JAVA 画图板实现（基本画图功能+界面UI）界面实现

Posted 2020-12-03 ITryagain

/*文章中用到的代码只是一部分，需要源码的可通过邮箱联系我 [e-mail]*/

这段时间在学JAVA的swing界面开发，试着做了个画图板。实现了直线、曲线、喷枪、矩形、圆形、文字、橡皮等操作，感觉收获很大。

既然要做画图板，那最好的参考当然是windows系统自带的画图啦！虽然技术有限不能做的一模一样，但感觉还是能看（手动滑稽）。下面就讲讲如何实现了。

首先不用想，肯定是先把界面做好了（这是我做的界面，emmmmmm。。。。功能和界面都还有待完善）

注：代码已上传至github：https://github.com/leo6033/Java_Project

仔细看一看大概就能想到怎么实现了，首先创建一个DrawMain类继承（extends）JFrame类

public class DrawMain extends JFrame {

	public static void main(String[] args) {
		DrawMain dm = new DrawMain();
		dm.setLookAndFeel();
		dm.initUI();
	}

	/**
	 * 为主面板设置皮肤，这个是我随便找的一个，具体可以自己去研究
	 */

	public void setLookAndFeel() {

		try {

			UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");

		} catch (Exception e) {

			e.printStackTrace();

		}

	}

	public void initUI() {
		this.setTitle("画图程序");
		this.setSize(1000, 700);
		this.setDefaultCloseOperation(3);
		this.setLocationRelativeTo(null);
		this.setLayout(new BorderLayout());
	　　　　　this.setVisible(true);

}

　　这当然只是主界面啦，那后面该怎么弄呢？上面可以有那么多个分区当然需要再放几个容器类型的组件啦。就是组件里放组件了，那么此时布局的选择很重要，首先利用主界面是BroderLayout，就在北方向上放上一个JPanel上去咯

		JPanel NorthJPanel = new JPanel();
		NorthJPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 1, 0));
		NorthJPanel.setBackground(new Color(240, 240, 240));//设置背景色
　　　　　　　　　　//NorthJPanel.setBorder(BorderFactory.createEtchedBorder(new Color(0, 0, 0), new Color(0, 255, 0)));设置边框，可以看看有什么区别
		this.add(NorthJPanel, BorderLayout.NORTH);

　　运行一下，再拉拉边框，有什么发现没有？这个刚贴上去的组件大小会随着你拉边框而改变，所以我们应该再贴一个JPanel到这个JPanel里，然后再设置好大小防止改变

		JPanel InNorthJPanel = new JPanel();
		InNorthJPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 1, 0));
		InNorthJPanel.setPreferredSize(new Dimension(900, 150));
		InNorthJPanel.setBackground(new Color(240, 240, 240));
		NorthJPanel.add(InNorthJPanel);

　　然后该怎么做呢？设置分区，自然，每个分区就是一个JPanel组件

/*
		 * 形状区域
		 * 
		 * @param ShapeJPanel 形状区域的面板,界面布局
		 * 
		 * @param InShapeJPanel 形状区域中放置形状选项的面板,放在ShapeJPanel中,流式布局
		 * 
		 * @param InShapeLabel 形状区域中标识区域的标签,放在ShapeJPanel中
		 */
		JPanel ShapeJPanel = null;
		ShapeJPanel = createJPanel(InNorthJPanel);
		ShapeJPanel.setPreferredSize(new Dimension(300, 150));
		JPanel InShapeJPanel = new JPanel();
		InShapeJPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
		InShapeJPanel.setBackground(null);// 设置背景色透明
		InShapeJPanel.setOpaque(false);
		InShapeJPanel.setPreferredSize(new Dimension(300, 110));
		ShapeJPanel.add(InShapeJPanel, BorderLayout.NORTH);
		JLabel InShapeLabel = null;
		InShapeLabel = createJLabel("形状", ShapeJPanel);

		/*
		 * 颜色区域
		 * 
		 * @param ColorJPanel 颜色区域面板,界面布局
		 * 
		 * @param InColorJPanel 颜色区域中放置颜色选项的面板，放在ColorJPanel中，流式布局
		 * 
		 * @param InColorLabel 颜色区域中标识区域的标签，放在ColorJPanel中
		 */
		JPanel ColorJPanel = null;
		ColorJPanel = createJPanel(InNorthJPanel);
		JPanel IncolorJPanel = new JPanel();
		IncolorJPanel.setPreferredSize(new Dimension(200, 110));
		IncolorJPanel.setBackground(null);// 设置背景色透明
		IncolorJPanel.setOpaque(false);
		IncolorJPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
		ColorJPanel.add(IncolorJPanel, BorderLayout.NORTH);
		JLabel InColorLabel = null;
		InColorLabel = createJLabel("颜色", ColorJPanel);

		/*
		 * 粗细设置区域
		 * 
		 * @param StrokeJPanel 粗细设置区域面板，界面布局
		 * 
		 * @param InStrokeJPanel 粗细设置区域中放置粗细选项的面板，放在StrokeJPanel中，流式布局
		 * 
		 * @param InStrokeLabel 粗细设置区域的标签，放在StrokeJPanel中
		 */
		JPanel StrokeJPanel = null;
		StrokeJPanel = createJPanel(InNorthJPanel);
		StrokeJPanel.setPreferredSize(new Dimension(50, 150));
		JPanel InStrokeJPanel = new JPanel();
		InStrokeJPanel.setPreferredSize(new Dimension(50, 110));
		InStrokeJPanel.setBackground(null);
		InStrokeJPanel.setOpaque(false);
		InStrokeJPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));
		StrokeJPanel.add(InStrokeJPanel, BorderLayout.NORTH);
		JLabel InStrokeLabel = null;
		InStrokeLabel = createJLabel("粗细", StrokeJPanel);

　　可能你会发现，我在里面用了createJLabel()和createJPanel()，这是我写的方法，因为在创建过程中很多代码是重复的，自己写两个方法用在里面代码看上去会舒服很多，而且也能少写很多代码。两个方法的具体实现

　　　　　private JPanel createJPanel(JPanel InNorthJPanel) {
		JPanel jp = new JPanel();
		jp.setBorder(BorderFactory.createEtchedBorder(new Color(0, 0, 0), new Color(0, 255, 0)));
		jp.setPreferredSize(new Dimension(200, 150));
		jp.setBackground(new Color(240, 240, 240));
		InNorthJPanel.add(jp);
		return jp;
	}

	private JLabel createJLabel(String s, JPanel jp) {
		JLabel jl = new JLabel(s);
		jl.setHorizontalAlignment(JLabel.CENTER);// 设置对其格式剧中
		jl.setFont(new Font("楷体", Font.BOLD, 20));// 设置字体 样式 大小
		jp.add(jl, BorderLayout.SOUTH);
		return jl;
	}

　　这样上面的边框就做好了，接下来就是贴按钮和文本框之类的了

　　　　　　　　　　/*
		 * 放置按钮
		 */
		String[] typeArray = { "Line", "Oval", "Rect", "RoundRect", "fill3DRect", "fillArc", "Image", "Text", "Pencil",
				"iso_Tri", "Polygon","喷枪", "Erase" };
		Color[] colorArray = { Color.red, Color.black, Color.green, Color.BLUE, new Color(255, 255, 255) };
		String[] widthArray = { "1", "3", "5" };
		JTextField text = new JTextField();
		text.setPreferredSize(new Dimension(100, 30));

		DrawListener dl = new DrawListener(this, text, list);

		for (int i = 0; i < typeArray.length; i++) {
			JButton button = new JButton(typeArray[i]);
			InShapeJPanel.add(button);
			button.addActionListener(dl);
			if(i>=12)
			{
				JButton button1 = new JButton(typeArray[i]);
				InNorthJPanel.add(button);
				button1.addActionListener(dl);
			}
		}
		for (int i = 0; i < colorArray.length; i++) {
			JButton button = new JButton();
			button.setBackground(colorArray[i]);
			button.setPreferredSize(new Dimension(30, 30));
			IncolorJPanel.add(button);
			button.addActionListener(dl);
		}
		for (int i = 0; i < widthArray.length; i++) {
			JButton button = new JButton(widthArray[i]);
			InStrokeJPanel.add(button);
			button.addActionListener(dl);
		}
		InNorthJPanel.add(text);

　　这样，我们的界面就做好了。