Java之创建窗口和程序片详解
Java之创建窗口和程序片详解,如下所示:
init()方法:程序片第一次被创建,初次运行初始化程序片时调用。
stop()方法:每次程序片从web浏览器的视线中离开时调用,时程序片能关闭代价高昂的操作;同样在调用destroy()前调用。
destroy()方法:程序片不再需要,将它从页面中卸载时调用。
start()方法:每当程序片进入web浏览器中,并且允许程序片启动他的常规操作时调用(特殊的程序片被stop()关闭);同样在init()后调用。
paint()方法:基础类Component的一部分(继承结构中上朔三级)。作为update()的一部分调用,以便对程序片的画布进行特殊的描绘。
2.事件模型:(1)先在类中添加addXXXXXListener()方法。
(2)重写执行接口的方法。
package thirteen;import java.awt.*;import java.awt.event.*;import java.applet.*;public class Button2New extends Applet { Button b1 = new Button("button1"), b2 = new Button("button2");public void init() { b1.addActionListener(new B1()); b2.addActionListener(new B2()); add(b1); add(b2); }class B1 implements ActionListener {public void actionPerformed(ActionEvent e) { getAppletContext().showStatus("BUTTon1"); } }class B2 implements ActionListener {public void actionPerformed(ActionEvent e) { getAppletContext().showStatus("Button2"); } } }
3.制作窗口:(1)main()方法中新建一个Frame类,并将applet的衍生类给其初始化。
(2)继承WindowAdapter类,并重写windowClosing()方法。
(3)执行Frame的setVisible()方法。
package thirteen;import java.applet.*;import java.applet.*;import java.awt.BorderLayout;import java.awt.Button;import java.awt.TextField;import java.awt.Desktop.Action;import java.awt.Frame;import java.awt.event.*;import java.time.temporal.TemporalQueries;import javax.swing.table.TableRowSorter;import org.omg.CORBA.FloatSeqHelper;public class TextNew extends Applet { Button b1 = new Button("Get Text"), b2 = new Button("Set Text"); TextField t1 = new TextField(30), t2 = new TextField(30), t3 = new TextField(30); String s = new String();public void init() { b1.addActionListener(new B1()); b2.addActionListener(new B2()); t1.addTextListener(new T1()); t1.addActionListener(new T1A()); t1.addKeyListener(new T1K()); add(b1); add(b2); add(t1); add(t2); add(t3); }class T1 implements TextListener {public void textValueChanged(TextEvent e) { t2.setText(t1.getText()); } }class T1A implements ActionListener {private int count = 0; @Overridepublic void actionPerformed(ActionEvent e) {// TODO 自动生成的方法存根t3.setText("t1 Action Event " + count++); } }class T1K extends KeyAdapter {public void keyTyped(KeyEvent e) { String tString = t1.getText();if (e.getKeyChar() == KeyEvent.VK_BACK_SPACE) {if (tString.length() > 0) { tString = tString.substring(0, tString.length() - 1); t1.setText(tString); } }elset1.setText(t1.getText()+Character.toUpperCase(e.getKeyChar())); t1.setCaretPosition(t1.getText().length()); e.consume(); } } class B1 implements ActionListener{public void actionPerformed(ActionEvent e){ s=t1.getSelectedText();if(s.length()==0)s=t1.getText(); t1.setEditable(true); } }class B2 implements ActionListener{public void actionPerformed(ActionEvent e){ t1.setText("Insert by Button2:"+s); t1.setEditable(false);; } } public static void main(String[] args){ TextNew applet=new TextNew(); Frame aFrame=new Frame("TextNew"); aFrame.addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e){ System.exit(0); } }); aFrame.add(applet, BorderLayout.CENTER); aFrame.setSize(300,200); applet.init(); applet.start(); aFrame.setVisible(true); } }
4.JavaBean要求:
(1)所有的类必须放在一个包中,在web中没有包是不存在的。
(2)所有的类必须声明为public class,这样才能够被外部访问。
(3)类中所有的属性都必须封装,使用private声明。
(4)封装的属性如果需要被外部所操作,则必须编写对应的setter,getter方法。
(5)一个JavaBean中至少存在一个无参构造方法。
5.Swing各种边框的一个例子:
package thirteen;import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.border.*;public class Borders extends JPanel {static JPanel showBorder(Border b) { JPanel jPanel = new JPanel(); jPanel.setLayout(new BorderLayout()); String nm = b.getClass().toString(); nm = nm.substring(nm.lastIndexOf('.') + 1); jPanel.add(new JLabel(nm, JLabel.CENTER), BorderLayout.CENTER); jPanel.setBorder(b);return jPanel; }public Borders() { setLayout(new GridLayout(2, 4)); add(showBorder(new TitledBorder("Title"))); add(showBorder(new EtchedBorder())); add(showBorder(new LineBorder(Color.blue))); add(showBorder(new MatteBorder(5, 5, 30, 30, Color.green))); add(showBorder(new BevelBorder(BevelBorder.RAISED))); add(showBorder(new SoftBevelBorder(BevelBorder.LOWERED))); add(showBorder(new CompoundBorder(new EtchedBorder(), new LineBorder(Color.red)))); }public static void main(String[] args) { Show.inFrame(new Borders(), 500, 300); } static class Show {public static void inFrame(JPanel jPanel, int width, int height) { String title = jPanel.getClass().toString();if (title.indexOf("class") != -1) title = title.substring(6); JFrame frame = new JFrame(title); frame.addWindowListener(new WindowAdapter() {public void WindowClosing(WindowEvent e) { System.exit(0); } }); frame.getContentPane().add(jPanel, BorderLayout.CENTER); frame.setSize(width, height); frame.setVisible(true); } } }
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