Swing实现透明窗体

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1、窗体顶端关于Swing实现透明窗体的。我也很喜欢，收藏！       Editor'snote:ThefollowingexamplefromSwingHacksisoneofthebook'smostvisuallydaringhacks--mimickingthearbitrarilyshapedwindowyoumightseeinannativeMP3playerskin.ThehackhereisnecessitatedbythefactthatJavadoesn'tsupportnon-rectangularwi

2、ndows,sotheonlyoptiontomakethisworkisfortheJavawindowtobeawareofwhat'sunderit,andtohandletheimagingofareaswithinthewindow'srectanglebutnotwithinitsarbitraryshape.Readonforhowthisisaccomplished.Createtranslucentandshapedwindows,whileavoidingnativecode,withcleveruseo

3、fascreenshot.OneofthemostcommonlyrequestedSwingfeaturesistransparentwindows.Alsocalledshapedwindows,thesearewindowsthathavetransparentportions,allowingthedesktopbackgroundandotherprogramstoshinethrough.Javadoesn'tprovideanywayofcreatingtransparentwindowswithoutusin

4、gtheJavaNativeInterface(JNI)(andeventhenthenativeplatformmustsupporttransparencyaswell),butthat'snotgoingtostopus.Wecancheatusingoneofmyfavoritetechniques,thescreenshot.Theprocessoffakingatransparentwindowisbasically:1.Takeascreenshotbeforethewindowisshown.2.Usetha

5、tscreenshotasthebackgroundofthewindow.3.Adjustthepositionsothatthescreenshotandtherealscreenlineup,creatingtheillusionoftransparency.Thisistheeasypart.Thehardpartisupdatingthescreenshotwhenthewindowmovesorchanges.Tostartoff,createaJPanelsubclassthatcancapturethescr

6、eenandpaintitasthebackground,asshowninExample6-1Example6-1.Atransparentbackgroundcomponentpublic class TransparentBackground extends Jcomponent {     private JFrame frame;     private Image background;    public TransparentBackground(JFrame frame) {    this.frame =

7、 frame;    updateBackground( );}public void updateBackground( ) {    try {        Robot rbt = new Robot( );        Toolkit tk = Toolkit.getDefaultToolkit( );        Dimension dim = tk.getScreenSize( );        background = rbt.createScreenCapture(        new Rectang

8、le(0,0,(int)dim.getWidth( ),(int)dim.getHeight( )));    } catch (Exception ex) {        p(ex.toString( ));        ex.printStackTrace( );    }}pub