gwt之mvc4g

Mvc4g是一个简单的框架来实现的GWT应用程序的MVC模式。

主要思想

其主要思想是，以减轻开发人员的工作，以单独的视图从模型。该框架是一个XML文件，将允许开发人员告诉视图发射事件时要执行什么样的行动需要配置。

框架如何工作

具体步骤如下图

事件
是创建活动的视图控制器。事件包含两部分信息：

    执行的动作的名称
    对象传递到行动

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UserBean user = new UserBean();

user.setName("John Smith");

new Event("CreateUser", user);

 控制器
控制器接收事件，并根据事件动作的名称，执行的行动。
例如，如果您有以下事件触发：

Event e =newEvent("doOperation","+");

以下Mvc4g配置文件：

<actionname="doOperation"class="com.mvc4g.example.client.OperationAction"/>

然后控制器调用以下行动的实例：

com.mvc4g.example.client.OperationAction

要创建一个视图，你需要：

    实施com.mvc4g.client.ViewInterface
    有一个默认的构造

视图可以创建事件和火灾控制器调用的handleEvent函数。

Event e =newEvent("doOperation","+");
controller.handleEvent(e);   

详细的示例

Action

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package com.mvc4g.example.client;

 

import com.mvc4g.client.ActionInterface;

import com.mvc4g.client.Controller;

 

public class OperationAction implements ActionInterface {

         

        private int value = 0;

 

        @Override

        public void execute(Controller controller, Object form) {

 

                //Execute action

                String operation = (String) form;

                if("+".equals(operation)){

                        value++;

                }

                else if("-".equals(operation)){

                        value--;

                }

                 

                //Update the view

                ((SimpleCalculatorView)controller.getView("mainView")).updateScreen(Integer.toString(value));

 

        }

 

}

 view

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package com.mvc4g.example.client;

 

import com.google.gwt.event.dom.client.ClickEvent;

import com.google.gwt.event.dom.client.ClickHandler;

import com.google.gwt.user.client.ui.Button;

import com.google.gwt.user.client.ui.Composite;

import com.google.gwt.user.client.ui.HorizontalPanel;

import com.google.gwt.user.client.ui.RootPanel;

import com.google.gwt.user.client.ui.TextBox;

import com.google.gwt.user.client.ui.VerticalPanel;

import com.mvc4g.client.Controller;

import com.mvc4g.client.Event;

import com.mvc4g.client.ViewInterface;

 

public class SimpleCalculatorView extends Composite implements ViewInterface {

         

        private Controller controller = null;

        private TextBox screen = new TextBox();

         

        public SimpleCalculatorView(){

                 

                screen.setWidth("50px"); screen.setEnabled(false); screen.setText("0");

                 

                Button add = new Button("+1");

                add.addClickHandler(new ClickHandler(){

                        @Override

                        public void onClick(ClickEvent event) {

                                //Create and fire event to the controller

                                Event e = new Event("doOperation", "+");

                                controller.handleEvent(e);                             

                        }                      

                });

                 

                Button less = new Button("-1");

                less.addClickHandler(new ClickHandler(){

                        @Override

                        public void onClick(ClickEvent event) {

                                //Create and fire event to the controller

                                Event e = new Event("doOperation", "-");

                                controller.handleEvent(e);                             

                        }                      

                });

                 

                HorizontalPanel buttons = new HorizontalPanel();

                buttons.add(add); buttons.add(less);

                 

                VerticalPanel mainPanel = new VerticalPanel();

                mainPanel.add(screen);mainPanel.add(buttons);

                 

                RootPanel.get().add(mainPanel);

                 

        }

         

        public void updateScreen(String value){

                screen.setText(value);

        }

 

        @Override

        public void setController(Controller controller) {

                this.controller = controller;

        }

         

}

 控制层

要创建一个动作，你需要：

    实施com.mvc4g.client.ActionInterface
    有一个默认的构造

要执行一个动作，控制器调用的动作执行功能。它在这个功能，你需要的代码行为的行动。要更新视图，动作可以检索到控制器，由控制器调用getView功能感谢。为了获取正确的观点，行动需要给视图的名称。

例如，如果你有以下调用：

controller.getView("mainView")

以下Mvc4g配置文件：

<viewname="mainView"class="com.mvc4g.example.client.SimpleCalculatorView"/>

您将检索的有以下几种观点的实例：

com.mvc4g.example.client.SimpleCalculatorView

Action

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package com.mvc4g.example.client;

 

import com.mvc4g.client.ActionInterface;

import com.mvc4g.client.Controller;

 

public class OperationAction implements ActionInterface {

         

        private int value = 0;

 

        @Override

        public void execute(Controller controller, Object form) {

 

                //Execute action

                String operation = (String) form;

                if("+".equals(operation)){

                        value++;

                }

                else if("-".equals(operation)){

                        value--;

                }

                 

                //Update the view

                ((SimpleCalculatorView)controller.getView("mainView")).updateScreen(Integer.toString(value));

 

        }

 

}

 view

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package com.mvc4g.example.client;

 

import com.google.gwt.event.dom.client.ClickEvent;

import com.google.gwt.event.dom.client.ClickHandler;

import com.google.gwt.user.client.ui.Button;

import com.google.gwt.user.client.ui.Composite;

import com.google.gwt.user.client.ui.HorizontalPanel;

import com.google.gwt.user.client.ui.RootPanel;

import com.google.gwt.user.client.ui.TextBox;

import com.google.gwt.user.client.ui.VerticalPanel;

import com.mvc4g.client.Controller;

import com.mvc4g.client.Event;

import com.mvc4g.client.ViewInterface;

 

public class SimpleCalculatorView extends Composite implements ViewInterface {

         

        private Controller controller = null;

        private TextBox screen = new TextBox();

         

        public SimpleCalculatorView(){

                 

                screen.setWidth("50px"); screen.setEnabled(false); screen.setText("0");

                 

                Button add = new Button("+1");

                add.addClickHandler(new ClickHandler(){

                        @Override

                        public void onClick(ClickEvent event) {

                                //Create and fire event to the controller

                                Event e = new Event("doOperation", "+");

                                controller.handleEvent(e);                             

                        }                      

                });

                 

                Button less = new Button("-1");

                less.addClickHandler(new ClickHandler(){

                        @Override

                        public void onClick(ClickEvent event) {

                                //Create and fire event to the controller

                                Event e = new Event("doOperation", "-");

                                controller.handleEvent(e);                             

                        }                      

                });

                 

                HorizontalPanel buttons = new HorizontalPanel();

                buttons.add(add); buttons.add(less);

                 

                VerticalPanel mainPanel = new VerticalPanel();

                mainPanel.add(screen);mainPanel.add(buttons);

                 

                RootPanel.get().add(mainPanel);

                 

        }

         

        public void updateScreen(String value){

                screen.setText(value);

        }

 

        @Override

        public void setController(Controller controller) {

                this.controller = controller;

        }

         

}