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社区首页 >问答首页 >如何在java编程中填充这些J组合框？

问如何在java编程中填充这些J组合框？
EN

Stack Overflow用户
提问于 2016-11-26 20:09:50
回答 1查看 43关注 0票数 0

我想用数组列表填充三个j组合框，如果是的话，如果是的话，condition.if我将从第一个combobox.then中选择一个depending jCombobox.Like，根据第二个comboboxes中的选择来逐个选择学期，如果我从学期jcombobox.then中选择了一个学期，那么根据学期jCombobox.Like的选择，jCombobox.Like会自动选择所有学期的书。Java J组合框是一个例子。

代码语言：javascript
复制
String[] dep={"Select Depertment","Compurter","Civil","Electrical","Telecom"};
String[] Compurter={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Civil={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Electrical={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Telecom={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};


String[]FirstSemester={"Select BooK Name","English1","Engineering Drawing","Mathematics-1","Chemistry","Computer Fundamental","Basic Electricity","Basic Electronics"};
String[]SecondSemester={"Select BooK Name","English 2","Physical Education","Physics-1","Mathematics-2","Computer Application-1","Bangla","Electronic Device & Circuit-1","Basic Workshop Practice"};
String[]ThirdSemester= {"Select BooK Name","Programming Language-1","Computer Application-2","Digital Electronics-1","Industrial Electronics","Mathematics-3","Physics-2","Social Science-1"};
String[]FourthSemester={"Select BooK Name","Programming Language-2","CAD & Graphics Design","Digital Electronics-2","Data Structure & Algorithm","Electrical Circuits & Machine","Discrete Mathematics","Social Science-2"};
String[]FifthSemester={"Select BooK Name","Microprocessor & Microcomputer-1","Computer Architecture","Programming Language-3","Database Management System","Web Design","Book Keeping & Accounting","Environmental Management"};
String[]SixthSemester={"Select BooK Name","Microprocessor & Microcomputer-2","Computer Peripherals","Data Comm. & Computer Network-1","Computer System Software","Computer Servicing","Web Development","Business Org. & Communication"};
String[]SeventhSemester={"Select BooK Name","Embedded Systems & PLC","Multimedia & Graphics","System Analysis & Design","Data Comm. & Computer Network-2","Computer Engineer Project","Industrial Management","Entrepreneurship"};        

public LibraryManage() {
    initComponents();

    divcomboDepertment.removeAllItems();

    for(int i=0; i< dep.length;i++) {
        divcomboDepertment.addItem(dep[i]);
    }   




    for(int i=0; i< Compurter.length;i++) {
        divcomboBook.addItem(Compurter[i]);
    }       

 }

 @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        divcomboDepertment = new javax.swing.JComboBox<>();
        divcomboSemester = new javax.swing.JComboBox<>();
        divcomboBook = new javax.swing.JComboBox<>();
        jPanel2 = new javax.swing.JPanel();
        txtSubmit = new javax.swing.JButton();

        jPanel1.setBackground(new java.awt.Color(51, 204, 255));

        jLabel1.setText("Depertment:");

        jLabel2.setText("Semester:");

        jLabel3.setText("Books:");

        divcomboDepertment.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
        divcomboDepertment.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                divcomboDepertmentItemStateChanged(evt);
            }
        });

        divcomboSemester.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
        divcomboSemester.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                divcomboSemesterItemStateChanged(evt);
            }
        });

        divcomboBook.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(141, 141, 141)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel1)
                    .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel3, javax.swing.GroupLayout.Alignment.LEADING))
                .addGap(74, 74, 74)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(divcomboSemester, 0, 335, Short.MAX_VALUE)
                    .addComponent(divcomboDepertment, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(divcomboBook, 0, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(40, 40, 40)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(divcomboDepertment, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(63, 63, 63)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel2)
                    .addComponent(divcomboSemester, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 91, Short.MAX_VALUE)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel3)
                    .addComponent(divcomboBook, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(84, 84, 84))
        );

        jPanel2.setBackground(new java.awt.Color(255, 255, 51));

        txtSubmit.setText("Submit");

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(273, 273, 273)
                .addComponent(txtSubmit)
                .addContainerGap(315, Short.MAX_VALUE))
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addComponent(txtSubmit)
                .addContainerGap(30, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void divcomboDepertmentItemStateChanged(java.awt.event.ItemEvent evt) {                                                    
        // TODO add your handling code here:
    divcomboSemester.removeAllItems();

        if(divcomboDepertment.getSelectedIndex() !=0)
        {
            String[] c;

            if (divcomboDepertment.getSelectedIndex()==1)
            {
                c=Compurter;
            }
            else if(divcomboDepertment.getSelectedIndex()==2)
            {
                c =Civil;
            }
            else if(divcomboDepertment.getSelectedIndex()==3)
            {
                c=Electrical;
            }

           else 
            {
                c=Telecom;
            }

            for(int i=0; i<c.length; i++)
            {
                divcomboSemester.addItem(c[i]);
            }
        }     


    }                                                   

    private void divcomboSemesterItemStateChanged(java.awt.event.ItemEvent evt) {                                                  
        // TODO add your handling code here:
          divcomboBook.removeAllItems();

        if(divcomboSemester.getSelectedIndex() !=0)
        {
            String[] b;

            if (divcomboSemester.getSelectedIndex()==1)
            {
                b=FirstSemester;
            }
            else if(divcomboSemester.getSelectedIndex()==2)
            {
                b =SecondSemester;
            }
            else if(divcomboSemester.getSelectedIndex()==3)
            {
                b=ThirdSemester;
            }
           else if(divcomboSemester.getSelectedIndex()==4)
            {
                b=FourthSemester;
            }
           else if(divcomboSemester.getSelectedIndex()==5)
            {
                b=FifthSemester;
            }
           else if(divcomboSemester.getSelectedIndex()==6)
            {
                b=SixthSemester;
            }
           else 
            {
                b=SeventhSemester;
            }

            for(int i=0; i<b.length; i++)
            {
                divcomboBook.addItem(b[i]);
            }
        }     

    }

我正在写我的源代码，像上面的Example.But，我的程序没有工作properly.Is，有什么办法吗？

java
combobox
EN

回答 1

Stack Overflow用户

回答已采纳

发布于 2016-11-27 09:03:54

老实说，我并没有仔细看过您的所有代码，但我确实在下面提供的代码示例中使用了字符串数组。我希望我没有曲解这里的任何东西。

在这种情况下，理想的情况是尽量为用户提供最愚蠢的证明。我的意思是，不要给用户从显示的JComboBoxes中选择错误的机会。您可以通过清除和禁用所有组合框(学期选择和图书选择)来完成此操作，直到实际部门已经选定为止。如果所有选择都已完成，并且用户决定在提交这些选择之前通过更改任何选择来更改主意，则在选择框之后的所有组合框将被清除或禁用，直到做出适当的选择为止。事实上，您的提交按钮也应该禁用，直到所有三个组合框都包含有效的选择，并在每个组合框的ItemStateChanged()事件中以这种方式维护。无论如何..。

现在，由于某种原因，字符串数组比实际需要的要多得多，例如：

代码语言：javascript
复制
String[] Compurter={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Civil={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Electrical={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};
String[] Telecom={"Select Semester","FirstSemester","SecondSemester","ThirdSemester","FourthSemester","FifthSemester","SixthSemester","SeventhSemester"};

所有这些数组都包含完全相同的字符串元素。不需要，因为您只需要一个数组来实际填写学期ComboBox。我们可以通过使用单个字符串数组(让我们将其称为学期)来完成这一任务：

代码语言：javascript
复制
String[] semesters={"Select Semester","First Semester","Second Semester","Third Semester",
                    "Fourth Semester","Fifth Semester","Sixth Semester","Seventh Semester"};

我明白你为什么这么做，但老实说，这不是必需的，你马上就会明白为什么。您还会注意到，我在每个元素中正确地排列了内容，这样在学期ComboBox中看起来更有吸引力。

在包含书名、(firstSemester[]，secondSemester[]，thirdSemester[]，等的所有字符串数组中，对每个书名可能与之相关的部门没有任何引用。一些书籍可能涉及多个部门，甚至可能涉及所有部门的一些标题。您需要提供一种方法，以便我们知道哪个标题可以与哪个部门相关。

为此，我修改了每个数组中的元素，使用分号(;)分隔符将相关部门添加到每个元素字符串中，这样就不需要进入二维数组，例如，数组元素可能包含：

代码语言：javascript
复制
"Engineering Drawing;Civil;Electrical"

在这里，第一个标记总是书名，任何其他的标记都是书名将与该学期相关的部门。很可能有一个包含以下内容的元素：

代码语言：javascript
复制
"Basic Workshop Practice"

此书名仅涉及在“部门”组合框中选定的特定部门。每个元素字符串使用String.split()方法进行拆分，以便检索在部门组合框中选择的图书标题和相关部门。我添加了一个名为addBooksToComboBox()的方法，它负责此业务(请参阅下面的代码)，并将适当的图书标题放在选定的部门和学期的图书组合框中。

以下是代码：

代码语言：javascript
复制
//Place under your class constructor:
String[] dep = {"Select Depertment","Computer","Civil","Electrical","Telecom"};

String[] semesters={"Select Semester","First Semester","Second Semester","Third Semester",
                    "Fourth Semester","Fifth Semester","Sixth Semester","Seventh Semester"};


String[] firstSemesterBooks = {"Select Book Name","English1;Civil;Telecom","Engineering Drawing;Civil;Electrical",
                               "Mathematics-1;Computer;Civil;Electrical;Telecom","Chemistry;Civil",
                               "Computer Fundamental;Computer;Civil;Electrical;Telecom","Basic Electricity;Electrical",
                               "Basic Electronics;Electrical"};

String[] secondSemesterBooks ={"Select Book Name","English 2;Civil;Telecom","Physical Education;Computer;Civil;Electrical;Telecom",
                               "Physics-1;Civil","Mathematics-2;Computer;Civil;Electrical;Telecom",
                               "Computer Application-1;Computer","Bangla;Telecom","Electronic Device & Circuit-1;Electrical",
                               "Basic Workshop Practice;Civil;Electrical"};

String[] thirdSemesterBooks = {"Select Book Name","Programming Language-1;Computer","Computer Application-2;Computer",
                               "Digital Electronics-1;Electrical", "Industrial Electronics;Electrical","Mathematics-3;Civil;Electrical",
                               "Physics-2;Civil","Social Science-1;Civil"};

String[] fourthSemesterBooks = {"Select Book Name","Programming Language-2;Computer","CAD & Graphics Design;Computer;Civil",
                                "Digital Electronics-2;Electrical", "Data Structure & Algorithm;Computer",
                                "Electrical Circuits & Machine;Electrical","Discrete Mathematics;Civil",
                                "Social Science-2;Civil"};

String[] fifthSemesterBooks = {"Select Book Name","Microprocessor & Microcomputer-1;Computer;Electrical",
                               "Computer Architecture;Computer;Electrical","Programming Language-3;Computer",
                               "Database Management System;Computer","Web Design;Computer","Book Keeping & Accounting;Civil;Telecom",
                               "Environmental Management;Civil"};

String[] sixthSemesterBooks = {"Select Book Name","Microprocessor & Microcomputer-2;Computer;Electrical",
                               "Computer Peripherals;Computer;Electrical", "Data Comm. & Computer Network-1;Computer",
                               "Computer System Software;Computer","Computer Servicing;Computer;Electrical",
                               "Web Development;Computer","Business Org. & Communication;Civil"};

String[] seventhSemesterBooks = {"Select Book Name","Embedded Systems & PLC;Electrical","Multimedia & Graphics;Computer",
                                 "System Analysis & Design;Computer;Civil","Data Comm. & Computer Network-2;Computer",
                                 "Computer Engineer Project;Computer","Industrial Management;Civil;Telecom",
                                 "Entrepreneurship;Computer;Civil;Electrical;Telecom"};   

// *******************************************************
// * I have added the Departements to Book Titles. It's up to YOU to make *
// * sure they are correct!                                                                 *
// *******************************************************


// JButton used to load up the Department ComboBox
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    divcomboDepartment.removeAllItems();
    divcomboSemester.removeAllItems();
    divcomboBook.removeAllItems();
    divcomboSemester.setEnabled(false);
    divcomboBook.setEnabled(false);

    for(int i=0; i< dep.length; i++) {
       divcomboDepartment.addItem(dep[i]);
    }  

}  

private void divcomboDepartmentItemStateChanged(java.awt.event.ItemEvent evt) {
    divcomboSemester.removeAllItems();
    divcomboBook.removeAllItems();

    if(divcomboDepartment.getSelectedIndex() == 0) {
        divcomboSemester.setEnabled(false);
        divcomboBook.setEnabled(false);
        return;
    }
    String depName = divcomboDepartment.getSelectedItem().toString();
    for(int i=0; i< semesters.length;i++) {
        divcomboSemester.addItem(semesters[i]);
    }
    divcomboSemester.setEnabled(true);
}

private void divcomboSemesterItemStateChanged(java.awt.event.ItemEvent evt) {
    divcomboBook.removeAllItems();
    String department = divcomboDepartment.getSelectedItem().toString();

    if(divcomboSemester.getSelectedIndex() == 0) {
        divcomboBook.setEnabled(false);
        return;
    }
    String[] semesterBooks = null;
    String semesterStrg = evt.getItem().toString(); 
    if (semesterStrg.equalsIgnoreCase("first semester")) { semesterBooks = firstSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("second semester")) { semesterBooks = secondSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("third semester")) { semesterBooks = thirdSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("fourth semester")) { semesterBooks = fourthSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("fifth semester")) { semesterBooks = fifthSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("sixth semester")) { semesterBooks = sixthSemesterBooks; }
    else if (semesterStrg.equalsIgnoreCase("seventh semester")) { semesterBooks = seventhSemesterBooks; } 
    else { return; }

    addBooksToComboBox(divcomboBook, semesterBooks, department);
    divcomboBook.setEnabled(true);
}

private static void addBooksToComboBox(final JComboBox combo, final String[] semesterArray, final String department) {
    for(int i = 0; i < semesterArray.length; i++) {
        String booksStrg = semesterArray[i];
        if (booksStrg.contains(";")) {
            String[] depts = booksStrg.split(";");
            for (int j = 0; j < depts.length; j++) {
                if (depts[j].equalsIgnoreCase(department)) {
                    combo.addItem(depts[0]);
                }
            }
        }
        else { combo.addItem(booksStrg); }
    }
}

希望这能在某种程度上帮助你或其他人:)

票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/40822641

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