本文實(shí)例講述了java swing中jlist選擇事件監(jiān)聽器listselectionlistener用法。分享給大家供大家參考，具體如下：
當(dāng)jlist中的元素被選中時(shí)，選擇事件將被觸發(fā)。對(duì)于jtable也是一樣，你可以把它看做是多個(gè)并列的jlist。那么，如果程序需要對(duì)該事件做出響應(yīng)，需要以下步驟：
(1)創(chuàng)建一個(gè)實(shí)現(xiàn)了 listselectionlistener的監(jiān)聽器；
(2)使用jlist或selectionmodel的addlistselectionlistener添加監(jiān)聽器；
(3)在監(jiān)聽器的valuechanged方法添加響應(yīng)代碼。
在響應(yīng)代碼中需要注意的是getvalueisadjusting值的判斷。測(cè)試表明，每當(dāng)我們進(jìn)行選擇時(shí)，valuechanged方法都會(huì)被激活多次，其中，在最后的鼠標(biāo)操作中，getvalueisadjusting值為false，而在一系列中間操作中，該值均為true。比如說(shuō)，用鼠標(biāo)連續(xù)劃過(guò)一串元素時(shí)，會(huì)有一系列g(shù)etvalueisadjusting為true的valuechanged方法激活，且最后一次為false。而我們對(duì)選擇事件的判定一般是以最后接觸為準(zhǔn)，因此這里對(duì)getvalueisadjusting值進(jìn)行一個(gè)判斷。
常用方法如下：
getleadselectionindex()
返回當(dāng)前選中的元素的index。
getminselectionindex()
返回選中的多個(gè)元素中index的最小值，如果選擇為空在返回-1。
getmaxselectionindex()
原理同上。
isselectedindex(int index)
判斷指定index是否被選中。
clearselection()
清除選中。
getselectedindex()
返回被選中的所有元素中最小的index。
getselectedindices()
返回一個(gè)整型數(shù)組，包含被選中的所有index。
getselectedvalue()
返回被選中的，index最小的元素值。
getselectedvalues()
返回一個(gè)object數(shù)組，包含被選中的所有元素對(duì)象。
getselectedvalueslist()
返回一個(gè)objectlist，包含被選中的所有元素對(duì)象。
下面的demo來(lái)自于listselectiondemo.java
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/* * copyright (c) 1995, 2008, oracle and/or its affiliates. all rights reserved. * * redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - neither the name of oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * this software is provided by the copyright holders and contributors "as * is" and any express or implied warranties, including, but not limited to, * the implied warranties of merchantability and fitness for a particular * purpose are disclaimed. in no event shall the copyright owner or * contributors be liable for any direct, indirect, incidental, special, * exemplary, or consequential damages (including, but not limited to, * procurement of substitute goods or services; loss of use, data, or * profits; or business interruption) however caused and on any theory of * liability, whether in contract, strict liability, or tort (including * negligence or otherwise) arising in any way out of the use of this * software, even if advised of the possibility of such damage. */ package awtdemo;/* * listselectiondemo.java requires no other files. */import javax.swing.*;import javax.swing.event.*;import java.awt.*;import java.awt.event.*;@suppresswarnings("serial")public class listselectiondemo extends jpanel { jtextarea output; @suppresswarnings("rawtypes") jlist list; jtable table; string newline = "\n"; listselectionmodel listselectionmodel; @suppresswarnings({ "unchecked", "rawtypes" }) public listselectiondemo() { super(new borderlayout()); string[] listdata = { "one", "two", "three", "four", "five", "six", "seven" }; @suppresswarnings("unused") string[] columnnames = { "french", "spanish", "italian" }; list = new jlist(listdata); listselectionmodel = list.getselectionmodel(); listselectionmodel.addlistselectionlistener( new sharedlistselectionhandler()); jscrollpane listpane = new jscrollpane(list); jpanel controlpane = new jpanel(); string[] modes = { "single_selection", "single_interval_selection", "multiple_interval_selection" }; final jcombobox combobox = new jcombobox(modes); combobox.setselectedindex(2); combobox.addactionlistener(new actionlistener() { public void actionperformed(actionevent e) { string newmode = (string)combobox.getselecteditem(); if (newmode.equals("single_selection")) { listselectionmodel.setselectionmode( listselectionmodel.single_selection); } else if (newmode.equals("single_interval_selection")) { listselectionmodel.setselectionmode( listselectionmodel.single_interval_selection); } else { listselectionmodel.setselectionmode( listselectionmodel.multiple_interval_selection); } output.append("----------" + "mode: " + newmode + "----------" + newline); } }); controlpane.add(new jlabel("selection mode:")); controlpane.add(combobox); //build output area. output = new jtextarea(1, 10); output.seteditable(false); jscrollpane outputpane = new jscrollpane(output, scrollpaneconstants.vertical_scrollbar_always, scrollpaneconstants.horizontal_scrollbar_as_needed); //do the layout. jsplitpane splitpane = new jsplitpane(jsplitpane.vertical_split); add(splitpane, borderlayout.center); jpanel tophalf = new jpanel(); tophalf.setlayout(new boxlayout(tophalf, boxlayout.line_axis)); jpanel listcontainer = new jpanel(new gridlayout(1,1)); listcontainer.setborder(borderfactory.createtitledborder( "list")); listcontainer.add(listpane); tophalf.setborder(borderfactory.createemptyborder(5,5,0,5)); tophalf.add(listcontainer); //tophalf.add(tablecontainer); tophalf.setminimumsize(new dimension(100, 50)); tophalf.setpreferredsize(new dimension(100, 110)); splitpane.add(tophalf); jpanel bottomhalf = new jpanel(new borderlayout()); bottomhalf.add(controlpane, borderlayout.page_start); bottomhalf.add(outputpane, borderlayout.center); //xxx: next line needed if bottomhalf is a scroll pane: //bottomhalf.setminimumsize(new dimension(400, 50)); bottomhalf.setpreferredsize(new dimension(450, 135)); splitpane.add(bottomhalf); } /** * create the gui and show it. for thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createandshowgui() { //create and set up the window. jframe frame = new jframe("listselectiondemo - www.jfrwli.cn"); frame.setdefaultcloseoperation(jframe.exit_on_close); //create and set up the content pane. listselectiondemo demo = new listselectiondemo(); demo.setopaque(true); frame.setcontentpane(demo); //display the window. frame.pack(); frame.setvisible(true); } public static void main(string[] args) { //schedule a job for the event-dispatching thread: //creating and showing this application's gui. javax.swing.swingutilities.invokelater(new runnable() { public void run() { createandshowgui(); } }); } class sharedlistselectionhandler implements listselectionlistener { public void valuechanged(listselectionevent e) { listselectionmodel lsm = (listselectionmodel)e.getsource(); //system.out.printf("leadselectionindex is %s%n",lsm.getleadselectionindex()); output.append("leadselectionindex is " + lsm.getleadselectionindex() + "\n"); int firstindex = e.getfirstindex(); int lastindex = e.getlastindex(); boolean isadjusting = e.getvalueisadjusting(); output.append("event for indexes " + firstindex + " - " + lastindex + "; isadjusting is " + isadjusting + "; selected indexes:"); if (lsm.isselectionempty()) { output.append(" <none>"); } else { // find out which indexes are selected. int minindex = lsm.getminselectionindex(); int maxindex = lsm.getmaxselectionindex(); for (int i = minindex; i <= maxindex; i++) { if (lsm.isselectedindex(i)) { output.append(" " + i); } } } output.append(newline); output.setcaretposition(output.getdocument().getlength()); } }} |
運(yùn)行效果：
希望本文所述對(duì)大家java程序設(shè)計(jì)有所幫助。
原文鏈接：http://www.cnblogs.com/pzy4447/p/4912584.html
