LWUIT 上使用List实现表格

最近在做个类似的 lwuit 表格形式的。可是就是到这里卡住了。。

幸运的是 张国威 发表了这篇文章。

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

最近越来越多人用LWUIT，问得问题也越来越多了。最近超级多人问的是，如何使用List实现表格。以前我用Grid实现了表格(http://blog.csdn.net/hellogv/archive/2009/01/12/3759984.aspx ),现在就来说说如何使用List是一个表格。

先来对比一下Grid表格与List表格：

Grid表格 List表格

Grid表格与List表格所消耗的资源差不多，List所使用的结构和控件(都是Label)略多，但是Grid使用的是Button(衍生于Label,但是多很多方法和属性)，所以两者的运行速度都差不多，至于用哪个，就看你喜欢了。

本文关键的两个文件是：Cls_CellList. java 和ListDemo.java, Cls_CellList. java 封装了本文所用的List,而 ListDemo.java则是演示使用，代码简单易明，一般人也能看懂，呵呵呵。

Cls_CellList. java主要使用了ListCellRenderer这个东西，源代码如下：

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package com.sun.lwuit.uidemo;
import com.sun.lwuit.Component;
import com.sun.lwuit.Container;
import com.sun.lwuit.Label;
import com.sun.lwuit.List;
import com.sun.lwuit.events.ActionListener;
import com.sun.lwuit.layouts.BorderLayout;
import com.sun.lwuit.layouts.BoxLayout;
import com.sun.lwuit.list.ListCellRenderer;
import com.sun.lwuit.plaf.Border;
public class Cls_CellList {
static public List createList(CellList[] celllist,int stringWidth,ActionListener lAListner) {
List list = new List(celllist);
list.getStyle().setBgTransparency(0);
//开始显示List
list.setListCellRenderer(new CellRenderer(celllist[0].getColumm().length,stringWidth));
//添加消息处理
list.addActionListener(lAListner);
return list;
}
static public class CellRenderer extends Container implements ListCellRenderer {
//初始化显示Columm每个字段的Label
private Label[] lbColumm ;
private Label focus = new Label("");
public CellRenderer(int size,final int stringWidth) {
lbColumm = new Label[size];
setLayout(new BorderLayout());
Container cnt = new Container(new BoxLayout(BoxLayout.X_AXIS));
for(int i=0;i<lbColumm.length;i++)//定义显示Columm每个字段的Label
{
lbColumm[i]=new Label(){
//很多人都问怎么setWidth平时没什么用，这是因为setWidth必须在重载的时候使用，LWUIT奇怪的地方之一！
public void setWidth(int arg0) {
super.setWidth(stringWidth);
}
};
lbColumm[i].getStyle().setFgColor(getStyle().getFgSelectionColor());//设置为最亮的颜色
lbColumm[i].getStyle().setBgTransparency(0);//设置背景为透明，不然会遮挡focus影响外观
cnt.addComponent(lbColumm[i]);
}

addComponent(BorderLayout.CENTER, cnt);
focus.getStyle().setBgTransparency(255);
focus.getStyle().setBorder(Border.createRoundBorder(10, 10));
}
public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {
CellList cellList = (CellList) value;
for(int i=0;i<lbColumm.length;i++)
{
lbColumm[i].setText(cellList.getColumm()[i]);
}
return this;
}
public Component getListFocusComponent(List list) {
//Columm栏不具备选中事件
if(list.getSelectedIndex()>0)
return focus;
return null;
}
}
static public class CellList {
//保存该列的所有字段
private String[] lstColumm;
public CellList(String[] columm) {
//复制数组
lstColumm=new String[columm.length];
System.arraycopy(columm, 0, lstColumm, 0, lstColumm.length);
}
//返回该列
public String[] getColumm(){
return lstColumm;
}
}
}
package com.sun.lwuit.uidemo;
import com.sun.lwuit.Component;
import com.sun.lwuit.Container;
import com.sun.lwuit.Label;
import com.sun.lwuit.List;
import com.sun.lwuit.events.ActionListener;
import com.sun.lwuit.layouts.BorderLayout;
import com.sun.lwuit.layouts.BoxLayout;
import com.sun.lwuit.list.ListCellRenderer;
import com.sun.lwuit.plaf.Border;
public class Cls_CellList {
static public List createList(CellList[] celllist,int stringWidth,ActionListener lAListner) {
List list = new List(celllist);
list.getStyle().setBgTransparency(0);
//开始显示List
list.setListCellRenderer(new CellRenderer(celllist[0].getColumm().length,stringWidth));
//添加消息处理
list.addActionListener(lAListner);
return list;
}
static public class CellRenderer extends Container implements ListCellRenderer {
//初始化显示Columm每个字段的Label
private Label[] lbColumm ;
private Label focus = new Label("");
public CellRenderer(int size,final int stringWidth) {
lbColumm = new Label[size];
setLayout(new BorderLayout());
Container cnt = new Container(new BoxLayout(BoxLayout.X_AXIS));
for(int i=0;i<lbColumm.length;i++)//定义显示Columm每个字段的Label
{
lbColumm[i]=new Label(){
//很多人都问怎么setWidth平时没什么用，这是因为setWidth必须在重载的时候使用，LWUIT奇怪的地方之一！
public void setWidth(int arg0) {
super.setWidth(stringWidth);
}
};
lbColumm[i].getStyle().setFgColor(getStyle().getFgSelectionColor());//设置为最亮的颜色
lbColumm[i].getStyle().setBgTransparency(0);//设置背景为透明，不然会遮挡focus影响外观
cnt.addComponent(lbColumm[i]);
}

addComponent(BorderLayout.CENTER, cnt);
focus.getStyle().setBgTransparency(255);
focus.getStyle().setBorder(Border.createRoundBorder(10, 10));
}
public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {
CellList cellList = (CellList) value;
for(int i=0;i<lbColumm.length;i++)
{
lbColumm[i].setText(cellList.getColumm()[i]);
}
return this;
}
public Component getListFocusComponent(List list) {
//Columm栏不具备选中事件
if(list.getSelectedIndex()>0)
return focus;
return null;
}
}
static public class CellList {
//保存该列的所有字段
private String[] lstColumm;
public CellList(String[] columm) {
//复制数组
lstColumm=new String[columm.length];
System.arraycopy(columm, 0, lstColumm, 0, lstColumm.length);
}
//返回该列
public String[] getColumm(){
return lstColumm;
}
}
}

ListDemo.java源代码如下：

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/*
* Copyright ?2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*
*/
package com.sun.lwuit.uidemo;
import com.sun.lwuit.Command;
import com.sun.lwuit.Font;
import com.sun.lwuit.Form;
import com.sun.lwuit.List;
import com.sun.lwuit.events.ActionEvent;
import com.sun.lwuit.events.ActionListener;
import com.sun.lwuit.layouts.BorderLayout;
public class ListDemo implements ActionListener {
public Form form = new Form("ListDemo");
private Command backCommand = new Command("Back", 1);
private String[][] myList = {
{" 标题1 "," 标题2 "," 标题3 "," 标题4 "},//表格每个字段的显示长度由标题栏的最长一项决定
{"aaaaa","bbbbb","ccccc","ddddd"},
{"11111","222222","33333","444444"},
{"aaaaa","bbbbb","ccccc","ddddd"},
{"11111","222222","33333","444444"},
{"aaaaa","bbbbb","ccccc","ddddd"},
{"11111","222222","33333","444444"},
{"aaaaa","bbbbb","ccccc","ddddd"},
{"11111","222222","33333","444444"}
};
ListDemo(){
form.setLayout(new BorderLayout());
form.addCommand(backCommand);
form.setScrollable(true);
//定义列表的列数
Cls_CellList.CellList[] cellArray = new Cls_CellList.CellList[myList.length];
for (int i = 0; i < cellArray.length; i++) {
cellArray[i] = new Cls_CellList.CellList(myList[i]);
}

//取得Columm的标题栏中长度最大的一项
int stringWidth=0;
for(int i=0;i<myList[0].length;i++)
{
int size=Font.getDefaultFont().stringWidth(myList[0][i])+8;//给最长的字段留点空余
if(stringWidth<size)
stringWidth=size;
}
//构造list并且显示
form.addComponent(BorderLayout.CENTER,Cls_CellList.createList(cellArray,stringWidth,new ListActionListener()));
form.setCommandListener(this);
}
public void actionPerformed(ActionEvent arg0) {
Command command=arg0.getCommand();
if(command==backCommand)
UIDemoMIDlet.backToMainMenu();
}
//按下列表触发的事件
private class ListActionListener implements ActionListener {
public void actionPerformed(ActionEvent evt) {
int selectIndex=((List)evt.getSource()).getSelectedIndex();
String str="";
for(int i=0;i<myList[selectIndex].length;i++)
str=str+myList[selectIndex][i]+"_";
form.setTitle(str);
}
}
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/hellogv/archive/2009/11/04/4767263.aspx