java swing 多个JLabel和多个JTextField的对齐，如下图所示，把JLabel都放在一个垂直的box1中，把JTextField放在另一个垂直的box2中，然后把box1和box2放在一个水平的boxA中。可是就如下图所示，文字和文本框对不齐。“初始信息素”、“迭代次数”、“蚂蚁数量”都太下了，“期望因子beta”和“信息素残留参数rho”都太上了。
[img]http://dl2.iteye.com/upload/attachment/0099/3919/69f853cd-e296-34f5-b627-2e8aa7ecf201.png[/img]
可是如果把一行中的JLabel和JTextField添加在一个JPanel，然后再把所有的JPanel再添加在一个垂直的Box中的话，这样文本框JTextField之间就会对不齐，文字也对不齐。该怎么样处理呢？
这个可以借助SpringUtilities这个处理对齐问题
[code="java"]
import javax.swing.*;
import javax.swing.SpringLayout;
import java.awt.*;
public class SpringUtilities {
![http://dl2.iteye.com/upload/attachment/0099/3919/69f853cd-e296-34f5-b627-2e8aa7ecf201.png[/img]](http://dl2.iteye.com/upload/attachment/0099/3919/69f853cd-e296-34f5-b627-2e8aa7ecf201.png%5B/img%5D){kind=link}
public static void printSizes(Component c) {
System.out.println("minimumSize = " + c.getMinimumSize());
System.out.println("preferredSize = " + c.getPreferredSize());
System.out.println("maximumSize = " + c.getMaximumSize());
}
public static void makeGrid(Container parent,
int rows, int cols,
int initialX, int initialY,
int xPad, int yPad) {
SpringLayout layout;
try {
layout = (SpringLayout)parent.getLayout();
} catch (ClassCastException exc) {
System.err.println("The first argument to makeGrid must use SpringLayout.");
return;
}
Spring xPadSpring = Spring.constant(xPad);
Spring yPadSpring = Spring.constant(yPad);
Spring initialXSpring = Spring.constant(initialX);
Spring initialYSpring = Spring.constant(initialY);
int max = rows * cols;
Spring maxWidthSpring = layout.getConstraints(parent.getComponent(0)).
getWidth();
Spring maxHeightSpring = layout.getConstraints(parent.getComponent(0)).
getHeight();
for (int i = 1; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
maxWidthSpring = Spring.max(maxWidthSpring, cons.getWidth());
maxHeightSpring = Spring.max(maxHeightSpring, cons.getHeight());
}
for (int i = 0; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
cons.setWidth(maxWidthSpring);
cons.setHeight(maxHeightSpring);
}
SpringLayout.Constraints lastCons = null;
SpringLayout.Constraints lastRowCons = null;
for (int i = 0; i < max; i++) {
SpringLayout.Constraints cons = layout.getConstraints(
parent.getComponent(i));
if (i % cols == 0) { //start of new row
lastRowCons = lastCons;
cons.setX(initialXSpring);
} else { //x position depends on previous component
cons.setX(Spring.sum(lastCons.getConstraint(SpringLayout.EAST),
xPadSpring));
}
if (i / cols == 0) { //first row
cons.setY(initialYSpring);
} else { //y position depends on previous row
cons.setY(Spring.sum(lastRowCons.getConstraint(SpringLayout.SOUTH),
yPadSpring));
}
lastCons = cons;
}
SpringLayout.Constraints pCons = layout.getConstraints(parent);
pCons.setConstraint(SpringLayout.SOUTH,
Spring.sum(
Spring.constant(yPad),
lastCons.getConstraint(SpringLayout.SOUTH)));
pCons.setConstraint(SpringLayout.EAST,
Spring.sum(
Spring.constant(xPad),
lastCons.getConstraint(SpringLayout.EAST)));
}
/* Used by makeCompactGrid. */
private static SpringLayout.Constraints getConstraintsForCell(
int row, int col,
Container parent,
int cols) {
SpringLayout layout = (SpringLayout) parent.getLayout();
Component c = parent.getComponent(row * cols + col);
return layout.getConstraints(c);
}
public static void makeCompactGrid(Container parent,
int rows, int cols,
int initialX, int initialY,
int xPad, int yPad) {
SpringLayout layout;
try {
layout = (SpringLayout)parent.getLayout();
} catch (ClassCastException exc) {
System.err.println("The first argument to makeCompactGrid must use SpringLayout.");
return;
}
//Align all cells in each column and make them the same width.
Spring x = Spring.constant(initialX);
for (int c = 0; c < cols; c++) {
Spring width = Spring.constant(0);
for (int r = 0; r < rows; r++) {
width = Spring.max(width,
getConstraintsForCell(r, c, parent, cols).
getWidth());
}
for (int r = 0; r < rows; r++) {
SpringLayout.Constraints constraints =
getConstraintsForCell(r, c, parent, cols);
constraints.setX(x);
constraints.setWidth(width);
}
x = Spring.sum(x, Spring.sum(width, Spring.constant(xPad)));
}
//Align all cells in each row and make them the same height.
Spring y = Spring.constant(initialY);
for (int r = 0; r < rows; r++) {
Spring height = Spring.constant(0);
for (int c = 0; c < cols; c++) {
height = Spring.max(height,
getConstraintsForCell(r, c, parent, cols).
getHeight());
}
for (int c = 0; c < cols; c++) {
SpringLayout.Constraints constraints =
getConstraintsForCell(r, c, parent, cols);
constraints.setY(y);
constraints.setHeight(height);
}
y = Spring.sum(y, Spring.sum(height, Spring.constant(yPad)));
}
//Set the parent's size.
SpringLayout.Constraints pCons = layout.getConstraints(parent);
pCons.setConstraint(SpringLayout.SOUTH, y);
pCons.setConstraint(SpringLayout.EAST, x);
}
}
[/code]
[b]具体用法[/b]
[code="java"]
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SpringLayout;
public class App {
private static void createAndShowGUI() {
String[] labels = { "姓名: ", "密码: ", "Email: ", "地址: " };
int numPairs = labels.length;
JPanel p = new JPanel(new SpringLayout());
for (int i = 0; i < numPairs; i++) {
JLabel l = new JLabel(labels[i], JLabel.TRAILING);
p.add(l);
JTextField textField = new JTextField(10);
l.setLabelFor(textField);
p.add(textField);
}
SpringUtilities.makeCompactGrid(p, numPairs, 2,
6, 6,
6, 6);
JFrame frame = new JFrame("SpringForm");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
p.setOpaque(true);
frame.setContentPane(p);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
[/code]
设置layout为null 指定对象宽度，采用绝对定位画出来的界面要好看些