com.googlecode.mgwt.ui.client.widget.input.slider.Slider.java Source code

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Here is the source code for com.googlecode.mgwt.ui.client.widget.input.slider.Slider.java

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/*
 * Copyright 2010 Daniel Kurka
 *
 * 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.googlecode.mgwt.ui.client.widget.input.slider;

import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.core.shared.GWT;
import com.google.gwt.dom.client.Element;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.event.dom.client.TouchCancelEvent;
import com.google.gwt.event.dom.client.TouchEndEvent;
import com.google.gwt.event.dom.client.TouchMoveEvent;
import com.google.gwt.event.dom.client.TouchStartEvent;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.uibinder.client.UiFactory;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.HasValue;
import com.google.gwt.user.client.ui.Widget;
import com.googlecode.mgwt.dom.client.event.touch.TouchHandler;
import com.googlecode.mgwt.ui.client.TouchSupport;
import com.googlecode.mgwt.ui.client.util.CssUtil;
import com.googlecode.mgwt.ui.client.widget.touch.TouchWidgetImpl;

/**
 * The mgwt pointer widget.
 *
 * The pointer element is moved along the bar element to represent the value of the Slider
 */
public class Slider extends Widget implements HasValue<Integer>, LeafValueEditor<Integer> {

    private class SliderTouchHandler implements TouchHandler {

        @Override
        public void onTouchStart(TouchStartEvent event) {
            setValueContrained(event.getTouches().get(0).getClientX());
            if (TouchSupport.isTouchEventsEmulatedUsingMouseEvents()) {
                DOM.setCapture(getElement());
            }
            event.stopPropagation();
            event.preventDefault();
        }

        @Override
        public void onTouchMove(TouchMoveEvent event) {

            setValueContrained(event.getTouches().get(0).getClientX());
            event.stopPropagation();
            event.preventDefault();
        }

        @Override
        public void onTouchEnd(TouchEndEvent event) {
            if (TouchSupport.isTouchEventsEmulatedUsingMouseEvents()) {
                DOM.releaseCapture(getElement());
            }
            event.stopPropagation();
            event.preventDefault();
        }

        @Override
        public void onTouchCancel(TouchCancelEvent event) {
            if (TouchSupport.isTouchEventsEmulatedUsingMouseEvents()) {
                DOM.releaseCapture(getElement());
            }
        }
    }

    private static final SliderAppearance DEFAULT_APPEARANCE = GWT.create(SliderAppearance.class);

    private static final TouchWidgetImpl TOUCH_WIDGET_IMPL = GWT.create(TouchWidgetImpl.class);

    private int value;
    private int max;
    private final SliderAppearance apperance;

    @UiField
    public Element pointer;
    @UiField
    public Element bar;

    public Slider() {
        this(DEFAULT_APPEARANCE);
    }

    public Slider(SliderAppearance apperance) {
        this.apperance = apperance;
        setElement(this.apperance.uiBinder().createAndBindUi(this));
        TOUCH_WIDGET_IMPL.addTouchHandler(this, new SliderTouchHandler());
        max = 100;
        value = 0;
    }

    @Override
    public HandlerRegistration addValueChangeHandler(ValueChangeHandler<Integer> handler) {
        return addHandler(handler, ValueChangeEvent.getType());
    }

    /**
     * Set the maximum of the pointer
     *
     * @param max the maximum to use
     */
    public void setMax(int max) {
        if (max <= 0) {
            throw new IllegalArgumentException("max > 0");
        }
        this.max = max;
    }

    /**
     * get the maximum of the pointer
     *
     * @return the maximum of the pointer
     */
    public int getMax() {
        return max;
    }

    @Override
    public Integer getValue() {
        return value;
    }

    @Override
    public void setValue(Integer value) {
        setValue(value, true);
    }

    @Override
    protected void onAttach() {
        super.onAttach();
        Scheduler.get().scheduleDeferred(new ScheduledCommand() {
            @Override
            public void execute() {
                setSliderPos(value);
            }
        });
    }

    @Override
    public void setValue(Integer value, boolean fireEvents) {
        setValue(value, fireEvents, true);
    }

    @UiFactory
    public SliderAppearance getApperance() {
        return apperance;
    }

    protected void setValue(Integer value, boolean fireEvents, boolean updateSlider) {
        if (value == null) {
            throw new IllegalArgumentException("value can not be null");
        }

        if (value < 0) {
            throw new IllegalArgumentException("value >= 0");
        }

        if (value >= max) {
            throw new IllegalArgumentException("value >= max");
        }

        int oldValue = this.value;
        this.value = value;
        if (updateSlider) {
            setSliderPos(value);
        }

        if (fireEvents) {
            ValueChangeEvent.fireIfNotEqual(this, oldValue, value);
        }
    }

    private void setSliderPos(int value) {

        if (!isAttached()) {
            return;
        }

        int width = bar.getOffsetWidth();
        int sliderPos = value * width / max;
        setPos(sliderPos);

    }

    private void setValueContrained(int x) {
        x = x - Slider.this.getAbsoluteLeft();
        int width = bar.getOffsetWidth();

        if (x < 0) {
            x = 0;
        }

        if (x > (width - 1)) {
            x = width - 1;
        }

        // scale it to max
        int componentValue = x * max / width;
        setValue(componentValue, true, false);

        setPos(x);
    }

    private void setPos(int x) {
        CssUtil.translate(pointer, x, 0);
    }
}