打算总结7篇笔记。来学习下断点续传---多线程下载进阶
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="sms.down"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="9" />
<application
android:icon="@drawable/icon"
android:label="@string/app_name" >
<activity
android:name=".MulThreadDownload"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<!-- 訪问 internet 权限 -->
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
</manifest>main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <ProgressBar android:id="@+id/progressBar1" style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > </ProgressBar> <TextView android:id="@+id/textView1" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <ProgressBar android:id="@+id/progressBar2" style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > </ProgressBar> <TextView android:id="@+id/textView2" android:layout_width="fill_parent" android:layout_height="wrap_content" /> </LinearLayout>
MulThreadDownload
package sms.down;
import java.io.File;
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 android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.widget.ProgressBar;
import android.widget.TextView;
public class MulThreadDownload extends Activity {
// 下载进度条1
private ProgressBar pb1 = null;
private TextView tv1 = null;
// 下载进度条2
private ProgressBar pb2 = null;
private TextView tv2 = null;
// 下载后存放的文件夹地址
private final String root = Environment.getExternalStorageDirectory()
.getAbsolutePath() + File.separator;
// 网络资源Url地址信息
private final String downloadFile = "http://gongxue.cn/yingyinkuaiche/UploadFiles_9323/201008/2010082909434077.mp3";
private final String downloadFile1 = "http://gongxue.cn/yingyinkuaiche/UploadFiles_9323/201008/2010082909434077.mp3";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main);
this.pb1 = (ProgressBar) this.findViewById(R.id.progressBar1);
this.tv1 = (TextView) this.findViewById(R.id.textView1);
this.pb2 = (ProgressBar) this.findViewById(R.id.progressBar2);
this.tv2 = (TextView) this.findViewById(R.id.textView2);
this.download(this.downloadFile, this.root, this.pb1, this.tv1);
this.download(this.downloadFile1, this.root, this.pb2, this.tv2);
}
/**
* 開始线程进行下载 參数：网络资源地址，存放的文件夹。进度条。提示的文本信息
*/
private void download(String url, String targetPath, ProgressBar pb,
TextView tv) {
DownloadThread dt = new DownloadThread(url, targetPath, pb, tv);
dt.start();
}
// 自己定义一个Handler类。处理线程消息
public class MyHandler extends Handler {
private final ProgressBar progressBar;
private final TextView textView;
// 通过构造函数来确定给哪个ProgressBar刷新
public MyHandler(ProgressBar progressBar, TextView textView) {
this.progressBar = progressBar;
this.textView = textView;
}
public void handleMessage(Message msg) {
this.progressBar.setProgress(msg.arg1);
this.textView.setText(msg.arg1 + "%");
super.handleMessage(msg);
}
}
// 下载线程
public class DownloadThread extends Thread {
private String url = "";
private String targetPath = "";
private ProgressBar pb = null;
private TextView tv = null;
public DownloadThread(String url, String targetPath, ProgressBar pb,
TextView tv) {
this.url = url;
this.targetPath = targetPath;
this.pb = pb;
this.tv = tv;
this.myHandler = new MyHandler(this.pb, this.tv);
}
// 初始化下载总大小为0
private int hasDownload = 0;
// 文件大小
private int size = 0;
// 下载比例
private int rate = 0;
// 读写流须要的
private int len = -1;
private final byte buffer[] = new byte[4 * 1024];
private MyHandler myHandler = null;
private Message msg = null;
@Override
public void run() {
// http://gongxue.cn/yingyinkuaiche/UploadFiles_9323/201008/2010082909434077.mp3
String targetFileName = this.targetPath
+ this.url.substring(this.url.lastIndexOf("/") + 1,
this.url.length());
File downloadFile = new File(targetFileName);
// 文件不存在。就进行创建工作
if (!downloadFile.exists()) {
try {
downloadFile.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
// 获取URL地址
URL fileUrl = new URL(this.url);
// 打开连接
HttpURLConnection conn = (HttpURLConnection) fileUrl
.openConnection();
// 获取文件大小
this.size = conn.getContentLength();
// 获取输入流
InputStream is = conn.getInputStream();
// 创建一个输出流
OutputStream os = new FileOutputStream(targetFileName);
while ((this.len = is.read(this.buffer)) != -1) {
// write(byte[] buffer)
os.write(this.buffer);
// 通过循环读取的，进而改变下载量--更新下载进度
this.hasDownload += this.len;
// 获取下载比例
this.rate = (this.hasDownload * 100 / this.size);
// 创建消息对象
this.msg = new Message();
// 携带下载比例
this.msg.arg1 = this.rate;
// 发送消息
this.myHandler.sendMessage(this.msg);
System.out.println(this.rate + "%");
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}