Java 在屏幕上拖动jlabel
因此,我尝试在JFrame周围单击并拖动一个JLabel。下面的代码允许在屏幕上任意点按下/拖动鼠标时在屏幕上移动JLabel,但我不确定如何添加第二个ActionListener来检查鼠标是否单击标签,假设这是解决方案 我希望屏幕上有多个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Java 在屏幕上拖动jlabel,java,swing,jlabel,Java,Swing,Jlabel,因此,我尝试在JFrame周围单击并拖动一个JLabel。下面的代码允许在屏幕上任意点按下/拖动鼠标时在屏幕上移动JLabel,但我不确定如何添加第二个ActionListener来检查鼠标是否单击标签,假设这是解决方案 我希望屏幕上有多个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") pu
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);
}
}
将鼠标侦听器添加到标签而不是面板。(您可能仍然需要面板上的鼠标侦听器进行拖动,但至少标签上的鼠标侦听器可以告诉您它是否已被选中)。另一种方法是将JLabel添加到JLayeredPane或JLayeredPane持有的JPanel中,并添加一个MouseAdapter作为JLayeredPane的鼠标侦听器和MouseMotionListener。然后,单击标签时,将其移动到JLayeredPane的JLayeredPane.DRAG_层,使其移动到其他所有内容的顶部,然后在鼠标释放时将JLabel放置在最合适的级别上。例如,在棋盘上移动棋子时,我发现这很有效,并且您希望确保在拖动时移动的棋子显示在所有其他棋子的上方 另外:您可能已经离开了此线程,但是如果您回来,或者为了其他人的利益,我想通过发布一个示例来澄清我使用JLayeredPane的意思
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();
}
});
}
}
import java.awt.*;
导入java.awt.event.*;
导入javax.swing.*;
公共类DragalBelonLayeredPane扩展了JLayeredPane{
公共静态最终整数宽度=680;
公共静态最终内部高度=480;
私有静态最终整数网格_行=8;
私有静态最终整数网格=6;
专用静态最终内部间隙=3;
私有静态最终尺寸分层窗格尺寸=新尺寸(宽度、高度);
专用静态最终尺寸标签尺寸=新尺寸(60,40);
私有GridLayout GridLayout=新的GridLayout(网格行、网格列、间隙、间隙);
专用JPanel backingPanel=新JPanel(网格布局);
private JPanel[][]panelGrid=新JPanel[GRID_ROWS][GRID_COLS];
私有JLabel redLabel=新JLabel(“红色”,SwingConstants.CENTER);
私有JLabel blueLabel=新JLabel(“蓝色”,SwingConstants.CENTER);
公共DragalBelonLayeredPane(){
backingPanel.setSize(分层窗格大小);
背板。设置位置(2*间隙,2*间隙);
背板.立根(颜色.黑色);
对于(int row=0;rowint x_pressed = 0;
int y_pressed = 0;
lbl_banner.addMouseListener(new MouseAdapter()
{
@Override
public void mousePressed(MouseEvent e) {
//catching the current values for x,y coordinates on screen
x_pressed = e.getX();
y_pressed = e.getY();
}
});
lbl_banner.addMouseMotionListener(new MouseMotionAdapter(){
@Override
public void mouseDragged(MouseEvent e){
//and when the Jlabel is dragged
setLocation(e.getXOnScreen() - x_pressed, e.getYOnScreen() - y_pressed);
}
});
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;
/**
* A demonstration of moving around labels in a panel.
* <p>
* Some labels show up layed out in a grid. Then the
* user can drag any label anywhere on the panel.
* </p>
*/
public class LabelDragger {
public static void main(final String[] args) {
final int labelRows = 5, //How many rows of labels.
labelColumns = 5, //How many columns of labels.
labelWidth = 55, //Width for each label.
labelHeight = 20; //Height for each label.
//Border colors for labels:
final Color[] colors = new Color[]{Color.BLUE, Color.GREEN, Color.BLACK, Color.GRAY};
final Random prng = new Random(); //For selecting border color for each label.
final JPanel dragP = new JPanel(null); //Nicely set to null! :D Did not know that trick.
//Creating the listener for the panel:
final MouseAdapter ma = new MouseAdapter() {
private JLabel selectedLabel = null; //Clicked label.
private Point selectedLabelLocation = null; //Location of label in panel when it was clicked.
private Point panelClickPoint = null; //Panel's click point.
//Selection of label occurs upon pressing on the panel:
@Override
public void mousePressed(final MouseEvent e) {
//Find which label is at the press point:
final Component pressedComp = dragP.findComponentAt(e.getX(), e.getY());
//If a label is pressed, store it as selected:
if (pressedComp != null && pressedComp instanceof JLabel) {
selectedLabel = (JLabel) pressedComp;
selectedLabelLocation = selectedLabel.getLocation();
panelClickPoint = e.getPoint();
//Added the following 2 lines in order to make selectedLabel
//paint over all others while it is pressed and dragged:
dragP.setComponentZOrder(selectedLabel, 0);
selectedLabel.repaint();
}
else {
selectedLabel = null;
selectedLabelLocation = null;
panelClickPoint = null;
}
}
//Moving of selected label occurs upon dragging in the panel:
@Override
public void mouseDragged(final MouseEvent e) {
if (selectedLabel != null
&& selectedLabelLocation != null
&& panelClickPoint != null) {
final Point newPanelClickPoint = e.getPoint();
//The new location is the press-location plus the length of the drag for each axis:
final int newX = selectedLabelLocation.x + (newPanelClickPoint.x - panelClickPoint.x),
newY = selectedLabelLocation.y + (newPanelClickPoint.y - panelClickPoint.y);
selectedLabel.setLocation(newX, newY);
}
}
};
dragP.addMouseMotionListener(ma); //For mouseDragged().
dragP.addMouseListener(ma); //For mousePressed().
//Filling the panel with labels:
for (int row = 0; row < labelRows; ++row)
for (int col = 0; col < labelColumns; ++col) {
//Create label for (row, col):
final JLabel lbl = new JLabel("Label" + (row * labelColumns + col));
lbl.setHorizontalAlignment(JLabel.CENTER);
//lbl.setVerticalAlignment(JLabel.CENTER);
lbl.setBounds(col * labelWidth, row * labelHeight, labelWidth, labelHeight); //Grid-like positioning.
lbl.setBorder(new LineBorder(colors[prng.nextInt(colors.length)], 2)); //Set a border for clarity.
//Add label to panel:
dragP.add(lbl);
}
//Creating and showing the main frame:
final JFrame frame = new JFrame(LabelDragger.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//The size of the content pane adds some extra room for moving the labels:
final Dimension paneSize = new Dimension((int)(1.5 * labelWidth * labelColumns),
(int)(1.5 * labelHeight * labelRows));
frame.getContentPane().setPreferredSize(paneSize);
frame.getContentPane().add(dragP);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}