拖动屏幕周围的jlabel [英] dragging a jlabel around the screen
本文介绍了拖动屏幕周围的jlabel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
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点击并正在拖动的标签。 / p>
谢谢。
import java.awt。*;
import java.awt.event。*;
import javax.swing。*;
@SuppressWarnings（serial）
公共类测试扩展JFrame实现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）;
}
}
解决方案
另一个这样做的方法是将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，我发现在国际象棋棋盘上移动国际象棋时效果很好，并且你想要确保你移动的棋子在拖动时显示在所有其他棋子上方。
补充：你可能已经离开了这个主题，但如果你回来，或为了别人的利益，我想通过使用JLayeredPane澄清我的意思发布示例。
import java.awt。*;
import java.awt.event。*;
import javax.swing。*;
公共类DragLabelOnLayeredPane扩展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] =新的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）;
}
私有类MyMouseAdapter扩展MouseAdapter {
private JLabel dragLabel = null;
private int dragLabelWidthDiv2;
private int dragLabelHeightDiv2;
private JPanel clickedPanel = null;
@Override
public void mousePressed（MouseEvent me）{
clickedPanel =（JPanel）backPanel.getComponentAt（me.getPoint（））;
Component [] components = clickedPanel.getComponents（）;
if（components.length == 0）{
return;
}
//如果我们点击jpanel，其中包含jlabel
if（components [0] instanceof JLabel）{
//从面板中删除标签
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）; //删除拖拉层JLayeredPane的dragLabel
JPanel droppedPanel =（JPanel）backingPanel.getComponentAt（me.getPoint（））;
if（droppedPanel == null）{
//如果离开网格，返回标签回到
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;
打破searchPanelGrid;
}
}
}
if（r == -1 || c == -1）{
//如果离开网格，将标签返回主页
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。
So I am trying to click and drag a JLabel around a JFrame. The following code allows a JLabel to be moved around the screen when the mouse is pressed / dragged at any point on the screen, but I am not sure how to add a second ActionListener to check if the mouse is clicking on the label, assuming that is the solution.
I would like to have multiple JLabels on the screen so that the only label being moved is the one that the mouse has clicked and is now dragging.
Thanks.
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);
}
}
解决方案
Another way to do this is to add the JLabel to a JLayeredPane or to a JPanel held by a JLayeredPane and add a MouseAdapter as the JLayeredPane's MouseListener and MouseMotionListener. Then when clicking on the label, move it to the JLayeredPane's JLayeredPane.DRAG_LAYER so it moves on top of everything else, then place the JLabel on whichever is the most appropriate level on mouse release. I've found this to work well when moving chess pieces on a chess board, for instance, and you want to make sure that the piece you're moving is displayed above all the other pieces when dragging.
Addition: You've probably left this thread, but if you come back, or for the benefit of others, I wanted to clarify what I meant by using a JLayeredPane by posting an example.
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();
}
});
}
}
Please feel free to post any questions, need for clarification, or corrections.
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