Java學習筆記-13.創建窗口和程序片
阿新 • • 發佈:2017-07-04
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1.init()方法:程序片第一次被創建,初次運行初始化程序片時調用。
start()方法:每當程序片進入web瀏覽器中,並且允許程序片啟動他的常規操作時調用(特殊的程序片被stop()關閉);同樣在init()後調用。
paint()方法:基礎類Component的一部分(繼承結構中上朔三級)。作為update()的一部分調用,以便對程序片的畫布進行特殊的描繪。
stop()方法:每次程序片從web瀏覽器的視線中離開時調用,時程序片能關閉代價高昂的操作;同樣在調用destroy()前調用。
destroy()方法:程序片不再需要,將它從頁面中卸載時調用。
2.事件模型:(1)先在類中添加addXXXXXListener()方法。
(2)重寫執行接口的方法。
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()方法中新建一個Frame類,並將applet的衍生類給其初始化。
(2)繼承WindowAdapter類,並重寫windowClosing()方法。
(3)執行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; @Override public void actionPerformed(ActionEvent e) { // TODO 自動生成的方法存根 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); } }else t1.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)所有的類必須放在一個包中,在web中沒有包是不存在的。
(2)所有的類必須聲明為public class,這樣才能夠被外部訪問。
(3)類中所有的屬性都必須封裝,使用private聲明。
(4)封裝的屬性如果需要被外部所操作,則必須編寫對應的setter,getter方法。
(5)一個JavaBean中至少存在一個無參構造方法。
5.Swing各種邊框的一個例子:
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); } } }
Java學習筆記-13.創建窗口和程序片