問題描述
我希望能夠單擊 JTextArea 并將其拖動到我的 JPanel 周圍.我不確定這樣做的方法.我想要做的是更改 JTextArea 的 x,y 坐標，因為它被拖動，我沒有將 JTextArea 拖動到另一個上方或下方.就在屏幕上，類似于在 Microsoft PowerPoint 等程序中移動文本框
I want to be able to click on a JTextArea and drag it around my JPanel. I'm not sure the method on doing so. What I'm trying to do is change the x,y coordinates of the JTextArea as it is dragged, I'm not dragging a JTextArea above or below another. Just around on the screen, similar to moving Text Boxes in a program like Microsoft PowerPoint
我能想到的唯一方法是使用 MouseListener 但我想知道除了檢測 JTextArea 上的懸停/按下/拖動之外，是否有更簡單的方法來實現它.關于如何開始的任何想法?
The only method I can think of is using a MouseListener but I'm wondering if there is an easier way to implement it other than detecting a hover/press/drag on the JTextArea. Any ideas on how I can start?
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class UMLEditor {
public static void main(String[] args) {
JFrame frame = new UMLWindow();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(30, 30, 1000, 700);
frame.getContentPane().setBackground(Color.white);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class UMLWindow extends JFrame {
Canvas canvas = new Canvas();
private static final long serialVersionUID = 1L;
public UMLWindow() {
addMenus();
}
public void addMenus() {
getContentPane().add(canvas);
JMenuBar menubar = new JMenuBar();
JMenuItem newTextBox = new JMenuItem("New Text Box");
newTextBox.setMnemonic(KeyEvent.VK_E);
newTextBox.setToolTipText("Exit application");
newTextBox.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
canvas.addTextBox();
}
});
menubar.add(newTextBox);
setJMenuBar(menubar);
setSize(300, 200);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
class Canvas extends JPanel {
JTextArea commentTextArea = new JTextArea(10, 10);
public Canvas() {
this.setOpaque(true);
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
public void addTextBox() {
commentTextArea.setLineWrap(true);
commentTextArea.setWrapStyleWord(true);
commentTextArea.setVisible(true);
commentTextArea.setLocation(0, 0);
this.add(commentTextArea);
commentTextArea.setBounds(0, 0, 100, 100);
revalidate();
repaint();
}
class MyMouseAdapter extends MouseAdapter {
@Override
public void mousePressed(MouseEvent e) {
}
@Override
public void mouseDragged(MouseEvent e) {
}
@Override
public void mouseMoved(MouseEvent e) {
}
}
}
推薦答案
你并不想嘗試在 JTextComponent 上拖動"，它們已經啟用了允許用戶單擊并拖動以突出顯示文本，您真的不想在其中競爭.
You don't really want to try and "drag" on JTextComponents, they already have functionality enabled which allows the user to click and drag to highlight text, you really don't want to be competing within this.
相反，您想在組件周圍定義一個熱區"區域，這將允許您突出顯示"某些組件并允許用戶通過它拖動組件.
Instead, you want to define a "hot zone" area around the component which would allow you "highlight" the component in some and allow the user to drag the component via it.
例如...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
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.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
public class DragMe {
public static void main(String[] args) {
new DragMe();
}
public DragMe() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JTextArea ta = new JTextArea(10, 20);
ta.setText("Bananas in pajamas");
JScrollPane sp = new JScrollPane(ta);
DragProxyPane proxy = new DragProxyPane(sp);
proxy.setSize(proxy.getPreferredSize());
proxy.setLocation(100 - proxy.getWidth() / 2, 100 - proxy.getHeight()/ 2);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new JPanel() {
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
});
frame.add(proxy);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class DragProxyPane extends JPanel {
public static final int BUFFER_ZONE = 10;
private boolean mouseInHouse;
private JComponent component;
private List<HotZone> hotZones;
public DragProxyPane(JComponent comp) {
MouseAdapter ma = new MouseAdapter() {
@Override
public void mouseEntered(MouseEvent e) {
mouseInHouse = true;
repaint();
}
@Override
public void mouseExited(MouseEvent e) {
mouseInHouse = false;
repaint();
}
@Override
public void mouseMoved(MouseEvent e) {
Cursor cursor = Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR);
for (HotZone hz : hotZones) {
if (hz.getBounds(getSize()).contains(e.getPoint())) {
cursor = hz.getCursor();
break;
}
}
setCursor(cursor);
}
};
addMouseListener(ma);
addMouseMotionListener(ma);
setOpaque(false);
setLayout(new BorderLayout());
add(comp);
setBorder(new EmptyBorder(BUFFER_ZONE, BUFFER_ZONE, BUFFER_ZONE, BUFFER_ZONE));
hotZones = new ArrayList<>(8);
// Top left, middle, right
hotZones.add(new HotZone(0f, 0f, Cursor.getPredefinedCursor(Cursor.NW_RESIZE_CURSOR)));
hotZones.add(new HotZone(0.5f, 0f, Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR)));
hotZones.add(new HotZone(1f, 0f, Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR)));
// Left, right
hotZones.add(new HotZone(0f, 0.5f, Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR)));
hotZones.add(new HotZone(1f, 0.5f, Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR)));
// Bottom left, middle, right
hotZones.add(new HotZone(0f, 1f, Cursor.getPredefinedCursor(Cursor.SW_RESIZE_CURSOR)));
hotZones.add(new HotZone(0.5f, 1f, Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR)));
hotZones.add(new HotZone(1f, 1f, Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR)));
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (mouseInHouse) {
g2d.setColor(Color.BLACK);
for (HotZone hotZone : hotZones) {
g2d.draw(hotZone.getBounds(getSize()));
}
}
g2d.dispose();
}
public class HotZone {
private float x, y;
private Cursor cursor;
public HotZone(float x, float y, Cursor cursor) {
this.x = x;
this.y = y;
this.cursor = cursor;
}
public Cursor getCursor() {
return cursor;
}
public Rectangle getBounds(Dimension size) {
return getBounds(size.width - 1, size.height - 1);
}
public Rectangle getBounds(int width, int height) {
int halfBuffer = BUFFER_ZONE / 2;
float xPos = (width * x) - halfBuffer;
float yPos = (height * y) - halfBuffer;
xPos = Math.min(Math.max(0, xPos), width - BUFFER_ZONE);
yPos = Math.min(Math.max(0, yPos), height - BUFFER_ZONE);
return new Rectangle(Math.round(xPos), Math.round(yPos), BUFFER_ZONE, BUFFER_ZONE);
}
}
}
}
這設置了一個簡單的代理組件，它充當熱區管理器，檢測鼠標進出它并根據光標在其中的位置更新光標，但不會破壞組件的正常操作.
This sets up a simple proxy component which acts as the hot zone manager, detecting the mouse coming into or out of it and updating the cursor based on its location within in it, but it does not disrupt the normal operations of the component.
現在，這個例子沒有拖拽，抱歉，你有很多其他的例子可以讓你越界，但是，你可以簡單地添加一個 MouseListener/MouseMoitionListener 到代理以檢測用戶何時拖動，但您需要向其添加更多功能以確定拖動的實際含義(調整大小或移動);)
Now, this example doesn't drag, sorry, you have plenty of other examples which should be able to get you over the line, but, you could simply add a MouseListener/MouseMoitionListener to the proxy to detect when the user drags, but you will need to add some more functionality to it to determine what that drag actually means (resize or move) ;)
這篇關于拖放以在 JPanel 上移動 JTextArea的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！