![](/img/trans.png)
[英]Limiting Component Size in JText Area in Vertical JScrollPane within Horizontal JScrollPane
[英]Horizontal JScrollPane inside vertical JScrollPane
下午好。 有必要从事件列表(水平)中制作一个列表(垂直):至少有2个问题:
import ivank.components.EventAdd;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class WindowAddCameras extends JFrame {
public static final List<JPanel> labels = new ArrayList<JPanel>();
public WindowAddCameras() {
super("Добавить камеру");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panelButton = new JPanel();
JButton addButton = new JButton("+");
addButton.setFocusable(false);
panelButton.add(addButton);
JButton remButton = new JButton("-");
remButton.setFocusable(false);
panelButton.add(remButton);
JPanel externalPanel = new JPanel();
externalPanel.setLayout(new BorderLayout(0, 0));
JScrollPane scrollPaneGroupEvent = new JScrollPane(
externalPanel,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER
);
JPanel internalPanel = new JPanel();
internalPanel.setLayout(new GridLayout(0, 1, 0, 0));
JScrollPane scrollPaneEvent = new JScrollPane(internalPanel);
scrollPaneEvent.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
scrollPaneEvent.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
externalPanel.add(scrollPaneEvent, BorderLayout.NORTH);
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int number = labels.size() + 1;
EventAdd eventAdd = new EventAdd();
Dimension labelSize = new Dimension(80, 80);
//add event to group event
Random rand = new Random();
for(int a = 0; a < 20; a++) {
//random color border event for TEST
Color randomColor = new Color(rand.nextFloat(), rand.nextFloat(), rand.nextFloat());
eventAdd.createEventLabel("Камера " + number, labelSize, randomColor);
}
labels.add(eventAdd);
internalPanel.add(eventAdd, BorderLayout.NORTH);
scrollPaneGroupEvent.revalidate();
}
});
remButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(labels.size() > 0) {
int index = labels.size() - 1;
JPanel panel = labels.remove(index);
internalPanel.remove(panel);
internalPanel.repaint();
scrollPaneGroupEvent.revalidate();
}
}
});
this.getContentPane().setLayout(new BorderLayout());
this.getContentPane().add(panelButton, BorderLayout.NORTH);
this.getContentPane().add(scrollPaneGroupEvent, BorderLayout.CENTER);
this.setPreferredSize(new Dimension(600, 400));
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
}
package ivank.components;
import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
public class EventAdd extends JPanel {
public EventAdd() {
super(new FlowLayout(FlowLayout.LEFT));
}
public JComponent createEventLabel(String name, Dimension labelSize, Color randomColor) {
this.setBorder(BorderFactory.createTitledBorder(name));
JLabel label = new JLabel();
label.setPreferredSize(labelSize);
label.setHorizontalAlignment(JLabel.CENTER);
label.setBorder(BorderFactory.createLineBorder(randomColor, 5));
this.add(label);
return label;
}
}
JScrollPane 必须使用 jscrollpane 方法setViewportView分配一个 JViewport。 您还应该给它一个滚动条策略 setVerticalScrollBarPolicy setHorizontalScrollBarPolicy 该策略int是前两种方法的 class 的一部分,称为“常量字段值”,请参阅 JScrollPane 的 API 文档。 要将 JScrollPane 展开,请将其放入具有 BorderLayout 的 JPanel中,并且在具有 JScrollPane 的特定面板中没有其他元素。 在 JPanel 上使用方法 setMinimumSize 和 setPreferredSize 和 setSize 或主窗口中的 BoxLayout(虽然我认为主 windows 有一个特殊的布局,所以如果是这样,则不需要 boxlayout)或堆栈中的更高级别面板,或者只是 setPreferredSize对于 JScrollPane。 A jscrollpane has a view set by its " setView " method, its view is a java.awt.Component note: a JComponent is a java.awt.Component, any javax swing J panel or J viewport is a java.awt.Component by等级制度。 注意一个 jviewport 是一个 java.awt.Component 所以得到一个 jscrollpane.setViewportView 添加 jviewport 引用 jviewport.setView 作为 JPanel 与 BorderLayout,添加另一个面板开始添加其他组件,但记住给所有 Jcomponents a.preferredSize 方法使用. If you are after javax.swing.JList<E> and javax.swing.DefaultListModel<E> The JList must be placed in a JPanel with a BorderLayout, or much more difficult system a java.awt.GridBagLayout then in a jscrollpane.
您可以只用一个 JScrollPane 进行水平和垂直滚动。 但是您需要的是呈现您的内容的底层 JComponent。 然而,这可以是一个JPanel,它可以根据您的需要延伸。
看看如何使用 ScrollPanes 。
另一个滚动区域内的滚动区域是用户界面反模式(反设计?)。 应该避免。
我将创建一个基于垂直 BoxLayout 的可滚动面板:
public class WindowAddCameras extends JFrame {
private static final long serialVersionUID = 1;
public static final List<JPanel> labels = new ArrayList<JPanel>();
private static class CameraListPanel
extends JPanel
implements Scrollable {
private static final long serialVersionUID = 1;
CameraListPanel() {
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
}
@Override
public Dimension getPreferredScrollableViewportSize() {
return getPreferredSize();
}
@Override
public boolean getScrollableTracksViewportWidth() {
return true;
}
@Override
public boolean getScrollableTracksViewportHeight() {
return false;
}
@Override
public int getScrollableUnitIncrement(Rectangle visibleRect,
int orientation,
int direction) {
return getScrollableIncrement(30,
visibleRect, orientation, direction);
}
@Override
public int getScrollableBlockIncrement(Rectangle visibleRect,
int orientation,
int direction) {
return getScrollableIncrement(
orientation == SwingConstants.HORIZONTAL ?
getWidth() : getHeight(),
visibleRect, orientation, direction);
}
private int getScrollableIncrement(int amount,
Rectangle visibleRect,
int orientation,
int direction) {
if (orientation == SwingConstants.HORIZONTAL) {
return Math.min(amount, direction < 0 ? visibleRect.x :
getWidth() - (visibleRect.x + visibleRect.width));
} else {
return Math.min(amount, direction < 0 ? visibleRect.y :
getHeight() - (visibleRect.y + visibleRect.height));
}
}
}
public WindowAddCameras() {
super("Добавить камеру");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panelButton = new JPanel();
JButton addButton = new JButton("+");
addButton.setFocusable(false);
panelButton.add(addButton);
JButton remButton = new JButton("-");
remButton.setFocusable(false);
panelButton.add(remButton);
JPanel camerasPanel = new CameraListPanel();
JScrollPane scrollPaneGroupEvent = new JScrollPane(camerasPanel);
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int number = labels.size() + 1;
EventAdd eventAdd = new EventAdd();
Dimension labelSize = new Dimension(80, 80);
//add event to group event
Random rand = new Random();
for(int a = 0; a < 20; a++) {
//random color border event for TEST
Color randomColor = new Color(rand.nextFloat(), rand.nextFloat(), rand.nextFloat());
eventAdd.createEventLabel("Камера " + number, labelSize, randomColor);
}
labels.add(eventAdd);
camerasPanel.add(eventAdd);
scrollPaneGroupEvent.revalidate();
}
});
remButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(labels.size() > 0) {
int index = labels.size() - 1;
JPanel panel = labels.remove(index);
camerasPanel.remove(panel);
camerasPanel.repaint();
scrollPaneGroupEvent.revalidate();
}
}
});
this.getContentPane().setLayout(new BorderLayout());
this.getContentPane().add(panelButton, BorderLayout.NORTH);
this.getContentPane().add(scrollPaneGroupEvent, BorderLayout.CENTER);
this.setPreferredSize(new Dimension(600, 400));
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> new WindowAddCameras());
}
}
CameraListPanel class 主要是一个基本的可滚动面板; 重要的部分是getScrollableTracksViewportWidth()
返回 true,这将导致面板的宽度与任何 JScrollPane 视口的宽度相匹配。 这消除了对水平滚动条的任何需要。
当然,您会希望以某种方式显示所有子组件。 为此,我会让 EventAdd class 计算可以容纳所有孩子的高度:
public class EventAdd extends JPanel {
private static final long serialVersionUID = 1;
private final FlowLayout layout;
public EventAdd() {
layout = new FlowLayout(FlowLayout.LEFT);
setLayout(layout);
}
@Override
public Dimension getPreferredSize() {
Rectangle childSize = new Rectangle();
Component[] children = getComponents();
for (Component child : children) {
childSize.add(new Rectangle(child.getPreferredSize()));
}
Insets insets = getInsets();
int hgap = layout.getHgap();
int vgap = layout.getVgap();
int childWidth = childSize.width + hgap;
Dimension size;
if (getParent() == null) {
size = new Dimension(
children.length * (childWidth * hgap) + hgap,
childSize.height + vgap * 2);
} else {
int width = getParent().getWidth();
width -= insets.left + insets.right;
int childrenPerRow =
childWidth == 0 ? 0 : (width - hgap) / childWidth;
int rows;
if (childrenPerRow == 0) {
rows = 0;
} else {
rows = children.length / childrenPerRow;
if (children.length % childrenPerRow > 0) {
rows++;
}
}
size = new Dimension(width,
vgap + rows * (childSize.height + vgap));
}
size.width += insets.left + insets.right;
size.height += insets.top + insets.bottom;
return size;
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.