如何在 GWT 中公开类功能 [英] How to expose class functionality in GWT

问题描述

我有一个用 Java 编写的类库，想将其转换为 Javascript.所有方法都非常简单，主要与操作集合有关.我有一个类，GameControl，我可以实例化它，我希望它的方法暴露给页面上的其他 Javascript 代码.

I have a class library written in Java and want to convert it to Javascript. All methods are pretty simple and mostly have to do with manipulating collections. I have this one class, GameControl, which I could instantiate and I want its methods exposed to other Javascript code on the page.

我想使用 GWT.我在 GWT 中有一个正在编译的正在运行的项目，但我不知道如何公开 GameControl 类的实例(+功能).

I thought to use GWT. I have a running project in GWT which compiles, but I can't figure out how to expose my instance (+functionality) of the GameControl class.

我认为使用 JSNI 来公开我的对象应该可以工作，但它没有.这是它现在的简短版本:

I thought using JSNI to expose my object should work, but it didn't. This is the short version of how it look like right now:

GameEntryPoint.java

import com.google.gwt.core.client.EntryPoint;

public class GameEntryPoint implements EntryPoint {

    private GameControl _gameControl;

    @Override
    public void onModuleLoad() {
        _gameControl = new GameControl();
        expose();
    }


    public native void expose()/*-{
        $wnd.game = [e-mail]::_gameControl;
    }-*/;

}

GameControl.java

package game.client;
public class GameControl {
    public boolean isEmpty(int id){
        // does stuff...
        return true;
    }   
}

所以，GWT 确实编译了代码，我看到有一个 GameControl_0 对象正在构建并设置到 $wnd.game 中，但没有 isEmpty() 方法被找到.

So, GWT indeed compiles the code, and I see that there is a GameControl_0 object being built and set into $wnd.game, but no isEmpty() method to be found.

我预期的最终结果是将 window.game 作为 GameControl 的一个实例，并带有 GameControl 公开的所有公共方法.

My expected end result is to have a window.game as an instance of GameControl with all public methods GameControl exposes.

我该怎么做?

编辑根据 @jusio 的回复，使用 JSNI 公开 window 属性是有效的，但它太冗长了.我正在尝试 gwt-exporter 解决方案.现在我有

Edit As per @jusio's reply, using JSNI to expose window properties explicitly worked, but it was too verbose. I'm trying the gwt-exporter solution. Now I have

GameEntryPoint.java

package game.client;

import org.timepedia.exporter.client.ExporterUtil;
import com.google.gwt.core.client.EntryPoint;

public class GameEntryPoint implements EntryPoint {

    @Override
    public void onModuleLoad() {
        ExporterUtil.exportAll();
    }

}

RoadServer.java

package game.client;

import org.timepedia.exporter.client.Export;
import org.timepedia.exporter.client.ExportPackage;
import org.timepedia.exporter.client.Exportable;


@ExportPackage("game")
@Export("RoadServer")
public class RoadServer implements Exportable {
    int _index;
    int _id;
    public RoadServer(int index,int id){
        this._id=id;
        this._index=index;
    }
}

但仍然没有导出任何代码(特别是不是 RoadServer).

but still none of the code is exported (specifically not RoadServer).

推荐答案

您只公开了 GameControl 的实例.如果你想公开其他方法，你也必须公开它们.例如:

You have exposed only instance of the GameControl. If you want to expose other methods, you'll have to expose them as well. For example:

 public native void expose()/*-{
        var control = [e-mail]::_gameControl;   
        var gameInstance = {
            gameControl: control,
            isEmpty:function(param){
              [e-mail]::isEmpty(*)(param);   
            }  

        }


        $wnd.game = gameInstance;
    }-*/;

还有一个名为 gwt-exporter 的框架，它可能会让事情变得更容易给你

Also there is a framework called gwt-exporter, it might make things easier for you

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