PackageManager packageManager=this.getPackageManager();
      try {
		PackageInfo packageInfo=packageManager.getPackageInfo(this.getPackageName(), 0);
		long firstInstallTime=packageInfo.firstInstallTime;//应用第一次安装的时间
		int versionCode=packageInfo.versionCode;//应用现在的版本号
		String versionName=packageInfo.versionName;//应用现在的版本名称
		System.out.println("firstInstallTime="+firstInstallTime+",versionCode="+versionCode+",versionName="+versionName);

                    //如下可获得更多信息
                       ApplicationInfo   applicationInfo=packageInfo.applicationInfo;
	          String name=applicationInfo.name;
		String packageName=applicationInfo.packageName;
		String permission=applicationInfo.permission;			
	} catch (Exception e) {
		e.printStackTrace();
       }