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
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
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
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
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
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;
}
}
