java如何使用AbstractTableModel方法向JTable添加行?
我想向已初始化的JTable添加行。除其他要素外,我还有以下(相关)代码:
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
class sscce extends JFrame {
private static final long serialVersionUID = 1L; // Serial ID...
// Interface-Elemente erzeugen
Container content = getContentPane();
DefaultTableModel myAbstractTableModel = new DefaultTableModel () {
private static final long serialVersionUID = 1L; // whatever
public String[] columnNames = {"AuftragNr", "Datum & Uhrzeit", "Von", "Nach", "erledigt?"};
public Object[][] data = {{"156", "31.12.2012 - 10:39:31", "5/5", "205/39", new Boolean(false)}};
public int getColumnCount() {
return columnNames.length;
}
public int getRowCount() {
return data.length;
}
public String getColumnName(int col) {
return columnNames[col];
}
public Object getValueAt(int row, int col) {
return data[row][col];
}
public Class getColumnClass(int c) {
return getValueAt(0, c).getClass();
}
public boolean isCellEditable(int row, int col) {
if (col != 4) {
return false;
} else {
return true;
}
}
public void setValueAt(Object value, int row, int col) {
data[row][col] = value;
fireTableCellUpdated(row, col);
}
};
JTable auftragTable = new JTable(myAbstractTableModel);
JScrollPane tableScrollPane = new JScrollPane(auftragTable);
JButton auftragAenderungSpeichern = new JButton("speichern");
public sscce() {
setTitle("Auftragsverwaltung");
setSize(700, 500);
setLocation(500, 200);
setLayout(null);
setResizable(false);
tableScrollPane.setBounds(50, 50, 500, 200);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e) {
}
@SuppressWarnings("deprecation")
public static void main(String[] args) {
JFrame f = new sscce();
f.show();
}
}
每当我试图运行程序时,我都会得到一个空点异常
at javax.swing.table.DefaultTableModel.setDataVector(Unknown Source)
at javax.swing.table.DefaultTableModel.<init>(Unknown Source)
at javax.swing.table.DefaultTableModel.<init>(Unknown Source)
at javax.swing.table.DefaultTableModel.<init>(Unknown Source)
对于以下代码行:
public int getRowCount() {
return data.length;
}
为什么呢?我的代码怎么了?程序难道不能“查找”数据吗
编辑:第二种方法
我试图使用ArrayList作为存储数据的位置。。。但是还有“cols rows问题”,如下面的评论所示。。。找不到数组值(因为我现在使用的是ArrayList)。我怎样才能解决这个问题
import java.awt.Container;
import java.awt.List;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
class sscce extends JFrame {
private static final long serialVersionUID = 1L; // Serial ID...
Container content = getContentPane();
AbstractTableModel myAbstractTableModel = new AbstractTableModel () {
private static final long serialVersionUID = 1L; // whatever
private String[] columnNames = {"AuftragNr", "Datum & Uhrzeit", "Von", "Nach", "erledigt?"};
private ArrayList<Object> data = new ArrayList<Object>();
public void addRow(List rowData) {
data.add(rowData);
fireTableRowsInserted(data.size() - 1, data.size() - 1);
}
public int getColumnCount() {
return columnNames.length;
}
public int getRowCount() {
return data.length;
// can be solved via .size();
}
public String getColumnName(int col) {
return columnNames[col];
}
public Object getValueAt(int row, int col) {
return data[row][col];
// no idea, how to solve that?!
}
public Class getColumnClass(int c) {
return getValueAt(0, c).getClass();
}
public boolean isCellEditable(int row, int col) {
if (col == 4) {
return true;
}
return false;
}
public void setValueAt(Object value, int row, int col) {
data[row][col] = value;
// same issue here...
fireTableCellUpdated(row, col);
}
};
JTable auftragTable = new JTable(myAbstractTableModel);
JScrollPane tableScrollPane = new JScrollPane(auftragTable);
JButton auftragAenderungSpeichern = new JButton("speichern");
public sscce() {
setTitle("Auftragsverwaltung");
setSize(700, 500);
setLocation(500, 200);
setLayout(null);
setResizable(false);
tableScrollPane.setBounds(50, 50, 500, 200);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
@SuppressWarnings("deprecation")
public static void main(String[] args) {
JFrame f = new sscce();
f.show();
}
}
编辑:第三种方法
sscce类:
import java.awt.Container;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
class sscce extends JFrame {
private static final long serialVersionUID = 1L; // Serial ID...
Container content = getContentPane();
AbstractTableModel myAbstractTableModel = new AbstractTableModel() {
private static final long serialVersionUID = 1L; // whatever
private String[] columnNames = {"AuftragNr", "Datum & Uhrzeit", "Von", "Nach", "erledigt?"};
private ArrayList<DataStore> data = new ArrayList<DataStore>();
public void addRow(DataStore rowData) {
data.add(rowData);
fireTableRowsInserted(data.size() - 1, data.size() - 1);
}
public int getColumnCount() {
return columnNames.length;
}
public int getRowCount() {
return data.size(); // length
// can be solved via .size();
}
public String getColumnName(int col) {
return columnNames[col];
}
public Object getValueAt(int row, int col) {
// change made here
DataStore rowElement = data.get(row);
Object value = rowElement.getItemOnPosition(col);
return value;
}
public Class getColumnClass(int c) {
return getValueAt(0, c).getClass();
}
public boolean isCellEditable(int row, int col) {
if (col == 4) {
return true;
}
return false;
}
public void setValueAt(Object value, int row, int col) {
// change made here
DataStore rowElement = data.get(row);
rowElement.setItemOnPosition(col, value);
fireTableCellUpdated(row, col);
}
};
JTable auftragTable = new JTable(myAbstractTableModel);
JScrollPane tableScrollPane = new JScrollPane(auftragTable);
JButton auftragAenderungSpeichern = new JButton("speichern");
public sscce() {
setTitle("Auftragsverwaltung");
setSize(700, 500);
setLocation(500, 200);
setLayout(null);
setResizable(false);
tableScrollPane.setBounds(50, 50, 500, 200);
content.add(tableScrollPane);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
@SuppressWarnings("deprecation")
public static void main(String[] args) {
JFrame f = new sscce();
f.show();
}
}
数据存储类:
public class DataStore {
Integer auftragNr;
String datumUhrzeit;
String von;
String nach;
Boolean status;
public DataStore(Integer a, String b, String c, String d, Boolean e) {
auftragNr = a;
datumUhrzeit = b;
von = c;
nach = d;
status = e;
}
public Object getItemOnPosition(int pos) {
if(pos == 1) {
return (Integer) auftragNr;
}
if(pos == 2) {
return datumUhrzeit;
}
if(pos == 3) {
return von;
}
if(pos == 4) {
return nach;
}
if(pos == 5) {
return (Boolean) status;
}
return null;
}
public Object setItemOnPosition(int pos, Object newValue) {
if(pos == 1) {
auftragNr = (Integer) newValue;
}
if(pos == 2) {
datumUhrzeit = (String) newValue;
}
if(pos == 3) {
von = (String) newValue;
}
if(pos == 4) {
nach = (String) newValue;
}
if(pos == 5) {
status = (Boolean) newValue;
}
return null;
}
}
# 1 楼答案
由于您试图创建自己的
myAbstractTableModel
,因此应该扩展AbstractTableModel,而不是像DefaultTableModel
这样的具体实现。 使用ArrayList存储数据对象How to Use Tables向您展示了如何执行此操作的基本知识顺便说一下,如果没有理由的话,会使字段的可见性尽可能降低
也
就这样
# 2 楼答案
是,找不到数组值,因为您没有使用数组。您需要从ArrayList中提取数据。如果您不熟悉ArrayList方法,请查看ArrayList API
关于您的代码,您有编译错误,无论您在哪里发现这些类型的错误,您都必须调查您可能做错了什么。主要是将ArrayList当作数组来处理,当然不是,所以使用array构造数组类型。长度或使用数组索引(array[i][j])将严重失败。同样,请查看上面链接的ArrayList API或一个像样的ArrayList教程,了解如何使用这些家伙。例如,如果编译器告诉您ArrayList没有长度属性或方法,那么请在ArrayList API中查找获取所需信息的适当方法。这就是API的用途
另外,您的ArrayList不应该包含对象,换句话说,它不应该是
ArrayList<Object>
,而是应该更加具体。通常,表模型的行将包含一个对象,该对象的属性表示行中的每个项。因此,如果我们调用保存每行数据的类RowData,您的ArrayList将被声明为ArrayList<RowData>
。因此,要获取row,col的值,需要从模型的ArrayList中提取行索引的RowData(假设这是行数据的类的名称),然后调用对象的getter方法来提取col索引关联项