Android检查更新（是否强制更新）

Android应用客户端通常会需要更新，而且根据需求分为普通更新和强制更新。是否强制更新可通过检查更新时从服务器获取的标志位来判断。

public class UpdateManager {    private Context mContext; //上下文    private String apkUrl =             "http://183.232.83.10/dd.myapp.com/16891/" +            "C4F9FF39FAE9184222DC278DC7309611.apk?mkey" +            "=5541c92b6a9cca8d&f=d388&fsname=com.yangmbin" +            ".beauty_1.1_2.apk&asr=8eff&p=.apk"; //apk下载地址    private static final String savePath = "/sdcard/updateAPK/"; //apk保存到SD卡的路径    private static final String saveFileName = savePath + "apkName.apk"; //完整路径名    private ProgressBar mProgress; //下载进度条控件    private static final int DOWNLOADING = 1; //表示正在下载    private static final int DOWNLOADED = 2; //下载完毕    private static final int DOWNLOAD_FAILED = 3; //下载失败    private int progress; //下载进度    private boolean cancelFlag = false; //取消下载标志位    private double serverVersion = 2.0; //从服务器获取的版本号    private double clientVersion = 1.0; //客户端当前的版本号    private String updateDescription = "更新描述"; //更新内容描述信息    private boolean forceUpdate = true; //是否强制更新    private AlertDialog alertDialog1, alertDialog2; //表示提示对话框、进度条对话框    /** 构造函数 */    public UpdateManager(Context context) {        this.mContext = context;    }    /** 显示更新对话框 */    public void showNoticeDialog() {        //如果版本最新，则不需要更新        if (serverVersion <= clientVersion)            return;        AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);        dialog.setTitle("发现新版本 ：" + serverVersion);        dialog.setMessage(updateDescription);        dialog.setPositiveButton("现在更新", new OnClickListener() {            @Override            public void onClick(DialogInterface arg0, int arg1) {                // TODO Auto-generated method stub                arg0.dismiss();                showDownloadDialog();            }        });        //是否强制更新        if (forceUpdate == false) {            dialog.setNegativeButton("待会更新", new OnClickListener() {                @Override                public void onClick(DialogInterface arg0, int arg1) {                    // TODO Auto-generated method stub                    arg0.dismiss();                }            });        }        alertDialog1  = dialog.create();        alertDialog1.setCancelable(false);        alertDialog1.show();    }    /** 显示进度条对话框 */    public void showDownloadDialog() {        AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);        dialog.setTitle("正在更新");        final LayoutInflater inflater = LayoutInflater.from(mContext);        View v = inflater.inflate(R.layout.softupdate_progress, null);        mProgress = (ProgressBar) v.findViewById(R.id.update_progress);        dialog.setView(v);        //如果是强制更新，则不显示取消按钮        if (forceUpdate == false) {            dialog.setNegativeButton("取消", new OnClickListener() {                @Override                public void onClick(DialogInterface arg0, int arg1) {                    // TODO Auto-generated method stub                    arg0.dismiss();                    cancelFlag = false;                }            });        }        alertDialog2  = dialog.create();        alertDialog2.setCancelable(false);        alertDialog2.show();        //下载apk        downloadAPK();    }    /** 下载apk的线程 */    public void downloadAPK() {        new Thread(new Runnable() {            @Override            public void run() {                // TODO Auto-generated method stub                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(DOWNLOADING);                          if(numread <= 0){                                  //下载完成通知安装                              mHandler.sendEmptyMessage(DOWNLOADED);                              break;                          }                          fos.write(buf, 0, numread);                      }while(!cancelFlag); //点击取消就停止下载.                      fos.close();                      is.close();                 } catch(Exception e) {                    mHandler.sendEmptyMessage(DOWNLOAD_FAILED);                    e.printStackTrace();                }            }        }).start();    }    /** 更新UI的handler */    private Handler mHandler = new Handler() {        @Override        public void handleMessage(Message msg) {            // TODO Auto-generated method stub            switch (msg.what) {            case DOWNLOADING:                mProgress.setProgress(progress);                break;            case DOWNLOADED:                if (alertDialog2 != null)                    alertDialog2.dismiss();                installAPK();                break;            case DOWNLOAD_FAILED:                Toast.makeText(mContext, "网络断开，请稍候再试", Toast.LENGTH_LONG).show();                break;            default:                break;            }        }    };    /** 下载完成后自动安装apk */    public void installAPK() {        File apkFile = new File(saveFileName);        if (!apkFile.exists()) {            return;        }        Intent intent = new Intent(Intent.ACTION_VIEW);        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);        intent.setDataAndType(Uri.parse("file://" + apkFile.toString()), "application/vnd.android.package-archive");           mContext.startActivity(intent);     }}

对话框中进度条用到的布局：softupdate_progress.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="wrap_content">    <ProgressBar        android:id="@+id/update_progress"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_centerHorizontal="true"        style="?android:attr/progressBarStyleHorizontal" /></RelativeLayout>

使用方法：

//这里来检测版本是否需要更新  mUpdateManager = new UpdateManager(this);  mUpdateManager.showNoticeDialog();

检查更新通常是在初始化的时候，请求服务器检查版本，如果有更新，则把相关url、是否强制更新和版本号等信息通过showNoticeDialog的参数传递进去，做相关的初始化即可。