JFrame画图基础和事件监听

消息框

JOptionPane.showMessageDialog(mine.this, "删除不成功!");

画图

class MyJPanel extends JPanel //继承面板类
{public void paint(Graphics g) //覆盖父类的方法,paint相当于画图{g.drawOval(30, 30, 80, 80);  //画圆g.drawLine(100, 100, 200, 200); //画直线 ,两点坐标g.setColor(Color.RED);g.drawRect(50,50,50,50);g.draw3DRect(100, 100, 100, 100,true); //画矩形 ,参数是做上角坐标和长宽g.setColor(Color.BLUE);g.fillRect(100, 100, 100, 100); //填充矩形g.fill3DRect(50, 50, 50, 50, false); //填充3d效果的矩形}
}

导入图片

Image tp=Toolkit.getDefaultToolkit().getImage(Panel.class.getResource("/龙猫2.jpg")); //固定格式,得到图片g.drawImage(tp, 30, 30, 100, 100, this); //画图

绘文字

g.setColor(Color.BLUE);g.setFont(new Font("华文彩云",Font.BOLD,50));g.drawString("很强", 100, 100);

监听事件

JButton bt=new JButton("运行");bt.addActionListener(this);  //自己的MyListener jt=new MyListener();bt.addActionListener(jt);  //另一个bt.setActionCommand("yunxing");public void actionPerformed(ActionEvent e) //必须实现监听器的抽象方法{if(e.getActionCommand()=="yunxing"){System.out.println("运行成功");}}}class MyListener implements ActionListener  //继承父类
{public void actionPerformed(ActionEvent e) //实现这个抽象函数{if(e.getActionCommand()=="yunxing") System.out.println("很强");}
}

键盘事件

this.add(mjp);
this.addKeyListener(mjp); //要添加监听器class MyJPanel extends JPanel implements KeyListener //给面板实现键盘监听接口,以下3个函数必须实现
{int x=50,y=50;public void paint(Graphics g){super.paint(g); //调用父类g.fillRect(x, y, 50, 50); //画矩形}public void keyPressed(KeyEvent e) { //按键事件// TODO Auto-generated method stub//System.out.println("键盘被按下");//System.out.println((char)e.getKeyCode());if(e.getKeyCode()==KeyEvent.VK_UP){    y-=5; }else if(e.getKeyCode()==KeyEvent.VK_DOWN){ y+=5; }else if(e.getKeyCode()==KeyEvent.VK_LEFT){ x-=5; }else if(e.getKeyCode()==KeyEvent.VK_RIGHT){ x+=5; }this.repaint();}public void keyReleased(KeyEvent e) { //松开事件// TODO Auto-generated method stub}public void keyTyped(KeyEvent e) { //打字事件// TODO Auto-generated method stub}
}

鼠标事件

this.add(mjp);
this.addMouseListener(mjp);class MyJPanel extends JPanel implements MouseListener //以下5个函数要写
{int x=50,y=50;public void paint(Graphics g){super.paint(g);g.drawOval(x, y, 50, 50);}public void mouseClicked(MouseEvent e) //鼠标点击事件{System.out.println(e.getX()+","+e.getY());x=e.getX();y=e.getY();this.repaint();}public void mouseReleased(MouseEvent e) //松开{}public void mouseExited(MouseEvent e)  //出界面{}public void mousePressed(MouseEvent e) //按下{}public void mouseEntered(MouseEvent e) //进入界面{}
}

增加新的对话窗口

public void actionPerformed(ActionEvent e) //原来窗口的监听{if(e.getActionCommand()=="tianjia"){Add add=new Add(this,"ok",true); //新的对话界面}}
class Add extends JDialog implements ActionListener
{public Add(Frame fck,String ckm,boolean msck){super(fck,ckm,msck);  //父类//this.setTitle("学生信息");this.setSize(500, 500);this.setLocation(100, 100);JButton jb=new JButton("取消");jb.addActionListener(this);jb.setActionCommand("quxiao");this.add(jb);this.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);this.setVisible(true);}public void actionPerformed(ActionEvent e){if(e.getActionCommand()=="quxiao"){this.dispose(); //关闭窗口}}
}