actioncontributionitem.java

jfa2ce 源码帮助开发人员更好的理解运用

                }

                if (imageChanged) {
                    // only substitute a missing image if it has no text
                    updateImages(!showText);
                }

                if (tooltipTextChanged || textChanged) {
                    String toolTip = action.getToolTipText();
					if ((toolTip == null) || (toolTip.length() == 0)) {
						toolTip = text;
					}
                    // if the text is showing, then only set the tooltip if
					// different
                    if (!showText || toolTip != null && !toolTip.equals(text)) {
                        ti.setToolTipText(toolTip);
                    } else {
                        ti.setToolTipText(null);
                    }
                }

                if (enableStateChanged) {
                    boolean shouldBeEnabled = action.isEnabled()
                            && isEnabledAllowed();

                    if (ti.getEnabled() != shouldBeEnabled) {
						ti.setEnabled(shouldBeEnabled);
					}
                }

                if (checkChanged) {
                    boolean bv = action.isChecked();

                    if (ti.getSelection() != bv) {
						ti.setSelection(bv);
					}
                }
                return;
            }

            if (widget instanceof MenuItem) {
                MenuItem mi = (MenuItem) widget;

                if (textChanged) {
                    int accelerator = 0;
					String acceleratorText = null;
					IAction updatedAction = getAction();
					String text = null;
					accelerator = updatedAction.getAccelerator();
					ExternalActionManager.ICallback callback = ExternalActionManager
							.getInstance().getCallback();

					// Block accelerators that are already in use.
					if ((accelerator != 0) && (callback != null)
                            && (callback.isAcceleratorInUse(accelerator))) {
                        accelerator = 0;
					}

					/*
					 * Process accelerators on GTK in a special way to avoid Bug
					 * 42009. We will override the native input method by
					 * allowing these reserved accelerators to be placed on the
					 * menu. We will only do this for "Ctrl+Shift+[0-9A-FU]".
					 */
					final String commandId = updatedAction
							.getActionDefinitionId();
					if (("gtk".equals(SWT.getPlatform())) && (callback instanceof IBindingManagerCallback) //$NON-NLS-1$
							&& (commandId != null)) {
						final IBindingManagerCallback bindingManagerCallback = (IBindingManagerCallback) callback;
						final IKeyLookup lookup = KeyLookupFactory.getDefault();
						final TriggerSequence[] triggerSequences = bindingManagerCallback
								.getActiveBindingsFor(commandId);
						for (int i = 0; i < triggerSequences.length; i++) {
							final TriggerSequence triggerSequence = triggerSequences[i];
							final Trigger[] triggers = triggerSequence
									.getTriggers();
							if (triggers.length == 1) {
								final Trigger trigger = triggers[0];
								if (trigger instanceof KeyStroke) {
									final KeyStroke currentKeyStroke = (KeyStroke) trigger;
									final int currentNaturalKey = currentKeyStroke
											.getNaturalKey();
									if ((currentKeyStroke.getModifierKeys() == (lookup
											.getCtrl() | lookup.getShift()))
											&& ((currentNaturalKey >= '0' && currentNaturalKey <= '9')
													|| (currentNaturalKey >= 'A' && currentNaturalKey <= 'F') || (currentNaturalKey == 'U'))) {
										accelerator = currentKeyStroke
												.getModifierKeys()
												| currentNaturalKey;
										acceleratorText = triggerSequence
												.format();
										break;
									}
								}
							}
						}
					}

                    if (accelerator == 0) {
                        if ((callback != null) && (commandId != null)) {
                            acceleratorText = callback
                                    .getAcceleratorText(commandId);
                        }
                    } else {
                        acceleratorText = Action
                                .convertAccelerator(accelerator);
                    }

                    IContributionManagerOverrides overrides = null;

                    if (getParent() != null) {
						overrides = getParent().getOverrides();
					}

                    if (overrides != null) {
						text = getParent().getOverrides().getText(this);
					}

                    mi.setAccelerator(accelerator);

                    if (text == null) {
						text = updatedAction.getText();
					}

                    if (text == null) {
						text = ""; //$NON-NLS-1$
					} else {
						text = Action.removeAcceleratorText(text);
					}

                    if (acceleratorText == null) {
						mi.setText(text);
					} else {
						mi.setText(text + '\t' + acceleratorText);
					}
                }

                if (imageChanged) {
					updateImages(false);
				}

                if (enableStateChanged) {
                    boolean shouldBeEnabled = action.isEnabled()
                            && isEnabledAllowed();

                    if (mi.getEnabled() != shouldBeEnabled) {
						mi.setEnabled(shouldBeEnabled);
					}
                }

                if (checkChanged) {
                    boolean bv = action.isChecked();

                    if (mi.getSelection() != bv) {
						mi.setSelection(bv);
					}
                }

                return;
            }

            if (widget instanceof Button) {
                Button button = (Button) widget;

                if (imageChanged && updateImages(false)) {
					textChanged = false; // don't update text if it has an image
				}

                if (textChanged) {
                    String text = action.getText();
                    if (text == null) {
						text = ""; //$NON-NLS-1$
					} else {
						text = Action.removeAcceleratorText(text);
					}
                    button.setText(text);
                }

                if (tooltipTextChanged) {
					button.setToolTipText(action.getToolTipText());
				}

                if (enableStateChanged) {
                    boolean shouldBeEnabled = action.isEnabled()
                            && isEnabledAllowed();

                    if (button.getEnabled() != shouldBeEnabled) {
						button.setEnabled(shouldBeEnabled);
					}
                }

                if (checkChanged) {
                    boolean bv = action.isChecked();

                    if (button.getSelection() != bv) {
						button.setSelection(bv);
					}
                }
                return;
            }
        }
    }

    /**
     * Updates the images for this action.
     *
     * @param forceImage <code>true</code> if some form of image is compulsory,
     *  and <code>false</code> if it is acceptable for this item to have no image
     * @return <code>true</code> if there are images for this action, <code>false</code> if not
     */
    private boolean updateImages(boolean forceImage) {

        ResourceManager parentResourceManager = JFaceResources.getResources();
        
        if (widget instanceof ToolItem) {
            if (USE_COLOR_ICONS) {
                ImageDescriptor image = action.getHoverImageDescriptor();
                if (image == null) {
                    image = action.getImageDescriptor();
                }
                ImageDescriptor disabledImage = action
                        .getDisabledImageDescriptor();

                // Make sure there is a valid image.
                if (image == null && forceImage) {
                    image = ImageDescriptor.getMissingImageDescriptor();
                }
        
                LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);
                
                // performance: more efficient in SWT to set disabled and hot image before regular image
                ((ToolItem) widget).setDisabledImage(disabledImage == null ? null : localManager.createImageWithDefault(disabledImage));
                ((ToolItem) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));

                disposeOldImages();
                imageManager = localManager;
                
                return image != null;
            }
            ImageDescriptor image = action.getImageDescriptor();
            ImageDescriptor hoverImage = action
                    .getHoverImageDescriptor();
            ImageDescriptor disabledImage = action
                    .getDisabledImageDescriptor();

            // If there is no regular image, but there is a hover image,
            // convert the hover image to gray and use it as the regular image.
            if (image == null && hoverImage != null) {
                image = ImageDescriptor.createWithFlags(action.getHoverImageDescriptor(), SWT.IMAGE_GRAY); 
            } else {
                // If there is no hover image, use the regular image as the hover image,
                // and convert the regular image to gray
                if (hoverImage == null && image != null) {
                    hoverImage = image;
                    image = ImageDescriptor.createWithFlags(action.getImageDescriptor(), SWT.IMAGE_GRAY);
                }
            }

            // Make sure there is a valid image.
            if (hoverImage == null && image == null && forceImage) {
                image = ImageDescriptor.getMissingImageDescriptor();
            }

            // Create a local resource manager to remember the images we've allocated for this tool item
            LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);
            
            // performance: more efficient in SWT to set disabled and hot image before regular image
            ((ToolItem) widget).setDisabledImage(disabledImage == null? null : localManager.createImageWithDefault(disabledImage));
            ((ToolItem) widget).setHotImage(hoverImage == null? null : localManager.createImageWithDefault(hoverImage));
            ((ToolItem) widget).setImage(image == null? null : localManager.createImageWithDefault(image));

            // Now that we're no longer referencing the old images, clear them out.
            disposeOldImages();
            imageManager = localManager;
            
            return image != null;
        } else if (widget instanceof Item || widget instanceof Button) {
            
            // Use hover image if there is one, otherwise use regular image.
            ImageDescriptor image = action.getHoverImageDescriptor();
            if (image == null) {
                image = action.getImageDescriptor();
            }
            // Make sure there is a valid image.
            if (image == null && forceImage) {
                image = ImageDescriptor.getMissingImageDescriptor();
            }
            
            // Create a local resource manager to remember the images we've allocated for this widget
            LocalResourceManager localManager = new LocalResourceManager(parentResourceManager);
            
            if (widget instanceof Item) {
                ((Item) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));
            } else if (widget instanceof Button) {
                ((Button) widget).setImage(image == null ? null : localManager.createImageWithDefault(image));
            }
            
            // Now that we're no longer referencing the old images, clear them out.
            disposeOldImages();
            imageManager = localManager;
            
            return image != null;
        }
        return false;
    }

    /**
     * Dispose any images allocated for this contribution item
     */
    private void disposeOldImages() {
        if (imageManager != null) {
            imageManager.dispose();
            imageManager = null;
        }
    }

    /**
     * Shorten the given text <code>t</code> so that its length doesn't
     * exceed the given width. The default implementation replaces characters
     * in the center of the original string with an ellipsis ("..."). Override
     * if you need a different strategy.
     */
    protected String shortenText(String textValue, ToolItem item) {
        if (textValue == null) {
			return null;
		}

        GC gc = new GC(item.getParent());

        int maxWidth = item.getImage().getBounds().width * 4;

        if (gc.textExtent(textValue).x < maxWidth) {
            gc.dispose();
            return textValue;
        }

        for (int i = textValue.length(); i > 0; i--) {
            String test = textValue.substring(0, i);
            test = test + ellipsis;
            if (gc.textExtent(test).x < maxWidth) {
                gc.dispose();
                return test;
            }

        }
        gc.dispose();
        //If for some reason we fall through abort
        return textValue;
    }
}