
   initFirst();
  } else {
   File file = new File(localPath + "/" + fileName);
   if (!file.exists()) {
    sqlTool.delete(urlstr);
    initFirst();
   } else {
    fileSize = downloadInfos.get(downloadInfos.size() - 1)
      .getEndPos();
    for (DownLoadInfo info : downloadInfos) {
     globalCompelete += info.getCompeleteSize();
    }
    Log.w(TAG, "globalCompelete:::" + globalCompelete);
   }
  }
 }
 public void start() {
  Log.w(TAG, "start");
  if (downloadInfos != null) {
   if (state == Download_State.Downloading) {
    return;
   }
   state = Download_State.Downloading;
   for (DownLoadInfo info : downloadInfos) {
    Log.v(TAG, "startThread");
    new DownloadThread(info.getThreadId(), info.getStartPos(),
      info.getEndPos(), info.getCompeleteSize(),
      info.getUrl()).start();
   }
  }
 }
 public void pause() {
  state = Download_State.Pause;
 }
 public void delete() {
  compelete();
  File file = new File(localPath + "/" + fileName);
  file.delete();
 }
 public void compelete() {
  sqlTool.delete(urlstr);
 }
 public int getFileSize() {
  return fileSize;
 }
 public int getCompeleteSize() {
  return globalCompelete;
 }
 //第一次下载初始化
 private void initFirst() {
  Log.w(TAG, "initFirst");
  try {
   URL url = new URL(urlstr);
   HttpURLConnection connection = (HttpURLConnection) url
     .openConnection();
   connection.setConnectTimeout(5000);
   connection.setRequestMethod("GET");
   fileSize = connection.getContentLength();
   Log.w(TAG, "fileSize::" + fileSize);
   File fileParent = new File(localPath);
   if (!fileParent.exists()) {
    fileParent.mkdir();
   }
   File file = new File(fileParent, fileName);
   if (!file.exists()) {
    file.createNewFile();
   }
   // 本地访问文件
   RandomAccessFile accessFile = new RandomAccessFile(file, "rwd");
   accessFile.setLength(fileSize);
   accessFile.close();
   connection.disconnect();
  } catch (Exception e) {
   e.printStackTrace();
  }
  int range = fileSize / threadCount;
  downloadInfos = new ArrayList<DownLoadInfo>();
  for (int i = 0; i < threadCount - 1; i++) {
   DownLoadInfo info = new DownLoadInfo(i, i * range, (i + 1) * range
     - 1, 0, urlstr);
   downloadInfos.add(info);
  }
  DownLoadInfo info = new DownLoadInfo(threadCount - 1, (threadCount - 1)
    * range, fileSize - 1, 0, urlstr);
  downloadInfos.add(info);
  sqlTool.insertInfos(downloadInfos);
 }
 //自定义下载线程
 private class DownloadThread extends Thread {
  private int threadId;
  private int startPos;
  private int endPos;
  private int compeleteSize;
  private String urlstr;
  private int totalThreadSize;
  public DownloadThread(int threadId, int startPos, int endPos,
        int compeleteSize, String urlstr) {
   this.threadId = threadId;
   this.startPos = startPos;
   this.endPos = endPos;
   totalThreadSize = endPos - startPos + 1;
   this.urlstr = urlstr;
   this.compeleteSize = compeleteSize;
  }
  @Override
  public void run() {
   HttpURLConnection connection = null;
   RandomAccessFile randomAccessFile = null;
   InputStream is = null;
   try {
    randomAccessFile = new RandomAccessFile(localPath + "/"
      + fileName, "rwd");
    randomAccessFile.seek(startPos + compeleteSize);
    URL url = new URL(urlstr);
    connection = (HttpURLConnection) url.openConnection();
    connection.setConnectTimeout(5000);
    connection.setRequestMethod("GET");
    connection.setRequestProperty("Range", "bytes="
      + (startPos + compeleteSize) + "-" + endPos);
    is = connection.getInputStream();
    byte[] buffer = new byte[1024];
    int length = -1;
    while ((length = is.read(buffer)) != -1) {
     randomAccessFile.write(buffer, 0, length);
     compeleteSize += length;
     Message message = Message.obtain();
     message.what = threadId;
     message.obj = urlstr;
     message.arg1 = length;
     mHandler.sendMessage(message);
     sqlTool.updataInfos(threadId, compeleteSize, urlstr);
     Log.w(TAG, "Threadid::" + threadId + " compelete::"
       + compeleteSize + " total::" + totalThreadSize);
     if (compeleteSize >= totalThreadSize) {
      break;
     }
     if (state != Download_State.Downloading) {
      break;
     }
    }
   } catch (Exception e) {
    e.printStackTrace();
   } finally {
    try {
     if (is != null) {
      is.close();
     }
     randomAccessFile.close();
     connection.disconnect();
    } catch (Exception e) {
     e.printStackTrace();
    }
   }
  }
 }
} 

八、再写一个接口类

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
/**
 * author:Created by ZhangPengFei.
 * Email: 1271396448@qq.com
 * data: 2018/1/18
 */
public class DownloadUtil {
 private DownloadHttpTool mDownloadHttpTool;
 private OnDownloadListener onDownloadListener;
 private int fileSize;
 private int downloadedSize = 0;
 @SuppressLint("HandlerLeak")
 private Handler mHandler = new Handler() {
  @Override
  public void handleMessage(Message msg) {
   // TODO Auto-generated method stub
   super.handleMessage(msg);
   int length = msg.arg1;
   synchronized (this) {//加锁保证已下载的正确性
    downloadedSize += length;
   }
   if (onDownloadListener != null) {
    onDownloadListener.downloadProgress(downloadedSize);
   }
   if (downloadedSize >= fileSize) {
    mDownloadHttpTool.compelete();
    if (onDownloadListener != null) {
     onDownloadListener.downloadEnd();
    }
   }
  }
 };
 public DownloadUtil(int threadCount, String filePath, String filename,
      String urlString, Context context) {
  mDownloadHttpTool = new DownloadHttpTool(threadCount, urlString,
    filePath, filename, context, mHandler);
 }
 //下载之前首先异步线程调用ready方法获得文件大小信息，之后调用开始方法
 public void start() {
  new AsyncTask<Void,Void,Void>() {
   @Override
   protected Void doInBackground(Void... arg0) {
    // TODO Auto-generated method stub
    mDownloadHttpTool.ready();
    return null;
   }
   @Override
   protected void onPostExecute(Void result) {
    // TODO Auto-generated method stub
    super.onPostExecute(result);
    fileSize = mDownloadHttpTool.getFileSize();
    downloadedSize = mDownloadHttpTool.getCompeleteSize();
    Log.w("Tag", "downloadedSize::" + downloadedSize);
    if (onDownloadListener != null) {
     onDownloadListener.downloadStart(fileSize);
    }
    mDownloadHttpTool.start();
   }
  }.execute();
 }
 public void pause() {
  mDownloadHttpTool.pause();
 }
 public void delete(){
  mDownloadHttpTool.delete();
 }
 public void reset(){
  mDownloadHttpTool.delete();
  start();
 }
 public void setOnDownloadListener(OnDownloadListener onDownloadListener) {
  this.onDownloadListener = onDownloadListener;
 }
 //下载回调接口
 public interface OnDownloadListener {
  public void downloadStart(int fileSize);
  public void downloadProgress(int downloadedSize);//记录当前所有线程下总和
  public void downloadEnd();
 }
} 

九、写一下自己的布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="com.mtd.MainActivity">
 <ProgressBar
  android:id="@+id/progressBar"
  style="?android:attr/progressBarStyleHorizontal"
  android:layout_width="fill_parent"
  android:layout_height="7.5dp"
  android:layout_centerInParent="true"
  android:layout_marginRight="8dp"
  android:max="100"
  android:progress="100"
  android:visibility="visible" />
 <TextView
  android:id="@+id/tv_Progress"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/progressBar"
  android:layout_centerHorizontal="true"
  android:layout_marginLeft="23dp"
  android:layout_marginStart="23dp"
  android:layout_marginTop="18dp"
  android:text="" />
 <Button
  android:id="@+id/downLoad"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentBottom="true"
  android:layout_marginLeft="100dp"
  android:text="下载" />
 <Button
  android:id="@+id/pause"
  android:layout_toRightOf="@id/downLoad"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentBottom="true"
  android:layout_marginLeft="48dp"
  android:layout_marginStart="48dp"
  android:text="暂停" />
</RelativeLayout> 

十、奉上自己的Java代码MainActivity类

import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
 private final String videoUrl = "http://2449.vod.myqcloud.com/2449_22ca37a6ea9011e5acaaf51d105342e3.f20.mp4";
 private TextView tv_progress;//进度显示
 private ProgressBar progressBar;//进度条
 private Button downLoad;//下载按钮
 private Button pause;//暂停按钮
 private String path;//下载路径
 private int max;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv_progress = (TextView) findViewById(R.id.tv_Progress);
  progressBar = (ProgressBar) findViewById(R.id.progressBar);
  downLoad = (Button) findViewById(R.id.downLoad);
  pause = (Button) findViewById(R.id.pause);
  path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/local";
  final DownloadUtil downloadUtil = new DownloadUtil(4, path, "drum.mp4", videoUrl, this);
  downloadUtil.setOnDownloadListener(new DownloadUtil.OnDownloadListener() {
   @Override
   public void downloadStart(int fileSize) {
    Log.i("TAG---fileSize", fileSize + "");
    max = fileSize;//文件总长度
    progressBar.setMax(fileSize);
   }
   @Override
   public void downloadProgress(int downloadedSize) {
    Log.i("TAG---downloadedSize", downloadedSize + "");
    progressBar.setProgress(downloadedSize);
    tv_progress.setText((int) downloadedSize * 100 / max + "%");
   }
   @Override
   public void downloadEnd() {
    Log.i("TAG---end", "End");
   }
  });
  /**
   * 下载的点击事件
   */
  downLoad.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    downloadUtil.start();
   }
  });
  /**
   * 暂停的点击事件
   */
  pause.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    downloadUtil.pause();
   }
  });
 }
} 

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