我正在尝试使用Swing类创建网格UI(5 * 5).我尝试了一个嵌套循环,并动态地将jPanel添加到jFrame.我还尝试在用户点击并删除时更改每个jPanel的背景颜色.
但是使用我的代码,每个单元格之间存在巨大差距,我无法使拖动事件起作用.
但是使用我的代码,每个单元格之间存在巨大差距,我无法使拖动事件起作用.
public class clsCanvasPanel extends JPanel {
private static final int intRows = 5;
private static final int intCols = 5;
private List<JPanel> jpllist = new ArrayList<JPanel>();
public clsCanvasPanel() {
/*
*
* Add eventListener to individual JPanel within CanvasPanel
*
*
* TODO :
* 1) mousePressed --> update Temperature and HeatConstant of clsElement Class
* 2) start a new thread and
* 3) call clsElement.run() method
*
*
* Right Now : it updates the colours of the JPanel
* */
MouseListener mouseListener = new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
JPanel panel = (JPanel) e.getSource();
Component[] components = panel.getComponents();
for (Component component : components) {
component.setVisible(!component.isVisible());
component.setBackground(new Color(255,255,0));
}
panel.revalidate();
panel.repaint();
}
};
//TODO : refactoring
GridLayout gdlyPlates = new GridLayout();
gdlyPlates.setColumns(intCols);
gdlyPlates.setRows(intRows);
gdlyPlates.setHgap(0);
gdlyPlates.setVgap(0);
setLayout(gdlyPlates);
//TODO : refactoring
for (int row = 0; row < intRows; row++) {
for (int col = 0; col < intCols; col++) {
JPanel panel = new JPanel(new GridBagLayout());
panel.setOpaque(false);
JPanel jl = new JPanel();
jl.setVisible(true);
panel.add(jl);
panel.addMouseListener(mouseListener);
jpllist.add(panel);
add(panel);
}
}
}
}
所以现在我尝试创建一个面板并在其上绘制网格,然后检测网格上的鼠标位置,进一步更改每个单元格的颜色.
有人可以给我一些关于如何在JPanel上实现这个网格的建议,并改变所选单元格的颜色.
解决方法
有许多方法可以让它发挥作用,这取决于你想要实现的目标.
第一个示例仅使用2D Graphics API渲染单元格,使用MouseMotionListener监视突出显示的单元格.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TestGrid01 {
public static void main(String[] args) {
new TestGrid01();
}
public TestGrid01() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private int columnCount = 5;
private int rowCount = 5;
private List<Rectangle> cells;
private Point selectedCell;
public TestPane() {
cells = new ArrayList<>(columnCount * rowCount);
MouseAdapter mouseHandler;
mouseHandler = new MouseAdapter() {
@Override
public void mouseMoved(MouseEvent e) {
Point point = e.getPoint();
int width = getWidth();
int height = getHeight();
int cellWidth = width / columnCount;
int cellHeight = height / rowCount;
selectedCell = null;
if (e.getX() >= xOffset && e.getY() >= yOffset) {
int column = (e.getX() - xOffset) / cellWidth;
int row = (e.getY() - yOffset) / cellHeight;
if (column >= 0 && row >= 0 && column < columnCount && row < rowCount) {
selectedCell = new Point(column,row);
}
}
repaint();
}
};
addMouseMotionListener(mouseHandler);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200,200);
}
@Override
public void invalidate() {
cells.clear();
selectedCell = null;
super.invalidate();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth();
int height = getHeight();
int cellWidth = width / columnCount;
int cellHeight = height / rowCount;
int xOffset = (width - (columnCount * cellWidth)) / 2;
int yOffset = (height - (rowCount * cellHeight)) / 2;
if (cells.isEmpty()) {
for (int row = 0; row < rowCount; row++) {
for (int col = 0; col < columnCount; col++) {
Rectangle cell = new Rectangle(
xOffset + (col * cellWidth),yOffset + (row * cellHeight),cellWidth,cellHeight);
cells.add(cell);
}
}
}
if (selectedCell != null) {
int index = selectedCell.x + (selectedCell.y * columnCount);
Rectangle cell = cells.get(index);
g2d.setColor(Color.BLUE);
g2d.fill(cell);
}
g2d.setColor(Color.GRAY);
for (Rectangle cell : cells) {
g2d.draw(cell);
}
g2d.dispose();
}
}
}
此示例使用窗口调整网格大小,但是使单元格固定大小将是一个微不足道的更改.
查看2D Graphics了解更多详情
使用组件示例更新
此示例使用一系列JPanel来表示每个单元格.
每个单元格都定义为固定的宽度和高度,并且不会随主窗口调整大小.
在此示例中,每个单元面板都有自己的鼠标侦听器.重新编码它不会太困难,因此主面板只有一个鼠标监听器,而是自己管理工作负载.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.Border;
import javax.swing.border.MatteBorder;
public class TestGrid02 {
public static void main(String[] args) {
new TestGrid02();
}
public TestGrid02() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
for (int row = 0; row < 5; row++) {
for (int col = 0; col < 5; col++) {
gbc.gridx = col;
gbc.gridy = row;
CellPane cellPane = new CellPane();
Border border = null;
if (row < 4) {
if (col < 4) {
border = new MatteBorder(1,1,Color.GRAY);
} else {
border = new MatteBorder(1,Color.GRAY);
}
} else {
if (col < 4) {
border = new MatteBorder(1,Color.GRAY);
}
}
cellPane.setBorder(border);
add(cellPane,gbc);
}
}
}
}
public class CellPane extends JPanel {
private Color defaultBackground;
public CellPane() {
addMouseListener(new MouseAdapter() {
@Override
public void mouseEntered(MouseEvent e) {
defaultBackground = getBackground();
setBackground(Color.BLUE);
}
@Override
public void mouseExited(MouseEvent e) {
setBackground(defaultBackground);
}
});
}
@Override
public Dimension getPreferredSize() {
return new Dimension(50,50);
}
}
}
