Java课程设计的图片浏览器的

.课程设计的任务及要求二.需求分析图形化界面（GUI）编程，编写一个图片浏览器程序可以支持“ “.GIF”，“.JPEG'，“.jpeg ”，“.TGA'，“.JPG”，“.jpg ” 等格式，单打开图片，可以将同一目录下的图片按缩略图打开按“上一”“下一”按钮可以显示相应图片。

运行Applet时，图像不是一气呵成的，因为方法不是吧图像完整的装入存再显示的。

于此相反，方法创建一个线程，该线程与Applet的原有线程并发执行，一边装入一边显示，从而产生上了不联需显示的现象。

为了提高图像才显示效果, 可以采用双缓冲技术：首先把图像装入存，然后再显示在屏幕上。

三.设计思路3.1界面设计选择图片按钮：主要用dir函数实现图片的遍历。

上一，下一：通过做标轴回调函数实现。

由于本软件为单机软件，不需要大量的数据读写和数据交换，实现上、下功能要求只能读取PictureBox控件当前加载的目录，读取当前路径，创建一维数组。

frame = n ewFrame( "Pictureviewer");Panel pb = n ewPa nel();Button select = newButton("选择图片");previous = newButton("上——");next = newButton( ”下一"); select.addActionListener( this );previous .addActionListener( this );3.2. 图像加载：Applet常用来显示储存在文件中的图像，多数Applet使用的是GIF或JPEG 格式的图像文件。

需Applet加载图像只需首先定义Image对象，然后使用getlmage()方法把图像和文件结合起来即可。

image_width = bi.getWidth(this);image_height = bi.getHeight(this);double image_proporti on = 1.0 * image_height / image_width;System.out.pri ntl n("image: w "+image_width+" ,h "+image_height+" ,p1 "+image_proportion);if(image_proporti on > scree n_ proportio n){ image_height = scree n_height;image_width = (i nt)(image_height / image_proportio n); System.out.pri ntl n(”p1>p0 w= "+image_width); }else{image_width = scree n_width; image_height = (in t)(image_width *image_proporti on); System.out.pri ntln (” p0>p1 h= "+image_height); }四.详细设计4.1.程序设计流程图4.2. 源程序代码package C;import java.io.File;import java.io.File nameFilter;public class MyFilter impleme nts File nameFilter{ private Strin g[] exte nsion; public MyFilter(){extension = newString[]{".jpg", ".JPG", ".gif", ".GIF", ".png", ".PNG", ".jpeg", ".JPEG"};}public MyFilter(Stri ng[] exte nsio n){this.exte nsion = exte nsion;}public boolea n accept(File dir,Stri ng n ame){for(Stri ng s : exte nsion){if(n ame.e ndsWith(s)){return true;}}return false;}}package C;import java.awt.*;import java.awt.eve nt.*;import java.awt.image.*;public class MyCa nvas exte nds Can vas impleme nts Comp onen tListe ner{ /****/private static fin al l ong serialVersi on UID = 1L;private Bufferedlmage bi;private Image im;private int image_width;private int image_height;public void setImage(BufferedImage bi){this.bi = bi;this.zoom();}public void pain t(Graphics g){g.drawlmage(im,(this.getWidth()-image_width)/2,(this.getHeight()-image_height)/2,this);}public void comp onen tResized(Comp onen tEve nt e){if(bi != null){System.out.pri ntln ("resize!!");this.zoom();this.repai nt();}}public void comp onen tMoved(Comp onen tEve nt e){}public void comp onen tShow n( Comp onen tEve nt e){}public void componentHidden(ComponentEvent e){}public void zoom(){if(bi == n ull)return;int scree n_width = this.getWidth();int scree n_height = this.getHeight();double scree n_proporti on = 1.0 * scree n_height / scree n_width;System.out.pri ntl n("scree n: w "+scree n_width+" ,h "+scree n_height+" ,p0 "+scree n_proporti on);image_width = bi.getWidth(this);image_height = bi.getHeight(this);double image_proporti on = 1.0 * image_height / image_width;System.out.pri ntl n("image: w "+image_width+" ,h "+image_height+" ,p1 "+image_proporti on);if(image_proporti on > scree n_proportio n){image_height = scree n_height;image_width = (i nt)(image_height / image_proportio n);System.out.pri ntl n(” p1>p0 w= "+image_width);}else{image_width = scree n_width;image_height = (in t)(image_width * image_proporti on);System.out.pri ntln (” p0>p1 h= "+image_height);} _im = bi.getScaledl nsta nce(image_width,image_height,lmage.SCALE_SMOOTH);} ~ ~ 一}package C;import java.awt.*;import java.awt.event.*;import java.awt.image.*;import java.io.*;import javax.imageio.*;public class T implements ActionListener{private privateFrame frame; MyCa nvas mc;private Stri ng fpath ; private Stri ng fname; private File[] files ;private int findex ;private FileDialog fd_load ;private MyFilter filter ;private Butt on previous ;private Butt on n ext ;public static void main( String args[]) throws Exception { n ewT().i ni t();}public void in it(){frame = n ewFrame( "Pictureviewer");Panel pb = n ewPa nel();Button select = newButton("选择图片"); previous = newButton("上——"); next = newButton( ”下一");select.addActionListener( this );previous .addActionListener( this );next .addActionListener( this );pb.add(select);pb.add( previous );pb.add( n ext);mc= n ewMyCa nvas(); mcsetBackground( newColor(200,210,230));mcaddComponentListener( m();frame.add(pb, "North");frame .add( mc "Center");frame .setSize(360,360);frame .setLocati on (400,200);frame .addWindowListener( newWindowAdapter(){public void windowClosing(WindowEvent e){System. exit (0);}});frame.setVisible( true );this .validateButton();filter = newMyFilter();fd」oad = n ewFileDialog( frame,"打开文件”,FileDialog. LOADfd」oad .setFilenameFilter( filter );} _public void action Performed(Acti on Eve nt e){Stri ng comma nd = e.getActio nComma nd();if (command.equals(” 选择图片")){fd」oad .setVisible( true );fpath = fd」oad .getDirectory();fname = fd_load .getFile();if ((fpath != null ) && ( fname != null )){this .display( newFile( fpath + fname));files = newFile( fpath ).listFiles( filter );this .setIndex();}} else if (command.equals(” 上一")){findex --;if (findex <0)fin dex = 0;this .display( files [ findex ]);} else if (command.equals(” 下一")){fin dex ++;if (findex >= files . length )findex = files . length -1;this .display( files [ findex ]);}this .validateButton();}public void display(File f){try {BufferedImage bi = ImageIO. read (f);mcsetImage(bi);frame .setTitle( "PictureViewer - [" + f.getName() + "]");} catch (Exception e){e.pri ntStackTrace();}mcrepai nt();}public void set In dex(){File current = newFile( fpath + fname);if (files != null ){for (int i=0;i< files . length ;i++){if (current.equals( files [i])){fin dex = i;}}}}public void validateButton(){previous .setEnabled(( files != null ) && ( findex > 0));next .setEnabled(( files != null ) && ( findex <(files . length -1))); }}五.运行调试与分析讨论5.1.将同一目录下的图片按缩略图打开5.2. 单打开图片53按”上一”，”下一”按钮打开图片厂[占」Piutu苗W合//卽-[気jpq] [ 口I六. 设计体会与小结我通过这次编程实践学习到了 Image 和Griphics 相关的类的使用。