Java GUI创建JTables表的最佳方法？

Question

[UPDATE!!!!] This is the finish product:

: )

So I am working on a program that helps me organize and print seatings for dinner. I have a student class with instance variables of their FirstName, LastName, etc. I also have a DinnerTable Class that has List of Student and String teacherName. I have created a GUI that so that it is easier to assign different seats. I already have one tab on JTabbedPane that organizes student information(if they are available or not) and randomizes the tables they sit. Now, to better visualize the tables and to make it easier to assign each student to a specific seat, I need to make something like this: I want to use the actual DinnerTable objects in the TableModel so that whenever I edit something on this Frame, the changes are translated to the objects. However, I am not really sure about what to do. Should I:

1.Create tables(one JTable for each DinnerTable) nested in the cells of a bigger JTable? But how can I perform actions such as swiping students between DinnerTable? Or 2.Align JTables in GridLayout or GridBagLayout? But again, how can I swap students?

Thank you! package DinnerList;

  public class Student 
  {
  private String lastName;
  private String firstName;
  private int grade;
  private int table;
  private boolean gender;//Male=true, female=false;
  private boolean available; //true=available;

public Student()
{
    lastName="";
    firstName="";
    grade=0;
    table=0;
    gender=true;
    available=true;
}
public Student(String l, String f, int i, boolean g, boolean a)
{

    lastName=l;
    firstName=f;
    grade=i;
    gender=g;
    available=a;
    //table is not written back to the txt.
    table=0;
}
//Getters

  public String getLastName()
   {
    return lastName;
  }
  public String getFirstName()
{
    return firstName;
}
public int getGrade()
{
    return grade;
}       
public int getTable()
{
    return table;
}
  public boolean getGender()
{
    return gender;
}
public boolean getAvailable()
{
    return available;
}

//Setters
public void setLastName(String s)
{
    this.lastName=s;
}
public void setFirstName(String s)
{
    firstName=s;
}
public void setGrade(int i)

{
    grade=i;
}
public void setTable(int hiahia)
{
    table=hiahia;
}
public void setGender(boolean b)
{
    gender=b;
}
public void setAvailable(boolean b)
{
    available=b;
}

//Miscellaneous
  public String toString()
  {
    String a="";

     a=lastName+","+firstName+","+Integer.toString(grade)+","+Boolean.toString(gender)+","+Boolean.toString(available);
    return a;
    }
 }

///////////////////////////////////

 package DinnerList;

   import java.util.ArrayList;
   import java.util.List;

  public class DinnerTable 
{
    private List<Student> members= new ArrayList<Student>();
    private int tableNumber=0;
    private int capacity=0;
    private String teacherName="";
    private boolean available=true;

public DinnerTable(int a, int b, String c, boolean d)
{
    tableNumber=a;
    capacity=b;
    teacherName=c;
    available=d;
}

public void setTableNumber(int a) {tableNumber=a;}
public void setCapacity(int a) {capacity=a;}
public void setTeacherName(String a) {teacherName=a;}
public void setAvailable(boolean b) {available=b;}
public void add(Student s)
{
    if(available&&(members.size()<capacity))
    { this.members.add(s); }
    else if(!available)
    { System.out.println("Adding Student failed, table "+tableNumber+" not available");}
    else
    { System.out.println("Adding Student failed, table "+tableNumber+" is full");}
}

public int getTableNumber() 
{return tableNumber;}
public int getCapacity() {return this.capacity;}
public String getTeacherName() {return teacherName;}
public boolean getAvailable() {return available;}
public List<Student> getMembers(){return members;}
public void remove(Student s) 
{
    if(members.contains(s))
    {
        members.remove(s);
    }
    else
    {
        System.out.println("Failed to remove student from table because it wasn't there");
    }
  }
}

/////////////////////

package DinnerList;

import java.awt.Component;

import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;

public class DinnerTableCellRenderer extends DefaultTableCellRenderer implements TableCellRenderer {

@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
          boolean hasFocus, int row, int column)
{
    Object huahua =table.getModel().getValueAt(row, column);
    String ppp="";
    if(huahua!=null)
    {
        if(huahua instanceof Student)
        {
            ppp=((Student) huahua).getLastName()+", "+((Student)huahua).getFirstName();
        }
        else if(huahua instanceof String)
        {
            ppp=(String)huahua;
        }
        else
        {
            System.out.println("Error: DinnerTableCellRenderer intakes unknown data type");
        }
    }
    else
    {
        ppp="";
    }
    JLabel label = (JLabel)super.getTableCellRendererComponent(table, ppp,isSelected, hasFocus,row, column);
    return label;
    }

}

//////////

package DinnerList;

import java.util.ArrayList;
import java.util.List;

import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableModel;

public class DinnerTableModel extends AbstractTableModel implements TableModel
 {
    private final String[] columnNames={"","","",""};
    private List<DinnerTable> tableCollection= new ArrayList<DinnerTable>();


public DinnerTableModel(List<DinnerTable> huhu)
{
    tableCollection.addAll(huhu);
}
public int getColumnCount() 
{
    return columnNames.length;
}

public int getRowCount() 
{
        if(tableCollection.size()%4==0)
        {
            return tableCollection.size()/4;
        }
        else
        {
            return (int)(tableCollection.size()/4)+1;
        }
}

public String getColumnName(int col) 
{
    return columnNames[col];
}

public DinnerTable getTableAt(int row, int column)
{
        if(tableCollection.size()>=(Integer)((row)/8)+column+1)
        {
            return tableCollection.get((Integer)((row)/8)+column);
        }
        else
        {
            return null;
        }

}
public Object getValueAt(int rowIndex, int colIndex) 
{
    DinnerTable dd= this.getTableAt(rowIndex, colIndex);
    String ss= "";
    if(dd==null)
    {
            return "";
    }
    else if(rowIndex%8==0)
    {
            return (dd.getTableNumber()+". "+dd.getTeacherName());
    }
    else if(dd.getMembers().size()>=rowIndex%8)
    {
            return dd.getMembers().get(rowIndex%8);
    }
    else
    {
            return "";
    }
}


public Class getColumnClass(int c) 
{
    return getValueAt(0, c).getClass();
}
public boolean isCellEditable(int row, int col) 
{
        if(this.getValueAt(row, col) instanceof Student)
        {
            return true;
        }
        else
        {
            return false;
        }
}
    public void setValueAt(Object aValue, int rowIndex, int columnIndex)
    {

  if(aValue instanceof Student)
  {
        if(rowIndex%8!=0)
        {
            if(null!=this.getTableAt(rowIndex,columnIndex))
            {
                this.getTableAt(rowIndex,columnIndex).getMembers().set(rowIndex%8-1, (Student)aValue);
            }
            else
            {
                System.out.println("error: Attempting to put student in nonexistent table in table list gui");
            }
        }
        else
        {
            System.out.println("error: Attempting to put student in a string in table list gui");
        }
  }
  else if(aValue instanceof String)
  {
        System.out.println("error: Attempting to change teacher name in tablelist gui");
  }
  else
  {
        System.out.println("error: Attempting to set unknown object type in tablelist gui");
  }
}

}

////****************////

JTable tableTable= new JTable(new DinnerTableModel(tables));
for(int hihihi=0;hihihi<tableTable.getColumnCount();hihihi++)
{
  tableTable.getColumnModel().getColumn(hihihi).setCellRenderer(new   DinnerTableCellRenderer());
}
JScrollPane scrollpaneB1= new JScrollPane();
scrollpaneB1.add(tableTable);
panelB.add(scrollpaneB1);

Answer 1

I am new to programming and have a lot of questions. It is very nice of you to be so patient! : ) However, I have another JTable that intakes another TableModel class. I ran tests and it seems that the model does change whenever the original objects change, even though I didn't use any propertychangelisteners. This is very confusing to me...

JTable is among one of the more complex components in the API ( JTree and text components been the next), if you can become comfortable with it, you will be a long way to becoming comfortable with the overall API.

There are any number of ways you could notify the TableModel that an object has changed, but one of the best ways is to do it in a decoupled way, so you don't have to maintain a reference to the TableModel every where the Student object might change.

This suggests that the Student object itself should generate some kind of change event, which interested parties (like the TabelModel ) can listen for and take action when they occur.

In this way, you can change the Student object anywhere in your code without caring about who might need to know that the object has changed.

Now, this basically boils down to an observer pattern, Swing implements this kind of functionality in it's listeners, ChangeListener springs to mind as a possible candidest, but PropertyChangeListener is a more powerful option, as it generates events based on the property that has changed.

In some cases, you probably won't care what property has changed, but in the case of TableModel , it's very useful.

This is a simple demonstration of the concept, using two tables. You can edit any value in either table and the opposing table will be updated when the value is committed. Now, you could also modify the instance of Student in your code and you'd get the same result, but this was a simple example to create.

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                Student student = new Student("Skywalker", "Luke", 0, true, true);
                StudentTabelModel leftModel = new StudentTabelModel(student);
                StudentTabelModel rightModel = new StudentTabelModel(student);

                JTable leftTable = new JTable(leftModel);
                leftTable.setGridColor(Color.GRAY);
                JTable rightTable = new JTable(rightModel);
                rightTable.setGridColor(Color.GRAY);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new GridLayout(0, 2));
                frame.add(new JScrollPane(leftTable));
                frame.add(new JScrollPane(rightTable));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class StudentTabelModel extends AbstractTableModel {

        private List<Student> students = new ArrayList<>(25);
        private PropertyChangeListener propertyChangeListener;

        public StudentTabelModel(Student... students) {
            propertyChangeListener = new StudentPropertyChangeListener();
            add(students);
        }

        public void add(Student... students) {
            if (students != null && students.length > 0) {
                int startRow = this.students.size();
                for (Student student : students) {
                    student.addPropertyChangeListener(propertyChangeListener);
                    this.students.add(student);
                }
                fireTableRowsInserted(startRow, this.students.size() - 1);
            }
        }

        public void remove(Student ...students) {
            if (students != null && students.length > 0) {
                for (Student student : students) {
                    int index = this.students.indexOf(student);
                    if (index != -1) {
                        student.removePropertyChangeListener(propertyChangeListener);
                        this.students.remove(student);
                        fireTableRowsDeleted(index, index);
                    }
                }
            }
        }

        @Override
        public boolean isCellEditable(int rowIndex, int columnIndex) {
            return true;
        }

        @Override
        public int getRowCount() {
            return students.size();
        }

        @Override
        public int getColumnCount() {
            return 6;
        }

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            switch (columnIndex) {
                case 0:
                case 1:
                    return String.class;
                case 2:
                case 3:
                    return Integer.class;
                case 4:
                case 5:
                    return Boolean.class;
            }
            return Object.class;
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
            Student student = students.get(rowIndex);
            switch (columnIndex) {
                case 0:
                    return student.getLastName();
                case 1:
                    return student.getFirstName();
                case 2:
                    return student.getGrade();
                case 3:
                    return student.getTable();
                case 4:
                    return student.getGender();
                case 5:
                    return student.getAvailable();
            }
            return "??";
        }

        @Override
        public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
            Student student = students.get(rowIndex);
            switch (columnIndex) {
                case 0:
                    student.setLastName(aValue == null ? null : aValue.toString());
                    break;
                case 1:
                    student.setFirstName(aValue == null ? null : aValue.toString());
                    break;
                case 2:
                    if (aValue instanceof Integer) {
                        student.setGrade((Integer) aValue);
                    }
                    break;
                case 3:
                    if (aValue instanceof Integer) {
                        student.setTable((Integer) aValue);
                    }
                    break;
                case 4:
                    if (aValue instanceof Boolean) {
                        student.setGender((Boolean) aValue);
                    }
                    break;
                case 5:
                    if (aValue instanceof Boolean) {
                        student.setAvailable((Boolean) aValue);
                    }
                    break;
            }
        }

        protected class StudentPropertyChangeListener implements PropertyChangeListener {

            @Override
            public void propertyChange(PropertyChangeEvent evt) {
                if (evt.getSource() instanceof Student) {
                    Student student = (Student) evt.getSource();
                    int row = students.indexOf(student);
                    if (row != -1) {
                        switch (evt.getPropertyName()) {
                            case "lastName":
                                fireTableCellUpdated(row, 0);
                                break;
                            case "firstName":
                                fireTableCellUpdated(row, 1);
                                break;
                            case "grade":
                                fireTableCellUpdated(row, 2);
                                break;
                            case "table":
                                fireTableCellUpdated(row, 3);
                                break;
                            case "gender":
                                fireTableCellUpdated(row, 4);
                                break;
                            case "avaliable":
                                fireTableCellUpdated(row, 5);
                                break;
                        }
                    }
                }
            }

        }

    }

    public class Student {

        private String lastName;
        private String firstName;
        private int grade;
        private int table;
        private boolean gender;//Male=true, female=false;
        private boolean available; //true=available;

        private PropertyChangeSupport propertyChangeSupport;

        public Student() {
            this("", "", 0, false, true);
        }

        public Student(String l, String f, int i, boolean g, boolean a) {

            lastName = l;
            firstName = f;
            grade = i;
            gender = g;
            available = a;
            //table is not written back to the txt.
            table = 0;
            propertyChangeSupport = new PropertyChangeSupport(this);
        }

        public void addPropertyChangeListener(PropertyChangeListener listener) {
            propertyChangeSupport.addPropertyChangeListener(listener);
        }

        public void removePropertyChangeListener(PropertyChangeListener listener) {
            propertyChangeSupport.removePropertyChangeListener(listener);
        }
//Getters

        public String getLastName() {
            return lastName;
        }

        public String getFirstName() {
            return firstName;
        }

        public int getGrade() {
            return grade;
        }

        public int getTable() {
            return table;
        }

        public boolean getGender() {
            return gender;
        }

        public boolean getAvailable() {
            return available;
        }

//Setters
        public void setLastName(String s) {
            String old = lastName;
            this.lastName = s;
            propertyChangeSupport.firePropertyChange("lastName", old, lastName);
        }

        public void setFirstName(String s) {
            String old = firstName;
            firstName = s;
            propertyChangeSupport.firePropertyChange("firstName", old, firstName);
        }

        public void setGrade(int i) {
            int old = grade;
            grade = i;
            propertyChangeSupport.firePropertyChange("grade", old, grade);
        }

        public void setTable(int hiahia) {
            int old = table;
            table = hiahia;
            propertyChangeSupport.firePropertyChange("table", old, table);
        }

        public void setGender(boolean b) {
            boolean old = gender;
            gender = b;
            propertyChangeSupport.firePropertyChange("gender", old, gender);
        }

        public void setAvailable(boolean b) {
            boolean old = available;
            available = b;
            propertyChangeSupport.firePropertyChange("available", old, available);
        }

//Miscellaneous
        @Override
        public String toString() {
            String a = "";

            a = lastName + "," + firstName + "," + Integer.toString(grade) + "," + Boolean.toString(gender) + "," + Boolean.toString(available);
            return a;
        }
    }
}

Remember, this relies on the INSTANCE of the Student been shared, if you create two different instances of the Student object and expect that changes in one instance will be reflected in the other, then you will be disappointed