SelectionButtonDialogField.java

/*
* Copyright (c) 2010-2012 Research In Motion Limited. All rights reserved.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Public License, Version 1.0,
* which accompanies this distribution and is available at
*
* http://www.eclipse.org/legal/epl-v10.html
*
*/
package net.rim.ejde.internal.ui.widgets.dialog;

import org.eclipse.jdt.internal.ui.util.SWTUtil;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * Dialog Field containing a single button such as a radio or checkbox button.
 */
public class SelectionButtonDialogField extends DialogField {

    private Button fButton;
    private boolean fIsSelected;
    private DialogField[] fAttachedDialogFields;
    private int fButtonStyle;

    /**
     * Creates a selection button. Allowed button styles: SWT.RADIO, SWT.CHECK, SWT.TOGGLE, SWT.PUSH
     */
    public SelectionButtonDialogField( int buttonStyle ) {
        super();
        fIsSelected = false;
        fAttachedDialogFields = null;
        fButtonStyle = buttonStyle;
    }

    /**
     * Attaches a field to the selection state of the selection button. The attached field will be disabled if the selection
     * button is not selected.
     */
    public void attachDialogField( DialogField dialogField ) {
        attachDialogFields( new DialogField[] { dialogField } );
    }

    /**
     * Attaches fields to the selection state of the selection button. The attached fields will be disabled if the selection
     * button is not selected.
     */
    public void attachDialogFields( DialogField[] dialogFields ) {
        fAttachedDialogFields = dialogFields;
        for( int i = 0; i < dialogFields.length; i++ ) {
            dialogFields[ i ].setEnabled( fIsSelected );
        }
    }

    /**
     * Returns <code>true</code> is teh gived field is attached to the selection button.
     */
    public boolean isAttached( DialogField editor ) {
        if( fAttachedDialogFields != null ) {
            for( int i = 0; i < fAttachedDialogFields.length; i++ ) {
                if( fAttachedDialogFields[ i ] == editor ) {
                    return true;
                }
            }
        }
        return false;
    }

    // ------- layout helpers

    /*
     * @see DialogField#doFillIntoGrid
     */
    public Control[] doFillIntoGrid( Composite parent, int nColumns ) {
        assertEnoughColumns( nColumns );

        Button button = getSelectionButton( parent );
        GridData gd = new GridData();
        gd.horizontalSpan = nColumns;
        gd.horizontalAlignment = GridData.FILL;
        if( fButtonStyle == SWT.PUSH ) {
            gd.widthHint = SWTUtil.getButtonWidthHint( button );
        }

        button.setLayoutData( gd );

        return new Control[] { button };
    }

    /*
     * @see DialogField#getNumberOfControls
     */
    public int getNumberOfControls() {
        return 1;
    }

    // ------- ui creation

    /**
     * Returns the selection button widget. When called the first time, the widget will be created.
     *
     * @param group
     *            The parent composite when called the first time, or <code>null</code> after.
     */
    public Button getSelectionButton( Composite group ) {
        if( fButton == null ) {
            assertCompositeNotNull( group );

            fButton = new Button( group, fButtonStyle );
            fButton.setFont( group.getFont() );
            fButton.setText( fLabelText );
            fButton.setEnabled( isEnabled() );
            fButton.setSelection( fIsSelected );
            fButton.addSelectionListener( new SelectionListener() {
                public void widgetDefaultSelected( SelectionEvent e ) {
                    doWidgetSelected( e );
                }

                public void widgetSelected( SelectionEvent e ) {
                    doWidgetSelected( e );
                }
            } );
        }
        return fButton;
    }

    private void doWidgetSelected( SelectionEvent e ) {
        if( isOkToUse( fButton ) ) {
            changeValue( fButton.getSelection() );
        }
    }

    private void changeValue( boolean newState ) {
        if( fIsSelected != newState ) {
            fIsSelected = newState;
            if( fAttachedDialogFields != null ) {
                boolean focusSet = false;
                for( int i = 0; i < fAttachedDialogFields.length; i++ ) {
                    fAttachedDialogFields[ i ].setEnabled( fIsSelected );
                    if( fIsSelected && !focusSet ) {
                        focusSet = fAttachedDialogFields[ i ].setFocus();
                    }
                }
            }
            dialogFieldChanged();
        } else if( fButtonStyle == SWT.PUSH ) {
            dialogFieldChanged();
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see org.eclipse.jdt.internal.ui.wizards.dialogfields.DialogField#setLabelText(java.lang.String)
     */
    public void setLabelText( String labeltext ) {
        fLabelText = labeltext;
        if( isOkToUse( fButton ) ) {
            fButton.setText( labeltext );
        }
    }

    // ------ model access

    /**
     * Returns the selection state of the button.
     */
    public boolean isSelected() {
        return fIsSelected;
    }

    /**
     * Sets the selection state of the button.
     */
    public void setSelection( boolean selected ) {
        changeValue( selected );
        if( isOkToUse( fButton ) ) {
            fButton.setSelection( selected );
        }
    }

    // ------ enable / disable management

    /*
     * @see DialogField#updateEnableState
     */
    protected void updateEnableState() {
        super.updateEnableState();
        if( isOkToUse( fButton ) ) {
            fButton.setEnabled( isEnabled() );
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see org.eclipse.jdt.internal.ui.wizards.dialogfields.DialogField#refresh()
     */
    public void refresh() {
        super.refresh();
        if( isOkToUse( fButton ) ) {
            fButton.setSelection( fIsSelected );
        }
    }

}