doublefield.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.TextField;

public class DoubleField
        extends TextField {
    private boolean error = false;
    private double defValue = 0.0;

    public DoubleField(double number) {
        super(Double.toString(number));
    }

    public void setNumber(double number) {
        setText(Double.toString(number));
    }

    public double getNumber() {
        try {
            double number = Double.valueOf(getText()).doubleValue();
            setNumber(number);
            error = false;
            return number;
        }
        catch (NumberFormatException nfe) {
            setText("INVALID");
            error = true;
            return defValue;
        }
    }

    public void setDefault(double _defValue) {
        defValue = _defValue;
    }

    public boolean getError() {
        return error;
    }
}