问题描述
我有一个带有两列的 jTable 。第一列设置为布尔值（用于复选框），第二列设置为字符串值。我正在使用 Netbeans ，复选框已添加到第一列的所有行中。我试图仅为那些在第二列中具有值的行添加它。我使用代码来尝试，
I have a jTable with two columns.First column is set as Boolean(for checkbox) and second column has String value.As I am using Netbeans,checkbox got added into all rows of first column. I tried to add it only for those rows which have value in the second column. I used the code for trying that,
private class CustomCellRenderer extends DefaultTableCellRenderer {
/* (non-Javadoc)
* @see javax.swing.table.DefaultTableCellRenderer#getTableCellRendererComponent(javax.swing.JTable, java.lang.Object, boolean, boolean, int, int)
*/
@Override
public Component getTableCellRendererComponent(JTable table, Object value,boolean isSelected, boolean hasFocus, int row, int column) {
Component rendererComp = super.getTableCellRendererComponent(table, value, isSelected, hasFocus,row, column);
for(int i=row;i<jTable1.getRowCount();i++){
if(jTable1.getValueAt(i, 1)==null){
jTable1.setValueAt(true, i, 0);
//checkbox.setOpaque(false);
}
}
return this ;
}
}
如果我尝试设置值'对于上面的for循环中的所有其他复选框都是true，它运行良好。如何将其设置为其余行不可见。
If I try to set value 'true' for all other checkbox in the above for loop it's working well. How can I set it invisible for rest of the rows.
编辑：
我在这个
package e2;
import java.awt.Component;
import javax.swing.JCheckBox;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
public class JTable_CheckBox extends javax.swing.JFrame {
/** Creates new form JTable_CheckBox */
JCheckBox checkbox=new JCheckBox();
public JTable_CheckBox() {
initComponents();
jTable1.setValueAt("John",0,1);
jTable1.setValueAt("James",1,1);
jTable1.setValueAt("Janet",2,1);
jTable1.setValueAt("Tom",3,1);
jTable1.getColumnModel().getColumn(0).setCellRenderer(new CheckboxCellRenderer());
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new JTable_CheckBox().setVisible(true);
}
});
}
public class CheckboxCellRenderer extends JCheckBox implements TableCellRenderer {
public CheckboxCellRenderer() {
setOpaque(false);
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
//here i am trying to set check box invisible,but here i am setting as selected
for(int i=row;i<table.getRowCount();i++){
if(table.getValueAt(i, 1)==null){
table.setValueAt(true, i, 0);
//checkbox.setOpaque(false);
}
}
return this;
}
}
// Variables declaration - do not modify
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTable jTable1;
// End of variables declaration
}
推荐答案
TableCellRenderer在表中用于绘制重用相同组件的表的各个单元格。该表自动设置正确的上下文，组件边界，并为需要绘制的表的每个单元格调用 getTableCellRendererComponent （第一次显示表格中的所有可见单元格绘制然后，在TableModel通知后，重新绘制相应的单元格。
TableCellRenderer are used in tables to paint the various cells of the table reusing the same component. The table automatically sets up the proper context, component bounds and invokes the getTableCellRendererComponent for each cell of the table that needs to be painted (the first time the table is displayed all visible cells are painted and then after, upon TableModel notification, the appropriate cells are repainted).
所以在你的TableCellRenderer中，你当然不需要迭代表格的单元格设定值。这没有意义。请记住，您正在实现接口 TableCellRender ，其中包含您需要尊重的合同。
So in your TableCellRenderer you certainly do not need to iterate over the cells of the table trying to set values. This just does not make sense. Remember you are implementing the interface TableCellRender which has a contract you need to respect.
来自Javadoc：
所以你需要做的就是返回一个代表的组件值参数正确。可能，您可以修改组件以指示单元格是否具有焦点，以及当前是否选择了单元格。没有更多，没有更少。
So all you need to do is return a component representing the value parameter properly. Possibly, you can modify the component to indicate that the cell has the focus or not, and wheter it is currently selected or not. Nothing more, nothing less.
现在，提出您的问题：如果您只想为具有值的行显示一个复选框，则实现TableCellRenderer返回一个复选框并修改根据第1列（第2列）中的值显示其可见性。
Now, coming to your question: if you want to display a checkbox only for rows that have a value implement a TableCellRenderer returning a checkbox and modify its visibility according to the value in column 1 (second column).
此示例正常运行：
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.FlowLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableCellRenderer;
public class TestTable {
public class CheckboxCellRenderer extends JPanel implements TableCellRenderer {
private JCheckBox checkBox;
public CheckboxCellRenderer() {
super(new FlowLayout(FlowLayout.CENTER, 0, 0));
setOpaque(false);
checkBox = new JCheckBox();
checkBox.setOpaque(false);
checkBox.setHorizontalAlignment(JCheckBox.CENTER);
add(checkBox);
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
Object valueInColumn1 = table.getValueAt(row, 1);
checkBox.setVisible(valueInColumn1 != null);
checkBox.setSelected(value instanceof Boolean && (Boolean) value);
return this;
}
}
private JFrame f;
private JTable table;
private class MyObject {
private PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);
private String value;
private boolean selected;
public MyObject(String value) {
this.value = value;
}
public PropertyChangeSupport getPropertyChangeSupport() {
return propertyChangeSupport;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
propertyChangeSupport.firePropertyChange("value", null, value);
}
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
if (this.selected != selected) {
this.selected = selected;
propertyChangeSupport.firePropertyChange("selected", !selected, selected);
}
}
}
protected void initUI() {
List<MyObject> objects = new ArrayList<TestTable.MyObject>();
for (int i = 0; i < 200; i++) {
MyObject object = new MyObject(i % 3 == 1 ? null : "Row " + (i + 1));
objects.add(object);
}
table = new JTable(new MyTableModel(objects));
table.setRowHeight(20);
table.getColumnModel().getColumn(0).setCellRenderer(new CheckboxCellRenderer());
f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new JScrollPane(table), BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
public class MyTableModel extends AbstractTableModel implements PropertyChangeListener {
private List<MyObject> objects;
public MyTableModel(List<MyObject> objects) {
super();
this.objects = objects;
for (MyObject object : objects) {
object.getPropertyChangeSupport().addPropertyChangeListener(this);
}
}
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getSource() instanceof MyObject) {
int index = objects.indexOf(evt.getSource());
fireTableRowsUpdated(index, index);
}
}
@Override
public int getColumnCount() {
return 2;
}
@Override
public int getRowCount() {
return objects.size();
}
public MyObject getValueAt(int row) {
return objects.get(row);
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
switch (columnIndex) {
case 0:
return getValueAt(rowIndex).isSelected();
case 1:
return getValueAt(rowIndex).getValue();
}
return null;
}
@Override
public void setValueAt(Object value, int rowIndex, int columnIndex) {
if (columnIndex == 0) {
getValueAt(rowIndex).setSelected(Boolean.TRUE.equals(value));
}
}
@Override
public boolean isCellEditable(int rowIndex, int columnIndex) {
return columnIndex == 0 && getValueAt(rowIndex).getValue() != null;
}
@Override
public Class<?> getColumnClass(int column) {
switch (column) {
case 0:
return Boolean.class;
case 1:
return String.class;
}
return Object.class;
}
@Override
public String getColumnName(int column) {
switch (column) {
case 0:
return "Selected";
case 1:
return "Value";
}
return null;
}
}
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException,
UnsupportedLookAndFeelException {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new TestTable().initUI();
}
});
}
}
PS：我没带isSelected / hasFocus考虑在内，如果你想我们可以稍后再说。
PS: I did not take isSelected/hasFocus into account, if you want we can come to that later.
这篇关于在jTable中设置jCheckBox不可见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！