从之前的安装中获取版本信息

Question

运行 "Update current installation" 选项，如何从之前的安装中获取版本信息？我经历过 API，我见过的最接近的是 public static interface ApplicationRegistry.ApplicationInfo。

编辑
这就是我目前的处理方式。可行，但我不确定这是否是最可行的方法。

import com.install4j.api.ApplicationRegistry;

ApplicationRegistry.ApplicationInfo[] AppInfo = ApplicationRegistry.getApplicationInfoById(context.getApplicationId());

return AppInfo[0].getVersion();

Answer 1

您可以使用

static ApplicationRegistry.ApplicationInfo getApplicationInfoByDir(java.io.File dir)

检查指定目录是否包含由 install4j 安装的应用程序并检索有关它的信息。

这将 return 一个 ApplicationInfo 而不是 ApplicationInfo[]。

Answer 2

例如，以下脚本检查是否已安装相同版本：

// The value returned by context.getInstallationDirectory() will be
// the last installation directory if the user has already installed the application
ApplicationRegistry.ApplicationInfo applicationInfo =
    ApplicationRegistry.getApplicationInfoByDir(context.getInstallationDirectory());

if (applicationInfo == null) {
  // The application has never been installed before
    return true;
}

// The version of this installer is contained in a system installer variable
String myVersion = (String)context.getVariable("sys.version");
if (applicationInfo.getVersion().equals(myVersion)) {
    // In that case the current version is already installed.
    Util.showErrorMessage("The current version is already installed in this directory");
    // By returning "false", the action will fail and the installer will quit.
    // Note that you have to set the "Failure strategy" property of your 
    // "Run script" action to "Quit on error", otherwise the installer will continue.
    return false;
} else {
    return true;
}

例如，这可以用于安装程序 "Startup" 节点中的 "Run script" 操作。

从之前的安装中获取版本信息

Obtain version information from prior installation

java

install4j