AWT的層次關(guān)系

1、第四章 圖形編程4.1AWT與Swing簡(jiǎn)介一.AWT工具包java的抽象窗口工具包（AWT:Abstract window Interface)包含在java.awt包中，它提供了許多用來(lái)設(shè)計(jì)GUI的組件類和容器類基本AWT庫(kù)處理用戶界面元素的方法是把這些元素的創(chuàng)建和行為委托給每個(gè)目標(biāo)平臺(tái)上的本地GUI工具箱進(jìn)行處理AWT的層次關(guān)系EventComponentGraphicsMenuComponButtonScrollBarContainerCanvasListCheckBoxLabelTextFieldTextAreaWindowFrameDialogFontAppletPanel二. J

2、ava Swing Swing：非基于對(duì)等體的GUI工具箱Swing具有更豐富并且更方便的用戶界面元素集合Swing對(duì)底層平臺(tái)的依賴更少Swing會(huì)帶來(lái)交叉平臺(tái)上的統(tǒng)一視覺體驗(yàn)Swing類被放在javax.Swing包上Swing 組件層次關(guān)系ComponemtContainerWindowFrameDialogJFrameJDialogJComponentJPanelJLabelJScrollerJMenuBarJButtonJtext.三.AWT與Swing的關(guān)系對(duì)于使用過(guò)Java早期版本的人來(lái)說(shuō)，大部分AWT組件都有其Swing等價(jià)物后者的名字一般是在前面添加一個(gè)字母“J”，如：JBut

3、ton,JFrame,JPanel等5.2組件和容器一.組件Java把由Component類的子類或間接子類創(chuàng)建的對(duì)象稱為一個(gè)組件例：Button button1=new Button();例：TextField textfield=new TextField();例：Label label=new Label();二.容器Java把由container類的子類或間接子類創(chuàng)建的對(duì)象稱為一個(gè)容器例：Frame fra=new Frame(“這是一個(gè)窗口”)；Applet是Panel的子類，是Container的間接子類Applet本身也是一個(gè)容器三.添加組件Component類提供了一個(gè)方法：a

4、dd();例：fra.add(button);例：fra.add(TextField);容器本身也可以看作是一個(gè)組件，因此可以把一個(gè)容器添加到另一個(gè)容器里，實(shí)現(xiàn)容器嵌套例：add(fra);四。布局管理器Java 采用非常優(yōu)秀的概念來(lái)進(jìn)行布局一個(gè)容器內(nèi)的所有組件都由一個(gè)布局管理器來(lái)進(jìn)行管理Java支持以下四種布局管理器 FlowLayout BorderLayout CardLayout GridBagLayout五.常用容器1.框架在Java中，頂層窗口（沒(méi)有包含在另一個(gè)窗口內(nèi)的窗口）稱為框架AWT庫(kù)中有一個(gè)基于對(duì)等體的Frame類對(duì)應(yīng)著頂層該類的Swing版本為JFrame,JFrame是

5、Frame 子類例：框架是容器的例子 SimpleFrameTest.java import javax.swing.*;public class SimpleFrameTest public static void main(String args) SimpleFrame myframe = new SimpleFrame(); myframe.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE); myframe.show(); class SimpleFrame extends JFrame public SimpleFrame() setSi

6、ze(WIDTH, HEIGHT); public static final int WIDTH = 300; public static final int HEIGHT = 200;2.定義相對(duì)框架通過(guò)調(diào)用toolkit來(lái)得到系統(tǒng)相關(guān)信息例：CenteredFrameTest.java例：獲得屏幕尺寸Toolkit kit = Toolkit.getDefaultToolkit(); Dimension screenSize = kit.getScreenSize();int screenHeight=screenSize.height;int screenWidth = screenSi

7、ze.width;class CenteredFrame extends JFrame public CenteredFrame() / get screen dimensions Toolkit kit = Toolkit.getDefaultToolkit Toolkit kit = Toolkit.getDefaultToolkit();(); Dimension screenSize = kit.getScreenSize(); Dimension screenSize = kit.getScreenSize(); int screenHeight = screenSize.heigh

8、t; int screenHeight = screenSize.height; int screenWidth = screenSize int screenWidth = screenSize.width;.width; / center frame in screen/ center frame in screen setSize(screenWidth / 2, screenHeight / 2); setSize(screenWidth / 2, screenHeight / 2); setLocation(screenWidth / 4, screenHeight setLocat

9、ion(screenWidth / 4, screenHeight / 4) / 4) / set frame icon and title / set frame icon and title Image img = kit.getImage(icon.gif); Image img = kit.getImage(icon.gif); setIconImage(img); setIconImage(img); setTitle(CenteredFrame setTitle(CenteredFrame);); 3.常見類及方法APIjava.awt.Componentboolean isVis

10、ible()檢查組件是否可見void setVisible(boolean b) 設(shè)置組件可見void setBounds(int x,int y,int width,int height)移動(dòng)并縮放組件Dimension getSize()得到組件的大小void setSize(int width,int height)void setSize(Dimension d) 把組件縮放到指定調(diào)度和寬度 java.awt.windowvoid toFrond()放在其它窗口前面void toBack()放在其它窗口后面java.awt.Framevoid setResizable(boolean

11、b)縮放框架void setTitle(String s)設(shè)置標(biāo)題void setIconImage(Image image) 將Image用作圖標(biāo)java.awt.Toolkit Dimension getScreenSize()得到用戶屏幕大小內(nèi)容窗格是用來(lái)添加組件的，獲得內(nèi)容窗格的代碼如下：在AWT中可調(diào)用add()把組件直接添加到AWT Frame中 ,但在Swing中組件只能添加到內(nèi)容窗格里六.顯示信息前面的例子中 ,信息都顯示在控制臺(tái)窗口,現(xiàn)在我們?cè)囍研畔@示到JFrame中 JFrame的結(jié)構(gòu)有點(diǎn)復(fù)雜，它由：根窗格、布局窗格、透明窗格和內(nèi)容窗格 用戶也可以創(chuàng)建一個(gè)畫板，然后在畫

12、板上進(jìn)行繪制，最后將畫板添加到內(nèi)容窗格里，此時(shí)需要重載paintComponent()paintComponent(Graphics g)是定義在JComponent中，每當(dāng)該方法被調(diào)用時(shí)，系統(tǒng)就自動(dòng)產(chǎn)生一個(gè)Graphics類型的參數(shù)，傳遞給paintComponent方法中的參數(shù)gContainer cp=getContentPane(); Component c=; cp.add(c);Graphics類提供繪制圖像和輸出文本的方法創(chuàng)建一個(gè)畫板class MyPanel extends JPanel public void paintComponent(Graphics g) super.

13、paintComponent(Graphics g) g.drawString(“Hello!world”) . MyPanel擴(kuò)展了擴(kuò)展了JPanel,但面板的背景但面板的背景顏色等工作要由顏色等工作要由Jpanel來(lái)完成，來(lái)完成，super.paintComponent確保父類也參預(yù)繪制確保父類也參預(yù)繪制只要窗口重新繪制，paintComponent()就被自動(dòng)調(diào)用（在AWT中上paint()例.在畫板上輸出信息NotHelloWorld.javaclass NotHelloWorldFrame extends JFrameclass NotHelloWorldFrame extends

14、JFrame public NotHelloWorldFrame public NotHelloWorldFrame()() setTitle(NotHelloWorld setTitle(NotHelloWorld); ); setSize setSize(WIDTH, HEIGHT);(WIDTH, HEIGHT); / add panel to frame / add panel to frame NotHelloWorldPanelNotHelloWorldPanel panel = new panel = new NotHelloWorldPanel NotHelloWorldPan

15、el();(); Container contentPane = getContentPane(); Container contentPane = getContentPane(); contentPane contentPane.add(panel); .add(panel); class NotHelloWorldPanel extends JPanel class NotHelloWorldPanel extends JPanel public void paintComponent public void paintComponent(Graphics g)(Graphics g)

16、super.paintComponent super.paintComponent(g);(g); g.drawString g.drawString(Not a Hello, World program, (Not a Hello, World program, MESSAGE_X, MESSAGE_Y); MESSAGE_X, MESSAGE_Y); public static final int public static final int MESSAGE_X = 75; MESSAGE_X = 75; public public static final intstatic fina

17、l int MESSAGE_Y = 100; MESSAGE_Y = 100;常用APIjavax.swing.JFrameContainer getContentPane() 返回JFrame的內(nèi)容窗格java.awt.Component void repain() 重新繪制組件void repaint(int x, int y,intwidth,int height) 重新繪制組件的一部分javax.swing.Jcomponentvoid paintComponent(Graphics g)需要重載該方法來(lái)說(shuō)明你的組件應(yīng)如何繪制5.3圖形編程一. 2D圖形 1.2D對(duì)象 隨著SDK2.0

18、版的到來(lái)，J2SE了包含一個(gè)Java 2D庫(kù)，該庫(kù)實(shí)現(xiàn)了一個(gè)非常強(qiáng)大的圖形操作集如何獲得Graphics 2D類對(duì)象該類是Graphics類的子類，通?？捎肎raphics對(duì)象轉(zhuǎn)換而來(lái).例：public void paintComponent(Graphics g) graphics2D g2=(graphics 2D)g; . 2.坐標(biāo) JDK 1.0版中使用整數(shù)像素坐標(biāo)系java 2D形體使用浮點(diǎn)數(shù)坐標(biāo)系，這樣可為坐標(biāo)指定單位。存在的問(wèn)題:Retangle2D r=.; float f=r.getWidth();/*Error*/getWidth()返回double值，應(yīng)進(jìn)行轉(zhuǎn)換： flo

19、at f=(float)r.getWidth();例：DrwaTest.java因此，2D庫(kù)的形體類有兩種版本： Retangle2D.Float Retangle2D.Doubleclass DrawPanel extends JPanel public void paintComponent(Graphics g) super.paintComponent(g); Graphics2D g2 = (Graphics2D)g;/ draw a rectangle double leftX = 100; double topY = 100; double width = 200; double

20、 height = 150; Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height); g2.draw(rect); / draw the enclosed ellipse Ellipse2D ellipse = new Ellipse2D.Double(); ellipse.setFrame(rect); g2.draw(ellipse);/ draw a diagonal line g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + he

21、ight); / draw a circle with the same center double centerX = rect.getCenterX(); double centerY = rect.getCenterY(); double radius = 150; Ellipse2D circle = new Ellipse2D.Double(); circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius); g2.draw(circle); 3.常用APIjava.awt.geom.R

22、etangle2D.DoubleRetangle2D.Float(float x,float y,float width, float height) Ellipse2D.Double(double x,double y, double width,double height)java.awt.geom.Ellipse2D.DoubleRetangle2D.Double(double x,double y, double width,double height)java.awt.geom.Retangle2D.Floatjava.awt.geom.Line2D.DoubleLine2D.dou

23、ble(Point2D start,Point2D end)Line2D.double(double startx,double starty, double endx,double endy)java.awt.geom.Point2D.DoublePoint2D.Double(double x,double y)fill(Graphics2D rec) 填充顏色drawGraphics2D rec) 繪制圖形rec二.顏色Graphics2D類的setPaint方法(Graphics類為setColor方法)用來(lái)設(shè)置顏色。例： g2.setPaint(Color.red); g2.drawS

24、tring(“Set Color”,100,100)1.標(biāo)準(zhǔn)顏色black、blue、cyan、darkgray、gray、green、lightgray、magenta、orange、pink、red、white、yellow2.復(fù)合色通過(guò)指定紅綠藍(lán)三色比例，用Color對(duì)象來(lái)復(fù)合成一種新的顏色。Color構(gòu)造器如下：Color(int redness,int greenness,int blueness) 其中參數(shù)取值為0-2553.常用APIjava.awt.Colorvoid Color(int r,int g,int b)例:g.setPaint(new Color(0,128,12

25、8); java.awt.Graphicsvoid setcolor(Color c)java.awt.Graphic2Dvoid setPaint(paint p) java.awt.Cmponentvoid setBackground(Color c)void setForeground(Color c)例：填充顏色的例子FillTest.javaclass FillPanel extends JPanelclass FillPanel extends JPanel public void paintComponent public void paintComponent(Graphics

26、 g)(Graphics g) super.paintComponent super.paintComponent(g);(g); Graphics2D g2 = (Graphics2D)g; Graphics2D g2 = (Graphics2D)g; / draw a rectangle / draw a rectangle double leftX double leftX = 100; = 100; double topY double topY = 100; = 100; double width = 200; double width = 200; double height =

27、150; double height = 150; Rectangle2D rect Rectangle2D rect = new Rectangle2D.Double = new Rectangle2D.Double (leftX, topY (leftX, topY,width, height);,width, height); g2. g2.setPaintsetPaint(Color.red)(Color.red); ; g2. g2.fillfill(rect(rect);); / draw the enclosed ellipse / draw the enclosed ellip

28、se Ellipse2D ellipse = new Ellipse2D.Double(); Ellipse2D ellipse = new Ellipse2D.Double(); ellipse.setFrame(rect ellipse.setFrame(rect);); g2. g2.setPaintsetPaint(new Color(0, 128, 128);(new Color(0, 128, 128); / a dull blue-green / a dull blue-green g2. g2.fillfill(ellipse);(ellipse); 三.文本和字體1.五個(gè)邏輯

29、字體名SanaSerifSerifMonospacedDialogDialogInput2.字體風(fēng)格Font.PLAIN Font.BOLDFond.ITALIC Fond.BOLD+Font.ITALIC 3.設(shè)置字體Font serif=new Font(“Serif”,Font.BOLD,14);g2.setFont(serif);4.編程控制字體字符輸出的效果取決于下面三個(gè)因素： 使用的字體 字符串 繪制字體的設(shè)備幾個(gè)基本術(shù)語(yǔ)： 上坡度下坡度空行 基線基線高度 調(diào)用Graphics2D類中的getFontRenderContext方法，可獲得一個(gè)FontRenderContext類的對(duì)

30、象,再調(diào)用Fond類的getStringBounds方法,該方法返回一個(gè)包圍字符串的矩形.代碼如下：String message=“Hello,World!”;Font f=new Foun(“serif”,Font.BOLD,14);FontRenderContext context= g2. getFontRenderContext();Retangle2D bounds= f. getStringBounds(message,context);獲得字符串寬度、高度、上坡度、下坡度的方法如下：double stringwidth= bounds.getWidth();double stri

31、ngheigth= bounds.getHeigth();double ascent= - bounds.getY();double descent= bounds.getHeigth() +bounds.getY();基點(diǎn)將字符串顯示在面板中央的代碼如下：String message=“Hello,World!”;Font f=new Foun(“serif”,Font.BOLD,14);FontRenderContext context= g2. getFontRenderContext();Retangle2D bounds= f. getStringBounds(message,con

32、text);double x=(getWidth()- bounds. getWidth()/2;double y=(getHeigth()- bounds.getWidth()/2;double ascent= - bounds.getY();double basey=y+ascent;g2.drawString(message, (int)x,(int)basey);例：將字符串顯示在畫板中央的例子 FontTest.javaAPI:java.awt.Font Font(String name,int style,int Size)String getFontName()String ge

33、tFamily()String getName()Retangle2D getStringBounds(String s, FountRenderContext context)java.awt.font.LineMetricsfloat getAscent()float getDecent()float getHeight()float getWeight()java.awt.Graphicsvoid setFont(Font font)void DrawString(String str,int x,int y)四.圖象在Java應(yīng)用程序中須通過(guò)使用Toolkit對(duì)象，調(diào)用getDefau

34、ltToolkit()，完成將一個(gè)圖象文件加載到程序中，再調(diào)用Graphics類提供的DrawImage()顯示它。目前只能讀取gif和JPEG格式的文件下面一段代碼用來(lái)在本地機(jī)上加載一個(gè)名為 msn.jpg的文件：Image img=ToolkitgetDefaultToolkit(). getImage(“msn.jpg”)若從網(wǎng)絡(luò)上加載，必須提供URL例：URL u=new URL( “http:/ img=ToolkitgetDefaultToolkit(). getImage(u)顯示代碼： public void paintComponent(Graphics g) . g.drawImage(img,x,y,null); 圖象的跟蹤加載使用MediaTracker類中的方法addImage()可以將一個(gè)圖象的加載過(guò)程放入媒體跟蹤器，從而實(shí)現(xiàn)對(duì)圖象加載過(guò)程的跟蹤MediaTracker tracker=new MediaTracker(); Image img=ToolkitgetDefaultToolkit(). get