Java基础 awt Button 鼠标放在按钮上背景颜色改变,鼠标离开背景颜色恢复

•     JDK ：OpenJDK-11
•      OS ：CentOS 7.6.1810
•      IDE ：Eclipse 2019‑03
• typesetting ：Markdown

 

code

package per.jizuiku.gui;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
/**
 * @author 给最苦
 * @date 2019/06/30
 * @blog www.cnblogs.com/jizuiku
 */
public class Demo {
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Frame f = new Frame();
        // 三原色的数值
        int r = 4;
        int g = 5;
        int b = 70;
        Color bgColor = new Color(r, g, b);
        // 设置背景颜色
        f.setBackground(bgColor);
        // 设置窗体布局 - 流式布局
        f.setLayout(new FlowLayout());
        Button button = new Button("change bgcolor");
        button.setSize(30, 50);
        // 该按钮对鼠标的变化进行监听
        button.addMouseListener(new MouseAdapter() {
            // 使用 alt+ / , 查看 该适配器类下有哪些方法
            // 然后阅读英文,不会的时候 再去看API和查文献
            // 当鼠标进入时
            @Override
            public void mouseEntered(MouseEvent e) {
                // TODO Auto-generated method stub
                f.setBackground(Color.BLUE);
            }
            // 当鼠标离开时,一切又回到了原点
            @Override
            public void mouseExited(MouseEvent e) {
                // TODO Auto-generated method stub
                f.setBackground(bgColor);
            }
        });
        int width = 400;
        int height = 500;
        f.setSize(width, height);
        f.add(button);
        f.setVisible(true);
    }
}

 

result

 

sourceCode

/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package java.awt.event;
/**
 * An abstract adapter class for receiving mouse events.
 * The methods in this class are empty. This class exists as
 * convenience for creating listener objects.
 * <P>
 * Mouse events let you track when a mouse is pressed, released, clicked,
 * moved, dragged, when it enters a component, when it exits and
 * when a mouse wheel is moved.
 * <P>
 * Extend this class to create a {@code MouseEvent}
 * (including drag and motion events) or/and {@code MouseWheelEvent}
 * listener and override the methods for the events of interest. (If you implement the
 * {@code MouseListener},
 * {@code MouseMotionListener}
 * interface, you have to define all of
 * the methods in it. This abstract class defines null methods for them
 * all, so you can only have to define methods for events you care about.)
 * <P>
 * Create a listener object using the extended class and then register it with
 * a component using the component's {@code addMouseListener}
 * {@code addMouseMotionListener}, {@code addMouseWheelListener}
 * methods.
 * The relevant method in the listener object is invoked  and the {@code MouseEvent}
 * or {@code MouseWheelEvent}  is passed to it in following cases:
 * <ul>
 * <li>when a mouse button is pressed, released, or clicked (pressed and  released)
 * <li>when the mouse cursor enters or exits the component
 * <li>when the mouse wheel rotated, or mouse moved or dragged
 * </ul>
 *
 * @author Carl Quinn
 * @author Andrei Dmitriev
 *
 * @see MouseEvent
 * @see MouseWheelEvent
 * @see MouseListener
 * @see MouseMotionListener
 * @see MouseWheelListener
 * @see <a href="http://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html">Tutorial: Writing a Mouse Listener</a>
 *
 * @since 1.1
 */
public abstract class MouseAdapter implements MouseListener, MouseWheelListener, MouseMotionListener {
    /**
     * {@inheritDoc}
     */
    public void mouseClicked(MouseEvent e) {}
    /**
     * {@inheritDoc}
     */
    public void mousePressed(MouseEvent e) {}
    /**
     * {@inheritDoc}
     */
    public void mouseReleased(MouseEvent e) {}
    /**
     * {@inheritDoc}
     */
    public void mouseEntered(MouseEvent e) {}
    /**
     * {@inheritDoc}
     */
    public void mouseExited(MouseEvent e) {}
    /**
     * {@inheritDoc}
     * @since 1.6
     */
    public void mouseWheelMoved(MouseWheelEvent e){}
    /**
     * {@inheritDoc}
     * @since 1.6
     */
    public void mouseDragged(MouseEvent e){}
    /**
     * {@inheritDoc}
     * @since 1.6
     */
    public void mouseMoved(MouseEvent e){}
}

 

resource

• [ JDK ] openjdk.java.net
• [ doc - 参考 ] docs.oracle.com/en/java/javase/11
• [ 规范 - 推荐 ] yq.aliyun.com/articles/69327
• [ 规范 - 推荐 ] google.github.io/styleguide
• [ 源码 ] hg.openjdk.java.net
• [ OS ] www.centos.org
• [ IDE ] www.eclipse.org/downloads/packages
• [ 平台 ] www.cnblogs.com

 

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感谢帮助过 给最苦 的人们。

Java、Groovy和Scala等基于JVM的语言，优秀，值得学习。

规范的命名和代码格式等，有助于沟通和理解。

JVM的配置、监控与优化，比较实用，值得学习。