3

問題のコード:

    textArea.addMouseListener(new MouseAdapter() {
        public void mousePressed(MouseEvent e) {
            posX = e.getX();
            posY = e.getY();
        }
    });
    textArea.addMouseMotionListener(new MouseAdapter() {
        public void mouseDragged(MouseEvent e) {
            setLocation(e.getXOnScreen() - posX, e.getYOnScreen() - posY);
        }
    });

バックグラウンド:

私は JFrame を持っています。その JFrame には JScrollPane があり、JScrollPane には「textArea」と呼ばれる JTextArea があります。この JTextArea は JFrame 全体を占有し、JFrame は装飾されていません。いくつかの視点を与えるために、JFrameは一般的に次のようになります...

サンプル画像

マウスが JTextArea 内をクリックして移動すると、ウィンドウ全体がドラッグされます。この作業ではすべてがフォーカスできないように設定されており、オーバーレイを意図しています。

問題:

上記のコードは正常に機能し、世界は平和です。しかし、垂直スクロール バーが表示されるのに十分なテキストが表示されると (行の折り返しのために水平スクロール バーがなくなります)、ウィンドウのドラッグが問題になります。クリックして動き始めると、JFrame は即座に画面のはるか上に移動します。JTextArea の行は、移動しようとすると上に移動します。get*OnScreen() メソッドはすべて JTextArea に関連しているため、問題があると思います。

問題のクラス:

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Main extends JFrame {
    private JTextArea textArea;
    private JScrollPane textAreaScroll;
    private int posX = 0;
    private int posY = 0;

public Main() {
    initComponents();
    initListeners();
    for(int i = 0; i < 20; i++){
        addLine(i+" Hello");            
    }
}

public void addLine(String line){
    textArea.append("\n> "+line);
    textArea.setCaretPosition(textArea.getDocument().getLength());
}

private void initListeners(){
    textArea.addMouseListener(new MouseAdapter() {
        public void mousePressed(MouseEvent e) {
            posX = e.getX();
            posY = e.getY();
        }
    });
    textArea.addMouseMotionListener(new MouseAdapter() {
        public void mouseDragged(MouseEvent e) {
            setLocation(e.getXOnScreen() - posX, e.getYOnScreen() - posY);
        }
    });
}

private void initComponents() {
    try {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException e) {}

    textAreaScroll = new JScrollPane();
    textArea = new JTextArea();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setUndecorated(true);
    setAlwaysOnTop(true);
    setAutoRequestFocus(false);
    setBackground(new Color(130,210,255,130));
    setFocusCycleRoot(false);
    setFocusable(false);
    setFocusableWindowState(false);
    setName("main");
    setOpacity(0.4f);
    setResizable(false);

    textAreaScroll.setBorder(null);
    textAreaScroll.setFocusable(false);
    textAreaScroll.setRequestFocusEnabled(false);

    textArea.setEditable(false);
    textArea.setBackground(new Color(0, 0, 0));
    textArea.setColumns(20);
    textArea.setFont(new Font("Consolas", 0, 14));
    textArea.setForeground(new Color(255, 255, 255));
    textArea.setLineWrap(true);
    textArea.setRows(5);
    textArea.setText("> Hello world!\n> another line!");
    textArea.setBorder(null);
    textArea.setFocusable(false);
    textArea.setRequestFocusEnabled(false);
    textAreaScroll.setViewportView(textArea);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(textAreaScroll, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
            );
    layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(textAreaScroll, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 214, Short.MAX_VALUE)
            );

    pack();
}

public static void main(String args[]) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            new Main().setVisible(true);
        }
    });
}

}

4

2 に答える 2

1

あなたは、JFrame が即座に画面上ではるかに高く移動すると言っています。JTextArea の行ですが、実際には下にスクロールされるため、最後の数行しか表示されません。

textArea の内容を上から見たい場合は変更はこちら

initComponents();
initListeners();
for (int i = 0; i < 20; i++) {
   addLine(i + " Hello");
}
//set scrolling position to top
textArea.setCaretPosition(0);
于 2012-12-09T09:11:55.340 に答える
1

Well your diagnosis was absolutely spot on:

When you click and just begin to move, the JFrame instantly moves much higher on the screen. The lines in JTextArea, the higher it moves up when you try to move it. I assume that the get*OnScreen() methods are issue because it's all relevant to the JTextArea.

So to resolve this use GlassPane of JFrame to attach MouseXXXListeners thus we can get correct co-ordinates when dragging, the main problem with this solution is glasspane will consume events that are meant for other components on JFrame, this can be overcome by redispatching the MouseEvents appropriately):

  • Create JPanel (this glassPane/JPanel will be transparent via setOpaque(false)), attach xxxAdapters here.

  • Create custom listener class to redispacth MouseEvents to the necessary components (as glasspane will consume all events to the JTextArea/JScollPane)

  • Set JPanel as GlassPane of your JFrame via JFrame#setGlassPane(..) .

  • set JFrame visible than set glassPane visible via setVisible(true) (this has been a Swing glitch for some time if you set it visible before the frame is visible it wont be shown).

Here is your fixed code:

import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.MouseInputAdapter;

public class Main extends JFrame {

    private JTextArea textArea;
    private JScrollPane textAreaScroll;
    private JPanel glassPane;//create variable for glasspane

    public Main() {
        initComponents();
        initListeners();
        for (int i = 0; i < 20; i++) {
            addLine(i + " Hello");
        }
    }

    public void addLine(String line) {
        textArea.append("\n> " + line);
        textArea.setCaretPosition(textArea.getDocument().getLength());
    }

    private void initListeners() {
        GlassPaneListener gpl = new GlassPaneListener(textAreaScroll.getVerticalScrollBar(), this);
        //add the adapters/listeners to the glasspane
        glassPane.addMouseMotionListener(gpl);
        glassPane.addMouseListener(gpl);
    }

    private void initComponents() {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException e) {
        }

        textAreaScroll = new JScrollPane();
        textArea = new JTextArea();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setUndecorated(true);
        setAlwaysOnTop(true);
        setAutoRequestFocus(false);
        setBackground(new Color(130, 210, 255, 130));
        setFocusCycleRoot(false);
        setFocusable(false);
        setFocusableWindowState(false);
        setName("main");
        setOpacity(0.4f);
        setResizable(false);

        textAreaScroll.setBorder(null);
        textAreaScroll.setFocusable(false);
        textAreaScroll.setRequestFocusEnabled(false);

        textArea.setEditable(false);
        textArea.setBackground(new Color(0, 0, 0));
        textArea.setColumns(20);
        textArea.setFont(new Font("Consolas", 0, 14));
        textArea.setForeground(new Color(255, 255, 255));
        textArea.setLineWrap(true);
        textArea.setRows(5);
        textArea.setText("> Hello world!\n> another line!");
        textArea.setBorder(null);
        textArea.setFocusable(false);
        textArea.setRequestFocusEnabled(false);
        textAreaScroll.setViewportView(textArea);
        textAreaScroll.setPreferredSize(new Dimension(200, 200));

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(textAreaScroll, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE));
        layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(textAreaScroll, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 214, Short.MAX_VALUE));

        //create and make glasspane not opaque
        glassPane = new JPanel();
        glassPane.setOpaque(false);

        //set glasspane as JFrame glassPane
        setGlassPane(glassPane);

        pack();

        setVisible(true);//set JFrame visible

        //glassPane can only be setVisible after JFrame is visible
        glassPane.setVisible(true);
    }

    public static void main(String args[]) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Main();
            }
        });
    }
}

class GlassPaneListener extends MouseInputAdapter {

    private int posX = 0;
    private int posY = 0;
    Toolkit toolkit;
    private final Container contentPane;
    private final Component textAreaScroll;
    private final Component glassPane;
    private final JFrame frame;
    private boolean wasClickOnInterestedComponent = false;

    public GlassPaneListener(Component textAreaScroll, JFrame frame) {
        toolkit = Toolkit.getDefaultToolkit();
        this.textAreaScroll = textAreaScroll;
        this.frame = frame;
        this.glassPane = frame.getGlassPane();
        this.contentPane = frame.getContentPane();
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        if (!redispatchMouseEvent(e)) {
            frame.setLocation(e.getXOnScreen() - posX, e.getYOnScreen() - posY);
        }
    }

    @Override
    public void mousePressed(MouseEvent e) {
        if (!redispatchMouseEvent(e)) {//check if event was redispatched if not its meant for us :)
            posX = e.getX();
            posY = e.getY();
        }
    }

    @Override
    public void mouseReleased(MouseEvent me) {
        wasClickOnInterestedComponent = false;
    }

    private boolean redispatchMouseEvent(MouseEvent e) {
        Point glassPanePoint = e.getPoint();
        Container container = contentPane;
        Point containerPoint = SwingUtilities.convertPoint(glassPane, glassPanePoint, contentPane);

        // The mouse event is probably over the content pane.
        // Find out exactly which component it's over.
        Component component = SwingUtilities.getDeepestComponentAt(container, containerPoint.x,
                containerPoint.y);

        if ((component != null) && (component.equals(textAreaScroll)) || wasClickOnInterestedComponent) {
            wasClickOnInterestedComponent = true;//so that if we drag iur cursor off JScrollBar tghe window wont be moved
            // Forward events over the scrollbar
            Point componentPoint = SwingUtilities.convertPoint(glassPane, glassPanePoint, component);
            component.dispatchEvent(new MouseEvent(component, e.getID(), e.getWhen(), e.getModifiers(),
                    componentPoint.x, componentPoint.y, e.getClickCount(), e.isPopupTrigger()));
            return true;//the event was redispatched
        } else {
            return false;//event was not redispatched
        }
    }
}
于 2012-12-09T14:18:17.963 に答える