Question

我正在为Vaadin申请我的课程。我必须在屏幕上绘制一些地图，所以我使用的是gwt-graphics lib。我还有一些等待请求的servlet。当一些特定的请求将来到地图的视图应该改变。它引导我准备自定义事件：

// class NewModulePositionHandler
package com.example.locator;

import com.google.gwt.event.shared.EventHandler;

public interface NewModulePositionHandler extends EventHandler {
    void onNewModulePosition(NewModulePositionEvent event);
}

我的自定义事件的实现：

import com.google.gwt.event.shared.GwtEvent;

public class NewModulePositionEvent extends GwtEvent<NewModulePositionHandler> {
    private static final Type<NewModulePositionHandler> TYPE = new Type<NewModulePositionHandler>();
    private final String m_Color;

    public NewModulePositionEvent(String color) {
        m_Color = color;
    }

    public static Type<NewModulePositionHandler> getType() {
        return TYPE;
    }

    public String getColor() {
        return m_Color;
    }

    @Override
    public com.google.gwt.event.shared.GwtEvent.Type<NewModulePositionHandler> getAssociatedType() {
        // TODO Auto-generated method stub
        return TYPE;
    }

    @Override
    protected void dispatch(NewModulePositionHandler handler) {
        handler.onNewModulePosition(this);
    }

}

是时候实现我的自定义小部件了：

a）MyComp.java

import com.google.gwt.event.shared.GwtEvent;

public class NewModulePositionEvent extends GwtEvent<NewModulePositionHandler> {
    private static final Type<NewModulePositionHandler> TYPE = new Type<NewModulePositionHandler>();
    private final String m_Color;

    public NewModulePositionEvent(String color) {
        m_Color = color;
    }

    public static Type<NewModulePositionHandler> getType() {
        return TYPE;
    }

    public String getColor() {
        return m_Color;
    }

    @Override
    public com.google.gwt.event.shared.GwtEvent.Type<NewModulePositionHandler> getAssociatedType() {
        // TODO Auto-generated method stub
        return TYPE;
    }

    @Override
    protected void dispatch(NewModulePositionHandler handler) {
        handler.onNewModulePosition(this);
    }

}

b）MyCompClientRpc.java

import com.vaadin.shared.communication.ClientRpc;

public interface MyCompClientRpc extends ClientRpc {

    // TODO example API
    public void alert(String message);
    public void changeColor(String color);
}

c）MyCompConnector.java

package com.example.locator.widgetset.client.mycomp;

import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ui.AbstractComponentConnector;
import com.vaadin.shared.ui.Connect;
import com.example.locator.MyComp;
import com.example.locator.NewModulePositionEvent;
import com.example.locator.NewModulePositionHandler;
import com.example.locator.widgetset.client.mycomp.MyCompWidget;
import com.example.locator.widgetset.client.mycomp.MyCompServerRpc;
import com.vaadin.client.communication.RpcProxy;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.vaadin.shared.MouseEventDetails;
import com.vaadin.client.MouseEventDetailsBuilder;
import com.example.locator.widgetset.client.mycomp.MyCompClientRpc;
import com.example.locator.widgetset.client.mycomp.MyCompState;
import com.vaadin.client.communication.StateChangeEvent;

@Connect(MyComp.class)
public class MyCompConnector extends AbstractComponentConnector {
MyCompServerRpc rpc = RpcProxy
        .create(MyCompServerRpc.class, this);

public MyCompConnector() {
    registerRpc(MyCompClientRpc.class, new MyCompClientRpc() {
        public void alert(String message) {
            // TODO Do something useful
            Window.alert(message);
        }
        public void changeColor(String color) {
            getWidget().InitMap(color);         
        }
    });

    // TODO ServerRpc usage example, do something useful instead
    getWidget().addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            final MouseEventDetails mouseDetails = MouseEventDetailsBuilder
                .buildMouseEventDetails(event.getNativeEvent(),
                            getWidget().getElement());
            rpc.clicked(mouseDetails);
        }
    });


    getWidget().addNewModulePositionHandler(new NewModulePositionHandler() {

        public void onNewModulePosition(NewModulePositionEvent event) {
            // TODO Auto-generated method stub
            rpc.newModulePosition(event.getColor());
        }

    });

}

@Override
protected Widget createWidget() {
    return GWT.create(MyCompWidget.class);
}

@Override
public MyCompWidget getWidget() {
    return (MyCompWidget) super.getWidget();
}

@Override
public MyCompState getState() {
    return (MyCompState) super.getState();
}

@Override
public void onStateChanged(StateChangeEvent stateChangeEvent) {
    super.onStateChanged(stateChangeEvent);

    // TODO do something useful
    final String color = getState().color;
    getWidget().InitMap(color);
}

}

d）MyCompServerRpc.java

package com.example.locator.widgetset.client.mycomp;

import com.vaadin.shared.MouseEventDetails;
import com.vaadin.shared.communication.ServerRpc;

public interface MyCompServerRpc extends ServerRpc {

    // TODO example API
    public void clicked(MouseEventDetails mouseDetails);
    public void newModulePosition(String color);
}

e）MyCompState.java

package com.example.locator.widgetset.client.mycomp;

public class MyCompState extends com.vaadin.shared.AbstractComponentState {

    // TODO example state
    public String color = "#000000";

}

最后实现了小部件：

f）MyCompWidget.java

package com.example.locator.widgetset.client.mycomp;
import org.vaadin.gwtgraphics.client.DrawingArea;
import org.vaadin.gwtgraphics.client.Line;
import org.vaadin.gwtgraphics.client.shape.Circle;
import org.vaadin.gwtgraphics.client.shape.Rectangle;

import com.example.locator.HasNewModulePositionHandlers;
import com.example.locator.NewModulePositionEvent;
import com.example.locator.NewModulePositionHandler;
import com.google.gwt.dev.util.collect.HashMap;
import com.google.gwt.event.shared.HandlerManager;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.touch.client.Point;
import com.example.locator.Module;

// TODO extend any GWT Widget


public class MyCompWidget extends DrawingArea implements HasNewModulePositionHandlers {

    public static final String CLASSNAME = "mycomp";
    public static double m_AreaWidth = 64.355;
    public static double m_AreaHeight = 17.385;
    public static int m_PictureWidth;
    public static int m_PictureHeight;
    public static double m_AreaToMapRatio;
    public static double m_RouteWidth = 3.5;
    public static double m_MainRouteCoordinateY = 8.0828;
    public Circle circle;
    //public HashMap<Integer, Module> ModuleMap = new HashMap<Integer, Module>();

    public MyCompWidget(){
        super(640, 320);

        //ModuleMap.put(666, new Module(666, 30.0, 8.08, new Circle((int)TranslateCoordinate(30.0), (int)TranslateCoordinate(8.0), 7)));
        //ModuleMap.put(15, new Module(15, 27.0, 8.08, new Circle((int)TranslateCoordinate(30.0), (int)TranslateCoordinate(8.0), 7)));

        double xRatio = m_AreaWidth / 640;
        double yRatio = m_AreaHeight / 320;
        m_AreaToMapRatio = xRatio > yRatio ? xRatio : yRatio;

        InitMap("#919491");
        setStyleName(CLASSNAME);
    }

    public void InitMap(String color)
    {
        m_PictureWidth  = (int)TranslateCoordinate(m_AreaWidth);
        m_PictureHeight  = (int)TranslateCoordinate(m_AreaHeight);
        Rectangle rectangle = new Rectangle(0, 0, m_PictureWidth, m_PictureHeight);
        rectangle.setFillColor(color);
        add(rectangle);
        Point point1Beg = new Point(0.0, 8.0828);
        Point point1End = new Point(64.355, 8.0838);

        Point point2Beg = new Point(20.2825, 8.0828);
        Point point2End = new Point(20.2825, 17.385);

        Point point3Beg = new Point(59.325, 0.0);
        Point point3End = new Point(59.325, 8.0828);

        point1Beg = TranslatePoint(point1Beg);
        point1End = TranslatePoint(point1End);

        point2Beg = TranslatePoint(point2Beg);
        point2End = TranslatePoint(point2End);

        point3Beg = TranslatePoint(point3Beg);
        point3End = TranslatePoint(point3End);

        Line line1 = new Line((int)point1Beg.getX(), (int)point1Beg.getY(), (int)point1End.getX(), (int)point1End.getY());
        Line line2 = new Line((int)point2Beg.getX(), (int)point2Beg.getY(), (int)point2End.getX(), (int)point2End.getY());
        Line line3 = new Line((int)point3Beg.getX(), (int)point3Beg.getY(), (int)point3End.getX(), (int)point3End.getY());

        line1.setStrokeColor("#FFFFFF");
        line2.setStrokeColor("#FFFFFF");
        line3.setStrokeColor("#FFFFFF");

        line1.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));
        line2.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));
        line3.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));

        add(line1);
        add(line2);
        add(line3);

        DrawWall(TranslateCoordinate(10.0));
        DrawWall(TranslateCoordinate(20.0));
        DrawWall(TranslateCoordinate(30.0));
        DrawWall(TranslateCoordinate(40.0));
        DrawWall(TranslateCoordinate(50.0));
        DrawWall(TranslateCoordinate(60.0));

        DrawDoor(3.0, 3.0);
        DrawDoor(13.0, 3.0);
        DrawDoor(23.0, 3.0);
        DrawDoor(33.0, 3.0);
        DrawDoor(43.0, 3.0);
        DrawDoor(53.0, 3.0);
        circle = new Circle((int)TranslateCoordinate(25.0), (int)TranslateCoordinate(8.0), 15);
        add(circle);
    }

    public void DrawWall(double a_Place)
    {
        Line line = new Line((int)a_Place, 0, (int)a_Place, (int)TranslateCoordinate(m_AreaHeight));
        line.setStrokeColor("#FFFFFF");
        add(line);
    }

    public void DrawDoor(double a_Position, double a_Width)
    {
        double realDoorPositionY = m_MainRouteCoordinateY - (m_RouteWidth / 2);
        int doorPositionYTop = (int)TranslateCoordinate(realDoorPositionY) - 1;
        int doorPositionYBottom = (int)TranslateCoordinate(realDoorPositionY + m_RouteWidth) + 1;

        Line line = new Line((int)TranslateCoordinate(a_Position), doorPositionYTop, (int)TranslateCoordinate(a_Position) + (int)TranslateCoordinate(a_Width), doorPositionYTop);
        line.setStrokeColor("#000000");
        line.setStrokeWidth(2);
        add(line);
        Line line2 = new Line((int)TranslateCoordinate(a_Position), doorPositionYBottom, (int)TranslateCoordinate(a_Position) + (int)TranslateCoordinate(a_Width), doorPositionYBottom);
        line2.setStrokeColor("#000000");
        line2.setStrokeWidth(2);
        add(line2);
    }

    public Point TranslatePoint(Point a_Point)
    {
        Point translatedPoint = new Point(TranslateCoordinate(a_Point.getX()), TranslateCoordinate(a_Point.getY()));
        return translatedPoint;
    }

    public double TranslateCoordinate(double a_Coordinate)
    {
        return (a_Coordinate) / (m_AreaToMapRatio);
    }

    public void Move(int id) {
        //ModuleMap.get(id).GetCircle().setX(10 + circle.getX());
    }


       public HandlerRegistration addNewModulePositionHandler(
                NewModulePositionHandler handler) {
            return addHandler(handler, NewModulePositionEvent.TYPE);
        }

        private void someMethod() {
            fireEvent(new NewModulePositionEvent("#000000"));
        }
        public void emulateEvent() {
            someMethod();
        }
}

g）HasNewModulesPositionHandlers.java

package com.example.locator;

import com.google.gwt.event.shared.HandlerRegistration;

public interface HasNewModulePositionHandlers {
    // Attention! method returns HandlerRegistration, so that handler can be cancelled
    public HandlerRegistration addNewModulePositionHandler(
            NewModulePositionHandler handler);
}

如果我编译包含MyCompWidget的小部件集然后在glassfish上运行我的应用程序，我会收到以下消息：

Widgetset'com.example.locator.widgetset.LocatorWidgetset'不包含com.example.locator.MyComp的实现。检查其组件连接器的@Connect映射，widgetsets GWT模块描述文件并重新编译您的widgetset。如果您下载了vaadin附加软件包，则可能需要参考附加说明。

如果我剪了

  public void addNewModulePositionHandler(
            NewModulePositionHandler handler) {
        handlerManager.addHandler(NewModulePositionEvent.getType(), handler);
        // TODO Auto-generated method stub
    }

小部件正常工作（当然我也必须从MyCompConnector中注释掉这些行）：

    getWidget().addNewModulePositionHandler(new NewModulePositionHandler() {

        public void onNewModulePosition(NewModulePositionEvent event) {
            // TODO Auto-generated method stub
            rpc.newModulePosition(event.getColor());
        }

    });

谁能告诉我问题出在哪里？似乎小部件的编译失败但我找不到任何有关它的信息。请帮我。提前谢谢。

Answer 1

编译问题非常明确：GWT编译器无法为指定的java类提供源代码。您可以通过两个步骤将源文件添加到GWT编译器范围：

*。必须可以通过classpath访问java文件（eclipse gwt编译器会自动将所有源文件夹包含到classpath中）
您需要告诉GWT它应该在编译期间考虑您的包
- 使用以下内容在PARENT包中创建.gwt.xml文件（相对于您的源文件）（如果您的包是pkg1.pkg2.pkg3，那么您应该在包pkg1.pkg2中创建文件＆＃34; Pkg3。 gwt.xml＆＃34;，pkg =＆＃34; pkg3＆＃34;，按惯例，pkg3通常命名为＆＃34; client＆＃34;）

<module>
    <source path="pkg3" />
</module>

!!!注意字母大小写，按照惯例，这些是正确的名称。

添加到您的widgetset.gwt.xml文件＆＃34;继承＆＃34;这样的指令

<inherits name="pkg1.pkg2.Pkg3" />

!!!注意字母案例（P是Pkg3中的大写，文件名Pkg3.gwt.xml之后），这里省略.gwt.xml

然后，首先，Vaadin使用GWT有一定的扭曲。我建议浏览自定义widgetset示例。您可能需要了解如何在Vaadin特定组件之间传播事件。下面我将解释如何实现和使用GWT事件。我不是Vaadin的专家，特别是在自定义widgetset等高级主题中。

所以，谈到GWT。

基本上，你需要理解两件事（非DOM，也知道无用）事件在GWT中有效。

代码支持
- 活动课程。在你的情况下NewModulePositionEvent。
- 事件处理程序界面。在你的情况下NewModulePositionHandler。
- 功能界面（可选但建议）。在你的情况下HasNewModulePositionHandlers。
使用模式
- 基本上，应该触发事件的组件应创建相关的Event对象并将其传递给fireEvent方法。调用必要的habdler的所有逻辑都是由EventBus（内部）
- 如果您需要提供外部触发事件的API（例如Button的click（）方法），则应该通过提供特殊方法来完成（不要公开内部资料如何触发事件）

DOM事件特别详细地说明了它们是如何创建的（通过浏览器）和调度的（它们需要显式启用）。无论如何，所有的浏览器事件都已经在GWT中实现了开箱即用。

所以，上述项目的典型实现：为了清楚起见，我提供了生产代码的摘录。

1）事件类

public class QuestionClickEvent extends GwtEvent<QuestionClickHandler> {

    public QuestionClickEvent(SScript script, SQuestion question) {
        super();
        this.script = script;
        this.question = question;
    }

    public static final Type<QuestionClickHandler> TYPE = new Type<QuestionClickHandler>();

    // internal event state
    private final SScript script;
    private final SQuestion question;

    @Override
    public Type<QuestionClickHandler> getAssociatedType() {
         return TYPE;
    }

    @Override
    protected void dispatch(QuestionClickHandler handler) {
        handler.onQuestionClicked(this);
    }


    // provide access to internal event state

    public SScript getScript() {
        return script;
    }

    public SQuestion getQuestion() {
        return question;
    }
}

2）处理程序界面

public interface QuestionClickHandler extends EventHandler {
    public void onQuestionClicked(QuestionClickEvent event);
}

3）功能界面

public interface HasQuestionClickHandlers {
    // Attention! method returns HandlerRegistration, so that handler can be cancelled
    public HandlerRegistration addQuestionClickHandler(
            QuestionClickHandler handler);
}

4）您的小部件/组件

public class SummaryPanel extends Widget implements HasQuestionClickHandlers {
// blah-blah-blah

        // implement your handler registration method
    @Override
    public HandlerRegistration addQuestionClickHandler(
            QuestionClickHandler handler) {
        return addHandler(handler, QuestionClickEvent.TYPE);
    }

// blah-blah-blah

    private someMethod() {
        // suddenly you realized that you need to to fire your event
        fireEvent(new QuestionClickEvent(script, question));
    }

// sample external API method

    public void emulateEvent() {
        someMethod();
    }
}

最后用法示例：

    SummaryPanel summary = new SummaryPanel();
    summary.addQuestionClickHandler(new QuestionClickHandler() {

        @Override
        public void onQuestionClicked(QuestionClickEvent event) {
            // your reaction goes here
        }
    });

GWT小部件中的自定义事件无效

1 个答案: