JTable不显示列名称 [英] JTable doesn't show columns names
问题描述
这是我的代码:
public class DownloadMainView extends JFrame{
private ArrayList<DownloadItem> downloadList = new ArrayList<DownloadItem>();
private JMenuBar menubar = new JMenuBar();
private JMenu m_task = new JMenu("Tasks");
private JMenu m_tool = new JMenu("Tools");
private JMenu m_help = new JMenu("Help");
private JMenuItem mi_add = new JMenuItem("Add");
private JMenuItem mi_exit = new JMenuItem("Exit");
private JMenuItem mi_options = new JMenuItem("Options");
private JMenuItem mi_help = new JMenuItem("Help");
private JMenuItem mi_about = new JMenuItem("About");
private JTree categoryTree = new JTree();
private JTable contentTable = new JTable(new Object[][]{},new Object[]{"No.","Filename","URL","Status","Size","Added Date"});
private JToolBar toolbar = new JToolBar();
private JScrollPane scrollPane = new JScrollPane();
private JButton btnAdd = new JButton("Add");
private JButton btnCancel = new JButton("Cancel");
private JButton btnDelete = new JButton("Delete");
private JButton btnOption = new JButton("Option");
public DownloadMainView() throws IOException{
super("KPDownloader");
setSize(800,400);
setLayout(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
//Build menubar
menubar.add(m_task);
menubar.add(m_tool);
menubar.add(m_help);
m_task.add(mi_add);
mi_add.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_A,ActionEvent.CTRL_MASK));
m_task.add(new JSeparator());
m_task.add(mi_exit);
mi_exit.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X,ActionEvent.ALT_MASK));
m_tool.add(mi_options);
mi_options.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,ActionEvent.CTRL_MASK));
m_help.add(mi_help);
mi_help.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F1,0));
m_help.add(mi_about);
mi_about.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_B,ActionEvent.CTRL_MASK));
setJMenuBar(menubar);
//about buttons
toolbar.add(btnAdd);
toolbar.add(btnOption);
toolbar.add(btnCancel);
toolbar.add(btnDelete);
toolbar.setLocation(0, 0);
toolbar.setSize(800,42);
this.add(toolbar);
//add table to mainview
String columns[] = {"No.","Filename","URL","Status","Size","Added Date"};
DefaultTableModel model = new DefaultTableModel(columns,1);
readDownloadList();
if(downloadList != null){
int length = downloadList.size();
for(int i = 0; i < length; i++)
model.insertRow(i, new Object[]{i,
downloadList.get(i).getFilename(),downloadList.get(i).getSize(),
downloadList.get(i).getStatus(),
downloadList.get(i).getURL(),downloadList.get(i).getAddedDate()});
}
contentTable.setModel(model);
contentTable.setSize(800, 350);
scrollPane.add(contentTable);
scrollPane.setSize(800, 350);
scrollPane.setLocation(0, 50);
this.add(scrollPane);
}
但是当我运行我的代码时,表格不会显示列名。当我将1设置为此行时,它只显示一个空行: DefaultTableModel model = new DefaultTableModel(columns,1);
But when I run my code, the table does not display column names. It just shows one empty row as I set 1 to this line: DefaultTableModel model = new DefaultTableModel(columns,1);
请告诉我我的代码错在哪里?
谢谢!
Please show me where my code is wrong?? Thanks!
编辑:有人问同样的问题(在JTable中没有标题),但答案是将Jtable添加到JScrollPane,这对@@没有帮助
编辑:您好 Dan ,我添加了完整的构造函数,这里是 readDownloadList()
方法的代码:
Edited: As someone asked same question (No titles in JTable) but the answer is add Jtable to a JScrollPane and this does not help @@
Edited: Hi Dan, I've added my full Constructor, and here is the code of the readDownloadList()
method:
void readDownloadList(){
File file = new File("downloadlist.dat");
ObjectInputStream ois = null;
if(!file.exists())
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
ois = new ObjectInputStream(new FileInputStream(file));
downloadList = (ArrayList<DownloadItem>) ois.readObject();
ois.close();
} catch (IOException e) {
// TODO Auto-generated catch block
downloadList = new ArrayList<DownloadItem>();
e.printStackTrace();
}catch(ClassNotFoundException e){
downloadList = new ArrayList<DownloadItem>();
e.printStackTrace();
}
}
谢谢!
推荐答案
您以错误的方式使用了 JScrollPane
。为了使其正常工作,只需执行以下操作。
You used the JScrollPane
in a wrong way. To make it work fine, just do the following.
将 JTable
实例传递给构造函数中的JScrollPane
:
private JScrollPane scrollPane = new JScrollPane(contentTable);
注释掉用于添加 JTable的行
到 JScrollPane
:
// scrollPane.add(contentTable);
当你将组件放在 JScrollPane $ c的构造函数中时$ c>,你提到哪个是要应用滚动的视图。
When you put the component inside the constructor of a JScrollPane
, you mention which is the view to which the scroll to be applied for.
另一方面,使用 add
方法,您只需将一个组件添加到容器中,例如将其添加到 JPanel
。这样,您就不会指定要添加滚动条的组件。
On the other side, using the add
method, you just add a component to a container, like adding it to a JPanel
. This way, you don't specify the component to add the scroll bars to.
这篇关于JTable不显示列名称的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!