所以我试图在JFrame周围单击并拖动JLabel.以下代码允许在屏幕上的任何位置按下/拖动鼠标时在屏幕上移动JLabel,但我不知道如何添加第二个ActionListener以检查鼠标是否在标签上单击,假设是解决方案.
我想在屏幕上有多个JLabel,以便移动的唯一标签是鼠标单击并正在拖动的标签.
谢谢.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
@SuppressWarnings("serial")
public class test extends JFrame implements MouseMotionListener {
private JPanel panel = new JPanel(null);
private JLabel dragLabel = new JLabel("drag test");
private int mouseX = 200;
private int mouseY = 200;
public test() {
this.add(panel);
panel.setBackground(Color.WHITE);
panel.add(dragLabel);
dragLabel.setForeground(Color.RED);
dragLabel.setBounds(mouseX, mouseY, 100, 50);
panel.addMouseMotionListener(this);
}
@Override
public void mouseDragged(MouseEvent e) {
mouseX = e.getX();
mouseY = e.getY();
dragLabel.setBounds(mouseX, mouseY, 100, 50);
}
@Override
public void mouseMoved(MouseEvent e) {}
public static void main(String[] args) {
test frame = new test();
frame.setVisible(true);
frame.setSize(600, 400);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Hov*_*els 20
另一种方法是将JLabel添加到JLayeredPane或JLayeredPane持有的JPanel,并添加MouseAdapter作为JLayeredPane的MouseListener和MouseMotionListener.然后单击标签时,将其移动到JLayeredPane的JLayeredPane.DRAG_LAYER,使其移动到其他所有位置,然后将JLabel放在鼠标释放最合适的级别上.例如,我发现这在国际象棋棋盘上移动棋子时效果很好,并且你想确保在拖动时你正在移动的棋子显示在所有其他棋子上方.
另外:你可能已经离开了这个主题,但是如果你回来,或为了别人的利益,我想通过发布一个例子来澄清我的意思是使用JLayeredPane.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class DragLabelOnLayeredPane extends JLayeredPane {
public static final int WIDTH = 680;
public static final int HEIGHT = 480;
private static final int GRID_ROWS = 8;
private static final int GRID_COLS = 6;
private static final int GAP = 3;
private static final Dimension LAYERED_PANE_SIZE = new Dimension(WIDTH, HEIGHT);
private static final Dimension LABEL_SIZE = new Dimension(60, 40);
private GridLayout gridlayout = new GridLayout(GRID_ROWS, GRID_COLS, GAP, GAP);
private JPanel backingPanel = new JPanel(gridlayout);
private JPanel[][] panelGrid = new JPanel[GRID_ROWS][GRID_COLS];
private JLabel redLabel = new JLabel("Red", SwingConstants.CENTER);
private JLabel blueLabel = new JLabel("Blue", SwingConstants.CENTER);
public DragLabelOnLayeredPane() {
backingPanel.setSize(LAYERED_PANE_SIZE);
backingPanel.setLocation(2 * GAP, 2 * GAP);
backingPanel.setBackground(Color.black);
for (int row = 0; row < GRID_ROWS; row++) {
for (int col = 0; col < GRID_COLS; col++) {
panelGrid[row][col] = new JPanel(new GridBagLayout());
backingPanel.add(panelGrid[row][col]);
}
}
redLabel.setOpaque(true);
redLabel.setBackground(Color.red.brighter().brighter());
redLabel.setPreferredSize(LABEL_SIZE);
panelGrid[4][3].add(redLabel);
blueLabel.setOpaque(true);
blueLabel.setBackground(Color.blue.brighter().brighter());
blueLabel.setPreferredSize(LABEL_SIZE);
panelGrid[1][1].add(blueLabel);
backingPanel.setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
setPreferredSize(LAYERED_PANE_SIZE);
add(backingPanel, JLayeredPane.DEFAULT_LAYER);
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
private class MyMouseAdapter extends MouseAdapter {
private JLabel dragLabel = null;
private int dragLabelWidthDiv2;
private int dragLabelHeightDiv2;
private JPanel clickedPanel = null;
@Override
public void mousePressed(MouseEvent me) {
clickedPanel = (JPanel) backingPanel.getComponentAt(me.getPoint());
Component[] components = clickedPanel.getComponents();
if (components.length == 0) {
return;
}
// if we click on jpanel that holds a jlabel
if (components[0] instanceof JLabel) {
// remove label from panel
dragLabel = (JLabel) components[0];
clickedPanel.remove(dragLabel);
clickedPanel.revalidate();
clickedPanel.repaint();
dragLabelWidthDiv2 = dragLabel.getWidth() / 2;
dragLabelHeightDiv2 = dragLabel.getHeight() / 2;
int x = me.getPoint().x - dragLabelWidthDiv2;
int y = me.getPoint().y - dragLabelHeightDiv2;
dragLabel.setLocation(x, y);
add(dragLabel, JLayeredPane.DRAG_LAYER);
repaint();
}
}
@Override
public void mouseDragged(MouseEvent me) {
if (dragLabel == null) {
return;
}
int x = me.getPoint().x - dragLabelWidthDiv2;
int y = me.getPoint().y - dragLabelHeightDiv2;
dragLabel.setLocation(x, y);
repaint();
}
@Override
public void mouseReleased(MouseEvent me) {
if (dragLabel == null) {
return;
}
remove(dragLabel); // remove dragLabel for drag layer of JLayeredPane
JPanel droppedPanel = (JPanel) backingPanel.getComponentAt(me.getPoint());
if (droppedPanel == null) {
// if off the grid, return label to home
clickedPanel.add(dragLabel);
clickedPanel.revalidate();
} else {
int r = -1;
int c = -1;
searchPanelGrid: for (int row = 0; row < panelGrid.length; row++) {
for (int col = 0; col < panelGrid[row].length; col++) {
if (panelGrid[row][col] == droppedPanel) {
r = row;
c = col;
break searchPanelGrid;
}
}
}
if (r == -1 || c == -1) {
// if off the grid, return label to home
clickedPanel.add(dragLabel);
clickedPanel.revalidate();
} else {
droppedPanel.add(dragLabel);
droppedPanel.revalidate();
}
}
repaint();
dragLabel = null;
}
}
private static void createAndShowUI() {
JFrame frame = new JFrame("DragLabelOnLayeredPane");
frame.getContentPane().add(new DragLabelOnLayeredPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
请随时发布任何问题,需要澄清或更正.