Java 如何在String.format'；JList中是否有DefaultListModel？
我已经在这里问过了，所以请通读一下。这个问题已经部分解决了。 现在我有另一个问题： 请先看这个例子Java 如何在String.format'；JList中是否有DefaultListModel？,java,string,jlist,defaultlistmodel,Java,String,Jlist,Defaultlistmodel,我已经在这里问过了，所以请通读一下。这个问题已经部分解决了。 现在我有另一个问题： 请先看这个例子 // Declarations String string1 = "Eggs"; String string2 = "Whole Chicken"; int quantity1 = 100; int quantity2 = 25; // HTML and PRE tags are added before and after string StringBuilder builder1 = ne
// Declarations
String string1 = "Eggs";
String string2 = "Whole Chicken";
int quantity1 = 100;
int quantity2 = 25;
// HTML and PRE tags are added before and after string
StringBuilder builder1 = new Stringbuilder;
builder.append("<html><pre>");
builder.append(String.format("%s \t %d", string1, quantity1));
builder.append("</pre></html>");
StringBuilder builder2 = new Stringbuilder;
builder.append("<html><pre>");
builder.append(String.format("%s \t %d", string2, quantity2));
builder.append("</pre></html>");
// JList is defined, and the builder is added to the list.
JList<String> list = new JList<String>();
list.addElement(builder1.toString());
list.addElement(builder2.toString());
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(320, 100);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
DefaultListModel<String> defaultListModel = new DefaultListModel<>();
defaultListModel.addElement(String.format("%-20s %d", "Eggs", 100));
defaultListModel.addElement(String.format("%-20s %d", "Whole Chicken", 25));
JList<String> jList = new JList<>(defaultListModel);
Font defaultListFont = jList.getFont();
jList.setFont(new Font("monospaced", defaultListFont.getStyle(), defaultListFont.getSize()));
contentPane.add(jList);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
编辑：有许多不同的方法可以影响格式，请参见此，或者最好研究指定所有现有格式模式的方法 正如@GhostCat所说，在格式字符串中使用宽度将解决您的问题 有关详细信息，请查看格式字符串的 然而，您试图做的事情让我想到，也许您可以使用JTable而不是JList
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(320, 150);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
DefaultListModel<String[]> defaultListModel = new DefaultListModel<>();
defaultListModel.addElement(new String[]{"Eggs", "100"});
defaultListModel.addElement(new String[]{"The longest Entry in the list", "12125"});
defaultListModel.addElement(new String[]{"Whole Chicken", "25"});
JList<String[]> jList = new JList<>(defaultListModel);
ListModelAwareColumnWidthProvider listModelAwareColumnWidthProvider = new ListModelAwareColumnWidthProvider();
listModelAwareColumnWidthProvider.setListModel(defaultListModel);
ColumnCellRenderer columnCellRenderer = new ColumnCellRenderer(listModelAwareColumnWidthProvider);
jList.setCellRenderer(columnCellRenderer);
contentPane.add(jList);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
最简单的解决方案是使用单间距字体和字符串格式
class ColumnCellRenderer implements ListCellRenderer<String[]> {
private ColumnWidthProvider columnWidthProvider;
public ColumnCellRenderer(ColumnWidthProvider columnWidthProvider) {
this.columnWidthProvider = columnWidthProvider;
}
@Override
public Component getListCellRendererComponent(JList<? extends String[]> list, String[] value, int index, boolean isSelected, boolean cellHasFocus) {
JPanel panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
for (int i = 0; i < value.length; i++) {
String valueElement = value[i];
JLabel label = new JLabel(valueElement);
align(label, i);
panel.add(label);
}
applyColors(list, panel, isSelected);
return panel;
}
private void applyColors(JList<?> list, JComponent component, boolean isSelected) {
if (isSelected) {
component.setForeground(list.getSelectionForeground());
component.setBackground(list.getSelectionBackground());
} else {
component.setForeground(list.getForeground());
component.setBackground(list.getBackground());
}
}
private void align(JComponent component, int columnIndex) {
Font font = component.getFont();
FontMetrics fontMetrics = component.getFontMetrics(font);
int fontHeight = fontMetrics.getHeight();
int columnWidth = columnWidthProvider.getColumnWidth(fontMetrics, columnIndex);
component.setPreferredSize(new Dimension(columnWidth, fontHeight));
}
}
class ListModelAwareColumnWidthProvider implements ColumnWidthProvider {
private class ListModelChangeAdapter implements ListDataListener {
@Override
public void intervalAdded(ListDataEvent e) {
initializeColumnWidths();
}
@Override
public void intervalRemoved(ListDataEvent e) {
initializeColumnWidths();
}
@Override
public void contentsChanged(ListDataEvent e) {
initializeColumnWidths();
}
}
private int defaultColumnWidth = 100;
private ListModelChangeAdapter listModelChangeAdapter = new ListModelChangeAdapter();
private ListModel<String[]> listModel;
private java.util.List<String> longestColumnStrings = new ArrayList<>();
public void setListModel(ListModel<String[]> listModel) {
if (this.listModel != null) {
this.listModel.removeListDataListener(listModelChangeAdapter);
}
this.listModel = listModel;
initializeColumnWidths();
if (this.listModel != null) {
this.listModel.addListDataListener(listModelChangeAdapter);
}
}
private void initializeColumnWidths() {
longestColumnStrings.clear();
if (listModel != null) {
int size = listModel.getSize();
for (int i = 0; i < size; i++) {
String[] elementAt = listModel.getElementAt(i);
for (int columnIndex = 0; columnIndex < elementAt.length; columnIndex++) {
String columnValue = elementAt[columnIndex];
while (columnIndex >= longestColumnStrings.size()) {
longestColumnStrings.add(null);
}
String lastLongestColumnString = longestColumnStrings.get(columnIndex);
if (lastLongestColumnString == null) {
longestColumnStrings.set(columnIndex, columnValue);
} else if (columnValue.length() > lastLongestColumnString.length()) {
longestColumnStrings.set(columnIndex, columnValue);
}
}
}
}
}
public void setDefaultColumnWidth(int defaultColumnWidth) {
this.defaultColumnWidth = defaultColumnWidth;
}
@Override
public int getColumnWidth(FontMetrics fontMetrics, int columnIndex) {
if (columnIndex < longestColumnStrings.size()) {
String longestColumnString = longestColumnStrings.get(columnIndex);
return fontMetrics.stringWidth(longestColumnString);
}
return defaultColumnWidth;
}
}
ListModel类ListModelAwareColumnWidthProvider实现ColumnWidthProvider{
私有类ListModelChangeAdapter实现ListDataListener{
@凌驾
添加了公共无效间隔（ListDataEvent e）{
初始化列宽（）；
}
@凌驾
删除公共无效间隔（ListDataEvent e）{
初始化列宽（）；
}
@凌驾
公共无效内容更改（ListDataEvent e）{
初始化列宽（）；
}
}
私有int defaultColumnWidth=100；
私有ListModelChangeAdapter ListModelChangeAdapter=新ListModelChangeAdapter（）；
私有列表模型列表模型；
private java.util.List longestColumnStrings=new ArrayList（）；
public void setListModel（ListModel ListModel）{
if（this.listModel！=null）{
this.listModel.removeListDataListener（listModelChangeAdapter）；
}
this.listModel=listModel；
初始化列宽（）；
if（this.listModel！=null）{
this.listModel.addListDataListener（listModelChangeAdapter）；
}
}
私有void initializeColumnWidths（）{
最长的ColumnStrings.clear（）；
if（listModel！=null）{
int size=listModel.getSize（）；
对于（int i=0；i=longestColumnStrings.size（））{
longestColumnStrings.add（null）；
}
String lastLongestColumnString=longestColumnStrings.get（columnIndex）；
如果（lastLongestColumnString==null）{
longestColumnStrings.set（columnIndex，columnValue）；
}else if（columnValue.length（）>lastLongestColumnString.length（））{
longestColumnStrings.set（columnIndex，columnValue）；
}
}
}
}
}
公共void setDefaultColumnWidth（int defaultColumnWidth）{
this.defaultColumnWidth=defaultColumnWidth；
}
@凌驾
public int getColumnWidth（FontMetrics FontMetrics，int columnIndex）{
if（columnIndex 效果非常好！还有一件事-我可以将string1/string2向左对齐而不是向右对齐吗？不客气。A）看看我的更新B）如果你高兴的话，考虑接受我的答案……直接从教程中得到的例子。只要稍微多做一点工作，创建一个定制的
TableModelpublic static void main(String[] args) {
JFrame frame = new JFrame();
frame.setSize(320, 150);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
DefaultListModel<String[]> defaultListModel = new DefaultListModel<>();
defaultListModel.addElement(new String[]{"Eggs", "100"});
defaultListModel.addElement(new String[]{"The longest Entry in the list", "12125"});
defaultListModel.addElement(new String[]{"Whole Chicken", "25"});
JList<String[]> jList = new JList<>(defaultListModel);
ListModelAwareColumnWidthProvider listModelAwareColumnWidthProvider = new ListModelAwareColumnWidthProvider();
listModelAwareColumnWidthProvider.setListModel(defaultListModel);
ColumnCellRenderer columnCellRenderer = new ColumnCellRenderer(listModelAwareColumnWidthProvider);
jList.setCellRenderer(columnCellRenderer);
contentPane.add(jList);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
class ColumnCellRenderer implements ListCellRenderer<String[]> {
private ColumnWidthProvider columnWidthProvider;
public ColumnCellRenderer(ColumnWidthProvider columnWidthProvider) {
this.columnWidthProvider = columnWidthProvider;
}
@Override
public Component getListCellRendererComponent(JList<? extends String[]> list, String[] value, int index, boolean isSelected, boolean cellHasFocus) {
JPanel panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
for (int i = 0; i < value.length; i++) {
String valueElement = value[i];
JLabel label = new JLabel(valueElement);
align(label, i);
panel.add(label);
}
applyColors(list, panel, isSelected);
return panel;
}
private void applyColors(JList<?> list, JComponent component, boolean isSelected) {
if (isSelected) {
component.setForeground(list.getSelectionForeground());
component.setBackground(list.getSelectionBackground());
} else {
component.setForeground(list.getForeground());
component.setBackground(list.getBackground());
}
}
private void align(JComponent component, int columnIndex) {
Font font = component.getFont();
FontMetrics fontMetrics = component.getFontMetrics(font);
int fontHeight = fontMetrics.getHeight();
int columnWidth = columnWidthProvider.getColumnWidth(fontMetrics, columnIndex);
component.setPreferredSize(new Dimension(columnWidth, fontHeight));
}
}
interface ColumnWidthProvider {
public int getColumnWidth(FontMetrics fontMetrics, int columnIndex);
}
class ListModelAwareColumnWidthProvider implements ColumnWidthProvider {
private class ListModelChangeAdapter implements ListDataListener {
@Override
public void intervalAdded(ListDataEvent e) {
initializeColumnWidths();
}
@Override
public void intervalRemoved(ListDataEvent e) {
initializeColumnWidths();
}
@Override
public void contentsChanged(ListDataEvent e) {
initializeColumnWidths();
}
}
private int defaultColumnWidth = 100;
private ListModelChangeAdapter listModelChangeAdapter = new ListModelChangeAdapter();
private ListModel<String[]> listModel;
private java.util.List<String> longestColumnStrings = new ArrayList<>();
public void setListModel(ListModel<String[]> listModel) {
if (this.listModel != null) {
this.listModel.removeListDataListener(listModelChangeAdapter);
}
this.listModel = listModel;
initializeColumnWidths();
if (this.listModel != null) {
this.listModel.addListDataListener(listModelChangeAdapter);
}
}
private void initializeColumnWidths() {
longestColumnStrings.clear();
if (listModel != null) {
int size = listModel.getSize();
for (int i = 0; i < size; i++) {
String[] elementAt = listModel.getElementAt(i);
for (int columnIndex = 0; columnIndex < elementAt.length; columnIndex++) {
String columnValue = elementAt[columnIndex];
while (columnIndex >= longestColumnStrings.size()) {
longestColumnStrings.add(null);
}
String lastLongestColumnString = longestColumnStrings.get(columnIndex);
if (lastLongestColumnString == null) {
longestColumnStrings.set(columnIndex, columnValue);
} else if (columnValue.length() > lastLongestColumnString.length()) {
longestColumnStrings.set(columnIndex, columnValue);
}
}
}
}
}
public void setDefaultColumnWidth(int defaultColumnWidth) {
this.defaultColumnWidth = defaultColumnWidth;
}
@Override
public int getColumnWidth(FontMetrics fontMetrics, int columnIndex) {
if (columnIndex < longestColumnStrings.size()) {
String longestColumnString = longestColumnStrings.get(columnIndex);
return fontMetrics.stringWidth(longestColumnString);
}
return defaultColumnWidth;
}
}