Java課程設計的圖片瀏覽器的

1、一.課程設計的任務及要求二.需求分析圖形化界面（GUI）編程，編寫一個圖片瀏覽器程序可以支持“.GIF”， “.JPEG”,“.jpeg”,“.TGA”,“.JPG”,“.jpg”等格式，單張打開圖片，可以將同一目錄下的圖片按縮略圖打開按“上一張”“下一張”按鈕可以顯示相應圖片。運行Applet時，圖像不是一氣呵成的，因為方法不是吧圖像完整的裝入內(nèi)存再顯示的。于此相反，方法創(chuàng)建一個線程，該線程與Applet的原有線程并發(fā)執(zhí)行，一邊裝入一邊顯示，從而產(chǎn)生上了不聯(lián)需顯示的現(xiàn)象。為了提高圖像才顯示效果，可以采用雙緩沖技術：首先把圖像裝入內(nèi)存，然后再顯示在屏幕上。三. 設計思路3.1界面設計選擇圖片按

2、鈕：主要用dir函數(shù)實現(xiàn)圖片的遍歷。上一張，下一張：通過做標軸回調(diào)函數(shù)實現(xiàn)。由于本軟件為單機軟件，不需要大量的數(shù)據(jù)讀寫和數(shù)據(jù)交換，實現(xiàn)上、下功能要求只能讀取PictureBox控件當前加載的目錄，讀取當前路徑，創(chuàng)建一維數(shù)組。frame = new Frame(PictureViewer); Panel pb = new Panel(); Button select = new Button(選擇圖片); previous = new Button(上一張); next = new Button(下一張); select.addActionListener(this); previous.add

3、ActionListener(this);3.2.圖像加載：Applet常用來顯示儲存在文件中的圖像，多數(shù)Applet使用的是GIF或JPEG格式的圖像文件。需Applet加載圖像只需首先定義Image對象，然后使用getImage()方法把圖像和文件結合起來即可。image_width = bi.getWidth(this); image_height = bi.getHeight(this); double image_proportion = 1.0 * image_height / image_width; System.out.println(image: w +image_widt

4、h+ ,h +image_height+ ,p1 +image_proportion);if(image_proportion screen_proportion) image_height = screen_height; image_width = (int)(image_height / image_proportion); System.out.println( p1p0 w= +image_width); else image_width = screen_width; image_height = (int)(image_width * image_proportion); Sys

5、tem.out.println( p0p1 h= +image_height); 四.詳細設計4.1.程序設計流程圖開始圖片上一張查找盤符圖片下一張查找文件夾結束查找文件4.2.源程序代碼package C;import java.io.File;import java.io.FilenameFilter;public class MyFilter implements FilenameFilter private String extension; public MyFilter() extension = new String.jpg, .JPG, .gif, .GIF, .png, .P

6、NG, .jpeg, .JPEG; public MyFilter(String extension) this.extension = extension; public boolean accept(File dir,String name) for(String s : extension) if(name.endsWith(s) return true; return false; package C;import java.awt.*;import java.awt.event.*;import java.awt.image.*;public class MyCanvas exten

7、ds Canvas implements ComponentListener /* * */private static final long serialVersionUID = 1L;private BufferedImage bi; private Image im; private int image_width; private int image_height; public void setImage(BufferedImage bi) this.bi = bi; this.zoom(); public void paint(Graphics g) g.drawImage(im,

8、(this.getWidth()-image_width)/2,(this.getHeight()-image_height)/2,this); public void componentResized(ComponentEvent e) if(bi != null) System.out.println(resize!); this.zoom(); this.repaint(); public void componentMoved(ComponentEvent e) public void componentShown(ComponentEvent e) public void compo

9、nentHidden(ComponentEvent e) public void zoom() if(bi = null) return; int screen_width = this.getWidth(); int screen_height = this.getHeight(); double screen_proportion = 1.0 * screen_height / screen_width; System.out.println(screen: w +screen_width+ ,h +screen_height+ ,p0 +screen_proportion); image

10、_width = bi.getWidth(this); image_height = bi.getHeight(this); double image_proportion = 1.0 * image_height / image_width; System.out.println(image: w +image_width+ ,h +image_height+ ,p1 +image_proportion); if(image_proportion screen_proportion) image_height = screen_height; image_width = (int)(imag

11、e_height / image_proportion); System.out.println( p1p0 w= +image_width); else image_width = screen_width; image_height = (int)(image_width * image_proportion); System.out.println( p0p1 h= +image_height); im = bi.getScaledInstance(image_width,image_height,Image.SCALE_SMOOTH); package C;import java.aw

12、t.*;import java.awt.event.*;import java.awt.image.*;import java.io.*;import javax.imageio.*;public class T implements ActionListener private Frame frame; private MyCanvas mc ; private String fpath; private String fname; private File files; private int findex ; private FileDialog fd_load; private MyF

13、ilter filter; private Button previous ; private Button next ; public static void main( String args) throws Exception new T().init(); public void init() frame = new Frame(PictureViewer); Panel pb = new Panel(); Button select = new Button(選擇圖片); previous = new Button(上一張); next = new Button(下一張); sele

14、ct.addActionListener(this); previous.addActionListener(this); next.addActionListener(this); pb.add(select); pb.add(previous); pb.add(next); mc = new MyCanvas(); mc.setBackground(new Color(200,210,230); mc.addComponentListener(mc); frame.add(pb,North); frame.add(mc,Center); frame.setSize(360,360); fr

15、ame.setLocation(400,200); frame.addWindowListener(new WindowAdapter() public void windowClosing(WindowEvent e) System.exit(0); ); frame.setVisible(true); this.validateButton(); filter = new MyFilter(); fd_load = new FileDialog(frame,打開文件,FileDialog.LOAD); fd_load.setFilenameFilter(filter); public vo

16、id actionPerformed(ActionEvent e) String command = e.getActionCommand(); if(command.equals(選擇圖片) fd_load.setVisible(true); fpath = fd_load.getDirectory(); fname = fd_load.getFile(); if(fpath != null) & (fname != null) this.display(new File(fpath + fname); files = new File(fpath).listFiles(filter); t

17、his.setIndex(); else if(command.equals(上一張) findex-; if(findex= files.length) findex = files.length-1; this.display(filesfindex); this.validateButton(); public void display(File f) try BufferedImage bi = ImageIO.read(f); mc.setImage(bi); frame.setTitle(PictureViewer - + f.getName() + ); catch(Except

18、ion e) e.printStackTrace(); mc.repaint(); public void setIndex() File current = new File(fpath + fname); if(files != null) for(int i=0;i 0); next.setEnabled(files!=null) & (findex(files.length-1); 五.運行調(diào)試與分析討論5.1.將同一目錄下的圖片按縮略圖打開 5.2.單張打開圖片5.3.按”上一張”,”下一張”按鈕打開圖片六. 設計體會與小結我通過這次編程實踐學習到了Image和Griphics相關的類的使用。首先我通過網(wǎng)上搜集資料和自己看jdk api對Image、graphics、swing中的類有了實質(zhì)的操練，對它們的理解有了進一步的理解。不象以前只有模糊的記憶，根本不會運用到實際的情況中，僅僅照著課本超代碼。不過由于技術水平限制，寫的代