com.google.gwt.event.dom.client.TouchEvent Maven / Gradle / Ivy
/*
* Copyright 2010 Google Inc.
*
* 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.google.gwt.event.dom.client;
import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.JsArray;
import com.google.gwt.dom.client.Touch;
import com.google.gwt.event.shared.EventHandler;
/**
* Abstract class representing touch events.
*
* See {@link Safari Touch Event Documentation}
* @param handler type
*/
public abstract class TouchEvent
extends HumanInputEvent {
/**
* Dectector for browser support for touch events.
*/
private static class TouchSupportDetector {
private final boolean isSupported = detectTouchSupport();
public boolean isSupported() {
return isSupported;
}
private native boolean detectTouchSupport() /*-{
return 'ontouchstart' in $wnd;
}-*/;
}
/**
* Detector for browsers that do not support touch events.
*/
@SuppressWarnings("unused")
private static class TouchSupportDetectorNo extends TouchSupportDetector {
@Override
public boolean isSupported() {
return false;
}
}
/**
* The implementation singleton.
*/
private static TouchSupportDetector impl;
/**
* Runtime check for whether touch scrolling is supported in this browser. Returns true if touch
* events are supported but touch based scrolling is not natively supported.
*
* @return true if touch events are supported, false if not
*/
public static boolean isSupported() {
if (impl == null) {
impl = GWT.create(TouchSupportDetector.class);
}
return impl.isSupported();
}
/**
* Get an array of {@link Touch touches} which have changed since the last
* touch event fired. Note, that for {@link TouchEndEvent touch end events},
* the touch which has just ended will not be present in the array. Moreover,
* if the touch which just ended was the last remaining touch, then a zero
* length array will be returned.
*
* @return an array of touches
*/
public JsArray getChangedTouches() {
return getNativeEvent().getChangedTouches();
}
/**
* Get an array of {@link Touch touches} all touch which originated at the
* same target as the current touch event. Note, that for {@link TouchEndEvent
* touch end events}, the touch which has just ended will not be present in
* the array. Moreover, if the touch which just ended was the last remaining
* touch, then a zero length array will be returned.
*
* @return an array of touches
*/
public JsArray getTargetTouches() {
return getNativeEvent().getTargetTouches();
}
/**
* Get an array of all current {@link Touch touches}. Note, that for
* {@link TouchEndEvent touch end events}, the touch which has just ended will
* not be present in the array. Moreover, if the touch which just ended was
* the last remaining touch, then a zero length array will be returned.
*
* @return an array of touches
*/
public JsArray getTouches() {
return getNativeEvent().getTouches();
}
}