我想知道是否有可能以这种方式实现 JFrame 的大小调整，它已被调整为例如 linux 中的标准窗口。更准确地说:如果用户开始拖动，则预览窗口时只会显示 future 的大小，而不会调整原始内容的大小。一旦用户释放鼠标，框架就会调整到该大小。在图片中:

(1)调整大小前的状态

(2) 用户开始拖动(红圈处)

(3) 用户释放鼠标，调整框架大小

有没有可能在Java Swing中实现？

编辑:

因为这个程序有一天也应该像 7 一样在较低的 Java RE 中运行，所以我尝试将 mKorbel 的建议和评论中的建议与半透明框架结合起来。结果接近目标，除了

• contentPane 的内容在我停止移动鼠标后调整大小，而不是在释放鼠标时调整
• 框架标题会立即调整大小，而不仅仅是在我停止拖动框架边框时。
• 仅当从右侧或底部调整大小时才有效，否则内容会随着拖动而移动。

我认为第一点可以通过代码和 MouseListener 的组合来解决，类似于 if mouseReleased(), then resize 。这是代码，请随意尝试。对于进一步的建议，我仍然很乐意接受任何建议。

代码是对 GradientTranslucentWindowDemo.java 的略微修改。来自 Java 教程。我希望它被允许在这里发布，否则请指出任何侵犯版权的原因。黑色的 JPanel 应该是应用程序的内容，因为 contentPane 保持不可见。

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.beans.PropertyChangeListener;

import javax.swing.*;
import static java.awt.GraphicsDevice.WindowTranslucency.*;

public class GroundFrame extends JFrame {

    Timer timer;
    JPanel panel2;

    public GroundFrame() {
        super("GradientTranslucentWindow");

        setBackground(new Color(0,0,0,0));
        setSize(new Dimension(300,200));
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel() {
        panel.setBackground(new Color(0,0,0,0));
        setContentPane(panel);

        setLayout(null);
        panel2 = new JPanel();
        panel2.setBackground(Color.black);
        panel2.setBounds(0,0,getContentPane().getWidth(), getContentPane().getHeight());
        getContentPane().add(panel2);

        addComponentListener(new ComponentListener() {

            @Override
            public void componentShown(ComponentEvent e) {}

            @Override
            public void componentResized(ComponentEvent e) {
                timer = new Timer(50, new Action() {

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        if(timer.isRunning()){

                        }else{
                            resizePanel(getContentPane().getSize());
                        }
                    }

                    @Override
                    public void setEnabled(boolean b) {}

                    @Override
                    public void removePropertyChangeListener(PropertyChangeListener listener) {}

                    @Override
                    public void putValue(String key, Object value) {}

                    @Override
                    public boolean isEnabled() {return false;}

                    @Override
                    public Object getValue(String key) {return null;}

                    @Override
                    public void addPropertyChangeListener(PropertyChangeListener listener) {}
                });
                timer.setRepeats(false);
                timer.start();

            }

            @Override
            public void componentMoved(ComponentEvent e) {}

            @Override
            public void componentHidden(ComponentEvent e) {}
        });
    }

    public void resizePanel(Dimension dim){
        panel2.setBounds(0,0,dim.width, dim.height);
        repaint();
    }

    public static void main(String[] args) {
        GraphicsEnvironment ge =
            GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice gd = ge.getDefaultScreenDevice();
        boolean isPerPixelTranslucencySupported =
            gd.isWindowTranslucencySupported(PERPIXEL_TRANSLUCENT);

        if (!isPerPixelTranslucencySupported) {
            System.out.println(
                "Per-pixel translucency is not supported");
                System.exit(0);
        }

        JFrame.setDefaultLookAndFeelDecorated(true);

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                GroundFrame gtw = new GroundFrame();
                gtw.setVisible(true);
            }
        });
    }
}

最佳答案

+1 到 mKorbel 和 Denis Tulskiy 的回答。

我做了一种抽象的解决方案，可能会有帮助。它支持从 JFrame 的所有四个边(NORTH、EAST、SOUTH 和 WEST)调整(增加和减少高度和宽度)JFrame 它也可以重新调整大小当鼠标移动到 for 角之一时，同时按宽度和高度。

基本上我所做的是:

• 将MouseMotionListener 和MouseListener 添加到JFrame
• 覆盖 mouseDragged(..)、mouseMoved(..)、mousePressed(..) 和 mouseReleased(.. ) 的 Listener。
• 将 JFrame 设置为不可调整大小。
• 在 mouseMoved(..) 中监听鼠标距离底部或右侧 10px 或更短的距离。 JFrame，然后设置调整大小的适当方向(高度或宽度)，更改鼠标 Cursor (Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR)最右边/宽度调整，Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR) 底部/高度调整，Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR) 顶部框架高度调整或Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR) 相应地调整左侧宽度)并调用 canResize(true)。
• 在 mouseDragged(..) 中更新新大小的宽度或高度，因为它的拖动方向
• 在 mouseReleased(..) 中将 JFrame 设置为新大小。
• 在 mousePressed(..) 中，我们检查用户按下的坐标(这允许我们查看帧大小是否在减小/增大)。

看看我做的这个例子:

import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class JFrameSizeAfterDrag extends JFrame {

    //direction holds the position of drag
    private int w = 0, h = 0, direction, startX = 0, startY = 0;

    public JFrameSizeAfterDrag() {
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        addMouseListener(new MouseAdapter() {
            //so we can see if from where the user clikced is he increasing or decraesing size
            @Override
            public void mousePressed(MouseEvent me) {
                super.mouseClicked(me);
                startX = me.getX();
                startY = me.getY();
                System.out.println("Clicked: " + startX + "," + startY);
            }

            //when the mouse is relaeased set size
            @Override
            public void mouseReleased(MouseEvent me) {
                super.mouseReleased(me);
                System.out.println("Mouse released");
                if (direction == 1 || direction == 2 || direction == 5 || direction == 6) {
                    setSize(w, h);
                } else {//this should move x and y by as much as the mouse moved then use setBounds(x,y,w,h);
                    setBounds(getX() - (startX - me.getX()), getY() - (startY - me.getY()), w, h);
                }
                validate();
            }
        });

        addMouseMotionListener(new MouseAdapter() {
            private boolean canResize;

            //while dragging check direction of drag
            @Override
            public void mouseDragged(MouseEvent me) {
                super.mouseDragged(me);
                System.out.println("Dragging:" + me.getX() + "," + me.getY());
                if (canResize && direction == 1) {//frame height  change
                    if (startY > me.getY()) {//decrease in height
                        h -= 4;
                    } else {//increase in height
                        h += 4;
                    }
                } else if (canResize && direction == 2) {//frame width  change
                    if (startX > me.getX()) {//decrease in width
                        w -= 4;
                    } else {//increase in width
                        w += 4;
                    }
                } else if (canResize && direction == 3) {//frame height  change
                    if (startX > me.getX()) {//decrease in width
                        w += 4;
                    } else {//increase in width
                        w -= 4;
                    }
                } else if (canResize && direction == 4) {//frame width  change
                    if (startY > me.getY()) {//decrease in height
                        h += 4;
                    } else {//increase in height
                        h -= 4;
                    }
                } else if (canResize && direction == 5) {//frame width and height  change bottom right
                    if (startY > me.getY() && startX > me.getX()) {//increase in height and width
                        h -= 4;
                        w -= 4;
                    } else {//decrease in height and with
                        h += 4;
                        w += 4;
                    }
                } /* Windows dont usually support reszing from top but if you want :) uncomment code in mouseMoved(..) also
                 else if (canResize && direction == 6) {//frame width and height  change top left
                 if (startY > me.getY() && startX > me.getX()) {//decrease in height and with
                 h += 4;
                 w += 4;
                 } else {//increase in height and width
                 h -= 4;
                 w -= 4;
                 }
                 } else if (canResize && direction == 8) {//frame width and height  change top right
                 if (startY > me.getY() && startX > me.getX()) {//increase in height and width
                 h -= 4;
                 w -= 4;
                 } else {//decrease in height and with
                 h += 4;
                 w += 4;
                 }
                 }
                 */ else if (canResize && direction == 7) {//frame width and height  change bottom left
                    if (startY > me.getY() && startX > me.getX()) {//increase in height and width
                        h -= 4;
                        w -= 4;
                    } else {//decrease in height and with
                        h += 4;
                        w += 4;
                    }
                }
            }

            @Override
            public void mouseMoved(MouseEvent me) {
                super.mouseMoved(me);
                if (me.getY() >= getHeight() - 10 && me.getX() >= getWidth() - 10) {//close to bottom and right side of frame show south east cursor and allow height witdh simaltneous increase/decrease
                    //System.out.println("resize allowed..");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR));
                    direction = 5;
                } /*Windows dont usually support reszing from top but if you want :) uncomment code in mouseDragged(..) too
                 else if (me.getY() <= 28 && me.getX() <= 28) {//close to top side and left side of frame show north west cursor and only allow increase/decrease in width and height simultaneosly
                 //System.out.println("resize allowed..");
                 canResize = true;
                 setCursor(Cursor.getPredefinedCursor(Cursor.NW_RESIZE_CURSOR));
                 direction = 6;
                 }  else if (me.getY() <= 28 && me.getX() >= getWidth() - 10) {//close to top and right side of frame show north east cursor and only allow increase/decrease in width and height simultaneosly
                 //System.out.println("resize allowed..");
                 canResize = true;
                 setCursor(Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR));
                 direction = 8;
                 } 
                 */ else if (me.getY() >= getHeight() - 10 && me.getX() <= 10) {//close to bottom side and left side of frame show north west cursor and only allow increase/decrease in width and height simultaneosly
                    //System.out.println("resize allowed..");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.SW_RESIZE_CURSOR));
                    direction = 7;
                } else if (me.getY() >= getHeight() - 10) {//close to bottom of frame show south resize cursor and only allow increase height
                    //System.out.println("resize allowed");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR));
                    direction = 1;
                } else if (me.getX() >= getWidth() - 10) {//close to right side of frame show east cursor and only allow increase width
                    //System.out.println("resize allowed");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR));
                    direction = 2;
                } else if (me.getX() <= 10) {//close to left side of frame show east cursor and only allow increase width
                    //System.out.println("resize allowed");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR));
                    direction = 3;
                } else if (me.getY() <= 28) {//close to top side of frame show east cursor and only allow increase height
                    // System.out.println("resize allowed..");
                    canResize = true;
                    setCursor(Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR));
                    direction = 4;
                } else {
                    canResize = false;
                    setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
                    // System.out.println("resize not allowed");
                }
            }
        });

        //just so GUI is visible and not small
        add(new JPanel() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(200, 200);
            }
        });

        pack();
        setVisible(true);
    }

    @Override
    public void setVisible(boolean bln) {
        super.setVisible(bln);
        w = getWidth();
        h = getHeight();
    }

    public static void main(String[] args) {

        /**
         * Create GUI and components on Event-Dispatch-Thread
         */
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new JFrameSizeAfterDrag();
            }
        });
    }
}

更新:

你做的很好的例子我通过添加 MouseAdapter 来修复代码，它覆盖了调用 resizePanel(...) 的 mouseReleased(..)当 mouseReleased(..)

请参阅此处查看已修复的代码(还修复了一些小问题，例如添加了 ComponentAdapter 而不是 ComponentListener 和 AbstractAction 而不是 Action ):

import java.awt.*;
import static java.awt.GraphicsDevice.WindowTranslucency.*;
import java.awt.event.ActionEvent;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;

public class JFrameSizeAfterDrag2 extends JFrame {

    private Timer timer;
    private JPanel panel2;
    boolean canResize = true,firstTime = true;


    public JFrameSizeAfterDrag2() {
        super("GradientTranslucentWindow");

        setBackground(new Color(0, 0, 0, 0));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setContentPane(new JPanel(null) {//contentpane layout is null only
            @Override
            protected void paintComponent(Graphics g) {
                Paint p = new GradientPaint(0.0f, 0.0f, new Color(0, 0, 0, 0), 0.0f, getHeight(), new Color(0, 0, 0, 0), true);
                Graphics2D g2d = (Graphics2D) g;
                g2d.setPaint(p);
                g2d.fillRect(0, 0, getWidth(), getHeight());
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 300);
            }
        });

        panel2 = new JPanel();
        panel2.setBackground(Color.black);
        getContentPane().add(panel2);

        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent me) {
                super.mouseReleased(me);
                if (canResize) {
                    resizePanel(getContentPane().getSize());
                }
            }
        });

        addComponentListener(new ComponentAdapter() {

            @Override
            public void componentResized(ComponentEvent e) {
                timer = new Timer(50, new AbstractAction() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        if (timer.isRunning()) {
                            canResize = false;
                        } else {
                            canResize = true;
                            if (firstTime == true) {
                                firstTime = false;
                                resizePanel(getContentPane().getSize());
                            }
                        }
                    }
                });
                timer.setRepeats(false);
                timer.start();

            }
        });
        pack();
    }

    public void resizePanel(Dimension dim) {
        panel2.setBounds(0, 0, dim.width, dim.height);
        revalidate();
    }

    public static void main(String[] args) {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice gd = ge.getDefaultScreenDevice();
        boolean isPerPixelTranslucencySupported = gd.isWindowTranslucencySupported(PERPIXEL_TRANSLUCENT);

        if (!isPerPixelTranslucencySupported) {
            System.out.println("Per-pixel translucency is not supported");
            System.exit(0);
        }

        JFrame.setDefaultLookAndFeelDecorated(true);

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrameSizeAfterDrag2 gtw = new JFrameSizeAfterDrag2();
                gtw.setVisible(true);
            }
        });
    }
}

关于java - Swing:调整 JFrame 的大小，例如 Linux 中的 Frames，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13065032/