Cursor Control in Java

For some strange reason, the capability to control the cursor is in the Frame class, so when you can control the cursor, the user sees when a frame has focus. The applet in Listing 17.38 enables you to select the cursor from a pop-up menu.

Listing 17.38. Selecting the cursor from a pop-up menu.

import java.awt.*;

import java.applet.Applet;

public class cursor_test extends Applet

{

    a_frame a_window;

    Button b_open, b_close;

    boolean window_visible;

    public void init()

    {

        b_open = new Button("Open Window");

        b_close = new Button("Close Window");

        add(b_open);

        add(b_close); 

        create_dialog("Pick a cursor");

    }

    public a_frame create_dialog(String the_title) {

        //create a new Frame

        a_window = new a_frame(the_title,this);

        //set its size to 300 by 80 pixels

        a_window.resize(300,80); 

        return a_window; 

    }

    public boolean action(Event the_event, Object the_arg) {

        String item_name; 

        //handle mouse clicks on the two buttons

        if(the_event.target instanceof Button) {

            item_name = (String)the_arg;

            if(item_name.equals("Open Window")) {

                if(!window_visible) {

                    a_window.show(); 

                    window_visible = true;

                } 

            } 

            if(item_name.equals("Close Window")) {

                if(window_visible) {

                    a_window.hide(); 

                    window_visible = false;

                } 

            } 

        }

        return true;

    }

}

class a_frame extends Frame {

    Button close_window;

    Choice a_menu;

    //this has to be of type cursor_test not Applet. If you 

    //use Applet instead of cursor_test it 

    //will still compile but you won't be able to use my_

    //parent to access the instance

    //variables of the dialogs applet such as window_visible.

    cursor_test my_parent;

    a_frame(String the_title, cursor_test host) {

        super(the_title); 

        FlowLayout fl; 

        my_parent = host; 

        //have to define a layout manager for the window

        fl = new FlowLayout(); 

        setLayout(fl); 

        close_window = new Button("Close Window");

        add(close_window); 

        a_menu = new Choice(); 

        a_menu.addItem("Crosshair cursor");

        a_menu.addItem("Default Arrow cursor");

        a_menu.addItem("Resize Window to the Right cursor");

        a_menu.addItem("Hand cursor");

        a_menu.addItem("Move Window cursor");

        a_menu.addItem("Resize Window Upwards cursor");

        a_menu.addItem("Resize Window using NorthEast corner cursor");

        a_menu.addItem("Resize Window using NorthWest corner cursor");

        a_menu.addItem("Resize Window Downwards cursor");

        a_menu.addItem("Resize Window using SouthEast corner cursor");

        a_menu.addItem("Resize Window using SouthWest corner cursor");

        a_menu.addItem("Text Editing cursor");

        a_menu.addItem("Resizing Window to the left cursor");

        a_menu.addItem("Hourglass cursor");

        add(a_menu);

    }

    public boolean action(Event an_event, Object arg) {

        String button_name; 

        String the_input; 

        String item_name; 

        if (an_event.target instanceof Button) {

            button_name = (String)arg;

            if(button_name.equals("Close Window")) {

              my_parent.window_visible = false;

                hide(); 

            } 

        }

        if(an_event.target instanceof Choice) {

            item_name = (String)arg;

            if(item_name.equals("Crosshair cursor")){

                setCursor(Frame.CROSSHAIR_CURSOR); 

            } 

            if(item_name.equals("Default Arrow cursor")){

                setCursor(Frame.DEFAULT_CURSOR); 

            } 

            if(item_name.equals("Resize Window to the Right cursor")){

                setCursor(Frame.E_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Hand cursor")){

                setCursor(Frame.HAND_CURSOR); 

            } 

            if(item_name.equals("Move Window cursor")){

                setCursor(Frame.MOVE_CURSOR); 

            } 

            if(item_name.equals("Resize Window Upwards cursor")){

                setCursor(Frame.N_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Resize Window using NorthEast corner cursor")){

                setCursor(Frame.NE_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Resize Window using NorthWest corner cursor")){

                setCursor(Frame.NW_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Resize Window Downwards cursor")){

                setCursor(Frame.S_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Resize Window using SouthEast corner cursor")){

                setCursor(Frame.SE_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Resize Window using SouthWest corner cursor")){

                setCursor(Frame.SW_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Text Editing cursor")){

                setCursor(Frame.TEXT_CURSOR); 

            } 

            if(item_name.equals("Resizing Window to the left cursor")){

                setCursor(Frame.W_RESIZE_CURSOR); 

            } 

            if(item_name.equals("Hourglass cursor")){

                setCursor(Frame.WAIT_CURSOR); 

            } 

        }

        return true;

    }

}