Spinner.java Source code

Introduction

Here is the source code for Spinner.java

Source

/*
 * 
 * (c) Copyright IBM Corp. 2000, 2001.
 * 
 * All Rights Reserved.
 *  
 */

import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.widgets.TypedListener;

public class Spinner extends Composite {

    static final int BUTTON_WIDTH = 16;

    Text text;

    Button up, down;

    int minimum, maximum;

    public Spinner(Composite parent, int style) {

        super(parent, style);

        text = new Text(this, style | SWT.SINGLE | SWT.BORDER);

        up = new Button(this, style | SWT.ARROW | SWT.UP);

        down = new Button(this, style | SWT.ARROW | SWT.DOWN);

        text.addListener(SWT.Verify, new Listener() {

            public void handleEvent(Event e) {

                verify(e);

            }

        });

        text.addListener(SWT.Traverse, new Listener() {

            public void handleEvent(Event e) {

                traverse(e);

            }

        });

        up.addListener(SWT.Selection, new Listener() {

            public void handleEvent(Event e) {

                up();

            }

        });

        down.addListener(SWT.Selection, new Listener() {

            public void handleEvent(Event e) {

                down();

            }

        });

        addListener(SWT.Resize, new Listener() {

            public void handleEvent(Event e) {

                resize();

            }

        });

        addListener(SWT.FocusIn, new Listener() {

            public void handleEvent(Event e) {

                focusIn();

            }

        });

        text.setFont(getFont());

        minimum = 0;

        maximum = 9;

        setSelection(minimum);

    }

    void verify(Event e) {

        try {

            Integer.parseInt(e.text);

        } catch (NumberFormatException ex) {

            e.doit = false;

        }

    }

    void traverse(Event e) {

        switch (e.detail) {

        case SWT.TRAVERSE_ARROW_PREVIOUS:

            if (e.keyCode == SWT.ARROW_UP) {

                e.doit = true;

                e.detail = SWT.NULL;

                up();

            }

            break;

        case SWT.TRAVERSE_ARROW_NEXT:

            if (e.keyCode == SWT.ARROW_DOWN) {

                e.doit = true;

                e.detail = SWT.NULL;

                down();

            }

            break;

        }

    }

    void up() {

        setSelection(getSelection() + 1);

        notifyListeners(SWT.Selection, new Event());

    }

    void down() {

        setSelection(getSelection() - 1);

        notifyListeners(SWT.Selection, new Event());

    }

    void focusIn() {

        text.setFocus();

    }

    public void setFont(Font font) {

        super.setFont(font);

        text.setFont(font);

    }

    public void setSelection(int selection) {

        if (selection < minimum) {

            selection = minimum;

        } else if (selection > maximum) {

            selection = maximum;

        }

        text.setText(String.valueOf(selection));

        text.selectAll();

        text.setFocus();

    }

    public int getSelection() {

        return Integer.parseInt(text.getText());

    }

    public void setMaximum(int maximum) {

        checkWidget();

        this.maximum = maximum;

        resize();

    }

    public int getMaximum() {

        return maximum;

    }

    public void setMinimum(int minimum) {

        this.minimum = minimum;

    }

    public int getMinimum() {

        return minimum;

    }

    void resize() {

        Point pt = computeSize(SWT.DEFAULT, SWT.DEFAULT);

        int textWidth = pt.x - BUTTON_WIDTH;

        int buttonHeight = pt.y / 2;

        text.setBounds(0, 0, textWidth, pt.y);

        up.setBounds(textWidth, 0, BUTTON_WIDTH, buttonHeight);

        down.setBounds(textWidth, pt.y - buttonHeight, BUTTON_WIDTH, buttonHeight);

    }

    public Point computeSize(int wHint, int hHint, boolean changed) {

        GC gc = new GC(text);

        Point textExtent = gc.textExtent(String.valueOf(maximum));

        gc.dispose();

        Point pt = text.computeSize(textExtent.x, textExtent.y);

        int width = pt.x + BUTTON_WIDTH;

        int height = pt.y;

        if (wHint != SWT.DEFAULT)
            width = wHint;

        if (hHint != SWT.DEFAULT)
            height = hHint;

        return new Point(width, height);

    }

    public void addSelectionListener(SelectionListener listener) {

        if (listener == null)
            throw new SWTError(SWT.ERROR_NULL_ARGUMENT);

        addListener(SWT.Selection, new TypedListener(listener));

    }

}