防止在較新版本上安裝較舊版本

Question

我想設置某些版本驗證以防止最終用戶在較新版本上安裝舊版本。防爆。防止安裝版本3時安裝版本1。做這個的最好方式是什麼？

Answer 1

您可以將「運行腳本」操作添加到安裝程序的「啓動」節點，以驗證已安裝的版本。

下面的代碼片段演示瞭如何驗證對較新版本，如果他們是簡單的整數：

// 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; 
} 

if (Integer.parseInt(applicationInfo.getVersion()) > 
    Integer.parseInt(context.getVersion())) { 
    Util.showErrorMessage("A more recent version has already been" + 
    " 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; 
}