1)java.awt.TextField 版本,我实在是想不出其他办法， 这个办法是比较低劣的：
public void setInputLimited(int min , int max TextField text){
t.addKeyListener(new java.awt.event.KeyAdapter (){
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() >max||e.getKeyCode()
t.setText(t.getText().substring(0,t.getText().length() -1) );
}
}
});
}
2）javax.swing.JTextField
JTextField和TextField不一样， 他有一个setDocument(Document doc)方法， 可以来设置输入。
如
import java.awt.*;
import javax.swing.text.*;
public void setInputLimited(int min , int max,JtextField text){
text.setDocument(new NumberOnlyDocument());
}
public class NumberOnlyDocument
extends PlainDocument {
private boolean haveDot = false;
private int length = 0;
private double max = Double.MIN_VALUE, min = Double.MAX_VALUE;
public NumberOnlyDocument(double max, double min) {
if (max >= min) {
this.max = max;
this.min = min;
}
}
public void insertString(int offs, String str, AttributeSet a) throws
BadLocationException {
if (str == null) {
return;
}
char[] number = str.toCharArray();
for (int i = 0; i < number.length; i++) {
if (offs == 0) {
if (! (number[i] >= '0' && number[i] <= '9' || number[i] == '.' ||
number[i] == '-' || number[i] == '+')) {
if (offs == length - 1) {
remove(offs + i, 1);
}
else {
return;
}
}
else {
length++;
}
}
else {
if (!haveDot) {
if (! (number[i] >= '0' && number[i] <= '9' || number[i] == '.')) {
if (offs == length - 1) {
remove(offs + i, 1);
}
else {
return;
}
}
else {
if (number[i] == '.') {
haveDot = true;
}
length++;
}
}
else {
if (! (number[i] >= '0' && number[i] <= '9')) {
if (offs == length - 1) {
remove(offs + i, 1);
}
else {
Toolkit.getDefaultToolkit().beep();
return;
}
}
else {
length++;
}
}
}
}
super.insertString(offs, new String(number), a);
}
}
