Android应用自动更新功能

一个好的应用软件都是需要好的维护，从初出版本到最后精品，这个过程需要版本不停的更新，那么如何让用户第一时间获取最新的应用安装包呢？那么就要求我们从第一个版本就要实现升级模块这一功能。

自动更新功能的实现原理，就是我们事先和后台协商好一个接口，我们在应用的主Activity里，去访问这个接口，如果需要更新，后台会返回一些数据(比如，提示语；最新版本的url等)。然后我们给出提示框，用户点击开始下载，下载完成开始覆盖安装程序，这样用户的应用就保持最新的拉。

为了让大家容易理解，我像往常一样准备一个小例子，这里为了方便我就省去了和后台交互部分了。步骤分别如下：

第一步：新建一个Android工程命名为:UpdateDemo.代码结构如下图所示：

第二步：新建一个UpdateManager.Java类，负责软件更新功能模块，代码如下：

[java] view plain copy print ? package com.tutor.update;    import java.io.File;  import java.io.FileOutputStream;  import java.io.IOException;  import java.io.InputStream;  import java.net.HttpURLConnection;  import java.net.MalformedURLException;  import java.net.URL;      import android.app.AlertDialog;  import android.app.Dialog;  import android.app.AlertDialog.Builder;  import android.content.Context;  import android.content.DialogInterface;  import android.content.Intent;  import android.content.DialogInterface.OnClickListener;  import android.net.Uri;  import android.os.Handler;  import android.os.Message;  import android.view.LayoutInflater;  import android.view.View;  import android.widget.ProgressBar;    public class UpdateManager {        private Context mContext;            //提示语      private String updateMsg = “有最新的软件包哦，亲快下载吧~”;            //返回的安装包url      private String apkUrl = “http://softfile.3g.qq.com:8080/msoft/179/24659/43549/qq_hd_mini_1.4.apk”;                  private Dialog noticeDialog;            private Dialog downloadDialog;       /* 下载包安装路径 */      private static final String savePath = “/sdcard/updatedemo/”;            private static final String saveFileName = savePath + “UpdateDemoRelease.apk”;        /* 进度条与通知ui刷新的handler和msg常量 */      private ProgressBar mProgress;              private static final int DOWN_UPDATE = 1;            private static final int DOWN_OVER = 2;            private int progress;            private Thread downLoadThread;            private boolean interceptFlag = false;            private Handler mHandler = new Handler(){          public void handleMessage(Message msg) {              switch (msg.what) {              case DOWN_UPDATE:                  mProgress.setProgress(progress);                  break;              case DOWN_OVER:                                    installApk();                  break;              default:                  break;              }          };      };            public UpdateManager(Context context) {          this.mContext = context;      }            //外部接口让主Activity调用      public void checkUpdateInfo(){          showNoticeDialog();      }                  private void showNoticeDialog(){          AlertDialog.Builder builder = new Builder(mContext);          builder.setTitle(”软件版本更新”);          builder.setMessage(updateMsg);          builder.setPositiveButton(”下载”, new OnClickListener() {                       @Override              public void onClick(DialogInterface dialog, int which) {                  dialog.dismiss();                  showDownloadDialog();                         }          });          builder.setNegativeButton(”以后再说”, new OnClickListener() {                         @Override              public void onClick(DialogInterface dialog, int which) {                  dialog.dismiss();                             }          });          noticeDialog = builder.create();          noticeDialog.show();      }            private void showDownloadDialog(){          AlertDialog.Builder builder = new Builder(mContext);          builder.setTitle(”软件版本更新”);                    final LayoutInflater inflater = LayoutInflater.from(mContext);          View v = inflater.inflate(R.layout.progress, null);          mProgress = (ProgressBar)v.findViewById(R.id.progress);                    builder.setView(v);          builder.setNegativeButton(”取消”, new OnClickListener() {               @Override              public void onClick(DialogInterface dialog, int which) {                  dialog.dismiss();                  interceptFlag = true;              }          });          downloadDialog = builder.create();          downloadDialog.show();                    downloadApk();      }            private Runnable mdownApkRunnable = new Runnable() {              @Override          public void run() {              try {                  URL url = new URL(apkUrl);                                HttpURLConnection conn = (HttpURLConnection)url.openConnection();                  conn.connect();                  int length = conn.getContentLength();                  InputStream is = conn.getInputStream();                                    File file = new File(savePath);                  if(!file.exists()){                      file.mkdir();                  }                  String apkFile = saveFileName;                  File ApkFile = new File(apkFile);                  FileOutputStream fos = new FileOutputStream(ApkFile);                                    int count = 0;                  byte buf[] = new byte[1024];                                    do{                                       int numread = is.read(buf);                      count += numread;                      progress =(int)(((float)count / length) * 100);                      //更新进度                      mHandler.sendEmptyMessage(DOWN_UPDATE);                      if(numread <= 0){                              //下载完成通知安装                          mHandler.sendEmptyMessage(DOWN_OVER);                          break;                      }                      fos.write(buf,0,numread);                  }while(!interceptFlag);//点击取消就停止下载.                                    fos.close();                  is.close();              } catch (MalformedURLException e) {                  e.printStackTrace();              } catch(IOException e){                  e.printStackTrace();              }                        }      };             /**      * 下载apk      * @param url      */            private void downloadApk(){          downLoadThread = new Thread(mdownApkRunnable);          downLoadThread.start();      }       /**      * 安装apk      * @param url      */      private void installApk(){          File apkfile = new File(saveFileName);          if (!apkfile.exists()) {              return;          }              Intent i = new Intent(Intent.ACTION_VIEW);          i.setDataAndType(Uri.parse(”file://” + apkfile.toString()), “application/vnd.android.package-archive”);           mContext.startActivity(i);            }  }   package com.tutor.update; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import android.app.AlertDialog; import android.app.Dialog; import android.app.AlertDialog.Builder; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.DialogInterface.OnClickListener; import android.net.Uri; import android.os.Handler; import android.os.Message; import android.view.LayoutInflater; import android.view.View; import android.widget.ProgressBar; public class UpdateManager { private Context mContext; //提示语 private String updateMsg = "有最新的软件包哦，亲快下载吧~"; //返回的安装包url private String apkUrl = "http://softfile.3g.qq.com:8080/msoft/179/24659/43549/qq_hd_mini_1.4.apk"; private Dialog noticeDialog; private Dialog downloadDialog; /* 下载包安装路径 */ private static final String savePath = "/sdcard/updatedemo/"; private static final String saveFileName = savePath + "UpdateDemoRelease.apk"; /* 进度条与通知ui刷新的handler和msg常量 */ private ProgressBar mProgress; private static final int DOWN_UPDATE = 1; private static final int DOWN_OVER = 2; private int progress; private Thread downLoadThread; private boolean interceptFlag = false; private Handler mHandler = new Handler(){ public void handleMessage(Message msg) { switch (msg.what) { case DOWN_UPDATE: mProgress.setProgress(progress); break; case DOWN_OVER: installApk(); break; default: break; } }; }; public UpdateManager(Context context) { this.mContext = context; } //外部接口让主Activity调用 public void checkUpdateInfo(){ showNoticeDialog(); } private void showNoticeDialog(){ AlertDialog.Builder builder = new Builder(mContext); builder.setTitle("软件版本更新"); builder.setMessage(updateMsg); builder.setPositiveButton("下载", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); showDownloadDialog(); } }); builder.setNegativeButton("以后再说", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); noticeDialog = builder.create(); noticeDialog.show(); } private void showDownloadDialog(){ AlertDialog.Builder builder = new Builder(mContext); builder.setTitle("软件版本更新"); final LayoutInflater inflater = LayoutInflater.from(mContext); View v = inflater.inflate(R.layout.progress, null); mProgress = (ProgressBar)v.findViewById(R.id.progress); builder.setView(v); builder.setNegativeButton("取消", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); interceptFlag = true; } }); downloadDialog = builder.create(); downloadDialog.show(); downloadApk(); } private Runnable mdownApkRunnable = new Runnable() { @Override public void run() { try { URL url = new URL(apkUrl); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.connect(); int length = conn.getContentLength(); InputStream is = conn.getInputStream(); File file = new File(savePath); if(!file.exists()){ file.mkdir(); } String apkFile = saveFileName; File ApkFile = new File(apkFile); FileOutputStream fos = new FileOutputStream(ApkFile); int count = 0; byte buf[] = new byte[1024]; do{ int numread = is.read(buf); count += numread; progress =(int)(((float)count / length) * 100); //更新进度 mHandler.sendEmptyMessage(DOWN_UPDATE); if(numread <= 0){ //下载完成通知安装 mHandler.sendEmptyMessage(DOWN_OVER); break; } fos.write(buf,0,numread); }while(!interceptFlag);//点击取消就停止下载. fos.close(); is.close(); } catch (MalformedURLException e) { e.printStackTrace(); } catch(IOException e){ e.printStackTrace(); } } }; /** * 下载apk * @param url */ private void downloadApk(){ downLoadThread = new Thread(mdownApkRunnable); downLoadThread.start(); } /** * 安装apk * @param url */ private void installApk(){ File apkfile = new File(saveFileName); if (!apkfile.exists()) { return; } Intent i = new Intent(Intent.ACTION_VIEW); i.setDataAndType(Uri.parse("file://" + apkfile.toString()), "application/vnd.android.package-archive"); mContext.startActivity(i); } } 第三步：在MainActivity.java也就是主Activity调用,代码如下:

[java] view plain copy print ? package com.tutor.update;    import android.app.Activity;  import android.os.Bundle;    public class MainAcitivity extends Activity {              private UpdateManager mUpdateManager;      @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);                    //这里来检测版本是否需要更新          mUpdateManager = new UpdateManager(this);          mUpdateManager.checkUpdateInfo();      }       }   package com.tutor.update; import android.app.Activity; import android.os.Bundle; public class MainAcitivity extends Activity { private UpdateManager mUpdateManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //这里来检测版本是否需要更新 mUpdateManager = new UpdateManager(this); mUpdateManager.checkUpdateInfo(); } } 第四步：添加程序所用的资源与权限：

下载的时候用到了ProgressBar,所以事先写了一个progress.xml布局文件，代码如下:

[java] view plain copy print ? <?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=”wrap_content”>        <ProgressBar      android:id=”@+id/progress”      android:layout_width=”fill_parent”      android:layout_height=”wrap_content”      style=”?android:attr/progressBarStyleHorizontal”    />  </LinearLayout>   <?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="wrap_content"> <ProgressBar android:id="@+id/progress" android:layout_width="fill_parent" android:layout_height="wrap_content" style="?android:attr/progressBarStyleHorizontal" /> </LinearLayout> 下载的时候用到了网络部分，所以要在AndroidManifest.xml中添加网络权限，代码如下:

[java] view plain copy print ? <uses-permission android:name=“android.permission.INTERNET” />   <uses-permission android:name="android.permission.INTERNET" /> 第五步:运行查看效果如下:

    

 图一:提示有最新包                                                                                   图二：点击开始下载

图三：下载完开始安装，我这里模拟器空间不足了。

OK~大功告成了，继续看球，阿森纳已经0:1了，希望范大将军救驾！大家晚安~稍后将会为大家分享更多内容，尽请期待！

源代码点击进入==>