apk自动安装 取得apk版本号 点击退出两次退出程序

 //打开APK安装程序代码

private void openFile(File file) {

                 // TODO Auto-generated method stub

                 Log.e("OpenFile", file.getName());

                 Intent intent = new Intent();

                 intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                 intent.setAction(android.content.Intent.ACTION_VIEW);

                 intent.setDataAndType(Uri.fromFile(file),

                                 "application/vnd.android.package-archive");

                 startActivity(intent);

         }

//获得apk 版本信息

public static int getAPPVersionCodeFromAPP(Context ctx) {

          int currentVersionCode = 0;

          PackageManager manager = ctx.getPackageManager();

          try {

               PackageInfo info = manager.getPackageInfo(ctx.getPackageName(), 0);

               String appVersionName = info.versionName; // 版本名

               currentVersionCode = info.versionCode; // 版本号

               System.out.println(currentVersionCode + " " + appVersionName);

          } catch (NameNotFoundException e) {

               // TODO Auto-generated catch blockd

               e.printStackTrace();

          }

          return currentVersionCode;

     }

//点击退出两次退出程序

    
     public boolean onKeyDown(int keyCode, KeyEvent event) {
          if (keyCode == KeyEvent.KEYCODE_BACK) {
               if ((System.currentTimeMillis() - mExitTime) > 2000) {
                    Toast.makeText(this, "再按一次退出程序", Toast.LENGTH_SHORT).show();
                    mExitTime = System.currentTimeMillis();
               } else {
                    finish();
               }
               return true;
          }
          return super.onKeyDown(keyCode, event);
     }