【移动应用开发技术】Android Studio如何下载视频到本地

【移动应用开发技术】AndroidStudio如何下载视频到本地

一、先上效果图/upload/information/20200623/125/124043.png/upload/information/20200623/125/124044.png二、使用GreenDao我们需要导入依赖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

}classpath

'org.greenrobot:greendao-gradle-plugin:3.2.2'<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="viders.gsf.permission.READ_GSERVICES"

/>三、当然还要有实体类写入实体类后,build下makeproject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@

*

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;

pelete_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

pelete_size;

}

public

void

setCompelete_size(Integer

compelete_size)

{

pelete_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@

*

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;

peleteSize

=

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)

{

peleteSize

=

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@

*

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

.HttpURLConnection;

import

.URL;

import

java.util.ArrayList;

import

java.util.List;

/**

*

author:Created

by

ZhangPengFei.

*

Email:

1271396448@

*

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;

peleteSize

=

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@

*

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)

{

mDownloadHttpTpelete();

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="/apk/res/android"

xmlns:app="/apk/res-auto"

xmlns:tools="/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context="com.mtd.MainActivity">

<ProgressBar

android:id="@+id/progressBar"

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.widge