JFrame —添加背景图片

添加背景图片有两种方法：
1.Jpanel类的paintComponent(Graphics g)重新绘制背景图片
2.利用LayeredPane为Swing控件增加了深度,
    由低到高的层次是:Default,Palette,Modal,PopUp,Drag。

方法一：

package examplee;

public class Java_JFrame {
	public static void main(String args[]) {
		new A();
	}
 }


package examplee;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;


public class A extends JFrame {
	Container con; 
	JButton button;
	BackgroundPanel bgp;
	public A() {
		con = this.getContentPane();//初始化容器
		this.setLayout(null);
		
		bgp = new BackgroundPanel(new ImageIcon("C:\\Users\\Administrator\\Desktop\\Example\\src\\examplee\\张艺兴.jpg").getImage());
		bgp.setBounds(0, 0, 500, 400);
		con.add(bgp);
		
		button = new JButton("按钮");
		button.setBounds(60, 30, 160, 30);
		con.add(button);
		
		this.setTitle("背景图片");
		this.setVisible(true);
		this.setBounds(250, 200, 500, 400);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
}



package examplee;

import java.awt.*;

import javax.swing.*;

public class BackgroundPanel extends JPanel {
	Image img;
	public BackgroundPanel(Image im) {
		this.img = im;
		this.setOpaque(true); //设置控件不透明，若是false那么就是透明的
	}
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.drawImage(img, 0, 0, this.getWidth(), this.getHeight(), this);
	}
}

方法二：

package examplee;

public class Back {
	public static void main(String args[]) {
		new B();
	}
}


package examplee;

import javax.swing.*;

public class B extends JFrame {
	JLayeredPane layeredPane;//分层窗格
	JPanel panel;
	JLabel label;//标签
	ImageIcon image;
	JButton button;
	public B() {
		layeredPane = new JLayeredPane();
		image = new ImageIcon("C:\\Users\\Administrator\\Desktop\\Example\\src\\examplee\\张艺兴.jpg");
		panel = new JPanel();
		panel.setBounds(0, 0, image.getIconWidth(), image.getIconHeight());//让图片充满整个面板
		label = new JLabel(image);//JLabel 对象可以显示文本、图像或同时显示二者
		
		panel.add(label);
		button = new JButton("按钮");
		button.setBounds(100, 100, 100, 100);
		layeredPane.add(panel, JLayeredPane.DEFAULT_LAYER);
		layeredPane.add(button, JLayeredPane.MODAL_LAYER);
		
		this.setTitle("图片");
		this.setLayeredPane(layeredPane); 
		this.setSize(image.getIconWidth(),image.getIconHeight());
		this.setVisible(true);   
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
              //this.setLocation(image.getIconWidth(),image.getIconHeight());  
        
	}
}

方法一的运行结果：

方法二的运行结果就不展示了，跟方法一的一样，不过是比他大而已。