我花了一点时间浏览堆栈溢出和互联网寻找我的问题的答案,但是我发现所有的答案都很难理解,我不确定它们中是否有任何一个与我的问题相关,所以我决定我需要帮助正确的背景。
我正在创建一个程序,将根据输入的特定类型的图形给出一系列解决方案。我真诚地挣扎着在第一个JFrame中从我的JComboBox中获取数据,并在第二个JFrame中显示它。
我有两个类,GraphEquationSolverGUI和定义方程。我使用的Netbean IDE和GraphEquationSolverGUI是我的"项目"。
图形方程Solvergui:
private void graphSelectionActionPerformed(java.awt.event.ActionEvent evt) {
String graphSelectionGUI = (String)graphSelection.getSelectedItem();
//graphSelectedTextField.setText(graphSelectionGUI);
DefineEquation graphSelectedObj = new DefineEquation(graphSelectionGUI);
graphSelectedObj.addItem(graphSelectionGUI);
这是JComboBox,我希望在其中选择将数据发送到另一个类。JComboBox被称为图形选择。你会注意到评论的文本是我将JTextField设置为JComboBox的值,这是在这个JForm里面,我用它来测试以确保数据输入正确,它可以工作,我可以在这个相同的JFrame。下面的另一个代码是我试图创建一个对象并通过它传递数据,我对对象有点生疏,因为我已经有一段时间没有使用它们了,如果我让你哭了,对不起。
定义方程:
public DefineEquation(String graphSelected) {
this.graphSelected = graphSelected;
} //If anyone cares here is my constructor for the object
public void addItem(String graphSelectedString1){
DefineEquation graphSelectedObj = new DefineEquation(graphSelected);
String graphSelectedStringMAIN = graphSelectedString1.toString();
selectedGraph.setText(graphSelectedStringMAIN);
}
以上是我创建的将数据添加到名为selectedGaphJTextField的方法。您会注意到,我有图形选择字符串1和图形选择字符串主,其中我将字符串转换为字符串,这显然是多余的。我这样做只是为了以防万一,这是多余的,抱歉让你畏缩。
我知道这可能很难理解,你可能很难理解我在问什么。简单地说,我如何将数据从一个JFrame JComboBox传递到一个单独的JFrame中的JTextField?我会使用对象吗?如果可以的话,请试着给我讲讲,我很困惑。如果你想通读所有内容,我会把我所有的代码粘贴在下面。
图形方程Solvergui:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package GUI;
/**
*
* @author MatthewAlanTroutman
*/
public class GraphEquationSolverGUI extends javax.swing.JFrame {
/**
* Creates new form GraphEquationSolverGUI
*/
public GraphEquationSolverGUI() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jSpinner1 = new javax.swing.JSpinner();
welcome = new javax.swing.JLabel();
programDescription = new javax.swing.JLabel();
graphsOffered = new javax.swing.JLabel();
linear = new javax.swing.JLabel();
bilinear = new javax.swing.JLabel();
quadratic = new javax.swing.JLabel();
cubic = new javax.swing.JLabel();
exponential = new javax.swing.JLabel();
graphSelectionText = new javax.swing.JLabel();
graphSelection = new javax.swing.JComboBox();
help = new javax.swing.JButton();
close = new javax.swing.JButton();
next = new javax.swing.JButton();
graphSelectedTextField = new javax.swing.JTextField();
graphSelectedLabel = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("GraphEquationSolver");
setBackground(new java.awt.Color(255, 255, 255));
welcome.setFont(new java.awt.Font("Lucida Grande", 0, 48)); // NOI18N
welcome.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
welcome.setText("Welcome");
welcome.setPreferredSize(new java.awt.Dimension(800, 100));
programDescription.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
programDescription.setText("You can use this program to find a variety of solutions for different types of graphs, please select a graph to begin");
programDescription.setPreferredSize(new java.awt.Dimension(800, 75));
graphsOffered.setFont(new java.awt.Font("Lucida Grande", 0, 18)); // NOI18N
graphsOffered.setText("Graphs we offer:");
linear.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
linear.setText("- Linear");
bilinear.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
bilinear.setText("- Bilinear");
quadratic.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
quadratic.setText("- Quadratic");
cubic.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
cubic.setText("- Cubic");
exponential.setFont(new java.awt.Font("Lucida Grande", 0, 14)); // NOI18N
exponential.setText("- Exponential");
graphSelectionText.setFont(new java.awt.Font("Lucida Grande", 0, 18)); // NOI18N
graphSelectionText.setText("Please select your graph");
graphSelection.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Linear", "Bilinear", "Quadratic", "Cubic", "Exponential" }));
graphSelection.setToolTipText("");
graphSelection.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
graphSelectionActionPerformed(evt);
}
});
help.setFont(new java.awt.Font("Lucida Grande", 0, 48)); // NOI18N
help.setText("Help");
close.setFont(new java.awt.Font("Lucida Grande", 0, 48)); // NOI18N
close.setText("Close");
close.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
closeActionPerformed(evt);
}
});
next.setFont(new java.awt.Font("Lucida Grande", 0, 48)); // NOI18N
next.setText("Next");
next.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
nextActionPerformed(evt);
}
});
graphSelectedTextField.setEditable(false);
graphSelectedLabel.setFont(new java.awt.Font("Lucida Grande", 0, 18)); // NOI18N
graphSelectedLabel.setText("Graph Selected");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(welcome, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(240, 240, 240))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(240, 240, 240)
.addComponent(programDescription, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(184, 184, 184)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(exponential)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(graphsOffered)
.addComponent(linear)
.addComponent(bilinear)
.addComponent(quadratic)
.addComponent(cubic))
.addGap(311, 311, 311)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(graphSelectionText, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(graphSelection, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(graphSelectedTextField)
.addComponent(graphSelectedLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))))
.addGroup(layout.createSequentialGroup()
.addGap(231, 231, 231)
.addComponent(help, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(close, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(next, javax.swing.GroupLayout.PREFERRED_SIZE, 255, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(240, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(34, 34, 34)
.addComponent(welcome, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(programDescription, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(73, 73, 73)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(graphsOffered)
.addComponent(graphSelectionText))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(graphSelection, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(linear)
.addComponent(graphSelectedLabel))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addComponent(bilinear)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(quadratic))
.addComponent(graphSelectedTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 28, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(cubic)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(exponential)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 219, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(help, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(close, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(next, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(169, 169, 169))))
);
graphSelection.getAccessibleContext().setAccessibleName("");
help.getAccessibleContext().setAccessibleName("help");
close.getAccessibleContext().setAccessibleName("close");
pack();
}// </editor-fold>
private void graphSelectionActionPerformed(java.awt.event.ActionEvent evt) {
String graphSelectionGUI = (String)graphSelection.getSelectedItem();
graphSelectedTextField.setText(graphSelectionGUI);
//DefineEquation graphSelectedObj = new DefineEquation(graphSelectionGUI);
//graphSelectedObj.addItem(graphSelectionGUI);
}
private void closeActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
}
private void nextActionPerformed(java.awt.event.ActionEvent evt) {
this.setVisible(false);
new DefineEquation().setVisible(true);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(GraphEquationSolverGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(GraphEquationSolverGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(GraphEquationSolverGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(GraphEquationSolverGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new GraphEquationSolverGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JLabel bilinear;
private javax.swing.JButton close;
private javax.swing.JLabel cubic;
private javax.swing.JLabel exponential;
private javax.swing.JLabel graphSelectedLabel;
private javax.swing.JTextField graphSelectedTextField;
private javax.swing.JComboBox graphSelection;
private javax.swing.JLabel graphSelectionText;
private javax.swing.JLabel graphsOffered;
private javax.swing.JButton help;
private javax.swing.JSpinner jSpinner1;
private javax.swing.JLabel linear;
private javax.swing.JButton next;
private javax.swing.JLabel programDescription;
private javax.swing.JLabel quadratic;
private javax.swing.JLabel welcome;
// End of variables declaration
}
定义方程:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package GUI;
/**
*
* @author MatthewAlanTroutman
*/
public class DefineEquation extends javax.swing.JFrame {
//public class DefineEquation extends GraphEquationSolverGUI {
public String graphSelected;
/**
* Creates new form DefineEquation
*/
public DefineEquation() {
initComponents();
}
public DefineEquation(String graphSelected) {
this.graphSelected = graphSelected;
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
selectedGraph = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
selectedGraph.setEditable(false);
selectedGraph.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
selectedGraphActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(435, 435, 435)
.addComponent(selectedGraph, javax.swing.GroupLayout.PREFERRED_SIZE, 249, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(596, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(126, 126, 126)
.addComponent(selectedGraph, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(646, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void selectedGraphActionPerformed(java.awt.event.ActionEvent evt) {
}
public void addItem(String graphSelectedString1){
DefineEquation graphSelectedObj = new DefineEquation(graphSelected);
String graphSelectedStringMAIN = graphSelectedString1.toString();
selectedGraph.setText(graphSelectedStringMAIN);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(DefineEquation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(DefineEquation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(DefineEquation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(DefineEquation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new DefineEquation().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JTextField selectedGraph;
// End of variables declaration
}
你会注意到我试图“扩展”我的第一个JFrame,但这导致了第二个JFrame“窗口”以某种方式与第一个JFrame“窗口”相结合
概念图像:
编辑1:这是最好的解决方法吗?如果是这样,我将如何移动数据?对象目前让我困惑,还有一些非静态和静态的问题,这些问题似乎是无效的,因为我没有任何静态的东西。如果这不是最好的方法,我该怎么做?我要睡觉了,请你给我建议和帮助,我不仅感到绝望,而且感到失落。
编辑2:我正在努力理解m.cekiera的答案,在回答之前参考他的答案,因为它可能会有所帮助。
编辑3:仍然困在那里,需要详细的帮助,很抱歉要求这么高,但我无法理解这一点。
编辑4:我想我已经找到了一个重大突破。我已经想出了如何解决这个问题,但我真的认为我需要理解这一点。总之,我有一个新的类和一个不同类的新文本字段。我仍然有问题,我不能显示textfield的值,但出于某种原因,我可以输出相同的值。我想这更容易展示
这就是类选择解决方案:
public void displayText(String textToSet) {
displayQuadraticEquation.setText(textToSet);
System.out.println(textToSet);
}
这就是定义的二次方程式:
private void nextActionPerformed(java.awt.event.ActionEvent evt) {
this.setVisible(false);
new SelectSolutionsQuadratic().setVisible(true);
SelectSolutionsQuadratic transferMe = new SelectSolutionsQuadratic();
transferData = aQuadraticSpinner.getValue().toString() + " " + addSubQuadraticComboBox.getSelectedItem();
transferMe.displayText(transferData);
}
所以基本上我很困惑为什么我可以把一个值从defineequationsquared发送到selectsolutionsquared,用系统输出。出来println();但不要将文本字段设置为该值
所以我真的很笨,创建了两个实例,其中一个我没有看到,另一个我没有改变。基本上,我做的是图形选择,我做的是:
this.graphSelectionGUI = (String)graphSelection.getSelectedItem();
然后在nextActionPerformed中我做到了:
new DefineEquation_1(graphSelectionGUI).setVisible(true);
接下来,在另一个类(DefineEquation)中,我使用了我的构造函数并执行了以下操作:
public DefineEquation(String graphSelected) {
this.graphSelected = graphSelected;
initComponents();
selectedGraph.setText(graphSelected);
}
最后,我哭着流泪,意识到我给了你们多少麻烦,我是多么愚蠢,赞美上帝!
抱歉打扰了大家,我的坏朋友。
如果您只是不想将数据发送到DefineEquation
类,那么应该在nextActionPerformed
中使用带String
参数的构造函数:
new DefineEquation((String)graphSelection.getSelectedItem()).setVisible(true);
而不是:
new DefineEquation().setVisible(true);
此外,你还需要让你的建造师:
public DefineEquation(String graphSelected) {
this.graphSelected = graphSelected;
initComponents();
}
因为现在如果没有initComponents
(),它将显示空帧。最后,您需要在DefineEquation
类中setText()
到JTextField
,例如:
selectedGraph = new javax.swing.JTextField(graphSelected);
不要使用addItem()
方法,也不要重写它,因为它会创建新的DefineEquation
对象,这是不必要的,甚至是有害的。这样,在新的框架中,它会显示带有选定文本的JTextField
。至少如果我正确理解了你的问题,这对我是有效的。
但是,我宁愿使用枚举
而不是普通的String
,因为它们更可靠。您的函数集是常数,因此您可以创建例如:
public enum Functions {NONE,LINEAR,BILINEAR,QUADRIATIC,CUBIC,EXPONENTIAL;}
这将需要更改构造函数和内容,但您可以在整个应用程序中使用它。Tou可以调用toString()
或name()
在需要显示String
的地方,但在事件处理等方面使用枚举。我认为您还应该重新考虑使用多个JFrame的方法,正如评论中所建议的那样。我也不建议这样做,但这取决于你。祝你好运
编辑
如果你不想改变定义方程
中的initComponents()
,你仍然可以这样修改addItem()
:
public void addItem(){
selectedGraph.setText(graphSelected);
}
然后在构造函数中调用call addItem(),用所选文本填充JTextField。或者,您可以将graphSelected
作为方法的参数传递,如果是这样,它不必是类字段。
我的建议是创建两个JPanel类,一个保存JComboBox,另一个显示或需要结果。假设您已经这样做了,并调用了第一个类,HoldsComboxPanel
,第二个类叫做ShowSelectionPanel
,那么您将为HoldsComboxPanel提供两个方法,一个是获取当前选择的方法,一个是“getter”方法,另一个是允许外部类向combobox添加ActionListener。例如,简而言之:
public class HoldsComboBoxPanel extends JPanel {
public static final String NAME = "holds combobox panel";
// sample data
private static final String[] DATA = { "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday" };
private JComboBox<String> comboBox = new JComboBox<>(DATA);
public HoldsComboBoxPanel() {
// add the comboBox into our class here
}
// method to add a listener
public void addComboBoxListener(ActionListener listener) {
comboBox.addActionListener(listener);
}
// getter method
public String getComboSelection() {
return (String) comboBox.getSelectedItem();
}
}
您的第二个类,即需要数据的类,将有一个setter方法,允许外部类将组合选择推入其中。假设它有一个名为displayField的JTextField来显示所选内容,它的代码可能是这样的:
public class ShowSelectionPanel extends JPanel {
public static final String NAME = "show selection panel";
private JTextField displayField = new JTextField(10);
public ShowSelectionPanel() {
// add the displayField to the JPanel here
}
// setter method
public void setDisplayText(String text) {
displayField.setText(text);
// or do whatever else you want to do with the selection
}
}
然后你会有另一个使用CardLayout的类,它允许在上面的视图JPanel之间进行交换,比如MainPanel。它可以使用CardLayout来允许您交换JPanel,有一个公共方法来允许外部类交换“card”JPanel,它可以同时保存一个HoldsComboxPanel字段和一个ShowSelectionPanel字段,并可以通过将ActionListener添加到combobox来链接它们,如下所示:
public class MainPanel extends JPanel {
private CardLayout cardLayout = new CardLayout();
private MenuPanel menuPanel = new MenuPanel();
private HoldsComboBoxPanel holdsComboBoxPanel = new HoldsComboBoxPanel();
private ShowSelectionPanel showSelectionPanel = new ShowSelectionPanel();
public MainPanel() {
// add an ActionListener to the JComboBox
holdsComboBoxPanel.addComboBoxListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// get the combo's selected String
String selection = holdsComboBoxPanel.getComboSelection();
if (selection != null) {
// push it into showSelection
showSelectionPanel.setDisplayText(selection);
}
}
});
setLayout(cardLayout);
add(menuPanel, MenuPanel.NAME);
add(holdsComboBoxPanel, HoldsComboBoxPanel.NAME);
add(showSelectionPanel, ShowSelectionPanel.NAME);
}
// method that allows outside classes to swap views
public void showCard(String key) {
cardLayout.show(this, key);
}
}
整个过程加上一些额外的代码,允许在“卡片”中移动,可能看起来像这样:
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.AbstractButton;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class SimpleMultPanels {
private static void createAndShowGui() {
// create JFrame
JFrame frame = new JFrame("SimpleMultPanels");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// add our MainPanel to the JFrame
frame.getContentPane().add(new MainPanel());
frame.pack(); // pack it
frame.setLocationByPlatform(true);
frame.setVisible(true); // show it
}
public static void main(String[] args) {
// this is for starting our Swing app on the event thread
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
@SuppressWarnings("serial")
class MainPanel extends JPanel {
private CardLayout cardLayout = new CardLayout();
// the three "card" JPanels that this JPanel displays:
private MenuPanel menuPanel = new MenuPanel();
private HoldsComboBoxPanel holdsComboBoxPanel = new HoldsComboBoxPanel();
private ShowSelectionPanel showSelectionPanel = new ShowSelectionPanel();
// Actions for our JButtons
private ExitAction exitAction = new ExitAction();
private ShowAction backToMenuAction = new ShowAction(this, "Back to Menu",
MenuPanel.NAME, KeyEvent.VK_B);
private ShowAction toHoldsComboAction = new ShowAction(this, "Combo Panel",
HoldsComboBoxPanel.NAME, KeyEvent.VK_C);
private ShowAction toShowSelectionAction = new ShowAction(this,
"Show Selection", ShowSelectionPanel.NAME, KeyEvent.VK_S);
public MainPanel() {
// add an ActionListener to the JComboBox
holdsComboBoxPanel.addComboBoxListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// get the combo's selected String
String selection = holdsComboBoxPanel.getComboSelection();
if (selection != null) {
// push it into showSelection
showSelectionPanel.setDisplayText(selection);
}
}
});
// add Actions to class to allow swapping of cards and
holdsComboBoxPanel.addButtonAction(backToMenuAction);
holdsComboBoxPanel.addButtonAction(toShowSelectionAction);
holdsComboBoxPanel.addButtonAction(exitAction); // and to exit gui
showSelectionPanel.addButtonAction(backToMenuAction);
showSelectionPanel.addButtonAction(toHoldsComboAction);
showSelectionPanel.addButtonAction(exitAction);
menuPanel.addButtonAction(toHoldsComboAction);
menuPanel.addButtonAction(toShowSelectionAction);
menuPanel.addButtonAction(exitAction);
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
// set our layout
setLayout(cardLayout);
// and add our "card" JPanels
add(menuPanel, MenuPanel.NAME);
add(holdsComboBoxPanel, HoldsComboBoxPanel.NAME);
add(showSelectionPanel, ShowSelectionPanel.NAME);
}
// method that allows outside classes to swap views
public void showCard(String key) {
cardLayout.show(this, key);
}
}
@SuppressWarnings("serial")
class HoldsComboBoxPanel extends JPanel {
// constant String that will be used by the CardLayout
public static final String NAME = "holds combobox panel";
// sample data
private static final String[] DATA = { "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday" };
private JComboBox<String> comboBox = new JComboBox<>(DATA);
// JPanel to hold buttons to allow moving between cards
private JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0));
public HoldsComboBoxPanel() {
comboBox.setSelectedIndex(-1);
JPanel centerPanel = new JPanel();
centerPanel.add(comboBox);
setLayout(new BorderLayout());
add(centerPanel, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.SOUTH);
}
// method to add a listener
public void addComboBoxListener(ActionListener listener) {
comboBox.addActionListener(listener);
}
// getter method
public String getComboSelection() {
return (String) comboBox.getSelectedItem();
}
// create a new JButton with an Action and add to buttonPanel
public void addButtonAction(Action action) {
buttonPanel.add(new JButton(action));
}
}
@SuppressWarnings("serial")
class ShowSelectionPanel extends JPanel {
public static final String NAME = "show selection panel";
private static final int PREF_W = 300;
private static final int PREF_H = PREF_W;
private JTextField displayField = new JTextField(10);
private JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0));
public ShowSelectionPanel() {
displayField.setFocusable(false);
JPanel centerPanel = new JPanel();
centerPanel.add(displayField);
setLayout(new BorderLayout());
add(centerPanel, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.SOUTH);
}
// code to make our GUI a little larger
@Override
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
int prefW = Math.max(superSz.width, PREF_W);
int prefH = Math.max(superSz.height, PREF_H);
return new Dimension(prefW, prefH);
}
// setter method
public void setDisplayText(String text) {
displayField.setText(text);
// or do whatever else you want to do with the selection
}
public void addButtonAction(Action action) {
buttonPanel.add(new JButton(action));
}
}
@SuppressWarnings("serial")
class MenuPanel extends JPanel {
public static final String NAME = "menu panel";
private JPanel buttonPanel = new JPanel(new GridLayout(0, 1, 0, 5));
public MenuPanel() {
setLayout(new GridBagLayout());
add(buttonPanel);
}
public void addButtonAction(Action action) {
buttonPanel.add(new JButton(action));
}
}
@SuppressWarnings("serial")
class ShowAction extends AbstractAction {
private MainPanel mainPanel;
private String key;
/**
* Abstract Action used by JButtons
* @param mainPanel: the JPanel that uses the CardLayout
* @param name: The name displayed by the button
* @param key: The key used in the CardLayout#show(String key) mehtod
* @param mnemonic: the JButton's mnemonic char
*/
public ShowAction(MainPanel mainPanel, String name, String key, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
this.mainPanel = mainPanel;
this.key = key;
}
@Override
public void actionPerformed(ActionEvent e) {
// tell the mainPanel to show the card associated with the key
mainPanel.showCard(key);
}
}
// class of mine to allow disposing of a window
// It's a little complex to allow it to work with either a JButton
// or a JMenuItem
@SuppressWarnings("serial")
class ExitAction extends AbstractAction {
public ExitAction() {
super("Exit");
putValue(MNEMONIC_KEY, KeyEvent.VK_X);
}
@Override
public void actionPerformed(ActionEvent e) {
// get the button that caused this action
Object source = e.getSource();
if (source instanceof AbstractButton) {
AbstractButton exitButton = (AbstractButton) source;
// get the parent top level window
Window topWindow = SwingUtilities.getWindowAncestor(exitButton);
if (topWindow == null) { // if null, then likely in a JMenuItem
// so we have to get its jpopupmenu parent
Container parent = exitButton.getParent();
if (parent instanceof JPopupMenu) {
JPopupMenu popupMenu = (JPopupMenu) parent;
// get the invoker for the pop up menu
Component invoker = popupMenu.getInvoker();
if (invoker != null) {
// and get *its* top level window
topWindow = SwingUtilities.getWindowAncestor(invoker);
}
}
}
if (topWindow != null) {
// dispose of the top-level window
topWindow.dispose();
}
}
}
}
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