关于paint背景的问题

侠雨飞飞 2006-12-11 11:13:03
public class Frame1 extends JFrame implements ActionListener {
。。。。。。

JPanel jPanel3 = new JPanel(){
//绘制背景
public void paintComponent(Graphics g) {

if(image!=null){

g.drawImage(image,0,0,this.getWidth(),this.getHeight(),null);


}else{
g.setColor(new Color(100, 155, 100));
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(new Color(80, 135, 80));
g.setFont(new Font("黑体", 1, 25));
g.drawString("无背景图片", this.getWidth()/2, 30);
}
}

};


。。。。。。。

/**
*加载背景图
* @return boolean
*/
public boolean loadBgPic(){
imageIcon=new ImageIcon(this.bgPicname);
image=imageIcon.getImage();
image = image.getScaledInstance(jPanel3.getWidth(), jPanel3.getHeight(), Image.SCALE_SMOOTH);

jPanel3.validate();
jPanel3.repaint();

return true;
}


。。。。。。。。。
}


上面的程序中，我在jPanel3里加了一幅背景图片，然后，在jFram1里定义loadBgPic用来生成image
现在的问题是，调用后，jPanel3显示的是jframe1的背景色，这时如果jPanel3被遮挡重绘时，就会显示部分背景图片，但为何第一次 jPanel3.validate();
jPanel3.repaint();不显示呢？

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realrealdragon 2006-12-12
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panel.setUIUpdate(true);
侠雨飞飞 2006-12-12
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http://community.csdn.net/Expert/topic/5223/5223973.xml?temp=.6551172

赫赫，多谢了
fool_leave 2006-12-12
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to sxnucseven(*)
什么人？一句玩笑而已，他给分我没看到那个帖子而已。

你有能耐去解决问题呀。
fool_leave 2006-12-12
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package gktsys.frame;

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.awt.event.*;
import javax.swing.BorderFactory;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.SystemColor;
import javax.swing.JLabel;
import java.awt.Point;
import java.io.*;
import java.awt.Component;
import java.awt.Frame;
import java.awt.FileDialog;
import java.awt.Image;
import java.awt.Graphics;
import javax.swing.ImageIcon;
import java.awt.Font;
import java.awt.*;

public class Frame1
extends JFrame
implements ActionListener {
//背景图片
private ImageIcon imageIcon = null;
transient Image image = null;
JPanel jPanel1 = new JPanel();
JButton jButton2 = new JButton();
FlowLayout flowLayout2 = new FlowLayout();
JPanel jPanel2 = new JPanel();
//主编辑panel
JPanel jPanel3 = new JPanel() {
//绘制背景
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(100, 155, 100));
g.fillRect(0, 0, this.getWidth(), this.getHeight());
if (image != null) {
g.drawImage(image, 0, 0, this.getWidth(), this.getHeight(), this);
}
else {
g.setColor(new Color(80, 135, 80));
g.setFont(new Font("黑体", 1, 25));
g.drawString("无背景图片", this.getWidth() / 2, 30);
}
}
};
int x = 0;
int y = 0;
JButton jButton3 = new JButton();
int START = 50;
BorderLayout borderLayout1 = new BorderLayout();
//重载
public void actionPerformed(ActionEvent e) {
if (e.getSource().getClass().getName().equals("javax.swing.JButton")) { //getSource判断哪个按钮被按下了。
//用来选择图片的
FileDialog filedlg = new FileDialog(this, "选择背景图片");

filedlg.setVisible(true);
String picpath = filedlg.getDirectory();
String picfile = filedlg.getFile();
System.out.println(picpath + picfile);
imageIcon = new ImageIcon(picpath + picfile);
image = imageIcon.getImage();
image = image.getScaledInstance(jPanel3.getWidth(), jPanel3.getHeight(),
Image.SCALE_SMOOTH);
MediaTracker mt=new MediaTracker(this);
mt.addImage(image,0);
try {
mt.waitForID(0);
}
catch (InterruptedException ex) {
}
jPanel3.validate();
jPanel3.updateUI();

}
}

public Frame1() {
try {
jbInit();
}
catch (Exception exception) {
exception.printStackTrace();
}
}

private void jbInit() throws Exception {
getContentPane().setLayout(borderLayout1);
jButton2.setText("添加标签");
jButton2.addMouseListener(new Frame1_jButton2_mouseAdapter(this));
jButton2.addActionListener(new Frame1_jButton2_actionAdapter(this));
jPanel1.setBorder(null);
jPanel1.setMaximumSize(new Dimension(7670, 7670));
jPanel1.setLayout(flowLayout2);
this.getContentPane().setBackground(SystemColor.controlText);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("test");
this.setVisible(true);
jPanel2.setBorder(null);
jPanel2.setPreferredSize(new Dimension(100, 10));
jPanel3.setBounds(0, 0, 800, 600);
jPanel3.setBackground(SystemColor.activeCaptionBorder);
jPanel3.setBorder(BorderFactory.createLoweredBevelBorder());
jPanel3.setOpaque(false);
jPanel3.setInputVerifier(null);
jPanel3.setLayout(null);
jPanel3.addMouseListener(new Frame1_jPanel3_mouseAdapter(this));
jPanel3.addMouseMotionListener(new Frame1_jPanel3_mouseMotionAdapter(this));
jButton3.setText("加载图像");
jButton3.addActionListener(this);
jPanel1.add(jButton3);
jPanel1.add(jButton2, null);
this.getContentPane().add(jPanel2, java.awt.BorderLayout.EAST);
this.getContentPane().add(jPanel3, java.awt.BorderLayout.CENTER);
this.getContentPane().add(jPanel1, java.awt.BorderLayout.NORTH);
}

public static void main(String[] args) {
Frame1 frame1 = new Frame1();
frame1.setSize(800, 600);
frame1.setVisible(true);
}

public void jButton2_actionPerformed(ActionEvent e) {

}

//增加测点
public void jButton2_mouseClicked(MouseEvent e) {

System.out.println("clicked");
Point p = new Point(50 + START, 100);
JLabel jcedian = new JLabel();
jcedian.setText("xin cedian");
jcedian.setBounds(50 + START, 100, 48, 15);
jPanel3.add(jcedian);
START += 50;
jPanel3.validate();
jPanel3.repaint();
}
}

class Frame1_jPanel3_mouseAdapter
extends MouseAdapter {
private Frame1 adaptee;
Frame1_jPanel3_mouseAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}
}

class Frame1_jPanel3_mouseMotionAdapter
extends MouseMotionAdapter {
private Frame1 adaptee;
Frame1_jPanel3_mouseMotionAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}
}

class Frame1_jButton2_actionAdapter
implements ActionListener {
private Frame1 adaptee;
Frame1_jButton2_actionAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.jButton2_actionPerformed(e);
}
}

class Frame1_jButton2_mouseAdapter
extends MouseAdapter {
private Frame1 adaptee;
Frame1_jButton2_mouseAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}

public void mouseClicked(MouseEvent e) {
adaptee.jButton2_mouseClicked(e);
}
}

好了

我修改了两个地方
一个是paintComponent方法，这个不碍事，不是原因所在，不过最好注意一下
还有一个是Image加载的地方，要用MediaTracker来等待，等到Image加载完毕为止。应为new Image（）虽然方法调用完毕，但图片加载还没完毕。
建议加载图片的方法放到Thread里面写

哈哈，那个帖子没看到哦
diggywang 2006-12-12
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来晚一步啊，重载的方法drawImage（）传null参数，哎，太不小心了，这些个情况下传null是最容易出错的
侠雨飞飞 2006-12-12
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赫赫
木关系
赏金猎人
：P
sxnucseven 2006-12-12
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竟然有这样的人...
无语.
fool_leave 2006-12-12
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是吗？
好，我去

再帮你看看这个，一定要拿上分
侠雨飞飞 2006-12-12
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哈哈，不是这个问题，不信你运行一下
上个帖子我在基础版已经开贴等你领分呢
fool_leave 2006-12-12
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如果是这个问题，你是不是又该开个帖子给我给分了？
fool_leave 2006-12-12
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等等

g.drawImage(image,0,0,this.getWidth(),this.getHeight(),null);
改为
g.drawImage(image,0,0,this.getWidth(),this.getHeight(),this);

ImageObserver怎么设置成null了？要用绘制面板才可以
侠雨飞飞 2006-12-12
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单步时候，jPanel3.paintComponent被执行了
sxnucseven 2006-12-12
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哦 没用imageBuffer啊，反正用到哪个放的图片，调试一下看图片放进去没，否则应该不会出黑色背景的。
sxnucseven 2006-12-12
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黑色背景，会不会是imageBuffer没装载图片阿。
侠雨飞飞 2006-12-12
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package gktsys.frame;

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.awt.event.*;
import javax.swing.BorderFactory;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.SystemColor;
import javax.swing.JLabel;
import java.awt.Point;
import java.io.*;
import java.awt.Component;
import java.awt.Frame;
import java.awt.FileDialog;
import java.awt.Image;
import java.awt.Graphics;
import javax.swing.ImageIcon;
import java.awt.Font;

public class Frame1 extends JFrame implements ActionListener {
//背景图片
private ImageIcon imageIcon = null;
transient Image image = null;
JPanel jPanel1 = new JPanel();
JButton jButton2 = new JButton();
FlowLayout flowLayout2 = new FlowLayout();
JPanel jPanel2 = new JPanel();
//主编辑panel
JPanel jPanel3 = new JPanel(){
//绘制背景
public void paintComponent(Graphics g) {

if(image!=null){
g.drawImage(image,0,0,this.getWidth(),this.getHeight(),null);
}else{
g.setColor(new Color(100, 155, 100));
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(new Color(80, 135, 80));
g.setFont(new Font("黑体", 1, 25));
g.drawString("无背景图片", this.getWidth()/2, 30);
}
}
};
int x=0;
int y=0;
JButton jButton3 = new JButton();
int START=50;
BorderLayout borderLayout1 = new BorderLayout();
//重载
public void actionPerformed(ActionEvent e)
{
if(e.getSource().getClass().getName().equals("javax.swing.JButton"))//getSource判断哪个按钮被按下了。
{
//用来选择图片的
FileDialog filedlg=new FileDialog(this,"选择背景图片");

filedlg.setVisible(true);
String picpath=filedlg.getDirectory();
String picfile=filedlg.getFile();
System.out.println(picpath+picfile);
imageIcon=new ImageIcon(picpath+picfile);
image=imageIcon.getImage();
image = image.getScaledInstance(jPanel3.getWidth(), jPanel3.getHeight(), Image.SCALE_SMOOTH);
jPanel3.validate();
jPanel3.updateUI();

}
}

public Frame1() {
try {
jbInit();
} catch (Exception exception) {
exception.printStackTrace();
}
}
private void jbInit() throws Exception {
getContentPane().setLayout(borderLayout1);
jButton2.setText("添加标签");
jButton2.addMouseListener(new Frame1_jButton2_mouseAdapter(this));
jButton2.addActionListener(new Frame1_jButton2_actionAdapter(this));
jPanel1.setBorder(null);
jPanel1.setMaximumSize(new Dimension(7670, 7670));
jPanel1.setLayout(flowLayout2);
this.getContentPane().setBackground(SystemColor.controlText);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setTitle("test");
this.setVisible(true);
jPanel2.setBorder(null);
jPanel2.setPreferredSize(new Dimension(100, 10));
jPanel3.setBounds(0,0,800,600);
jPanel3.setBackground(SystemColor.activeCaptionBorder);
jPanel3.setBorder(BorderFactory.createLoweredBevelBorder());
jPanel3.setOpaque(false);
jPanel3.setInputVerifier(null);
jPanel3.setLayout(null);
jPanel3.addMouseListener(new Frame1_jPanel3_mouseAdapter(this));
jPanel3.addMouseMotionListener(new Frame1_jPanel3_mouseMotionAdapter(this));
jButton3.setText("加载图像");
jButton3.addActionListener(this);
jPanel1.add(jButton3);
jPanel1.add(jButton2, null);
this.getContentPane().add(jPanel2, java.awt.BorderLayout.EAST);
this.getContentPane().add(jPanel3, java.awt.BorderLayout.CENTER);
this.getContentPane().add(jPanel1, java.awt.BorderLayout.NORTH);
}

public static void main(String[] args) {
Frame1 frame1 = new Frame1();
frame1.setSize(800,600);
frame1.setVisible(true);
}

public void jButton2_actionPerformed(ActionEvent e) {

}

//增加测点
public void jButton2_mouseClicked(MouseEvent e) {

System.out.println("clicked");
Point p=new Point(50+START,100);
JLabel jcedian = new JLabel();
jcedian.setText("xin cedian");
jcedian.setBounds(50+START,100,48,15);
jPanel3.add(jcedian);
START+=50;
jPanel3.validate();
jPanel3.repaint();
}
}


class Frame1_jPanel3_mouseAdapter extends MouseAdapter {
private Frame1 adaptee;
Frame1_jPanel3_mouseAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}
}

class Frame1_jPanel3_mouseMotionAdapter extends MouseMotionAdapter {
private Frame1 adaptee;
Frame1_jPanel3_mouseMotionAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}
}

class Frame1_jButton2_actionAdapter implements ActionListener {
private Frame1 adaptee;
Frame1_jButton2_actionAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.jButton2_actionPerformed(e);
}
}


class Frame1_jButton2_mouseAdapter extends MouseAdapter {
private Frame1 adaptee;
Frame1_jButton2_mouseAdapter(Frame1 adaptee) {
this.adaptee = adaptee;
}

public void mouseClicked(MouseEvent e) {
adaptee.jButton2_mouseClicked(e);
}
}


这是源程序，运行后，加载一jpg格式的图片，会出现黑色背景将jPanel3覆盖
fool_leave 2006-12-11
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在paintComponent的第一行加上super.paintComponent(g);
diggywang 2006-12-11
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有没有调试啊?
关键是你的loadBgPic是什么时候调用的恶，如果在jpanel3初始化之前调用，那肯定是可以的，如果在jpanel3初始化后调用，第一次肯定是不会出来的，而是默认的颜色，类似于灰色。
建议把源码都贴出来看看
fool_leave 2006-12-11
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lz能不能按我说的做一下，或者把整个代码贴出来
我们在教你怎么调试呢
侠雨飞飞 2006-12-11
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图片给frame的背景色挡住了
fool_leave 2006-12-11
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你把JPanel的背景涂成红色，看看只是图片没出来，还是整个JPanel没出来
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