JPanel top=new JPanel(){
private static final long serialVersionUID = 1L;
protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
// 绘制渐变
g2.setPaint(new GradientPaint(0, 0, new Color(116, 149, 226), getWidth(),
getHeight(), new Color(199, 212, 247)));
g2.fillRect(0, 0, getWidth(), getHeight());
super.paintComponent(g);
}
};
怎样背景没有渐变颜色,没有颜色,只有一个面板而已.这应怎样改呢.
如果把JPanel改成JLabel则有渐变的颜色.
------解决方案--------------------
再优化一下：
- Java code
import java.awt.BorderLayout;import java.awt.Color;import java.awt.GradientPaint;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.LayoutManager;import java.awt.Paint;import javax.swing.JComponent;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.plaf.PanelUI;@SuppressWarnings("serial")public class ColorfulPanel extends JPanel { private Color color1 = new Color(116, 149, 226); private Color color2 = new Color(199, 212, 247); private void init() { setUI(new PanelUI() { public void update(Graphics g, JComponent c) { if (c.isOpaque()) { Graphics2D g2 = (Graphics2D) g; Paint old = g2.getPaint(); int w = c.getWidth(); int h = c.getHeight(); g2.setPaint(new GradientPaint(0, 0, color1, w, h , color2)); g2.fillRect(0, 0, w, h); g2.setPaint(old); } paint(g, c); } }); } public ColorfulPanel() { super(); init(); } public ColorfulPanel(Color lt, Color rb) { super(); if (lt != null) this.color1 = lt; if (rb != null) this.color2 = rb; init(); } public ColorfulPanel(boolean isDoubleBuffered) { super(isDoubleBuffered); init(); } public ColorfulPanel(LayoutManager layout) { super(layout); init(); } public ColorfulPanel(LayoutManager layout, boolean isDoubleBuffered) { super(layout, isDoubleBuffered); init(); } public Color getColor1() { return this.color1; } public void setColor1(Color c) { if (c != null) this.color1 = c; } public Color getColor2() { return this.color2; } public void setColor2(Color c) { if (c != null) this.color2 = c; } public static void main(String[] args) { JFrame frm = new JFrame("Test"); frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frm.getContentPane().add(new ColorfulPanel(), BorderLayout.CENTER); frm.setBounds(60, 60, 260, 260); frm.setVisible(true); }}