1.原理
原理非常简单：就是一个jlabel和jpanel。jlabel显示标题文字以及标明控件当前是处于展开还是折叠状态的图片；而jpanel主要就一个作用——承载控件的容器。jlabel通过响应鼠标事件来控制jpanel是否显示。这样就可以达到折叠或展开的效果。
下面话不多说了，来一起看看详细的示例代码
2.代码
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public class jshrinkablepanel extends jpanel {private jlabellabel;private stringtitle ="";private jpanelcontentpanel =null;private boolean isexpanded =true;private jlistlist =new jlist();private iconiconexpand =null;private iconiconcollapse =null;public jshrinkablepanel(string title, jpanel contentpanel) {super();this.title = title;this.contentpanel = contentpanel;initcomponents();initcomponentsstatus();initlayout();initresources();unregisterevents();registerevents();}private void initcomponents() {this.label =new jlabel();}private void initcomponentsstatus() {this.label.sethorizontalalignment(jlabel.left);this.label.setverticalalignment(jlabel.center);this.label.setverticaltextposition(jlabel.center);this.label.setbackground(this.list.getselectionbackground());this.iconexpand =new imageicon("src/resources/expand.png");this.iconcollapse =new imageicon("src/resources/collapse.png");}private void initlayout() {this.setlayout(new gridbaglayout());this.add(this.label,new gridbagconstraints(0,0,1,1,1,0, gridbagconstraints.west, gridbagconstraints.horizontal,new insets(0,0,0,0),0,0));this.add(this.contentpanel,new gridbagconstraints(0,1,1,1,1,0, gridbagconstraints.west, gridbagconstraints.horizontal,new insets(0,0,0,0),0,0));}private void initresources() {this.label.seticon(this.iconexpand);this.label.settext(this.title);}private void unregisterevents() {this.label.removemouselistener(this.mouselistener);}private void registerevents() {this.label.addmouselistener(this.mouselistener);}private mouselistenermouselistener =new mouseadapter() {@overridepublic void mouseclicked(mouseevent e) {isexpanded = !isexpanded;panelvisible();}@overridepublic void mouseentered(mouseevent e) {label.setopaque(true);label.repaint();}@overridepublic void mouseexited(mouseevent e) {label.setopaque(false);label.repaint();}};private void panelvisible() {this.contentpanel.setvisible(this.isexpanded);this.label.seticon(this.isexpanded ?this.iconexpand :this.iconcollapse);}public static void main(string[] args) {jframe jf =new jframe("jshrinkablepanel");jf.setbounds(400,200,400,300);jf.setdefaultcloseoperation(jframe.exit_on_close);jpanel panel=new jpanel();panel.add(new jbutton("just for show"));panel.setborder(borderfactory.createtitledborder("border"));jshrinkablepanel scrollpane=new jshrinkablepanel("testjshrinkablepanel",panel);jf.add(scrollpane);jf.setvisible(true);}} |
3.效果
panel展开鼠标在标题label上
panel展开鼠标没在标题label上
panel折叠鼠标在标题label上
panel折叠鼠标没在标题label上
总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对服务器之家的支持。
原文链接：https://www.jianshu.com/p/e96bd21e0fa9
