GUI基础知识点

简介

GUI的核心技术：AWT(是Swing 的前身) Swing

• 不流行的原因
  • 界面不美观
  • 运行需要jre环境(可能一个项目的大小比jre还要大)
• 为什么我们需要学习
  • 了解MVC架构和监听

AWT

介绍

全名：abstract windows tools

awt包含了很多类和接口

里面有各种各样的元素 eg:窗口、按钮、文本框

用到java.awt.*

组件和容器(核心类)

Frame

窗口是我们日常使用软件最常看到的

import java.awt.*;

Frame frame=new Frame("JAVA WINDOWS");
//需要设置可见性 w h
frame.setVisible(true);
//设置窗口大小
frame.setSize(400,900);
Color color = new Color(128,128,128);
frame.setBackground(color);
//弹出的初始位置
frame.setLocation(new Point(200,300));
//设置大小固定，窗口不能拉伸
frame.setResizable(false);

Panel

可以看成一个空间，但是不能单独存在,必须添加到某个容器中

public static void main(String[] args) {
    Frame frame = new Frame();
    Panel panel = new Panel();
    //设置布局
    frame.setLayout(null);
    //坐标
    frame.setBounds(300,300,500,500);
    frame.setBackground(Color.yellow);
    //panel设置坐标,相对于frame
    panel.setBounds(50,50,400,400);
    panel.setBackground(Color.blue);
    frame.add(panel);
    frame.setVisible(true);
    //监听事件，解决点击窗口关闭
    //WindowAdapter 适配器模式,只需写需要的override
    //WindowListener 实现所有的监听，很多个override
    //匿名内部类
    frame.addWindowListener(new WindowAdapter() {
        @Override
        public void windowClosing(WindowEvent e) {
            //先隐藏再关闭
            setVisible(false);
            //结束程序
            System.exit(0);
        }
    });
}

备注：如果是JFrame,关闭窗口可以不用写一个监听事件，一行代码直接搞定

布局管理器

• ​ 流式布局

  public static void main(String[] args) {
      Frame frame = new Frame();
      //组件 按钮
      Button button01 = new Button("button01");
      Button button02 = new Button("button02");
      Button button03 = new Button("button03");
      frame.setBounds(300,300,500,500);
      frame.setVisible(true);
      //设置为流式布局
      frame.setLayout(new FlowLayout(FlowLayout.LEFT));
      frame.add(button01);
      frame.add(button02);
      frame.add(button03);
  }
  

  

• ​ 东西南北中

  public static void main(String[] args) {
      Frame frame = new Frame();
      Button button1 = new Button("East");
      Button button2 = new Button("West");
      Button button3 = new Button("South");
      Button button4 = new Button("North");
      Button button5 = new Button("Center");
      frame.add(button1,BorderLayout.EAST);
      frame.add(button2,BorderLayout.WEST);
      frame.add(button3,BorderLayout.SOUTH);
      frame.add(button4,BorderLayout.NORTH);
      frame.add(button5,BorderLayout.CENTER);
      frame.setVisible(true);
      frame.setBounds(500,500,500,500);
  }
  

  

• ​ 表格布局 Grid

  public static void main(String[] args) {
      Frame frame = new Frame();
      Button button1 = new Button("1");
      Button button2 = new Button("2");
      Button button3 = new Button("3");
      Button button4 = new Button("4");
      Button button5 = new Button("5");
      Button button6 = new Button("6");
      frame.setVisible(true);
      frame.setBounds(500,500,500,500);
      frame.setLayout(new GridLayout(3,2));
      frame.add(button1);
      frame.add(button2);
      frame.add(button3);
      frame.add(button4);
      frame.add(button5);
      frame.add(button6);
  }
  

  

• 综合练习

public static void main(String[] args) {
        Frame frame = new Frame();
        frame.setSize(400,300);
        frame.setLocation(300,400);
        frame.setVisible(true);
        Panel p1 = new Panel(new BorderLayout());
        Panel p2 = new Panel(new GridLayout(2,1));
        p1.add(new Button("east"),BorderLayout.EAST);
        p1.add(new Button("west"),BorderLayout.WEST);
        p2.add(new Button("center1"));
        p2.add(new Button("center2"));
        p1.add(p2,BorderLayout.CENTER);
        frame.add(p1);
    }

事件监听

简单的例子

public class TestFrame {
    public static void main(String[] args) {
        Frame frame = new Frame();
        Button button = new Button();
        //因为addActionListener需要一个ActionListener，所以我们需要构建一个ActionListener
        MyActionListener myActionListener = new MyActionListener();
        button.addActionListener(myActionListener);

        frame.add(button,BorderLayout.CENTER);
        frame.setVisible(true);
        frame.pack();//窗口自适应  
    }   
}
class MyActionListener implements ActionListener{
    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("点击了一下，在控制台输出");
    }
}

输入框监听

public class TestFrame {
    public static void main(String[] args) {
        new MyFrame();
    }
}
class MyFrame extends Frame{
    public MyFrame(){
        TextField textField = new TextField();
        add(textField);

        //监听文本输入框的文字
        MyActionListener myActionListener = new MyActionListener();
        textField.addActionListener(myActionListener);
        //设置替换编码  密码处理
        textField.setEchoChar('*');
        setVisible(true);
        pack();
    }
}
class MyActionListener implements ActionListener{
    @Override
    public void actionPerformed(ActionEvent e) {
        //获得一些资源,返回一个对象
        TextField field = (TextField)e.getSource();
        //获得输入框中的文本
        System.out.println(field.getText());
        field.setText("");
    }
}

简易计算器

方法一：组合写法

import java.awt.*;
import java.awt.event.*;
//简易计算
public class TestFrame {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算类
class Calculator extends Frame{
    TextField num1,num2,num3;
    public void loadFrame(){
        //3个文本框
        num1 = new TextField(10);//10表示输入最大字符数，框的大小也会改变
        num2  = new TextField(10);
        num3 = new TextField(12);
        num1.setText("");
        num2.setText("");
        num3.setText("");
        //1个按钮
        Button button = new Button("=");
        button.addActionListener(new MyActionListener(this));
        //1个标签
        Label label = new Label("+");
        //流式布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
}
//监听类
class MyActionListener implements ActionListener{
    //获得计算器对象，在一个类中组合另外一个类
    Calculator calculator = null;

    public MyActionListener(Calculator calculator){
        this.calculator=calculator;
    }
    @Override
    public void actionPerformed(ActionEvent e) {
        //清空
        if("".equals(calculator.num3.getText())!=true){
            calculator.num1.setText("");
            calculator.num2.setText("");
            calculator.num3.setText("");
        }else{
            //获得加数和被加数
            int a=Integer.parseInt(calculator.num1.getText());
            int b=Integer.parseInt(calculator.num2.getText());
            //将+结果放入第三个框
            calculator.num3.setText(""+(a+b));
        }
    }
}

方法二：内部类写法（推荐）

内部类最大的好处就是畅通无阻访问外部类

//简易计算
public class TestFrame {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算类
class Calculator extends Frame{
    TextField num1,num2,num3;
    public void loadFrame(){
        //3个文本框
        num1 = new TextField(10);//10表示输入最大字符数，框的大小也会改变
        num2  = new TextField(10);
        num3 = new TextField(12);
        num1.setText("");
        num2.setText("");
        num3.setText("");
        //1个按钮
        Button button = new Button("=");
        button.addActionListener(new MyActionListener());
        //1个标签
        Label label = new Label("+");
        //流式布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
    //监听类
    private class MyActionListener implements ActionListener{
        @Override
        public void actionPerformed(ActionEvent e) {
            //清空
            if("".equals(num3.getText())!=true){
                num1.setText("");
                num2.setText("");
                num3.setText("");
            }else{
                //获得加数和被加数
                int a=Integer.parseInt(num1.getText());
                int b=Integer.parseInt(num2.getText());
                //将+结果放入第三个框
                num3.setText(""+(a+b));
            }
        }
    }
}

画笔

public class TestFrame {
    public static void main(String[] args) {
        new MyFrame().loadFrame();
    }
}
class MyFrame extends Frame{
    public void loadFrame(){
        setBounds(200,200,600,500);
        setVisible(true);
    }
    //画笔
    @Override
    public void paint(Graphics g) {
        //设置画笔颜色
        g.setColor(Color.blue);
        g.fillOval(100,100,100,100);
        //养成习惯，画笔用完，还原最初的颜色
        g.setColor(Color.black);
    }
}

鼠标监听

class MyFrame extends Frame{
    //画画需要画笔
    //需要监听鼠标当前的位置
    //需要集合存储这个点
    ArrayList<Point> points;
    public MyFrame(String title) {
        super(title);
        setBounds(200,200,400,300);
        points = new ArrayList<Point>();
        this.addMouseListener(new MyMouseListener());
        setVisible(true);
    }
    public class MyMouseListener extends MouseAdapter {
        @Override
        public void mousePressed(MouseEvent e) {
            MyFrame myFrame =(MyFrame)e.getSource();
            points.add(new Point(e.getX(),e.getY()));
            //每次点击鼠标都重新画一遍
            myFrame.repaint();
        }
    }
    @Override
    public void paint(Graphics g) {
        Iterator iterator = points.iterator();
        //注意是画一个数组
        while(iterator.hasNext()){
            Point point = (Point) iterator.next();
            g.setColor(Color.blue);
            //画一个小点
            g.fillOval(point.x,point.y,10,10);
        }
    }
}

键盘监听

public class TestFrame {
    public static void main(String[] args) {
        new MyFrame();

    }
}
class MyFrame extends Frame{
    public MyFrame() {
        setBounds(100,200,300,300);
        setVisible(true);
        this.addKeyListener(new KeyAdapter() {
            //键盘按下
            @Override
            public void keyPressed(KeyEvent e) {
                int keyCode = e.getKeyCode();
                if(keyCode==KeyEvent.VK_UP){
                    System.out.println("你按下了上键");
                }
            }
        });
    }
}

Swing

窗口 JFrame

public class TestJFrame {
    public void init(){
        //顶级窗口
        JFrame frame = new JFrame("JFrame窗口");
        frame.setVisible(true);
        frame.setBounds(100,100,200,200);
        /*注意必须要在容器中加入颜色，单纯下面这样写，无法生效
        frame.setBackground(Color.yellow);*/
        //获得一个容器
        Container container = frame.getContentPane();
        container.setBackground(Color.yellow);
        //设置文字Jlabel
        JLabel label = new JLabel("欢迎你");
        //文本标签居中
        label.setHorizontalAlignment(SwingConstants.CENTER);
        frame.add(label);
        //关闭事件 相当于awt的窗口监听 代码少多了吧
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new TestJFrame().init();
    }
}

弹窗 JDialog

public class TestJFrame extends JFrame{
    public TestJFrame() {
        this.setVisible(true);
        this.setSize(700,500);
        //JFrame 放东西 容器
        Container container = this.getContentPane();
        //绝对布局
        container.setLayout(null);
        
        JButton button  = new JButton("点击弹出对话框");//创建把
        button.setBounds(30,30,200,50);
        container.add(button);
        //点击按钮弹出弹窗
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                //弹窗
                new MyJDialog();
            }
        });
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new TestJFrame();
    }
}
class MyJDialog extends JDialog{
    public MyJDialog(){
        this.setVisible(true);
        this.setBounds(100,100,500,500);
        Container container = this.getContentPane();
        container.add(new JLabel("我是一个弹窗"));
    }
}

图标

import javax.swing.*;
import java.awt.*;

public class IconDemo extends JFrame implements Icon{
    private int width;
    private int height;
    public static void main(String[] args) {
        new IconDemo().init();
    }
    public void  init(){
        IconDemo iconDemo = new IconDemo(15,15);
        //图标可以放在按钮上或者标签上
        JLabel label = new JLabel("icontest",iconDemo,SwingConstants.CENTER);
        Container container = getContentPane();
        container.add(label);

        this.setVisible(true);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
    public IconDemo(){ }
    public IconDemo(int width,int height){
        this.width=width;
        this.height=height;
    }
    @Override
    public void paintIcon(Component c, Graphics g, int x, int y) {
        g.fillOval(x,y,width,height);
    }

    @Override
    public int getIconWidth() {
        return this.width;
    }

    @Override
    public int getIconHeight() {
        return this.height;
    }
}

图片

import javax.swing.*;
import java.awt.*;
import java.net.URL;

public class ImageDemo extends JFrame{
    private int width;
    private int height;
    public static void main(String[] args) {
        new ImageDemo();
    }
    public ImageDemo(){
        
        JLabel label = new JLabel("Imageicon");
		//这个url需要注意 容易写错找不到
        URL url= ImageDemo.class.getResource("icon.png");

        ImageIcon imageIcon = new ImageIcon(url);

        label.setIcon(imageIcon);
        label.setHorizontalAlignment(SwingConstants.CENTER);

        Container container = getContentPane();
        container.add(label);
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setBounds(0,0,200,200);
    }
}

面板

public class TestJFrame extends JFrame{
    public TestJFrame(){
        //获得容器
        Container container = this.getContentPane();
        //后面的参数是间距
        container.setLayout(new GridLayout(2,1,10,10));
        JPanel panel1 = new JPanel(new GridLayout(1,3));
        panel1.add(new Button("1"));
        panel1.add(new Button("1"));
        panel1.add(new Button("1"));
        container.add(panel1);
        this.setVisible(true);
        this.setSize(500,500);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
    public static void main(String[] args) {
        new TestJFrame();
    }
}

下拉框

public TestJFrame(){
        //获得容器
        Container container = this.getContentPane();
        JComboBox jComboBox = new JComboBox();
        jComboBox.addItem("下拉选项一");
        jComboBox.addItem("下拉选项二");
        jComboBox.addItem("下拉选项三");
        container.add(jComboBox);
//        System.out.println(jComboBox.getSelectedIndex());
//        System.out.println(jComboBox.getSelectedItem());
        this.setVisible(true);
        this.setSize(500,500);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
    public static void main(String[] args) {
        new TestJFrame();
    }

文本域/JscrollPan滚动条

public class TestJFrame extends JFrame{
    public TestJFrame(){
        //获得容器
        Container container = this.getContentPane();
        //文本域
        JTextArea jTextArea = new JTextArea(20,50);
        jTextArea.setText("大家好，你们的DJ同学又来喽");
        JScrollPane jScrollPan = new JScrollPane(jTextArea);
        container.add(jScrollPan);
        this.setVisible(true);
        this.setSize(500,500);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }
    public static void main(String[] args) {
        new TestJFrame();
    }
}

文本框

JTextField

密码框

JPasswordField