學會了使用按鈕監聽以及鼠標監聽器之後，我們就可以制作一個屬於自己的畫圖板了，以下是我之前制作的一個簡易的畫圖板，功能方面尚還不足，不過已經可以完成鉛筆，橡皮，畫直線，圓等基本工作了，還可以完成顏色的自由選擇，大家不放自己也動手做做吧。
首先是界面類：
Java代碼
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
@SuppressWarnings("serial")
public class Draw extends JFrame{
public Color color=Color.BLACK;//設置初始顏色
private Color colorselector;
private JButton colorselectorbu[]=new JButton[6];
//創建對象時需要new一個對象，否則他的默認值就是NULL
private JPanel colorjp=new JPanel();
public static void main(String args[]){
Draw dr=new Draw();
dr.showframe();
}
public void showframe(){
JPanel north=new JPanel(); //上方區域，存放顏色按鈕以及顏色選擇器
JPanel west=new JPanel(); //左邊區域，存放圖形按鈕
JPanel center=new JPanel(); //中間區域，存放畫板
JPanel south=new JPanel(); //下面區域，用來顯示當前鼠標所在前位置以及所畫圖形的大小
//-----------------中間區域---------------
center.setLayout(new FlowLayout(FlowLayout.LEFT));//將中間區域的布局設置為左對齊
JPanel drawjp=new JPanel();
drawjp.setBackground(Color.white);
drawjp.setPreferredSize(new Dimension(600,500));
center.add(drawjp);
//-----------------上方區域----------------
JButton colorchooserbu=new JButton("更多顏色");
colorchooserbu.addActionListener(colorlistener);
colorjp.setPreferredSize(new Dimension(120,60));
colorjp.setLayout(new GridLayout(3,6,0,0));
//創建一個顏色組
Color color[]=new Color[]{Color.BLACK,Color.BLUE,Color.CYAN,Color.DARK_GRAY,Color.GRAY,Color.GREEN
,Color.LIGHT_GRAY,Color.GREEN,Color.MAGENTA,Color.ORANGE,Color.PINK,Color.YELLOW};
Dimension d=new Dimension(20,20);
for(int i=0;i<color.length;i++){
JButton colorbu=new JButton();
colorbu.setBackground(color[i]);
colorbu.setPreferredSize(d);
colorjp.add(colorbu);
colorbu.addActionListener(listener);
}
//按鈕選擇器的自定義顏色組
for(int j=0;j<colorselectorbu.length;j++){
colorselectorbu[j]=new JButton();
colorselectorbu[j].setPreferredSize(d);
colorjp.add(colorselectorbu[j]);
colorselectorbu[j].addActionListener(listener);
}
north.add(colorjp);
north.add(colorchooserbu);
//-----------------左邊區域----------------
String img[]=new String[]{"Line", "oval", "rect", "roundrect", "eraser", "fill",
"pencil", "select"};
String img1[]=new String[]{"Line1","oval1","rect1","roundrect1","eraser1","fill1",
"pencil1","select1"};
ButtonGroup bg=new ButtonGroup();
for(int i=0;i<img.length;i++){
//創建Icon組
ImageIcon shapeicon=new ImageIcon("back/"+img[i]+".jpg");
ImageIcon shapeicon1=new ImageIcon("back/"+img1[i]+".jpg");
JRadioButton shapebu=new JRadioButton(shapeicon);
bg.add(shapebu);
shapebu.setPressedIcon(shapeicon1);
//設置選中時的圖案
shapebu.setSelectedIcon(shapeicon1);
shapebu.setActionCommand(img[i]);
west.add(shapebu);
}
//---------------下方區域-------------
JLabel la1=new JLabel();
JLabel la2=new JLabel();
JLabel la3=new JLabel("600x500像素");
JLabel la4=new JLabel();
south.add(la4);
south.add(la1);
south.add(la2);
south.add(la3);
south.setLayout(new GridLayout(1,4,20,20));
north.setPreferredSize(new Dimension(200,80));
west.setPreferredSize(new Dimension(80,200));
south.setPreferredSize(new Dimension(200,20));
north.setBackground(Color.GRAY);
west.setBackground(Color.DARK_GRAY);
center.setBackground(Color.LIGHT_GRAY);
south.setBackground(Color.WHITE);
this.setLayout(new BorderLayout());
this.add(north,BorderLayout.NORTH);
this.add(west,BorderLayout.WEST);
this.add(south,BorderLayout.SOUTH);
this.add(center,BorderLayout.CENTER);
this.setTitle("畫圖板復習");
this.setSize(900,700);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(3);
this.setVisible(true);
//在畫板上獲取畫布權限
Graphics g=drawjp.getGraphics();
DrawListener listener=new DrawListener(g,bg,this,la1,la2);
drawjp.addMouseListener(listener);
drawjp.addMouseMotionListener(listener);
}
//添加按鈕監聽，獲取按鈕的背景顏色
ActionListener listener=new ActionListener(){
public void actionPerformed(ActionEvent e) {
//獲取事件源，發生事件的對象
Object obj=e.getSource();
if(obj instanceof JButton){
color=((JButton) obj).getBackground();
}
}
};
ActionListener colorlistener=new ActionListener(){
//按鈕數組累加器
int i = 0;
public void actionPerformed(ActionEvent e){
colorselector=JColorChooser.showDialog(null, "顏色選擇器", Color.BLACK);
colorselectorbu[i].setBackground(colorselector);
i++;
if(i>=6){
//超出六個按鈕,返回0
i=0;
}
}
};
}
下面是監聽類：
Java代碼
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
import javax.swing.ButtonGroup;
import javax.swing.ButtonModel;
import javax.swing.JLabel;
public class DrawListener extends MouseAdapter{
private int x1,x2,y1,y2;
private Graphics g; //將畫布對象傳過來
private ButtonGroup bg; //將按鈕組傳過來
private Draw dr;
private JLabel la1;
private JLabel la2;
public DrawListener(Graphics g,ButtonGroup bg,Draw dr,JLabel la1,JLabel la2){
this.g=g;
this.bg=bg;
this.dr=dr;
this.la1=la1;
this.la2=la2;
}
//鼠標按下
public void mousePressed(MouseEvent e){
x1=e.getX();
y1=e.getY();
g.setColor(dr.color);
}
//鼠標釋放
public void mouseReleased(MouseEvent e){
x2=e.getX();
y2=e.getY();
ButtonModel bm=bg.getSelection();
String com=bm.getActionCommand();
if(com.equals("Line")){
g.drawLine(x1, y1, x2, y2);
//改變la2中的數字
la2.setText(Math.abs(x1-x2)+"x"+Math.abs(y1-y2));
}
else if(com.equals("oval")){
g.drawOval(Math.min(x1, x2),Math.min(y1, y2),Math.abs(x1-x2),Math.abs(y1-y2));
la2.setText(Math.abs(x1-x2)+"x"+Math.abs(y1-y2));
}
else if(com.equals("rect")){
g.drawRect(Math.min(x1,x2), Math.min(y1,y2), Math.abs(x1-x2),Math.abs(y1-y2));
la2.setText(Math.abs(x1-x2)+"x"+Math.abs(y1-y2));
}
else if(com.equals("roundrect")){
g.drawRoundRect(Math.min(x1,x2), Math.min(y1,y2),Math.abs(x1-x2),Math.abs(y1-y2), Math.abs(x1-x2)/4,Math.abs(y1-y2)/4);
la2.setText(Math.abs(x1-x2)+"x"+Math.abs(y1-y2));
}
}
//
public void mouseMoved(MouseEvent e){
int X=e.getX();
int Y=e.getY();
la1.setText(X+","+Y);
}
public void mouseExited(MouseEvent e) {
la1.setText("");
}
//鼠標拖動
public void mouseDragged(MouseEvent e){
int X=e.getX();
int Y=e.getY();
la1.setText(X+","+Y);
x2=e.getX();
y2=e.getY();
String com=bg.getSelection().getActionCommand();
if(com.equals("pencil")){
g.drawLine(x1, y1, x2, y2);
x1=x2;
y1=y2;
}
else if(com.equals("eraser")){
g.setColor(Color.WHITE);
for(int i=-8;i<8;i++){
g.drawLine(x1+i,y1+i,x2+i,y2+i);
}
x1=x2;
y1=y2;
}
else if(com.equals("select")){
g.drawLine(x1,y1,x2,y2);
}
else if(com.equals("fill")){
Random ran=new Random();
int a=ran.nextInt(16)-8;
g.drawLine(x1+a, y1+a, x2+a, y2+a);
x1=x2;
y1=y2;
}
}
}
使用到的圖片是從WINDOWS中的畫圖板中截圖下來的，附件中已提供給大家，自己也動手試試吧
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