102 lines
2.7 KiB
Java
102 lines
2.7 KiB
Java
package org.gcube.portlets.widgets.ckandatapublisherwidget.client.ui.TwinColumnSelection;
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import com.google.gwt.event.dom.client.ScrollEvent;
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import com.google.gwt.event.dom.client.ScrollHandler;
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import com.google.gwt.user.cellview.client.AbstractPager;
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import com.google.gwt.user.client.ui.ScrollPanel;
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import com.google.gwt.user.client.ui.Widget;
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import com.google.gwt.view.client.HasRows;
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/**
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* Basically a scroll panel
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* Partially changed from the code at http://samples.gwtproject.org/samples/Showcase/Showcase.html#!CwCellList
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* @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
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*/
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public class ShowMorePagerPanel extends AbstractPager{
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/**
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* The default increment size.
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*/
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public static final int DEFAULT_INCREMENT = 10;
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/**
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* The increment size.
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*/
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private int incrementSize = DEFAULT_INCREMENT;
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/**
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* The last scroll position.
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*/
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private int lastScrollPos = 0;
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/**
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* The scrollable panel.
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*/
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private final ScrollPanel scrollable = new ScrollPanel();
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/**
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* Construct a new {@link ShowMorePagerPanel}.
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*/
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public ShowMorePagerPanel() {
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initWidget(scrollable);
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// Do not let the scrollable take tab focus.
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scrollable.getElement().setTabIndex(-1);
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// Handle scroll events.
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scrollable.addScrollHandler(new ScrollHandler() {
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public void onScroll(ScrollEvent event) {
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// If scrolling up, ignore the event.
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int oldScrollPos = lastScrollPos;
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lastScrollPos = scrollable.getVerticalScrollPosition();
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if (oldScrollPos >= lastScrollPos) {
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return;
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}
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HasRows display = getDisplay();
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if (display == null) {
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return;
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}
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int maxScrollTop = scrollable.getWidget().getOffsetHeight()
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- scrollable.getOffsetHeight();
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if (lastScrollPos >= maxScrollTop) {
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// We are near the end, so increase the page size.
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int newPageSize = Math.min(
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display.getVisibleRange().getLength() + incrementSize,
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display.getRowCount());
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display.setVisibleRange(0, newPageSize);
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}
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}
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});
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}
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/**
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* Get the number of rows by which the range is increased when the scrollbar
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* reaches the bottom.
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* @return the increment size
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*/
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public int getIncrementSize() {
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return incrementSize;
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}
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@Override
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public void setDisplay(HasRows display) {
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assert display instanceof Widget : "display must extend Widget";
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scrollable.setWidget((Widget) display);
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super.setDisplay(display);
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}
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/**
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* Set the number of rows by which the range is increased when the scrollbar
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* reaches the bottom.
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* @param incrementSize the incremental number of rows
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*/
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public void setIncrementSize(int incrementSize) {
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this.incrementSize = incrementSize;
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}
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@Override
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protected void onRangeOrRowCountChanged() {
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}
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}
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