第二人生的源码分析(八十一)创建UI的显示板（Panel）

在第二人生里， UI部分主要有三种大组件组成：显示板、浮动窗口、菜单。显示板是固定在窗口里面，上面可以放浮动的窗口。像登录的界面，就是一个显示板组成，那么它是怎么样实现的呢？现在就分析下面这段代码，如下：

#001 BOOL LLUICtrlFactory::buildPanel(LLPanel* panelp, const LLString &filename,

#002                                     const LLCallbackMap::map_t*

#003 factory_map)

#004 {

#005     BOOL didPost = FALSE;

#006     LLXMLNodePtr root;

#007 

 

下面读取 XML描述文件，然后通过前面介绍的XML类来分析XML文件，生成所有节点数据返回。

#008     if (!LLUICtrlFactory::getLayeredXMLNode(filename, root))

#009     {

#010         return didPost;

#011     }

#012 

 

判断这个 XML文件里是否有panel定义，也就是判断它是否用来构造显示板的。

#013     // root must be called panel

#014     if( !root->hasName("panel" ) )

#015     {

#016         llwarns << "Root node should be named panel in : " << filename << llendl;

#017         return didPost;

#018     }

#019 

 

保存这个工厂图到工厂栈里。

#020     if (factory_map)

#021     {

#022         mFactoryStack.push_front(factory_map);

#023     }

#024 

 

根据 XML里的数据节点来生成显示板。

#025     didPost = panelp->initPanelXML(root, NULL, this);

#026    

 

设置显示板的提示文件名称。

#027     if (LLUI::sShowXUINames)

#028     {

#029         panelp->setToolTip(filename);

#030     }

#031 

 

获取显示板的句柄。

#032     LLHandle<LLPanel> handle = panelp->getHandle();

 

把构造的显示板和 XML文件关联起来。

#033     mBuiltPanels[handle] = filename;

#034 

 

弹出 factory_map对象。

#035     if (factory_map)

#036     {

#037         mFactoryStack.pop_front();

#038     }

#039 

#040     return didPost;

#041 }

 

在这个函数里，主要通过 XML文件生成XML的节点数据，然后调用函数initPanelXML从XML的节点数据里生成显示板的组件。

下面再来仔细地看一下显示板的 XML数据是怎么样的，如下：

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>

<panel bottom="0" follows="left|top|right|bottom" height="600" left="0"

     mouse_opaque="true" name="panel_login" width="800">

<web_browser border_visible="false" bottom="0" follows="top|left|bottom|right" left="0"

     name="login_html" right="-1"

     start_url="data:text/html,%3Chtml%3E%3Chead%3E%3C/head%3E%3Cbody bgcolor=%22#000000%22 text=%22ffffff%22%3E%3Ch1%3E%3Ctt%3Eloading...%3C/tt%3E%3C/h1%3E %3C/body%3E %3C/html%3E"

     top="-1" />

<string name="real_url">

     http://secondlife.com/app/login/

</string>

<string name="forgot_password_url">

     http://secondlife.com/account/request.php

</string>

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="54" drop_shadow_visible="true" follows="left|bottom"

     font="SansSerif" h_pad="0" halign="left" height="16" hidden="false"

     left="32" mouse_opaque="true" name="first_name_text" v_pad="0" width="120">

     First Name:

</text>

<line_editor bevel_style="in" border_style="line" border_thickness="1" bottom_delta="-24"

     follows="left|bottom" font="SansSerif" handle_edit_keys_directly="true"

     height="20" hidden="false" left="32" max_length="31" mouse_opaque="true"

     name="first_name_edit" select_all_on_focus_received="true" width="120" />

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="54" drop_shadow_visible="true" follows="left|bottom"

     font="SansSerif" h_pad="0" halign="left" height="16" hidden="false"

     left="164" mouse_opaque="true" name="last_name_text" v_pad="0" width="120">

     Last Name:

</text>

<line_editor bevel_style="in" border_style="line" border_thickness="1" bottom_delta="-24"

     follows="left|bottom" font="SansSerif" handle_edit_keys_directly="true"

     height="20" hidden="false" left="164" max_length="31" mouse_opaque="true"

     name="last_name_edit" select_all_on_focus_received="true" width="120" />

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="54" drop_shadow_visible="true" follows="left|bottom"

     font="SansSerif" h_pad="0" halign="left" height="16" hidden="false"

     left="296" mouse_opaque="true" name="password_text" v_pad="0" width="120">

     Password:

</text>

<line_editor bevel_style="in" border_style="line" border_thickness="1" bottom_delta="-24"

     follows="left|bottom" font="SansSerif" handle_edit_keys_directly="true"

     height="20" hidden="false" left="296" max_length="16" mouse_opaque="true"

     name="password_edit" select_all_on_focus_received="true" width="120" />

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="10" drop_shadow_visible="true" follows="left|bottom"

     font="SansSerif" h_pad="0" halign="left" height="16" hidden="false"

     left="32" mouse_opaque="true" name="start_location_text" v_pad="0"

     width="95">

     Start Location:

</text>

<combo_box allow_text_entry="true" bottom="8" follows="left|bottom" height="18"

     hidden="false" left_delta="97" max_chars="128" mouse_opaque="true"

     name="start_location_combo" width="155">

     <combo_item name="MyHome" value="My Home">

         My Home

     </combo_item>

     <combo_item name="MyLastLocation" value="My Last Location">

         My Last Location

     </combo_item>

     <combo_item name="Typeregionname" value="&lt;Type region name&gt;">

         &lt;Type region name&gt;

     </combo_item>

</combo_box>

<check_box bottom="10" follows="left|bottom" font="SansSerifSmall" height="16"

     hidden="false" initial_value="false" label="Remember password"

     left_delta="165" mouse_opaque="true" name="remember_check" width="138" />

<button bottom="28" follows="left|bottom" font="SansSerif" halign="center" height="24"

     hidden="false" label="Connect" label_selected="Connect" left="440"

     mouse_opaque="true" name="connect_btn" scale_image="TRUE" width="120" />

<button bottom="28" follows="left|bottom" font="SansSerif" halign="center" height="24"

     hidden="false" label="Quit" label_selected="Quit" left="572"

     mouse_opaque="true" name="quit_btn" scale_image="TRUE" width="120" />

<combo_box allow_text_entry="true" bottom="32" follows="left|bottom" height="18"

     hidden="false" left_delta="135" max_chars="20" mouse_opaque="true"

     name="server_combo" width="120" />

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="30" drop_shadow_visible="true" follows="right|bottom"

     font="SansSerifSmall" h_pad="0" halign="right" height="12" hidden="false"

     hover="true" left="-202" mouse_opaque="true" name="channel_text" v_pad="0"

     width="200">

     [Viewer Channel Name]

</text>

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="18" drop_shadow_visible="true" follows="right|bottom"

     font="SansSerifSmall" h_pad="0" halign="right" height="12" hidden="false"

     hover="true" left="-102" mouse_opaque="true" name="version_text" v_pad="0"

     width="100">

     1.23.4 (5)

</text>

<text bg_visible="false" border_drop_shadow_visible="false" border_visible="false"

     bottom="2" drop_shadow_visible="true" follows="right|bottom"

     font="SansSerifSmall" h_pad="0" halign="right" height="12" hidden="false"

     hover="true" left="-172" mouse_opaque="true" name="forgot_password_text"

     v_pad="0" width="170">

     Forgot your password?

</text>

</panel>