Please download the following classes from our web site. Make sure to ‘right-click’ and ‘save as
…’ to put the files into the current BlueJ project directory.
Class Console
This class facilitates reading input from “standard in”, i.e. the keyboard, in simple text programs.
Methods provided are:
public static double readDouble()
when the user presses RETURN or ENTER, the method returns a double as entered if
possible. If the user enters a non-double number, the program quits.
public static int readInt()
when the user presses RETURN or ENTER, the method returns an int as entered if
possible. If the user enters a non-int number, the program quits.
public static String readString()
when the user presses RETURN or ENTER, the method returns a String as entered.
Class DoubleField
This class provides a GUI input field to hold and return a double number. Methods provided are:
public double getDouble()
returns the number entered into the GUI field as a double if possible, or returns 0.0 and
shows “ERROR”.
public void setDouble(double x)
puts the double number x into the GUI field, properly formatted.
Class SimpleWindow
This class helps to create a simple window, containing GUI elements in one row. Methods
provided are:
public void addLabel(String msg)
Adds a String as label to the current line
public void addField(JTextField field)
Adds an input field such as a DoubleField to the current line
public void addButton(JButton button)
Adds a button to the current line
public void setWindowTitle(String title)
Sets the title displayed in the window’s title bar