Java 不可见组件仍然占用空间JPanel

在一个JPanel集合中，我有一系列组件在彼此下面，作为一个GridLayout。 我需要暂时隐藏组件，但是

setVisible（false）

无法将其剪切，因为组件所在的位置仍然有一个空白

有没有一个快速简单的方法来做到这一点？还是我必须保存JPanel的状态，删除组件，然后恢复它

SSCCE：

[GridLayout2.java]

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Insets;

public class GridLayout2 extends GridLayout 
{
  public GridLayout2() {
    this(1, 0, 0, 0);
  }

  public GridLayout2(int rows, int cols) {
    this(rows, cols, 0, 0);
  }

  public GridLayout2(int rows, int cols, int hgap, int vgap) {
    super(rows, cols, hgap, vgap);
  }

  public Dimension preferredLayoutSize(Container parent) {
    //System.err.println("preferredLayoutSize");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getPreferredSize();
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      int nw = 0;
      for (int j = 0; j < ncols; j ++) {
        nw += w[j];
      }
      int nh = 0;
      for (int i = 0; i < nrows; i ++) {
        nh += h[i];
      }
      return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(), 
          insets.top + insets.bottom + nh + (nrows-1)*getVgap());
    }
  }

  public Dimension minimumLayoutSize(Container parent) {
    System.err.println("minimumLayoutSize");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getMinimumSize();
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      int nw = 0;
      for (int j = 0; j < ncols; j ++) {
        nw += w[j];
      }
      int nh = 0;
      for (int i = 0; i < nrows; i ++) {
        nh += h[i];
      }
      return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(), 
          insets.top + insets.bottom + nh + (nrows-1)*getVgap());
    }
  }

  public void layoutContainer(Container parent) {
    //System.err.println("layoutContainer");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (ncomponents == 0) {
        return;
      }
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int hgap = getHgap();
      int vgap = getVgap();
      // scaling factors      
      Dimension pd = preferredLayoutSize(parent);
      double sw = (1.0 * parent.getWidth()) / pd.width;
      double sh = (1.0 * parent.getHeight()) / pd.height;
      // scale
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getPreferredSize();
        d.width = (int) (sw * d.width);
        d.height = (int) (sh * d.height);
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      for (int c = 0, x = insets.left; c < ncols; c ++) {
        for (int r = 0, y = insets.top; r < nrows; r ++) {
          int i = r * ncols + c;
          if (i < ncomponents) {
            parent.getComponent(i).setBounds(x, y, w[c], h[r]);
          }
          y += h[r] + vgap;
        }
        x += w[c] + hgap;
      }
    }
  }  
}

import java.awt.Color;
import javax.swing.*;
import javax.swing.border.*;

public class SSCCE extends JFrame{

    JPanel innerPane = new JPanel();
    JScrollPane scr  = new JScrollPane(innerPane);

    public static void main(String[] args) {
        new SSCCE();
    }


    public SSCCE() {

        setSize(400, 800);
        innerPane.setLayout(new GridLayout2(0, 1));

        add(scr);

        for (int i = 0; i < 30; i++)
        {
            innerPane.add(getPane());
        }

        setVisible(true);

        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {}

        for (int i = 0; i < 30; i++)
        {
            if (i%2==0)
                innerPane.getComponent(i).setVisible(false);
        }

    }


    private JPanel getPane()
    {
        JPanel ret = new JPanel();
        JLabel lbl = new JLabel("This is a pane.");

        ret.add(lbl);
        ret.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
        ret.setBackground(Color.gray);

        return ret;

    }

}

导入java.awt.Component；
导入java.awt.Container；
导入java.awt.Dimension；
导入java.awt.GridLayout；
导入java.awt.Insets；
公共类GridLayout2扩展了GridLayout
{
公共网格布局2（）{
这（1,0,0,0）；
}
公共网格布局2（int行、int列）{
这（行、列、0、0）；
}
公共网格布局2（int行、int列、int hgap、int vgap）{
超级（行、列、hgap、vgap）；
}
公共维度preferredLayoutSize（容器父级）{
//System.err.println（“preferredLayoutSize”）；
已同步（父级.getTreeLock（））{
Insets Insets=parent.getInsets（）；
int ncomponents=parent.getComponentCount（）；
int nrows=getRows（）；
int ncols=getColumns（）；
如果（nrows>0）{
ncols=（ncomponents+nrows-1）/nrows；
} 
否则{
nrows=（ncomponents+ncols-1）/ncols；
}
int[]w=新的int[ncols]；
int[]h=新的int[nrows]；
对于（int i=0；i0）{
ncols=（ncomponents+nrows-1）/nrows；
} 
否则{
nrows=（ncomponents+ncols-1）/ncols；
}
int[]w=新的int[ncols]；
int[]h=新的int[nrows]；
对于（int i=0；i0）{
ncols=（ncomponents+nrows-1）/nrows；
} 
否则{
nrows=（ncomponents+ncols-1）/ncols；
}
int hgap=getHgap（）；
int vgap=getVgap（）；
//比例因子
维度pd=首选布局大小（父级）；
double sw=（1.0*parent.getWidth（））/pd.width；
double sh=（1.0*parent.getHeight（））/pd.height；
//鳞片
int[]w=新的int[ncols]；
int[]h=新的int[nrows]；
对于（int i=0；i

[SSCCE.java]

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Insets;

public class GridLayout2 extends GridLayout 
{
  public GridLayout2() {
    this(1, 0, 0, 0);
  }

  public GridLayout2(int rows, int cols) {
    this(rows, cols, 0, 0);
  }

  public GridLayout2(int rows, int cols, int hgap, int vgap) {
    super(rows, cols, hgap, vgap);
  }

  public Dimension preferredLayoutSize(Container parent) {
    //System.err.println("preferredLayoutSize");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getPreferredSize();
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      int nw = 0;
      for (int j = 0; j < ncols; j ++) {
        nw += w[j];
      }
      int nh = 0;
      for (int i = 0; i < nrows; i ++) {
        nh += h[i];
      }
      return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(), 
          insets.top + insets.bottom + nh + (nrows-1)*getVgap());
    }
  }

  public Dimension minimumLayoutSize(Container parent) {
    System.err.println("minimumLayoutSize");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getMinimumSize();
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      int nw = 0;
      for (int j = 0; j < ncols; j ++) {
        nw += w[j];
      }
      int nh = 0;
      for (int i = 0; i < nrows; i ++) {
        nh += h[i];
      }
      return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(), 
          insets.top + insets.bottom + nh + (nrows-1)*getVgap());
    }
  }

  public void layoutContainer(Container parent) {
    //System.err.println("layoutContainer");
    synchronized (parent.getTreeLock()) {
      Insets insets = parent.getInsets();
      int ncomponents = parent.getComponentCount();
      int nrows = getRows();
      int ncols = getColumns();
      if (ncomponents == 0) {
        return;
      }
      if (nrows > 0) {
        ncols = (ncomponents + nrows - 1) / nrows;
      } 
      else {
        nrows = (ncomponents + ncols - 1) / ncols;
      }
      int hgap = getHgap();
      int vgap = getVgap();
      // scaling factors      
      Dimension pd = preferredLayoutSize(parent);
      double sw = (1.0 * parent.getWidth()) / pd.width;
      double sh = (1.0 * parent.getHeight()) / pd.height;
      // scale
      int[] w = new int[ncols];
      int[] h = new int[nrows];
      for (int i = 0; i < ncomponents; i ++) {
        int r = i / ncols;
        int c = i % ncols;
        Component comp = parent.getComponent(i);
        Dimension d = comp.getPreferredSize();
        d.width = (int) (sw * d.width);
        d.height = (int) (sh * d.height);
        if (w[c] < d.width) {
          w[c] = d.width;
        }
        if (h[r] < d.height) {
          h[r] = d.height;
        }
      }
      for (int c = 0, x = insets.left; c < ncols; c ++) {
        for (int r = 0, y = insets.top; r < nrows; r ++) {
          int i = r * ncols + c;
          if (i < ncomponents) {
            parent.getComponent(i).setBounds(x, y, w[c], h[r]);
          }
          y += h[r] + vgap;
        }
        x += w[c] + hgap;
      }
    }
  }  
}

import java.awt.Color;
import javax.swing.*;
import javax.swing.border.*;

public class SSCCE extends JFrame{

    JPanel innerPane = new JPanel();
    JScrollPane scr  = new JScrollPane(innerPane);

    public static void main(String[] args) {
        new SSCCE();
    }


    public SSCCE() {

        setSize(400, 800);
        innerPane.setLayout(new GridLayout2(0, 1));

        add(scr);

        for (int i = 0; i < 30; i++)
        {
            innerPane.add(getPane());
        }

        setVisible(true);

        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {}

        for (int i = 0; i < 30; i++)
        {
            if (i%2==0)
                innerPane.getComponent(i).setVisible(false);
        }

    }


    private JPanel getPane()
    {
        JPanel ret = new JPanel();
        JLabel lbl = new JLabel("This is a pane.");

        ret.add(lbl);
        ret.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
        ret.setBackground(Color.gray);

        return ret;

    }

}

导入java.awt.Color；
导入javax.swing.*；
导入javax.swing.border.*；
公共类SSCCE扩展JFrame{
JPanel innerPane=新的JPanel（）；
JScrollPane scr=新的JScrollPane（内部窗格）；
公共静态void main（字符串[]args）{
新SSCCE（）；
}
公共服务{
设置大小（400800）；
setLayout（新的GridLayout2（0，1））；
添加（scr）；
对于（int i=0；i<30；i++）
{
添加（getPane（））；
}
setVisible（真）；
试一试{
《睡眠》（2000年）；
}捕获（中断异常e）{}
对于（int i=0；i<30；i++）
{
如果（i%2==0）
innerPane.getComponent（i）.setVisible（false）；
}
}
私有JPanel getPane（）
{
JPanel ret=新的JPanel（）；
JLabel lbl=新的JLabel（“这是一个窗格”）；
重新添加（lbl）；
ret.setboorder（BorderFactory.createBevelOrder（BevelOrder.RAISED））；
后退地面（颜色为灰色）；
返回ret；
}
}

b

button.setVisible(false);

button.setEnabled(false);

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class DisableComponents {

    public static void main(String args[]) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JPanel gui = new JPanel(new BorderLayout());
                JToolBar tb = new JToolBar();
                gui.add(tb, BorderLayout.NORTH);
                final JButton openTool = new JButton("Open");
                final JButton saveTool = new JButton("Save");
                tb.add( openTool );
                tb.add( saveTool );

                JPanel buttonFlow = new JPanel(new FlowLayout(3));
                gui.add(buttonFlow, BorderLayout.CENTER);
                final JButton openFlow = new JButton("Open");
                final JButton saveFlow = new JButton("Save");
                buttonFlow.add( openFlow );
                buttonFlow.add( saveFlow );

                JPanel buttonBox = new JPanel();
                gui.add(buttonBox, BorderLayout.EAST);
                BoxLayout bl = new BoxLayout(buttonBox, BoxLayout.Y_AXIS);
                buttonBox.setLayout(bl);
                final JButton openBox = new JButton("Open");
                final JButton saveBox = new JButton("Save");
                buttonBox.add( openBox );
                buttonBox.add( saveBox );

                final JCheckBox openChoice = new JCheckBox("Enable open", true);
                openChoice.addActionListener(new ActionListener() {
                    public void actionPerformed(ActionEvent ae) {
                        openTool.setEnabled(openChoice.isSelected());
                        openFlow.setEnabled(openChoice.isSelected());
                        openBox.setEnabled(openChoice.isSelected());
                    }
                });
                gui.add(openChoice, BorderLayout.SOUTH);

                JOptionPane.showMessageDialog(null, gui);
            }
        });
    }
}

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.border.*;

public class SSCCE extends JFrame {

    private static final long serialVersionUID = 1L;
    private JPanel innerPane = new JPanel();
    private JScrollPane scr = new JScrollPane(innerPane);
    private Timer timer;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                SSCCE sSCCE = new SSCCE();
            }
        });
    }

    private JPanel getPane() {
        JPanel ret = new JPanel();
        JLabel lbl = new JLabel("This is a pane.");
        ret.add(lbl);
        ret.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
        ret.setBackground(Color.gray);
        return ret;
    }

    public SSCCE() {
        innerPane.setLayout(new GridLayout(0, 1));
        add(scr);
        for (int i = 0; i < 30; i++) {
            innerPane.add(getPane());
        }
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
        start();
    }

    private void start() {
        timer = new javax.swing.Timer(2000, updateCol());
        timer.start();
        timer.setRepeats(false);
    }

    private Action updateCol() {
        return new AbstractAction("Hide Row Action") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                for (int i = 0; i < 30; i++) {
                    if (i % 2 == 0) {
                        innerPane.getComponent(i).setVisible(false);
                    }
                }
            }
        };
    }
}

JPanel innerPane = new JPanel();
BoxLayout innerPaneLayout = new BoxLayout(innerPane,BoxLayout.Y_AXIS);
innerPane.setLayout(innerPaneLayout);

for (int i = 0; i < 30; i++)
{
     JPane newPane = getPane();
     innerPane.add(newPane);
     newPane.setAlignmentY(Component.TOP_ALIGNMENT);
}

for (int i = 0; i < 30; i++)
{
      if (i%2==0)
         innerPane.getComponent(i).setVisible(false);
}