这篇文章将为大家详细讲解有关Android Studio如何下载视频到本地，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
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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
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 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 getInfos(String urlstr) {
List list = new ArrayList();
List 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 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();
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() {
@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
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();
}
});
}
}关于“Android Studio如何下载视频到本地”这篇文章就分享到这里了，希望以上内容可以对大家有一定的帮助，使各位可以学到更多知识，如果觉得文章不错，请把它分享出去让更多的人看到。
文章题目：AndroidStudio如何下载视频到本地
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http://cdweb.net/article/jscsse.html
