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今天我们学习如何实现Android应用的自动更新版本功能，这是在各种语言编写的应用中都会经常遇到的情景。当我们的应用检测到网络上有新版本发布时，系统会提示是否下载新版本应用，当新版本应用下载完毕后，系统会自动安装下载的新版本应用（或跳转到相关安装页面询问）。我们将下载的应用存放在sdcard中，由于整个流程涉及对sdcard的读写操作，所以要赋给我们应用读写外存的权限。下面给出该场景的案例：
1案例技术要点
1.1程序清单文件中需要配置如下权限：
访问网络
<uses-permission android:name="android.permission.INTERNET"/>读取sdcard
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>写入sdcard
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
1.2创建一个HttpURLConnection连接，从网络下载新版本应用到本地
1.3创建一个ProgressBar下载进度条，实时显示下载应用的进度
1.4应用下载完毕后，构建Intent跳转至其安装页面，该Intent的配置如下：
Action：Intent.ACTION_VIEW
DataAndType：Uri.parse("file://" + appFile.toString())，"application/vnd.android.package-archive"
2案例代码陈列
2.1AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.lynn.autoupdate"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".AutoUpdateMainActivity"
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>
</manifest>2.2strings.xml<resources>
<string name="app_name">Android实现应用自动更新</string>
</resources>2.3main.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
2.4下载进度条布局文件：progressBar.xml<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>2.5AutoUpdateMainActivity.javapackage cn.lynn.autoupdate;
import android.app.Activity;
import android.os.Bundle;
public class AutoUpdateMainActivity extends Activity {
private UpdateAppManager updateManager;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
updateManager = new UpdateAppManager(this);
updateManager.checkUpdateInfo();
}
}
2.6UpdateAppManager.javapackage cn.lynn.autoupdate;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ProgressBar;
public class UpdateAppManager {
// 文件分隔符
private static final String FILE_SEPARATOR = "/";
// 外存sdcard存放路径
private static final String FILE_PATH = Environment.getExternalStorageDirectory() + FILE_SEPARATOR +"autoupdate" + FILE_SEPARATOR;
// 下载应用存放全路径
private static final String FILE_NAME = FILE_PATH + "autoupdate.apk";
// 更新应用版本标记
private static final int UPDARE_TOKEN = 0x29;
// 准备安装新版本应用标记
private static final int INSTALL_TOKEN = 0x31;
private Context context;
private String message = "检测到本程序有新版本发布，建议您更新！";
// 以华为天天聊hotalk.apk为例
private String spec = "http://222.42.1.209:81/1Q2W3E4R5T6Y7U8I9O0P1Z2X3C4V5B/mt.hotalk.com:8080/release/hotalk1.9.17.0088.apk";
// 下载应用的对话框
private Dialog dialog;
// 下载应用的进度条
private ProgressBar progressBar;
// 进度条的当前刻度值
private int curProgress;
// 用户是否取消下载
private boolean isCancel;
public UpdateAppManager(Context context) {
this.context = context;
}
private final Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case UPDARE_TOKEN:
progressBar.setProgress(curProgress);
break;
case INSTALL_TOKEN:
installApp();
break;
}
}
};
/**
* 检测应用更新信息
*/
public void checkUpdateInfo() {
showNoticeDialog();
}
/**
* 显示提示更新对话框
*/
private void showNoticeDialog() {
new AlertDialog.Builder(context)
.setTitle("软件版本更新")
.setMessage(message)
.setPositiveButton("下载", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
showDownloadDialog();
}
}).setNegativeButton("以后再说", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
}).create().show();
}
/**
* 显示下载进度对话框
*/
private void showDownloadDialog() {
View view = LayoutInflater.from(context).inflate(R.layout.progressbar, null);
progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("软件版本更新");
builder.setView(view);
builder.setNegativeButton("取消", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
isCancel = true;
}
});
dialog = builder.create();
dialog.show();
downloadApp();
}
/**
* 下载新版本应用
*/
private void downloadApp() {
new Thread(new Runnable() {
@Override
public void run() {
URL url = null;
InputStream in = null;
FileOutputStream out = null;
HttpURLConnection conn = null;
try {
url = new URL(spec);
conn = (HttpURLConnection) url.openConnection();
conn.connect();
long fileLength = conn.getContentLength();
in = conn.getInputStream();
File filePath = new File(FILE_PATH);
if(!filePath.exists()) {
filePath.mkdir();
}
out = new FileOutputStream(new File(FILE_NAME));
byte[] buffer = new byte[1024];
int len = 0;
long readedLength = 0l;
while((len = in.read(buffer)) != -1) {
// 用户点击“取消”按钮，下载中断
if(isCancel) {
break;
}
out.write(buffer, 0, len);
readedLength += len;
curProgress = (int) (((float) readedLength / fileLength) * 100);
handler.sendEmptyMessage(UPDARE_TOKEN);
if(readedLength >= fileLength) {
dialog.dismiss();
// 下载完毕，通知安装
handler.sendEmptyMessage(INSTALL_TOKEN);
break;
}
}
out.flush();
} catch (Exception e) {
e.printStackTrace();
} finally {
if(out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(conn != null) {
conn.disconnect();
}
}
}
}).start();
}
/**
* 安装新版本应用
*/
private void installApp() {
File appFile = new File(FILE_NAME);
if(!appFile.exists()) {
return;
}
// 跳转到新版本应用安装页面
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + appFile.toString()), "application/vnd.android.package-archive");
context.startActivity(intent);
}
}
3案例效果展示
