Question

我已经为我的JTextPane添加了一些组件，所有内容都打印得很好但是当我想打印更多时，我的JScrollPane没有出现，所以我可以向下滚动查看其他组件。

int p=0;
    int y1=0;
    int y2=20;
    int i=0;
 while (i< 10){    
    JLabel date= new JLabel();
    date.setSize(100, 21);
    date.setText("date posted");

    JLabel username= new JLabel();
    username.setSize(100,21);
    username.setText("username");

    JLabel picture= new JLabel();
    picture.setSize(120, 120);
    try {
        ImageIcon ii=new ImageIcon(scaleImage(120, 120, ImageIO.read(new 
    File(System.getProperty("user.dir")+"\\ProfilePicture.png"))));
        picture.setIcon(ii);
    } catch (Exception ex) {
        ex.printStackTrace();
    }

    JTextArea caption= new JTextArea();
    caption.setText("caption here...");
    caption.setLineWrap(true);
    caption.setEditable(false);
    caption.setSize(100, 100);
    JScrollPane CaptionScroll = new JScrollPane (caption, 
    JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, 
    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
    CaptionScroll.setSize(100,100);

    JTextArea comments= new JTextArea();
    comments.setText("comments here...");
    comments.setLineWrap(true);
    comments.setSize(100, 100);
    JScrollPane CommentScroll = new JScrollPane (comments, 
    JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, 
    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
    CommentScroll.setSize(100,100);

    JButton CommentButton= new JButton();
    CommentButton.setText("Submit");
    CommentButton.setSize(100, 21);
    CommentButton.addActionListener(new ActionListener(){
        @Override
        public void actionPerformed(ActionEvent ae) {
            //do stufff
        }
    });

    likes=0;
    final JLabel likeLabel= new JLabel();
    likeLabel.setText("LIKES: "+ Integer.toString(likes));
    likeLabel.setSize(100,21);

    final JButton LikeButton= new JButton();
    LikeButton.setText("Like");
    LikeButton.setSize(100, 21);
    LikeButton.addActionListener(new ActionListener(){
        @Override
        public void actionPerformed(ActionEvent ae) {
            if (liked == false) {
                likes++;
                likeLabel.setText("LIKES: "+ Integer.toString(likes));
                LikeButton.setText("UnLike");
                liked=true;
            }
            else{
                likes--;
                likeLabel.setText("LIKES: "+ Integer.toString(likes));
                LikeButton.setText("Like");
                liked=false;
            }
        }
    });

    DMInboxOutputTextPane.add(username, p).setLocation(125, y1);
    p++;
    DMInboxOutputTextPane.add(CaptionScroll,p).setLocation(120, y2);
    p++;
    DMInboxOutputTextPane.add(CommentButton,p).setLocation(230,y1);
    p++;
    DMInboxOutputTextPane.add(CommentScroll, p).setLocation(230, y2);
    p++;
    DMInboxOutputTextPane.add(LikeButton,p).setLocation(340, y1);
    p++;
    DMInboxOutputTextPane.add(likeLabel,p).setLocation(340, y2);
    p++;
    DMInboxOutputTextPane.add(date,p).setLocation(450, y1);
    p++;
    DMInboxOutputTextPane.add(picture, p).setLocation(0, y1);
    p++;
    DMInboxOutputTextPane.repaint();
    i++;
    y1=y1+130;
    y2=y2+130;
}

我可以打印我想要打印的三个对象，但之后其他所有内容都会被切断，并且不会出现scrollPane。

Answer 1

通常，对于这类事情，您可以在使用垂直BoxLayout布局的JPanel中添加组件。类似的东西：

    JPanel pane = new JPanel();
    pane.setLayout(new BoxLayout(pane, BoxLayout.PAGE_AXIS));

您可以将窗格设置为可滚动：

    JPanel pane = new JPanel();
    pane.setLayout(new BoxLayout(pane, BoxLayout.PAGE_AXIS));
    JScrollPane scroll = new JScrollPane(pane);

鉴于您的用例，您可能需要实现Scrollable接口以获得对scrollPane的更多控制：

public static class VerticalScrollablePane extends JPanel implements Scrollable {
    public VerticalScrollablePane(LayoutManager layout) {super(layout);}
    public VerticalScrollablePane() {}
    @Override
    public Dimension getPreferredScrollableViewportSize() {return getPreferredSize();}
    @Override
    public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
        switch(orientation) {
        case SwingConstants.VERTICAL:
            return visibleRect.height / 10;
        case SwingConstants.HORIZONTAL:
            return visibleRect.width / 10;
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }
    @Override
    public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
        switch(orientation) {
        case SwingConstants.VERTICAL:
            return visibleRect.height;
        case SwingConstants.HORIZONTAL:
            return visibleRect.width;
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }
    @Override
    public boolean getScrollableTracksViewportWidth() {return true;}
    @Override
    public boolean getScrollableTracksViewportHeight() {return false;}

}

然后你会：

    JPanel pane = new VerticalScrollablePane();
    pane.setLayout(new BoxLayout(pane, BoxLayout.PAGE_AXIS));
    JScrollPane scroll = new JScrollPane(pane);

希望它有所帮助！

JScrollPane问题，没有出现

1 个答案: