如何使用ImageIcon制作可拖动的组件 [英] How to make draggable components with ImageIcon
本文介绍了如何使用ImageIcon制作可拖动的组件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试为国际象棋游戏构建用户界面。我使用 GridBagLayout 填充 JLabels ，棋子是 JLabels 的 ImageIcons 。
I'm trying to build a user interface for a chess game. I've used a GridBagLayout filled with JLabels and the chess pieces are ImageIcons of the JLabels.
现在我想通过在板上拖动来移动碎片。有没有办法用 ImageIcons 来做到这一点？或者有更好的方法来解决问题吗？
Now I would like to move the pieces by dragging it on the board. Is there a way to do this with ImageIcons? Or is there a better way to solve the problem?
编辑：这是一个示例代码。你可以注意到你可以移动iconImage，但它不会用鼠标拖动。
here is a sample code. you can notice that you can move the iconImage, but it doesn't "drag" with the mouse.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.HashMap;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class MainDebug extends JFrame implements MouseListener {
private JPanel BoardPanel;
private String buffercase_mousepressed;
private String buffercase_mouseentered;
private JLabel A8 = new JLabel("A8");
private JLabel B8 = new JLabel("B8");
private HashMap componentMap;
private ImageIcon RookIcon = createImageIcon("50px-Rook.png", "Rook");
public MainDebug(String name) {
super(name);
setResizable(true);
}
private ImageIcon createImageIcon(String path, String description) {
java.net.URL imgURL = getClass().getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL, description);
} else {
System.err.println("Couldn't find file: " + path);
return null;
}
}
public void addComponentsToPane(final Container pane) {
BoardPanel = new JPanel();
BoardPanel.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
Dimension dim50 = new Dimension(50,50);
A8.setOpaque(true);
A8.setBackground(Color.white);
A8.setPreferredSize(dim50);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 0;
BoardPanel.add(A8,c);
A8.setName("A8");
A8.addMouseListener(this);
B8.setOpaque(true);
B8.setBackground(Color.lightGray);
B8.setPreferredSize(dim50);
B8.setName("B8");
c.gridx=1;
BoardPanel.add(B8,c);
B8.addMouseListener(this);
A8.setIcon(RookIcon);
pane.add(BoardPanel, BorderLayout.CENTER);
createComponentMap();
}
private void createComponentMap() {
componentMap = new HashMap<String,Component>();
int max_components = BoardPanel.getComponentCount();
//Component[] components = BoardPanel.getComponentCount();
//Component[] components = BoardPanel.getContentPane().getComponents();
for (int i=0; i < max_components; i++) {
componentMap.put(BoardPanel.getComponent(i).getName(), BoardPanel.getComponent(i));
}
}
public Component getComponentByName(String name) {
if (componentMap.containsKey(name)) {
return (Component) componentMap.get(name);
}
else return null;
}
public void mousePressed(MouseEvent e) {
buffercase_mousepressed = e.getComponent().getName();
}
public void mouseReleased(MouseEvent e) {
moveIcon(buffercase_mousepressed,buffercase_mouseentered);
}
public void mouseEntered(MouseEvent e) {
buffercase_mouseentered = e.getComponent().getName();
}
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
public void moveIcon(String A, String B){
if ((A != null) && (B != null)){
JLabel Ja = (JLabel)getComponentByName(A);
JLabel Jb = (JLabel)getComponentByName(B);
Icon iconeA = Ja.getIcon();
Icon iconeB = Jb.getIcon();
if (iconeA != null && iconeB == null){
Ja.setIcon(null);
Jb.setIcon(iconeA);
}
}
buffercase_mousepressed = null;
buffercase_mouseentered = null;
}
private static void createAndShowGUI() {
//Create and set up the window.
MainDebug frame = new MainDebug("Test interface");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Set up the content pane.
frame.addComponentsToPane(frame.getContentPane());
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
推荐答案
好的，这是我对你问题的一点看法......
Okay, this is my little swing at you problem...
现在，而不是使用 GridBagLayout ，我已经设计了自己的布局管理器，这将允许我指定一块应该放置的网格位置，并允许电路板和布局管理器计算该块将出现的物理位置。就个人而言，我认为你会发现它比使用 GridBagLayout 更容易。
Now, rather then using a GridBagLayout, I've devised my own layout manager, which will allow me to specify the "grid" location a piece should be placed and allow the board and layout manager to calculate the physical location the piece will appear. Personally, I think you will find it easier than using a GridBagLayout.
代码有两种模式。它有一个对齐模式，这将导致该片段在它开始拖动时想要捕捉到网格和一个自由模式，这将允许片段在你拖动时滑动到整个板上...
The code has two modes. It has a "snap-to" mode, that will cause the piece to want to "snap" to the grid as it's begin dragged and a "free" mode, that will allow the piece to "glide" across the board as you drag...
如果您选择继续使用 GridBagLayout ，则基本拖动过程不会更改。你可以使用 GridBagLayout #setConstraint 修改给定组件的约束
If you choice to continue to use the GridBagLayout, the basic drag process won't change. You can use GridBagLayout#setConstraint to modify the constraints for a given component
public class Chess {
public static void main(String[] args) {
new Chess();
}
public Chess() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new Board());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static final int GRID_SIZE = 50;
public static final boolean SNAP_TO_GRID = false;
public class Board extends JPanel {
private BufferedImage board;
private Point highlightCell;
public Board() {
setLayout(new BoardLayoutManager());
int width = GRID_SIZE * 8;
int height = GRID_SIZE * 8;
board = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = board.createGraphics();
g2d.setColor(Color.WHITE);
g2d.fill(new Rectangle(0, 0, width, height));
g2d.setColor(Color.BLACK);
for (int row = 0; row < 8; row++) {
int xPos = (row % 2 == 0) ? GRID_SIZE : 0;
for (int col = 0; col < 8; col += 2) {
g2d.fill(new Rectangle(xPos, row * GRID_SIZE, GRID_SIZE, GRID_SIZE));
xPos += (GRID_SIZE * 2);
}
}
JLabel piece = new JLabel();
try {
piece.setIcon(new ImageIcon(ImageIO.read(getClass().getResource("/Luke.png"))));
} catch (IOException ex) {
piece.setBackground(new Color(255, 0, 0, 64));
piece.setOpaque(true);
}
add(piece, new Point(0, 0));
MouseHandler mouseHandler = new MouseHandler(this);
addMouseListener(mouseHandler);
addMouseMotionListener(mouseHandler);
}
protected Rectangle getBoardBounds() {
return new Rectangle(getBoardOffset(), new Dimension(GRID_SIZE * 8, GRID_SIZE * 8));
}
public Point gridToPoint(Point grid) {
Point p = new Point();
if (grid != null) {
Point offset = getBoardOffset();
p.x = grid.x * GRID_SIZE + offset.x;
p.y = grid.y * GRID_SIZE + offset.y;
}
return p;
}
public Point pointToGrid(Point p) {
Point grid = null;
Rectangle board = getBoardBounds();
if (board.contains(p)) {
p.x = p.x - board.x;
p.y = p.y - board.y;
grid = new Point();
grid.x = p.x / GRID_SIZE;
grid.y = p.y / GRID_SIZE;
}
return grid;
}
public void setPieceGrid(Component comp, Point grid) {
((BoardLayoutManager) getLayout()).setPieceGrid(comp, grid);
invalidate();
revalidate();
repaint();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
protected Point getBoardOffset() {
int width = getWidth();
int height = getHeight();
Point p = new Point();
p.x = (width - board.getWidth()) / 2;
p.y = (height - board.getHeight()) / 2;
return p;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
Point p = getBoardOffset();
g2d.drawImage(board, p.x, p.y, this);
if (highlightCell != null) {
Point cell = gridToPoint(highlightCell);
Rectangle bounds = new Rectangle(cell.x, cell.y, GRID_SIZE, GRID_SIZE);
g2d.setColor(Color.RED);
g2d.draw(bounds);
}
g2d.dispose();
}
public void setHightlightCell(Point p) {
if (highlightCell != p) {
highlightCell = p;
repaint();
}
}
}
public class MouseHandler extends MouseAdapter {
private Component dragComponent;
private Board board;
private Point dragOffset;
public MouseHandler(Board board) {
this.board = board;
}
public Board getBoard() {
return board;
}
@Override
public void mousePressed(MouseEvent e) {
Component comp = getBoard().getComponentAt(e.getPoint());
if (comp != null) {
dragComponent = comp;
dragOffset = new Point();
dragOffset.x = e.getPoint().x - comp.getX();
dragOffset.y = e.getPoint().y - comp.getY();
}
}
@Override
public void mouseReleased(MouseEvent e) {
if (dragComponent != null) {
Board board = getBoard();
Point p = board.pointToGrid(e.getPoint());
System.out.println(p);
board.setPieceGrid(dragComponent, p);
dragComponent = null;
board.setHightlightCell(null);
}
}
@Override
public void mouseDragged(MouseEvent e) {
if (dragComponent != null) {
Board board = getBoard();
Point grid = board.pointToGrid(e.getPoint());
if (SNAP_TO_GRID) {
Point p = board.gridToPoint(grid);
dragComponent.setLocation(p);
} else {
Point dragPoint = new Point();
dragPoint.x = e.getPoint().x - dragOffset.x;
dragPoint.y = e.getPoint().y - dragOffset.y;
dragComponent.setLocation(dragPoint);
}
board.setHightlightCell(grid);
}
}
}
public class BoardLayoutManager implements LayoutManager2 {
private Map<Component, Point> mapGrid;
public BoardLayoutManager() {
mapGrid = new HashMap<>(25);
}
public void setPieceGrid(Component comp, Point grid) {
mapGrid.put(comp, grid);
}
@Override
public void addLayoutComponent(Component comp, Object constraints) {
if (constraints instanceof Point) {
mapGrid.put(comp, (Point) constraints);
} else {
throw new IllegalArgumentException("Unexpected constraints, expected java.awt.Point, got " + constraints);
}
}
@Override
public Dimension maximumLayoutSize(Container target) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public float getLayoutAlignmentX(Container target) {
return 0.5f;
}
@Override
public float getLayoutAlignmentY(Container target) {
return 0.5f;
}
@Override
public void invalidateLayout(Container target) {
}
@Override
public void addLayoutComponent(String name, Component comp) {
}
@Override
public void removeLayoutComponent(Component comp) {
mapGrid.remove(comp);
}
@Override
public Dimension preferredLayoutSize(Container parent) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public Dimension minimumLayoutSize(Container parent) {
return new Dimension(GRID_SIZE * 8, GRID_SIZE * 8);
}
@Override
public void layoutContainer(Container parent) {
Point offset = ((Board) parent).getBoardOffset();
for (Component comp : parent.getComponents()) {
Point p = mapGrid.get(comp);
if (p == null) {
comp.setBounds(0, 0, 0, 0); // Remove from sight :P
} else {
int x = p.x * GRID_SIZE + offset.x;
int y = p.y * GRID_SIZE + offset.y;
comp.setBounds(x, y, GRID_SIZE, GRID_SIZE);
}
}
}
}
}
这篇关于如何使用ImageIcon制作可拖动的组件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！
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