Java JScrollBar scrollByBlock(JScrollBar scrollbar, int direction)

Description

scroll By Block

License

Apache License

Declaration

public static void scrollByBlock(JScrollBar scrollbar, int direction) 

Method Source Code

//package com.java2s;
/*//from   www .j  a  v a  2  s .c om
 * Copyright 2014 kohii.
 * 
 * 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.
 */

import javax.swing.JScrollBar;

public class Main {
    public static void scrollByBlock(JScrollBar scrollbar, int direction) {
        // This method is called from BasicScrollPaneUI to implement wheel
        // scrolling, and also from scrollByBlock().
        int oldValue = scrollbar.getValue();
        int blockIncrement = scrollbar.getBlockIncrement(direction);
        int delta = blockIncrement * ((direction > 0) ? +1 : -1);
        int newValue = oldValue + delta;

        // Check for overflow.
        if (delta > 0 && newValue < oldValue) {
            newValue = scrollbar.getMaximum();
        } else if (delta < 0 && newValue > oldValue) {
            newValue = scrollbar.getMinimum();
        }

        scrollbar.setValue(newValue);
    }
}

Related

1. isPaintRequiredFor(javax.swing.JScrollBar jScrollBar)
2. scrollByUnits(JScrollBar scrollbar, int direction, int units, boolean limitToBlock)