获取当前的版本号

 public double getVersionCode() {
    try {
        int versionCode = getPackageManager().getPackageInfo(getPackageName(), 0).versionCode;
        return versionCode;
    } catch (PackageManager.NameNotFoundException e) {
        e.printStackTrace();
    }
    return 0;
}

将版本号设置成1.0

         double version = getVersionCode();
         String result = String.format("%.1f",version);
         title.setText(String.format(getResources().getString(R.string.version_code, result)));