我对 oracle 网站上提出的布局对角布局有一个小问题......事实上，我只会在保持布局的同时拉伸屏幕宽度上的最后一个按钮，但我不能，但我已经尝试过这段代码：
public void stretchLastComponent(Container container){
int nComps = container.getComponentCount();
Component c = container.getComponent(nComps-1);
c.setSize(container.getWidth(), c.getHeight());
我也使用了repaint()和revalidate()，但是没有结果。这是使用的类（这是一项强制工作，我无法更改布局）：
为了简单起见，我还在论坛中提供了代码：
package layout;
/*
* 1.2+ version. Used by CustomLayoutDemo.java.
*/
import java.awt.*;
public class DiagonalLayout implements LayoutManager {
private int vgap;
private int minWidth = 0, minHeight = 0;
private int preferredWidth = 0, preferredHeight = 0;
private boolean sizeUnknown = true;
public DiagonalLayout() {
this(5);
}
public DiagonalLayout(int v) {
vgap = v;
}
/* Required by LayoutManager. */
public void addLayoutComponent(String name, Component comp) {
}
/* Required by LayoutManager. */
public void removeLayoutComponent(Component comp) {
}
private void setSizes(Container parent) {
int nComps = parent.getComponentCount();
Dimension d = null;
//Reset preferred/minimum width and height.
preferredWidth = 0;
preferredHeight = 0;
minWidth = 0;
minHeight = 0;
for (int i = 0; i < nComps; i++) {
Component c = parent.getComponent(i);
if (c.isVisible()) {
d = c.getPreferredSize();
if (i > 0) {
preferredWidth += d.width/2;
preferredHeight += vgap;
} else {
preferredWidth = d.width;
}
preferredHeight += d.height;
minWidth = Math.max(c.getMinimumSize().width,
minWidth);
minHeight = preferredHeight;
}
}
}
/* Required by LayoutManager. */
public Dimension preferredLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
int nComps = parent.getComponentCount();
setSizes(parent);
//Always add the container's insets!
Insets insets = parent.getInsets();
dim.width = preferredWidth
+ insets.left + insets.right;
dim.height = preferredHeight
+ insets.top + insets.bottom;
sizeUnknown = false;
return dim;
}
/* Required by LayoutManager. */
public Dimension minimumLayoutSize(Container parent) {
Dimension dim = new Dimension(0, 0);
int nComps = parent.getComponentCount();
//Always add the container's insets!
Insets insets = parent.getInsets();
dim.width = minWidth
+ insets.left + insets.right;
dim.height = minHeight
+ insets.top + insets.bottom;
sizeUnknown = false;
return dim;
}
/* Required by LayoutManager. */
/*
* This is called when the panel is first displayed,
* and every time its size changes.
* Note: You CAN'T assume preferredLayoutSize or
* minimumLayoutSize will be called -- in the case
* of applets, at least, they probably won't be.
*/
public void layoutContainer(Container parent) {
Insets insets = parent.getInsets();
int maxWidth = parent.getWidth()
- (insets.left + insets.right);
int maxHeight = parent.getHeight()
- (insets.top + insets.bottom);
int nComps = parent.getComponentCount();
int previousWidth = 0, previousHeight = 0;
int x = 0, y = insets.top;
int rowh = 0, start = 0;
int xFudge = 0, yFudge = 0;
boolean oneColumn = false;
// Go through the components' sizes, if neither
// preferredLayoutSize nor minimumLayoutSize has
// been called.
if (sizeUnknown) {
setSizes(parent);
}
if (maxWidth <= minWidth) {
oneColumn = true;
}
if (maxWidth != preferredWidth) {
xFudge = (maxWidth - preferredWidth)/(nComps - 1);
}
if (maxHeight > preferredHeight) {
yFudge = (maxHeight - preferredHeight)/(nComps - 1);
}
for (int i = 0 ; i < nComps ; i++) {
Component c = parent.getComponent(i);
if (c.isVisible()) {
Dimension d = c.getPreferredSize();
// increase x and y, if appropriate
if (i > 0) {
if (!oneColumn) {
x += previousWidth/2 + xFudge;
}
y += previousHeight + vgap + yFudge;
}
// If x is too large,
if ((!oneColumn) &&
(x + d.width) >
(parent.getWidth() - insets.right)) {
// reduce x to a reasonable number.
x = parent.getWidth()
- insets.bottom - d.width;
}
// If y is too large,
if ((y + d.height)
> (parent.getHeight() - insets.bottom)) {
// do nothing.
// Another choice would be to do what we do to x.
}
// Set the component's size and position.
c.setBounds(x, y, d.width, d.height);
previousWidth = d.width;
previousHeight = d.height;
}
}
}
public String toString() {
String str = "";
return getClass().getName() + "[vgap=" + vgap + str + "]";
}
}
先感谢您。
