名词解释

什么是GUI ？

图形用户界面

什么是AWT

基本的程序设计类库，抽象接口工具箱。将处理界面的的任务下派给每一个平台（windows等）

什么是swing

与AWT不同在不同平台显示的界面是一样的。建立在AWT之上

Swing的优势

1. Swing拥有丰富的、便捷的、用户界面元素集合
2. Swing对底层平台依赖极少
3. Swing对于不同平台一致的观感
4. 基本事件采用AWT

框架创建和定位

写一个显示空框架的简单程序

  package SimpeFrame;

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

public class SimpeFrameTest {
    public static void main(String[] args){
        EventQueue.invokeLater(()->{
            SimpleFrame frame = new SimpleFrame();
            frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}
class SimpleFrame extends JFrame{
    private static final int DEAULT_WIDTH = 300;
    private static final int DEAULT_Height = 200;
    public SimpleFrame(){
        setSize(DEAULT_WIDTH,DEAULT_Height);
    }

}

所有的Swing组件必须由时间分派线程（EventQueue.invokeLater）配置

调整框架的大小

package SimpeFrame;
import javax.swing.*;
import java.awt.*;
public class SizeFrameTest {

    public static void main(String[] args){
        EventQueue.invokeLater(() -> {
            JFrame frame = new SizeFrame();
            frame.setTitle("SizedFrame");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}
class SizeFrame extends JFrame{
    public SizeFrame(){
        Toolkit kit = Toolkit.getDefaultToolkit();
        Dimension screenSize = kit.getScreenSize();
        int screenWidth = screenSize.width;
        int screenHeight = screenSize.height;
        setSize(screenWidth/2,screenHeight/2);
        setLocationByPlatform(true) ;
        // set frame icon
        Image img = new ImageIcon("snail.png").getImage() ;
        setIconImage(img) ;
    }
}

JFrame内部层级.png

显示文字组件

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

import static com.sun.tools.internal.xjc.reader.Ring.add;

public class SizeFrameTest {

    public static void main(String[] args){
        EventQueue.invokeLater(() -> {
            JFrame frame = new NotHelloWordFrame();
            frame.setTitle("NotHelloWord");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}

class NotHelloWordFrame extends JFrame{
    public NotHelloWordFrame(){
        add(new NotHelloWorldComponent());
        pack();
    }
}
class NotHelloWorldComponent extends JComponent{

    public static final int MESSAGE_X = 75;
    public static final int MESSAGE_Y = 100;
    private static final int DEFAULT_WIDTH = 300;
    private static final int DEFAULT_HEIGHT = 200;
    public void paintComponent(Graphics g){
        g.drawString("Not a Hello, World program", MESSAGE_X, MESSAGE_Y) ;
    }
    public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}