学步园

List控件的使用是很频繁的，今天就介绍一下Lwuit中List的使用方法：

    private String globalstrURL = "";

    public void initform() {
        removeAll();
        removeAllCommands();
        String[][] strAccessories = EsionData.getInstance()
                .GetSiteList("05342");
        this.addCommand(new Command("返回", 0) {
            public void actionPerformed(ActionEvent ev) {
                FormFactory.getInstance().getMainForm().show();
            }
        });
        if (strAccessories != null) {
            SiteListInfo[] accessoryinfoarray = new SiteListInfo[strAccessories.length];
            Image img = getRes().getImage("YdFj.gif");
            for (int i = 0; i < strAccessories.length; i++) {
                accessoryinfoarray[i] = new SiteListInfo(strAccessories[i][0],
                        strAccessories[i][1], img);
            }
            // 设置使得list的选中状态的层能够自适应的足够撑开
            setLayout(new BorderLayout());
            setScrollable(false);
                        //创建List并传入相应的数据
            addComponent(BorderLayout.CENTER, createList(accessoryinfoarray,
                    List.VERTICAL, new ContactsRenderer()));
            this.addCommand(new Command("确定", 1) {
                public void actionPerformed(ActionEvent ev) {
                    try {
                        EsionMIDlet.midlet.platformRequest(globalstrURL);
                    } catch (ConnectionNotFoundException e) {
                        e.printStackTrace();
                    }
                }
            });
        } else
            addComponent(new Label("网络出现异常,没有找到任何资讯站点!"));
    }

    // List初始化
    private List createList(final SiteListInfo[] SiteLists, int orientation,
            ListCellRenderer renderer) {
        final List list = new List(SiteLists);
        list.getStyle().setBgTransparency(0);
        list.setListCellRenderer(renderer);
        list.setOrientation(orientation);
        // list列表选择焦点监听事件
        list.addSelectionListener(new SelectionListener() {
            public void selectionChanged(int oldSelected, int newSelected) {
                globalstrURL = SiteLists[list.getSelectedIndex()].siteurl;
            }
        });
        list.addFocusListener(new FocusListener() {
            // list获得焦点
            public void focusGained(Component cmp) {
                globalstrURL = SiteLists[list.getSelectedIndex()].siteurl;
            }

            // list失去焦点
            public void focusLost(Component cmp) {
                globalstrURL = "";
            }
        });
                //list事件 ---手机中间按键相应的事件
        list.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent evt) {
                try {
                    EsionMIDlet.midlet.platformRequest(globalstrURL);
                } catch (ConnectionNotFoundException e) {
                    e.printStackTrace();
                }
            }
        });
        return list;
    }

    // list数据绑定
    class ContactsRenderer extends Container implements ListCellRenderer {
        private Label name = new Label("");
        private Label pic = new Label("");
        private Label focus = new Label("");

        public ContactsRenderer() {
            setLayout(new BorderLayout());
                        //设置list每一列的图标
            addComponent(BorderLayout.WEST, pic);
            Container cnt = new Container(new BoxLayout(BoxLayout.Y_AXIS));
            name.getStyle().setBgTransparency(0);
            name.getStyle().setFont(
                    Font.createSystemFont(Font.FACE_SYSTEM, Font.STYLE_BOLD,
                            Font.SIZE_MEDIUM));
                        //设置list每一列内容
            cnt.addComponent(name);
            addComponent(BorderLayout.CENTER, cnt);
            // 这里设置选中颜色，也可不设置通过Lwuit的资源管理器设置选中颜色也可
                           // 不过不能跟底色重合，否则看不见效果，其实这也是相对于多普达的手机才需要这样设置
            focus.getStyle().setBgColor(0xffffff);
            focus.getStyle().setBgTransparency(100);
        }

        public Component getListCellRendererComponent(List list, Object value,
                int index, boolean isSelected) {
            SiteListInfo sitelist = (SiteListInfo) value;
            name.setText(sitelist.getsitename());
            pic.setIcon(sitelist.getpic());
            return this;
        }

        public Component getListFocusComponent(final List list) {
            return focus;
        }
    }
        //创建一个类用来放置List中需要的数据，类似的如需要传值到另一个窗体，或者list中列显示的数据
    class SiteListInfo {
        private String sitename;
        private String siteurl;
        private Image pic;

        public SiteListInfo(String sitename, String siteurl, Image pic) {
            this.sitename = sitename;
            this.siteurl = siteurl;
            this.pic = pic;
        }

        public String getsitename() {
            return sitename;
        }

        public String getsiteurl() {
            return siteurl;
        }

        public Image getpic() {
            return pic;
        }
    }

需要注意的事项及其说明都标注在源码上，List的使用还是比较简单的，不过Tab选项卡与List合起来使用真的是要下一番功夫，后续将会有一篇Tab与List结合使用的文章。

上图：