JPanel 如何改背景颜色

nandizhu 2009-10-27 09:11:56



public class BallPanel extends javax.swing.JPanel{

	private final int INIT_X=75;

	private final int INIT_Y=75;

	private final int DIAMETER=60;

	private SmartEllipse _ball;

	

	

	public BallPanel(){

		super();

		_ball=new SmartEllipse(java.awt.Color.green);

		_ball.setLocation(INIT_X,INIT_Y);

		_ball.setSize(DIAMETER,DIAMETER);

		this.setBackground(java.awt.Color.white);//我想把背景改成白色，但是不行。。。

	}

	public void paintComponent(java.awt.Graphics aBrush){

		super.paintComponents(aBrush);

		java.awt.Graphics2D betterBrush=(java.awt.Graphics2D)

		aBrush;

		_ball.fill(betterBrush);

		_ball.draw((java.awt.Graphics2D) aBrush);

	}

}

...全文

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mhlwjsso001 2011-03-23

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我是菜鸟，我看你们写的代码都好复杂啊

nandizhu 2009-10-30

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[Quote=引用 19 楼 zhuyouyong 的回复:]
JFrame f = new JFrame();
JPanel p = new JPanel();
f.add(p);
p.setBackground(Color.RED);
this.setVisible(true);
[/Quote]

你可以在我原程序上改吗，，我这样改了也不行

lishigui 2009-10-30

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public class BallApp extends javax.swing.JFrame {

	/** * @param args */

	private BallPanel p;



	public BallApp(String title) {

		super(title);

		this.setSize(600, 450);



                this.setBackground(java.awt.Color.red);



		this.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

		p = new BallPanel();

		this.add(p);

		this.setVisible(true);

	}



	public static void main(String[] args) { // TODO Auto-generated method stub

		BallApp app = new BallApp("Jam's first window"); // pane1.

	}

}



public class BallPanel extends javax.swing.JPanel {

	private final int INIT_X = 75;

	private final int INIT_Y = 75;

	private final int DIAMETER = 250;

	private SmartEllipse _ball;



	public BallPanel() {

		super();

		_ball = new SmartEllipse(java.awt.Color.green);

		_ball.setLocation(INIT_X, INIT_Y);

		_ball.setSize(DIAMETER, DIAMETER);

	}



	public void paintComponent(java.awt.Graphics aBrush) {

		super.paintComponents(aBrush);

		java.awt.Graphics2D betterBrush = (java.awt.Graphics2D) aBrush;

		_ball.fill(betterBrush);

		_ball.draw((java.awt.Graphics2D) aBrush);

	}

}



public class SmartEllipse extends java.awt.geom.Ellipse2D.Double {

	private java.awt.Color _borderColor, _fillColor;

	private int _rotation;

	private final int STROKE_WIDTH = 2;



	public SmartEllipse(java.awt.Color aColor) {

		super();

		_borderColor = aColor;

		_fillColor = aColor;

		_rotation = 0;

	}



	public void setBorderColor(java.awt.Color aColor) {

		_borderColor = aColor;

	}



	public void setFillColor(java.awt.Color aColor) {

		_fillColor = aColor;

	}



	public void setColor(java.awt.Color aColor) {

		_fillColor = aColor;

		_borderColor = aColor;

	}



	public void setRotation(int aRotation) {

		_rotation = aRotation;

	}



	public void setLocation(double x, double y) {

		this.setFrame(x, y, this.getWidth(), this.getHeight());

	}



	public void setSize(int aWidth, int aHeight) {

		this.setFrame(this.getX(), this.getY(), aWidth, aHeight);

	}



	public void move(int aChangeInX, int aChangeInY) {

		this.setFrame((int) this.getX() + aChangeInX, (int) this.getY()

				+ aChangeInY, this.getWidth(), this.getHeight());

	}



	public void fill(java.awt.Graphics2D aBetterBrush) {

		java.awt.Color saveColor = aBetterBrush.getColor();

		aBetterBrush.setColor(_fillColor);

		aBetterBrush.fill(this);

		aBetterBrush.setColor(saveColor);

	}



	public void draw(java.awt.Graphics2D aBrush) {

		java.awt.Color savedColor = aBrush.getColor();

		aBrush.setColor(_borderColor);

		java.awt.Stroke savedStroke = aBrush.getStroke();

		aBrush.setStroke(new java.awt.BasicStroke(STROKE_WIDTH));

		aBrush.draw(this);

		aBrush.setStroke(savedStroke);

		aBrush.setColor(savedColor);

	}

}

老张-AI 2009-10-28

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路过学习

顶顶

miluo539 2009-10-28

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java.awt.Color.white，white是不是要大写？

Jack_Skipper 2009-10-28

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顶6楼

lz12366007 2009-10-28

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getContentPane().setVisible(false);
this.setBackground(Color.WHITE);

这样写也是可以的

lz12366007 2009-10-28

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很好。。。

chenlian911 2009-10-28

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jbuild 一下就可以了咱刚学不要怪我嘎嘎

zhuyouyong 2009-10-28

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JFrame f = new JFrame();
JPanel p = new JPanel();
f.add(p);
p.setBackground(Color.RED);
this.setVisible(true);

littlemonster 2009-10-28

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是的，把Jpanel放在Jframe上，在用你那句就ok了。

[Quote=引用 7 楼 hui94781674 的回复:]
jpanel要有容器才可以显示的。不象JFrame之类的可以独立显示。。
[/Quote]

超超王贱贱 2009-10-28

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再试试图

超超王贱贱 2009-10-28

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public class BallApp extends javax.swing.JFrame {



    /**

     * @param args

     */

    private BallComponent c;//换成c

    public BallApp(String title){

        super(title);

        

        this.setSize(600,450);

        this.setDefaultCloseOperation

        (javax.swing.JFrame.EXIT_ON_CLOSE);

//        p=new BallPanel();

//        this.add(p);

        c=new BallComponent();//换成c

        this.add(c);

        this.getContentPane().setBackground(java.awt.Color.RED);//背景色改成红

        

        this.setVisible(true);

    }

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        BallApp app=

            new BallApp("Jam's first window");

        //pane1.

    }

}



/**

 * 照搬一个JComponent

 * @author Administrator

 *

 */

class BallComponent extends javax.swing.JComponent{

	    private final int INIT_X=75;

	    private final int INIT_Y=75;

	    private final int DIAMETER=250;

	    private SmartEllipse _ball;

	    

	    

	    public BallComponent(){

	        super();

	        _ball=new SmartEllipse(java.awt.Color.green);

	        _ball.setLocation(INIT_X,INIT_Y);

	        _ball.setSize(DIAMETER,DIAMETER);

	    }

	    public void paintComponent(java.awt.Graphics aBrush){

	        super.paintComponents(aBrush);

	        java.awt.Graphics2D betterBrush=(java.awt.Graphics2D)

	        aBrush;

	        _ball.fill(betterBrush);

	        _ball.draw((java.awt.Graphics2D) aBrush);

	    }

	}



class SmartEllipse extends java.awt.geom.Ellipse2D.Double{

//public class SmartEllipse extends java.awt.geom.Ellipse2D.Double{ //去掉了public

    private java.awt.Color _borderColor,_fillColor;

    private int _rotation;

    private final int STROKE_WIDTH=2;

    public SmartEllipse(java.awt.Color aColor){

        super();

        _borderColor=aColor;

        _fillColor=aColor;

        _rotation=0;

    }

    public void setBorderColor(java.awt.Color aColor){

        _borderColor=aColor;

    }

    public void setFillColor(java.awt.Color aColor){

        _fillColor=aColor;

    }

    public void setColor(java.awt.Color aColor){

        _fillColor=aColor;

        _borderColor=aColor;

    }

    public void setRotation(int aRotation){

        _rotation=aRotation;

    }

    public void setLocation(double x,double y){

        this.setFrame(x,y,this.getWidth(),this.getHeight());

    }

    public void setSize(int aWidth,int aHeight){

        this.setFrame(this.getX(),this.getY(),aWidth,aHeight);

    }

    public void move(int aChangeInX,int aChangeInY){

        this.setFrame((int)this.getX()+aChangeInX,

                (int)this.getY()+aChangeInY,

            this.getWidth(),this.getHeight());

    }

    public void fill(java.awt.Graphics2D aBetterBrush){

        java.awt.Color saveColor=aBetterBrush.getColor();

        aBetterBrush.setColor(_fillColor);

        aBetterBrush.fill(this);

        aBetterBrush.setColor(saveColor);

    }

    public void draw(java.awt.Graphics2D aBrush){

        java.awt.Color savedColor=aBrush.getColor();

        aBrush.setColor(_borderColor);

        java.awt.Stroke savedStroke=aBrush.getStroke();

        aBrush.setStroke(new java.awt.BasicStroke(STROKE_WIDTH));

        aBrush.draw(this);

        aBrush.setStroke(savedStroke);

        aBrush.setColor(savedColor);

    }

}

我也是刚开始学；
1.5.0_17 Eclipse 调试

结果：

超超王贱贱 2009-10-28

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JPanel 换成 JComponent

nandizhu 2009-10-27

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我是先加了JFrame类的了~~~~~~~请你们帮帮忙~~~

nandizhu 2009-10-27

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看来我该把全部程序贴出来，我的意图是先有一个JFrame类了，在里面放一个JPanel的类型，然后在JPanel上面显示一个圆，然后可以改JPanel的背景颜色，代码如下：





public class BallApp extends javax.swing.JFrame {



	/**

	 * @param args

	 */

	private BallPanel p;

	public BallApp(String title){

		super(title);

		

		this.setSize(600,450);

		this.setDefaultCloseOperation

		(javax.swing.JFrame.EXIT_ON_CLOSE);

		p=new BallPanel();

		this.add(p);

		

		this.setVisible(true);

	}

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		BallApp app=

			new BallApp("Jam's first window");

		//pane1.

	}

}





public class BallPanel extends javax.swing.JPanel{

	private final int INIT_X=75;

	private final int INIT_Y=75;

	private final int DIAMETER=250;

	private SmartEllipse _ball;

	

	

	public BallPanel(){

		super();

		_ball=new SmartEllipse(java.awt.Color.green);

		_ball.setLocation(INIT_X,INIT_Y);

		_ball.setSize(DIAMETER,DIAMETER);

	}

	public void paintComponent(java.awt.Graphics aBrush){

		super.paintComponents(aBrush);

		java.awt.Graphics2D betterBrush=(java.awt.Graphics2D)

		aBrush;

		_ball.fill(betterBrush);

		_ball.draw((java.awt.Graphics2D) aBrush);

	}

}





public class SmartEllipse extends java.awt.geom.Ellipse2D.Double{

	private java.awt.Color _borderColor,_fillColor;

	private int _rotation;

	private final int STROKE_WIDTH=2;

	public SmartEllipse(java.awt.Color aColor){

		super();

		_borderColor=aColor;

		_fillColor=aColor;

		_rotation=0;

	}

	public void setBorderColor(java.awt.Color aColor){

		_borderColor=aColor;

	}

	public void setFillColor(java.awt.Color aColor){

		_fillColor=aColor;

	}

	public void setColor(java.awt.Color aColor){

		_fillColor=aColor;

		_borderColor=aColor;

	}

	public void setRotation(int aRotation){

		_rotation=aRotation;

	}

	public void setLocation(double x,double y){

		this.setFrame(x,y,this.getWidth(),this.getHeight());

	}

	public void setSize(int aWidth,int aHeight){

		this.setFrame(this.getX(),this.getY(),aWidth,aHeight);

	}

	public void move(int aChangeInX,int aChangeInY){

		this.setFrame((int)this.getX()+aChangeInX,

				(int)this.getY()+aChangeInY,

			this.getWidth(),this.getHeight());

	}

	public void fill(java.awt.Graphics2D aBetterBrush){

		java.awt.Color saveColor=aBetterBrush.getColor();

		aBetterBrush.setColor(_fillColor);

		aBetterBrush.fill(this);

		aBetterBrush.setColor(saveColor);

	}

	public void draw(java.awt.Graphics2D aBrush){

		java.awt.Color savedColor=aBrush.getColor();

		aBrush.setColor(_borderColor);

		java.awt.Stroke savedStroke=aBrush.getStroke();

		aBrush.setStroke(new java.awt.BasicStroke(STROKE_WIDTH));

		aBrush.draw(this);

		aBrush.setStroke(savedStroke);

		aBrush.setColor(savedColor);

	}

}

hui94781674 2009-10-27

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jpanel要有容器才可以显示的。不象JFrame之类的可以独立显示。。

justinavril 2009-10-27

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没看到你extends的JPanel，我以为是JFrame呢。我把你代码改了一下，你看看，当然这是示意如何显示背景色

public class BallPanel extends javax.swing.JFrame{//改成JFrame，为什么？看3楼

    private final int INIT_X=75;

    private final int INIT_Y=75;

    private final int DIAMETER=260;//改大点 60实在太小了

    //private SmartEllipse _ball;//我注释掉了

    

    

    public BallPanel(){

        super();

        //_ball=new SmartEllipse(java.awt.Color.green);//同上 注释掉了

        this.setLocation(INIT_X,INIT_Y);

        this.setSize(DIAMETER,DIAMETER);

        this.getContentPane().setBackground(java.awt.Color.red);//为了直白，改成红色

        this.setVisible(true);//显示改组件

    }

    

    

    public static void main(String args[]){

    	new BallPanel();

    }

}