如何将主类的实例传递给多个侦听器? [英] How do I pass instances of the main class to multiple listeners?

问题描述

所以，我一直在研究插件.一切都很好，直到我偶然发现了一个问题.我正在使用单独的Listener(implements Listener)类来管理事件，但是对于其中某些事件，我需要访问JavaPlugin方法，例如获取配置文件.

So, I've been working on a plugin. It was going great, until I stumbled on an issue. I'm using separate Listener (implements Listener) classes to manage my events, but for some of them, I need to access JavaPlugin methods, like for getting the configuration file.

在我的侦听器类中使用下面的构造函数是有效的，但是如果我尝试在另一个类中使用相同的东西，则Eclipse会给它加上一个可爱的红色下划线，表示blank final field plugin may have not been initialized

Using the constructor below in my listener class works, but if I try to use the same thing in another class, Eclipse gives it a lovely red underline, saying blank final field plugin may have not been initialized

private final MainClass plugin;
public ListenerClass(MainClass instance){
    this.plugin = instance;
}

如前所述，以上代码有效，但仅适用于一个侦听器. 当使用返回对象的方法时，构造函数以下会引发NPE.我不知道这是否是因为插件实例实际上是 返回为null还是 if 是否没有句柄是null.

As said before, the above code works, but only for one listener. The constructor below throws an NPE when using a method that returns an object. I don't know if this is because the plugin instance is actually returning as null or if there is no handle for if it is null.

// The only difference between this constructor and the last is that the final
// modifier was removed.
private MainClass plugin;
public ListenerClass(MainClass instance){
    this.plugin = instance;
}

FileConfiguration config = plugin.getConfig(); // throws NPE
// Let's pretend that the line above isn't there, and I just use the getConfig() method instead.

@EventHandler
public void onJoin(PlayerJoinEvent event){
    if(plugin.getConfig().getString("Strings.cat-toy").toLowerCase().equals("string")){ // throws NPE
        // do stuff
    }
}

推荐答案

我做的事情与大多数人不同.假设您的类extends JavaPlugin是Main.java，则应在任何方法内添加以下代码:

I do something a lot different than most people do. Say your class that extends JavaPlugin is Main.java, you would add the following code NOT inside of any methods:

public static Main plugin;

然后将其添加到您的onEnable():

plugin = this

因此，您的Main类可能看起来像这样.

So, your Main class could look something like this.

public class Main extends JavaPlugin{
  public static Main plugin; //create the variable

  @Override
  public void onEnable(){
    plugin = this; //assign plugin to this class
    //other onEnable things
  }

  @Override
  public void onDisable(){
    //onDisable things
    plugin = null; //best to put this AFTER running any methods here
  }
}

然后，在要使用JavaPlugin方法的任何类中，只需使用Main.plugin

Then, in any class that you want to use the JavaPlugin methods in, just use Main.plugin

因此，如果您想在另一个类中获取插件的配置，则可以执行以下操作:

So, if you wanted to get the config for your plugin in another class, you could do:

YamlConfiguration config = Main.plugin.getConfig();

在将plugin分配给主文件后，请确保执行此操作.假设Handler.setup()在其中使用YamlConfiguration config = Main.plugin.getConfig();，并且您想在启用插件时运行该方法.您可以这样做:

Just make sure that you do this AFTER you assign plugin to your Main file. Let's say Handler.setup() uses YamlConfiguration config = Main.plugin.getConfig(); in it, and you want to run that method when your plugin is enabled. You could do this:

public void onEnable(){
  plugin = this;
  Handler.setup();
}

但是不:

public void onEnable(){
  Handler.setup();
  plugin = this;
}

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