net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/wizards/dialogfields/DialogField.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.wizards.dialogfields;
  12
  13 import org.eclipse.jface.util.Assert;
  14 import org.eclipse.swt.SWT;
  15 import org.eclipse.swt.layout.GridData;
  16 import org.eclipse.swt.widgets.Composite;
  17 import org.eclipse.swt.widgets.Control;
  18 import org.eclipse.swt.widgets.Display;
  19 import org.eclipse.swt.widgets.Label;
  20
  21 /**
  22  * Base class of all dialog fields.
  23  * Dialog fields manage controls together with the model, independed
  24  * from the creation time of the widgets.
  25  * - support for automated layouting.
  26  * - enable / disable, set focus a concept of the base class.
  27  *
  28  * DialogField have a label.
  29  */
  30 public class DialogField {
  31
  32         private Label fLabel;
  33         protected String fLabelText;
  34
  35         private IDialogFieldListener fDialogFieldListener;
  36
  37         private boolean fEnabled;
  38
  39         public DialogField() {
  40                 fEnabled= true;
  41                 fLabel= null;
  42                 fLabelText= ""; //$NON-NLS-1$
  43         }
  44
  45         /**
  46          * Sets the label of the dialog field.
  47          */
  48         public void setLabelText(String labeltext) {
  49                 fLabelText= labeltext;
  50         }
  51
  52         // ------ change listener
  53
  54         /**
  55          * Defines the listener for this dialog field.
  56          */
  57         public final void setDialogFieldListener(IDialogFieldListener listener) {
  58                 fDialogFieldListener= listener;
  59         }
  60
  61         /**
  62          * Programatical invocation of a dialog field change.
  63          */
  64         public void dialogFieldChanged() {
  65                 if (fDialogFieldListener != null) {
  66                         fDialogFieldListener.dialogFieldChanged(this);
  67                 }
  68         }
  69
  70         // ------- focus management
  71
  72         /**
  73          * Tries to set the focus to the dialog field.
  74          * Returns <code>true</code> if the dialog field can take focus.
  75          *      To be reimplemented by dialog field implementors.
  76          */
  77         public boolean setFocus() {
  78                 return false;
  79         }
  80
  81         /**
  82          * Posts <code>setFocus</code> to the display event queue.
  83          */
  84         public void postSetFocusOnDialogField(Display display) {
  85                 if (display != null) {
  86                         display.asyncExec(
  87                                 new Runnable() {
  88                                         public void run() {
  89                                                 setFocus();
  90                                         }
  91                                 }
  92                         );
  93                 }
  94         }
  95
  96         // ------- layout helpers
  97
  98         /**
  99          * Creates all controls of the dialog field and fills it to a composite.
 100          * The composite is assumed to have <code>MGridLayout</code> as
 101          * layout.
 102          * The dialog field will adjust its controls' spans to the number of columns given.
 103          *      To be reimplemented by dialog field implementors.
 104          */
 105         public Control[] doFillIntoGrid(Composite parent, int nColumns) {
 106                 assertEnoughColumns(nColumns);
 107
 108                 Label label= getLabelControl(parent);
 109                 label.setLayoutData(gridDataForLabel(nColumns));
 110
 111                 return new Control[] { label };
 112         }
 113
 114         /**
 115          * Returns the number of columns of the dialog field.
 116          *      To be reimplemented by dialog field implementors.
 117          */
 118         public int getNumberOfControls() {
 119                 return 1;
 120         }
 121
 122         protected static GridData gridDataForLabel(int span) {
 123                 GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_FILL);
 124                 gd.horizontalSpan= span;
 125                 return gd;
 126         }
 127
 128         // ------- ui creation
 129
 130         /**
 131          * Creates or returns the created label widget.
 132          * @param parent The parent composite or <code>null</code> if the widget has
 133          * already been created.
 134          */
 135         public Label getLabelControl(Composite parent) {
 136                 if (fLabel == null) {
 137                         assertCompositeNotNull(parent);
 138
 139                         fLabel= new Label(parent, SWT.LEFT | SWT.WRAP);
 140                         fLabel.setFont(parent.getFont());
 141                         fLabel.setEnabled(fEnabled);
 142                         if (fLabelText != null && !"".equals(fLabelText)) { //$NON-NLS-1$
 143                                 fLabel.setText(fLabelText);
 144                         } else {
 145                                 // XXX: to avoid a 16 pixel wide empty label - revisit
 146                                 fLabel.setText("."); //$NON-NLS-1$
 147                                 fLabel.setVisible(false);
 148                         }
 149                 }
 150                 return fLabel;
 151         }
 152
 153         /**
 154          * Creates a spacer control.
 155          * @param parent The parent composite
 156          */
 157         public static Control createEmptySpace(Composite parent) {
 158                 return createEmptySpace(parent, 1);
 159         }
 160
 161         /**
 162          * Creates a spacer control with the given span.
 163          * The composite is assumed to have <code>MGridLayout</code> as
 164          * layout.
 165          * @param parent The parent composite
 166          */
 167         public static Control createEmptySpace(Composite parent, int span) {
 168                 Label label= new Label(parent, SWT.LEFT);
 169                 GridData gd= new GridData();
 170                 gd.horizontalAlignment= GridData.BEGINNING;
 171                 gd.grabExcessHorizontalSpace= false;
 172                 gd.horizontalSpan= span;
 173                 gd.horizontalIndent= 0;
 174                 gd.widthHint= 0;
 175                 gd.heightHint= 0;
 176                 label.setLayoutData(gd);
 177                 return label;
 178         }
 179
 180         /**
 181          * Tests is the control is not <code>null</code> and not disposed.
 182         */
 183         protected final boolean isOkToUse(Control control) {
 184                 return (control != null) && !(control.isDisposed());
 185         }
 186
 187         // --------- enable / disable management
 188
 189         /**
 190          * Sets the enable state of the dialog field.
 191          */
 192         public final void setEnabled(boolean enabled) {
 193                 if (enabled != fEnabled) {
 194                         fEnabled= enabled;
 195                         updateEnableState();
 196                 }
 197         }
 198
 199         /**
 200          * Called when the enable state changed.
 201          * To be extended by dialog field implementors.
 202          */
 203         protected void updateEnableState() {
 204                 if (fLabel != null) {
 205                         fLabel.setEnabled(fEnabled);
 206                 }
 207         }
 208
 209         /**
 210          * Gets the enable state of the dialog field.
 211          */
 212         public final boolean isEnabled() {
 213                 return fEnabled;
 214         }
 215
 216         protected final void assertCompositeNotNull(Composite comp) {
 217                 Assert.isNotNull(comp, "uncreated control requested with composite null"); //$NON-NLS-1$
 218         }
 219
 220         protected final void assertEnoughColumns(int nColumns) {
 221                 Assert.isTrue(nColumns >= getNumberOfControls(), "given number of columns is too small"); //$NON-NLS-1$
 222         }
 223
 224
 225
 226
 227 }