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GWT Bibliothek fuer Mobile Plattformen der SWM
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/*
* Copyright 2011 SWM Services GmbH.
*
* 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 de.swm.commons.mobile.client.widgets.scroll;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Style;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.event.dom.client.MouseWheelEvent;
import com.google.gwt.event.dom.client.MouseWheelHandler;
import com.google.gwt.user.client.ui.HasWidgets;
import com.google.gwt.user.client.ui.Widget;
import de.swm.commons.mobile.client.SWMMobile;
import de.swm.commons.mobile.client.base.PanelBase;
import de.swm.commons.mobile.client.event.*;
import de.swm.commons.mobile.client.utils.Utils;
import de.swm.commons.mobile.client.widgets.ScrollBar;
/**
* Scroll panel - has the ability to keep the {@link de.swm.commons.mobile.client.widgets.itf.IHeaderPanel} implementations always on the top.
*/
public class ScrollPanelWithScrollbar extends PanelBase implements HasWidgets, DragEventsHandler, SwipeEventsHandler, IScrollPanel {
private static final int TIME_FACTOR = 3000;
private static final double DISTANCE_FACTOR = 0.25;
public static final int DEFAULT_TRANSITION_DURATION = 500;
private static final int OFFSET = 2;
private boolean myHasTextBox = false;
private IScrollMonitor scrollMonitor;
private final ScrollBar scrollBar;
private boolean showScrollBar = true;
/**
* Default constructor.
*/
public ScrollPanelWithScrollbar() {
setStyleName(SWMMobile.getTheme().getMGWTCssBundle().getScrollPanelCss().scrollPanel());
this.scrollBar = new ScrollBar();
}
public void setHasTextBox(boolean hasTextBox) {
myHasTextBox = hasTextBox && SWMMobile.getOsDetection().isAndroid();
}
public boolean getHasTextBox() {
return myHasTextBox;
}
@Override
public void onLoad() {
boolean isDesktop = SWMMobile.getOsDetection().isDesktop();
DragController.get().addDragEventsHandler(this);
DragController.get().addSwipeEventsHandler(this);
if (isDesktop) {
addMouseWheelHandler();
}
}
@Override
public void onUnload() {
DragController.get().removeDragEventsHandler(this);
DragController.get().removeSwipeEventHandler(this);
}
@Override
public Widget getWidget() {
return myFlowPanel.getWidget(1);
}
/**
* Scrolls to the default position.
*/
private void addMouseWheelHandler() {
this.addDomHandler(new MouseWheelHandler() {
@Override
public void onMouseWheel(MouseWheelEvent mouseWheelEvent) {
int newScrollPosition = getScrollPosition() - mouseWheelEvent.getDeltaY() * 10;
if (newScrollPosition > 0) {
newScrollPosition = 0;
} else if (-newScrollPosition + Utils.getHeight(getElement()) > getWidget().getElement().getOffsetHeight()) {
newScrollPosition = Utils.getHeight(getElement()) - getWidget().getElement().getOffsetHeight();
}
int screeHeight = Utils.getHeight(getElement());
int widgetHeight = getWidget().getElement().getOffsetHeight();
if (screeHeight > widgetHeight) {
newScrollPosition = 0;
}
setScrollPosition(newScrollPosition);
}
}, MouseWheelEvent.getType());
}
public void reset() {
Utils.setTransitionDuration(getWidget().getElement(), 0);
Utils.setTranslateY(getWidget().getElement(), 0);
}
@Override
public void setScrollMonitor(IScrollMonitor scrollMonitor) {
this.scrollMonitor = scrollMonitor;
}
/**
* Scrolls to the top.
*/
public void setPostionToTop() {
setScrollPosition(0, 0);
}
/**
* Scrolls to the button.
*/
public void setPositionToBottom() {
setScrollPosition(this.getElement().getClientHeight() - this.getElement().getScrollHeight(), 0);
}
public void setScrollPosition(int pos) {
setScrollPosition(pos, 0);
}
/**
* Sets the scroll position
*
* @param pos the y axis pos
*/
public void setScrollPosition(int pos, int transitionDuration) {
Element element = getWidget().getElement();
Utils.setTransitionDuration(element, transitionDuration);
if (myHasTextBox) {
setStyleTop(pos);
} else {
Utils.setTranslateY(element, pos);
}
if (showScrollBar) {
int panelHeight = Utils.getHeight(this.getElement());
int widgetHeight = getWidget().getElement().getOffsetHeight();
this.scrollBar.renderScrollbar(widgetHeight, panelHeight, -pos, transitionDuration);
this.scrollBar.fadeOut((int) transitionDuration + DEFAULT_TRANSITION_DURATION * 2);
} else {
this.scrollBar.hide();
}
}
/**
* Returns the current scroll position.
*
* @return the position
*/
public int getScrollPosition() {
if (myHasTextBox) {
return getStyleTop();
} else {
Element element = getWidget().getElement();
return Utils.getTranslateY(element);
}
}
/**
* Returns the next scroll position
*
* @return then next scroll position
*/
public int getScrollToPosition() {
if (myHasTextBox) {
return getStyleTop();
} else {
Element element = getWidget().getElement();
return Utils.getMatrixY(element);
}
}
@Override
public void setOffsetHeight(int offsetHeight) {
}
@Override
public void onDragStart(DragEvent e) {
if (scrollMonitor != null) {
scrollMonitor.onScrollStart();
}
int matrix = getScrollToPosition();
int current = getScrollPosition();
if (current != matrix) { // scroll on going
int diff = current - matrix;
int offset = diff > OFFSET ? OFFSET : diff > -OFFSET ? diff : -OFFSET;
setScrollPosition(matrix + offset, 0);
DragController.get().suppressNextClick();
}
e.stopPropagation();
}
@Override
public void onDragMove(DragEvent e) {
Element widgetEle = getWidget().getElement();
int panelHeight = Utils.getHeight(this.getElement());
int widgetHeight = widgetEle.getOffsetHeight();
int current = getScrollPosition();
if (current > 0) {
// exceed top boundary
if (e.getOffsetY() > 0) { // resist scroll down.
current += (int) (e.getOffsetY() / OFFSET); // need the cast for production mode.
} else {
current += e.getOffsetY() * OFFSET;
}
} else if (-current + panelHeight > widgetHeight) { // exceed bottom boundary
if (e.getOffsetY() < 0) { // resist scroll up.
current += (int) (e.getOffsetY() / OFFSET);
} else {
current += e.getOffsetY() * OFFSET;
}
} else {
current += e.getOffsetY();
}
setScrollPosition(current, 0);
e.stopPropagation();
}
@Override
public void onDragEnd(DragEvent e) {
Element widgetEle = getWidget().getElement();
if (scrollMonitor != null) {
scrollMonitor.onScrollEnd();
}
int current = getScrollPosition();
if (current == 0) {
return;
}
int panelHeight = Utils.getHeight(this.getElement());
int widgetHeight = widgetEle.getOffsetHeight();
if (current > 0 // exceed top boundary
|| panelHeight > widgetHeight) {
setScrollPosition(0, DEFAULT_TRANSITION_DURATION);
} else if (-current + panelHeight > widgetHeight) { // exceed bottom boundary
setScrollPosition(panelHeight - widgetHeight, DEFAULT_TRANSITION_DURATION);
}
e.stopPropagation();
}
@Override
public void onSwipeVertical(SwipeEvent e) {
Element widgetEle = getWidget().getElement();
int panelHeight = Utils.getHeight(this.getElement());
int widgetHeight = widgetEle.getOffsetHeight();
long current = getScrollPosition();
if ((current >= 0) // exceed top boundary
|| (-current + panelHeight >= widgetHeight)) { // exceed bottom boundary
return;
}
double speed = e.getSpeed();
double timeFactor = TIME_FACTOR;
long time = (long) Math.abs(speed * timeFactor);
double dicstanceFactor = DISTANCE_FACTOR;
long distance = (long) (speed * time * dicstanceFactor);
// Utils.Console("speed " + speed + " time " + time + " distance " + distance + " current " + current);
current += distance;
// exceed top boundary?
if (current > 0) {
double timeAdj = 1 - (double) current / distance;
time = (long) (time * timeAdj);
current = 0;
} else if (-current + panelHeight > widgetHeight) { // exceed bottom boundary
long bottom = panelHeight - widgetHeight;
double timeAdj = 1 - (double) (current - bottom) / distance;
time = (long) (time * timeAdj);
current = bottom;
}
setScrollPosition((int) current, (int) time);
}
@Override
public void onSwipeHorizontal(SwipeEvent e) {
}
@Override
public void add(Widget w) {
assert myFlowPanel.getWidgetCount() == 0 : "Can only add one widget to ScrollPanel.";
super.add(this.scrollBar);
super.add(w);
if (SWMMobile.getOsDetection().isIOs()) {
Utils.setTranslateY(w.getElement(), 0); // anti-flickering on iOS.
}
}
/**
* Returns the top style
*
* @return the top style in px
*/
private int getStyleTop() {
Style style = getWidget().getElement().getStyle();
String top = style.getTop();
if (top.isEmpty()) {
return 0;
} else {
return Integer.parseInt(top.replace("px", ""));
}
}
/**
* Sets the top stype in pixel
*
* @param top the top syle
*/
private void setStyleTop(int top) {
Style style = getWidget().getElement().getStyle();
style.setTop(top, Unit.PX);
}
/**
* Indicates if the scroll bar should be shown or not.
*
* @return .
*/
public boolean isShowScrollBar() {
return showScrollBar;
}
/**
* Indicates if the scroll bar should be shown or not.
*
* @param showScrollBar true if it should be shown, false if not.
*/
public void setShowScrollBar(boolean showScrollBar) {
this.showScrollBar = showScrollBar;
}
}