Java ActionListeners到獨立類

Question

有什麼方法可以將actionListener類移動到獨立類？

我做了一個使用Java和MVC設計模式的例子。我有3個按鈕可以改變背景顏色。

這裏的型號

public class ChangeFontColorApplicationModel { 
    public ChangeFontColorApplicationModel(){} 
} 

查看

import java.awt.event.*; 
import javax.swing.*; 

public class ChangeFontColorApplicationView extends JFrame{ 
private JButton changeToYellowButton = new JButton("Yellow font"); 
private JButton changeToBlackButton = new JButton("Black font"); 
private JButton changeToBlueButton = new JButton("Blue font"); 

public ChangeFontColorApplicationView(){ 
    super("Change font"); 
    JPanel buttonPanel = new JPanel(); 

    buttonPanel.add(changeToYellowButton); 
    buttonPanel.add(changeToBlackButton); 
    buttonPanel.add(changeToBlueButton); 

    this.add(buttonPanel); 
} 

public void addButtonActionListener(){ 
    changeToYellowButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlackButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlueButton.addActionListener(new yellowBackgroundHandler()); 
} 
} 

控制器

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

public class ChangeFontColorApplicationController { 
private ChangeFontColorApplicationView changeFontColorApplicationViewObject; 
backgroundHandler yellowBackgroundHandlerObject = new yellowBackgroundHandler(); 
backgroundHandler blackBackgroundHandlerObject = new blackBackgroundHandler(); 
backgroundHandler blueBackgroundHandlerObject = new blueBackgroundHandler(); 

public ChangeFontColorApplicationController(ChangeFontColorApplicationView changeFontColorApplicationViewObject){ 
    this.changeFontColorApplicationViewObject = changeFontColorApplicationViewObject; 

    yellowBackgroundHandlerObject.setNextHandlerInChain(blackBackgroundHandlerObject); 
    blackBackgroundHandlerObject.setNextHandlerInChain(blueBackgroundHandlerObject); 

    this.changeFontColorApplicationViewObject.addButtonActionListener(); 
} 
} 

現在，我創建了處理按鈕事件的接口

public interface backgroundHandler extends ActionListener{ 
public void setNextHandlerInChain(backgroundHandler nextInChain); 
public void handleCommand(String getActionCommandString); 
public void actionPerformed(ActionEvent event); 
} 

每個實現接口的類都處理ActionEvent。如果不能，把它傳遞給下一個類（如責任鏈）

黃色字體句柄

import java.awt.Color; 
import java.awt.event.ActionEvent; 

public class yellowBackgroundHandler implements backgroundHandler{ 
private backgroundHandler nextInChain; 
private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 

public yellowBackgroundHandler(){} 

@Override 
public void setNextHandlerInChain(backgroundHandler nextInChain) { 
    this.nextInChain = nextInChain; 
} 

@Override 
public void handleCommand(String getActionCommandString) { 
    if(getActionCommandString.equalsIgnoreCase("Yellow font")){ 
     ChangeFontColorApplicationViewObject.setBackground(Color.yellow); 
    } 
    else { 
     nextInChain.handleCommand(getActionCommandString); 
    } 
} 

@Override 
public void actionPerformed(ActionEvent event) { 
    try{ 
     handleCommand(event.getActionCommand()); 
    } 
    catch (Exception exeption){ 
     ChangeFontColorApplicationViewObject.setTitle(exeption.toString());    
    } 
} 
} 

黑字體句柄

import java.awt.Color; 
import java.awt.event.ActionEvent; 

public class blackBackgroundHandler implements backgroundHandler{ 
private backgroundHandler nextInChain; 
private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 

public blackBackgroundHandler(){} 

@Override 
public void setNextHandlerInChain(backgroundHandler nextInChain) { 
    this.nextInChain = nextInChain; 
} 

@Override 
public void handleCommand(String getActionCommandString) { 
    if(getActionCommandString.equalsIgnoreCase("Black font")){ 
     ChangeFontColorApplicationViewObject.setBackground(Color.BLACK); 
    } 
    else { 
     nextInChain.handleCommand(getActionCommandString); 
    } 
} 

@Override 
public void actionPerformed(ActionEvent event) { 
    try{ 
     handleCommand(event.getActionCommand()); 
    } 
    catch (Exception exeption){ 
     ChangeFontColorApplicationViewObject.setTitle(exeption.toString());    
    } 
} 
} 

藍色字體句柄

import java.awt.Color; 
import java.awt.event.ActionEvent; 

public class blueBackgroundHandler implements backgroundHandler{ 
private backgroundHandler nextInChain; 
private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 

public blueBackgroundHandler(){} 

@Override 
public void setNextHandlerInChain(backgroundHandler nextInChain) { 
    this.nextInChain = nextInChain; 
} 

@Override 
public void handleCommand(String getActionCommandString) { 
    if(getActionCommandString.equalsIgnoreCase("Μπλε φόντο")){ 
     ChangeFontColorApplicationViewObject.setBackground(Color.BLUE); 
    } 
    else { 
     ChangeFontColorApplicationViewObject.setTitle("This is the back end of COR"); 
    } 
} 

@Override 
public void actionPerformed(ActionEvent event) { 
    try{ 
     handleCommand(event.getActionCommand()); 
    } 
    catch (Exception exeption){ 
     ChangeFontColorApplicationViewObject.setTitle(exeption.toString());    
    } 
} 
} 

最後，我用主要方法創建類

public class ChangeFontColorApp { 
public static void main(String[] args){ 
    ChangeFontColorApplicationView changeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 
    ChangeFontColorApplicationController changeFontColorApplicationControllerObject = new ChangeFontColorApplicationController(changeFontColorApplicationViewObject); 

    changeFontColorApplicationViewObject.setVisible(true); 
    changeFontColorApplicationViewObject.setSize(600, 600); 
     changeFontColorApplicationViewObject.setDefaultCloseOperation(ChangeFontColorApplicationView.EXIT_ON_CLOSE); 
} 
} 

有什麼辦法可以使這項工作？我不希望有一個內部類與事件處理與多個如果blick中。任何建議將非常感激。

Answer 1

這是行不通的。但是，問題不是因爲你有獨立的類（使用獨立的類很好）。相反，問題是：

在視圖類，你必須：

public void addButtonActionListener(){ 
    changeToYellowButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlackButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlueButton.addActionListener(new yellowBackgroundHandler()); 
} 

這意味着，所有按鈕的點擊次數是按yellowBackgroundHandler處理。但是，yellowBackgroundHandler只接受來自changeToYellowButton的點擊。除此之外，yellowBackgroundHandler沒有配置下一個處理程序。

爲了解決這個問題，考慮到類，改變該：

public void addButtonActionListener(){ 
    changeToYellowButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlackButton.addActionListener(new yellowBackgroundHandler()); 
    changeToBlueButton.addActionListener(new yellowBackgroundHandler()); 
} 

到

public void addButtonActionListener(backgroundHandler handler){ 
    changeToYellowButton.addActionListener(handler); 
    changeToBlackButton.addActionListener(handler); 
    changeToBlueButton.addActionListener(handler); 
} 

和控制器類，改變該：

this.changeFontColorApplicationViewObject.addButtonActionListener(); 

到

this.changeFontColorApplicationViewObject.addButtonActionListener(yellowBackgroundHandlerObject); 

我看到的另一個問題是，yellowBackgroundHandler，blackBackgroundHandler和blueBackgroundHandler具有專用變量ChangeFontColorApplicationViewObject，它指向自己的ChangeFontColorApplicationView實例。我們需要這個變量來指向在main方法中創建的實例。要做到這一點，改變這種：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 
public blueBackgroundHandler(){} 

到：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject; 
public blueBackgroundHandler(ChangeFontColorApplicationView ChangeFontColorApplicationViewObject){ 
    this.ChangeFontColorApplicationViewObject = ChangeFontColorApplicationViewObject; 
} 

並改變這一點：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 
public blackBackgroundHandler(){} 

到：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject; 
public blackBackgroundHandler(ChangeFontColorApplicationView ChangeFontColorApplicationViewObject){ 
    this.ChangeFontColorApplicationViewObject = ChangeFontColorApplicationViewObject; 
} 

並改變這一點：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject = new ChangeFontColorApplicationView(); 
public blueBackgroundHandler(){} 

到：

private ChangeFontColorApplicationView ChangeFontColorApplicationViewObject; 
public blueBackgroundHandler(ChangeFontColorApplicationView ChangeFontColorApplicationViewObject){ 
    this.ChangeFontColorApplicationViewObject = ChangeFontColorApplicationViewObject; 
} 

最後，改變這種：

backgroundHandler yellowBackgroundHandlerObject = new yellowBackgroundHandler(); 
backgroundHandler blackBackgroundHandlerObject = new blackBackgroundHandler(); 
backgroundHandler blueBackgroundHandlerObject = new blueBackgroundHandler(); 

public ChangeFontColorApplicationController(ChangeFontColorApplicationView changeFontColorApplicationViewObject){ 
    this.changeFontColorApplicationViewObject = changeFontColorApplicationViewObject; 

    yellowBackgroundHandlerObject.setNextHandlerInChain(blackBackgroundHandlerObject); 
    blackBackgroundHandlerObject.setNextHandlerInChain(blueBackgroundHandlerObject); 

    this.changeFontColorApplicationViewObject.addButtonActionListener(); 
} 

到

backgroundHandler yellowBackgroundHandlerObject = new yellowBackgroundHandler(); 
backgroundHandler blackBackgroundHandlerObject = new blackBackgroundHandler(); 
backgroundHandler blueBackgroundHandlerObject = new blueBackgroundHandler(); 

public ChangeFontColorApplicationController(ChangeFontColorApplicationView changeFontColorApplicationViewObject){ 
    this.changeFontColorApplicationViewObject = changeFontColorApplicationViewObject; 
    this.yellowBackgroundHandlerObject = new yellowBackgroundHandler(this.changeFontColorApplicationViewObject); 
    this.blackBackgroundHandlerObject = new blackBackgroundHandler(this.changeFontColorApplicationViewObject); 
    this.blueBackgroundHandlerObject = new blueBackgroundHandler(this.changeFontColorApplicationViewObject); 

    yellowBackgroundHandlerObject.setNextHandlerInChain(blackBackgroundHandlerObject); 
    blackBackgroundHandlerObject.setNextHandlerInChain(blueBackgroundHandlerObject); 

    this.changeFontColorApplicationViewObject.addButtonActionListener(this.changeFontColorApplicationViewObject); 
}