Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.vaadin.client.ui; import com.google.gwt.aria.client.Roles; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.NativeEvent; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.KeyCodes; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.ui.FocusWidget; import com.vaadin.client.ApplicationConnection; import com.vaadin.client.BrowserInfo; import com.vaadin.client.Util; import com.vaadin.client.WidgetUtil; import com.vaadin.client.WidgetUtil.ErrorUtil; public class VButton extends FocusWidget implements ClickHandler, HasErrorIndicatorElement { public static final String CLASSNAME = "v-button"; private static final String CLASSNAME_PRESSED = "v-pressed"; // mouse movement is checked before synthesizing click event on mouseout protected static int MOVE_THRESHOLD = 3; protected int mousedownX = 0; protected int mousedownY = 0; /** For internal use only. May be removed or replaced in the future. */ public ApplicationConnection client; /** For internal use only. May be removed or replaced in the future. */ public final Element wrapper = DOM.createSpan(); /** For internal use only. May be removed or replaced in the future. */ private Element errorIndicatorElement; /** For internal use only. May be removed or replaced in the future. */ public final Element captionElement = DOM.createSpan(); /** For internal use only. May be removed or replaced in the future. */ public Icon icon; /** * Helper flag to handle special-case where the button is moved from under * mouse while clicking it. In this case mouse leaves the button without * moving. */ protected boolean clickPending; private boolean enabled = true; private int tabIndex = 0; /** * Switch for disabling mouse capturing. * * @see #isCapturing */ private boolean capturingEnabled = true; /* * BELOW PRIVATE MEMBERS COPY-PASTED FROM GWT CustomButton */ /** * If <code>true</code>, this widget is capturing with the mouse held down. */ private boolean isCapturing; /** * If <code>true</code>, this widget has focus with the space bar down. This * means that we will get events when the button is released, but we should * trigger the button only if the button is still focused at that point. */ private boolean isFocusing; /** * Used to decide whether to allow clicks to propagate up to the superclass * or container elements. */ private boolean disallowNextClick = false; private boolean isHovering; /** For internal use only. May be removed or replaced in the future. */ public int clickShortcut = 0; private long lastClickTime = 0; public VButton() { super(DOM.createDiv()); setTabIndex(0); sinkEvents(Event.ONCLICK | Event.MOUSEEVENTS | Event.FOCUSEVENTS | Event.KEYEVENTS); // Add a11y role "button" Roles.getButtonRole().set(getElement()); getElement().appendChild(wrapper); wrapper.appendChild(captionElement); setStyleName(CLASSNAME); addClickHandler(this); } @Override public void setStyleName(String style) { super.setStyleName(style); wrapper.setClassName(getStylePrimaryName() + "-wrap"); captionElement.setClassName(getStylePrimaryName() + "-caption"); } @Override public void setStylePrimaryName(String style) { super.setStylePrimaryName(style); wrapper.setClassName(getStylePrimaryName() + "-wrap"); captionElement.setClassName(getStylePrimaryName() + "-caption"); } public void setText(String text) { captionElement.setInnerText(text); } public void setHtml(String html) { captionElement.setInnerHTML(html); } @SuppressWarnings("deprecation") @Override /* * Copy-pasted from GWT CustomButton, some minor modifications done: * * -for IE/Opera added CLASSNAME_PRESSED * * -event.preventDefault() removed from ONMOUSEDOWN (Firefox won't apply * :active styles if it is present) * * -Tooltip event handling added * * -onload event handler added (for icon handling) */ public void onBrowserEvent(Event event) { if (DOM.eventGetType(event) == Event.ONLOAD) { Util.notifyParentOfSizeChange(this, true); } // Should not act on button if disabled. if (!isEnabled()) { // This can happen when events are bubbled up from non-disabled // children return; } int type = DOM.eventGetType(event); switch (type) { case Event.ONCLICK: // fix for #14632 - on mobile safari 8, if we press the button long // enough, we might get two click events, so we are suppressing // second if it is too soon BrowserInfo browserInfo = BrowserInfo.get(); boolean isPhantomClickPossible = browserInfo.isSafariOrIOS() && browserInfo.isTouchDevice() && browserInfo.getBrowserMajorVersion() == 8; long clickTime = isPhantomClickPossible ? System.currentTimeMillis() : 0; // If clicks are currently disallowed or phantom, keep it from // bubbling or being passed to the superclass. // the maximum interval observed for phantom click is 69, with // majority under 50, so we select 100 to be safe if (disallowNextClick || isPhantomClickPossible && (clickTime - lastClickTime < 100)) { event.stopPropagation(); disallowNextClick = false; return; } lastClickTime = clickTime; break; case Event.ONMOUSEDOWN: if (DOM.isOrHasChild(getElement(), DOM.eventGetTarget(event))) { // This was moved from mouseover, which iOS sometimes skips. // We're certainly hovering at this point, and we don't actually // need that information before this point. setHovering(true); } if (event.getButton() == Event.BUTTON_LEFT) { // save mouse position to detect movement before synthesizing // event later mousedownX = event.getClientX(); mousedownY = event.getClientY(); disallowNextClick = true; clickPending = true; setFocus(true); DOM.setCapture(getElement()); isCapturing = true; addStyleName(CLASSNAME_PRESSED); } break; case Event.ONMOUSEUP: if (isCapturing) { isCapturing = false; DOM.releaseCapture(getElement()); if (isHovering() && event.getButton() == Event.BUTTON_LEFT) { // Click ok disallowNextClick = false; } removeStyleName(CLASSNAME_PRESSED); } break; case Event.ONMOUSEMOVE: clickPending = false; if (isCapturing && !isDraggable()) { // Prevent dragging (on other browsers); DOM.eventPreventDefault(event); } break; case Event.ONMOUSEOVER: if (isCapturing && isTargetInsideButton(event)) { // This means a mousedown happened on the button and a mouseup // has not happened yet setHovering(true); addStyleName(CLASSNAME_PRESSED); } break; case Event.ONMOUSEOUT: if (isTargetInsideButton(event)) { if (clickPending && Math.abs(mousedownX - event.getClientX()) < MOVE_THRESHOLD && Math.abs(mousedownY - event.getClientY()) < MOVE_THRESHOLD) { onClick(); break; } clickPending = false; setHovering(false); removeStyleName(CLASSNAME_PRESSED); } break; case Event.ONBLUR: if (isFocusing) { isFocusing = false; } break; case Event.ONLOSECAPTURE: if (isCapturing) { isCapturing = false; } break; } super.onBrowserEvent(event); // Synthesize clicks based on keyboard events AFTER the normal key // handling. if ((event.getTypeInt() & Event.KEYEVENTS) != 0) { switch (type) { case Event.ONKEYDOWN: // Stop propagation when the user starts pressing a button that // we are handling to prevent actions from getting triggered if (event.getKeyCode() == 32 /* space */) { isFocusing = true; event.preventDefault(); event.stopPropagation(); } else if (event.getKeyCode() == KeyCodes.KEY_ENTER) { event.stopPropagation(); } break; case Event.ONKEYUP: if (isFocusing && event.getKeyCode() == 32 /* space */) { isFocusing = false; onClick(); event.stopPropagation(); event.preventDefault(); } break; case Event.ONKEYPRESS: if (event.getKeyCode() == KeyCodes.KEY_ENTER) { onClick(); event.stopPropagation(); event.preventDefault(); } break; } } } /** * Check if the event occurred over an element which is part of this button */ private boolean isTargetInsideButton(Event event) { Element to = event.getRelatedTarget(); return getElement().isOrHasChild(DOM.eventGetTarget(event)) && (to == null || !getElement().isOrHasChild(to)); } final void setHovering(boolean hovering) { if (hovering != isHovering()) { isHovering = hovering; } } final boolean isHovering() { return isHovering; } /* * (non-Javadoc) * * @see * com.google.gwt.event.dom.client.ClickHandler#onClick(com.google.gwt.event * .dom.client.ClickEvent) */ @Override public void onClick(ClickEvent event) { if (BrowserInfo.get().isSafariOrIOS()) { VButton.this.setFocus(true); } clickPending = false; } /* * ALL BELOW COPY-PASTED FROM GWT CustomButton */ /** * Called internally when the user finishes clicking on this button. The * default behavior is to fire the click event to listeners. Subclasses that * override {@link #onClickStart()} should override this method to restore * the normal widget display. * <p> * To add custom code for a click event, override * {@link #onClick(ClickEvent)} instead of this. * <p> * For internal use only. May be removed or replaced in the future. */ public void onClick() { // Allow the click we're about to synthesize to pass through to the // superclass and containing elements. Element.dispatchEvent() is // synchronous, so we simply set and clear the flag within this method. disallowNextClick = false; // Screen coordinates are not always available (e.g., when the click is // caused by a keyboard event). // Set (x,y) client coordinates to the middle of the button int x = getElement().getAbsoluteLeft() - getElement().getScrollLeft() - getElement().getOwnerDocument().getScrollLeft() + WidgetUtil.getRequiredWidth(getElement()) / 2; int y = getElement().getAbsoluteTop() - getElement().getScrollTop() - getElement().getOwnerDocument().getScrollTop() + WidgetUtil.getRequiredHeight(getElement()) / 2; NativeEvent evt = Document.get().createClickEvent(1, 0, 0, x, y, false, false, false, false); getElement().dispatchEvent(evt); } /** * Sets whether this button is enabled. * * @param enabled * <code>true</code> to enable the button, <code>false</code> to * disable it */ @Override public final void setEnabled(boolean enabled) { if (isEnabled() != enabled) { this.enabled = enabled; if (!enabled) { cleanupCaptureState(); Roles.getButtonRole().setAriaDisabledState(getElement(), !enabled); super.setTabIndex(-1); } else { Roles.getButtonRole().removeAriaDisabledState(getElement()); super.setTabIndex(tabIndex); } } } @Override public final boolean isEnabled() { return enabled; } @Override public final void setTabIndex(int index) { super.setTabIndex(index); tabIndex = index; } /** * Resets internal state if this button can no longer service events. This * can occur when the widget becomes detached or disabled. */ private void cleanupCaptureState() { if (isCapturing || isFocusing) { DOM.releaseCapture(getElement()); isCapturing = false; isFocusing = false; } } /** * Returns if this button has been made <code>draggable</code> or not. * * @return {@literal true} if draggable is enabled, {@literal false} * otherwise */ private boolean isDraggable() { return getElement().getPropertyBoolean("draggable"); } private static native int getHorizontalBorderAndPaddingWidth(Element elem) /*-{ // THIS METHOD IS ONLY USED FOR INTERNET EXPLORER, IT DOESN'T WORK WITH OTHERS var convertToPixel = function(elem, value) { // From the awesome hack by Dean Edwards // http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291 // Remember the original values var left = elem.style.left, rsLeft = elem.runtimeStyle.left; // Put in the new values to get a computed value out elem.runtimeStyle.left = elem.currentStyle.left; elem.style.left = value || 0; var ret = elem.style.pixelLeft; // Revert the changed values elem.style.left = left; elem.runtimeStyle.left = rsLeft; return ret; } var ret = 0; var sides = ["Right","Left"]; for (var i=0; i<2; i++) { var side = sides[i]; var value; // Border ------------------------------------------------------- if (elem.currentStyle["border"+side+"Style"] != "none") { value = elem.currentStyle["border"+side+"Width"]; if ( !/^\d+(px)?$/i.test( value ) && /^\d/.test( value ) ) { ret += convertToPixel(elem, value); } else if (value.length > 2) { ret += parseInt(value.substr(0, value.length-2)); } } // Padding ------------------------------------------------------- value = elem.currentStyle["padding"+side]; if ( !/^\d+(px)?$/i.test( value ) && /^\d/.test( value ) ) { ret += convertToPixel(elem, value); } else if (value.length > 2) { ret += parseInt(value.substr(0, value.length-2)); } } return ret; }-*/; @Override public Element getErrorIndicatorElement() { return errorIndicatorElement; } @Override public void setErrorIndicatorElementVisible(boolean visible) { if (visible) { if (errorIndicatorElement == null) { errorIndicatorElement = ErrorUtil.createErrorIndicatorElement(); wrapper.insertFirst(errorIndicatorElement); } } else if (errorIndicatorElement != null) { wrapper.removeChild(errorIndicatorElement); errorIndicatorElement = null; } } }