Android开发之TextView控件设置颜色切换器的问题

今天遇到了一个问题，我在开发一个Tab导航的时候，在导航栏中使用TextView进行布局，然后想在点击和选中的时候TextView控件上的文字显示不一样的颜色效果，结果如下设置后，一点效果也没有，哎呀！
[sourcecode]
<!--drawable文件夹下的nav_font_color_selector.xml-->
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:color="@color/nav_font_color_selector" android:state_selected="true"/>
<item android:color="@color/nav_font_color_selector" android:state_selected="true" android:state_checkable="true"/>
<item android:color="@color/nav_font_color" android:state_selected="false"/>
</selector>
[/sourcecode]

[sourcecode]
<!--values文件夹下的colors.xml-->
<resources>
<color name="text_font_color">#FFFFFF</color>
<color name="nav_font_color">#CCCCCC</color>
<color name="nav_font_color_selector">#00a0e9</color>
</resources>
[/sourcecode]

[sourcecode]
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/zspg_nav_rl"
android:layout_width="fill_parent"
android:layout_height="@dimen/slidingmenu_offset"
android:layout_alignParentBottom="true"
android:background="@android:color/transparent"
android:gravity="center" >

<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:gravity="center"
android:orientation="horizontal" >

<TextView
android:focusable="true"
android:id="@+id/news_tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:drawableTop="@drawable/news_main_btn"
android:gravity="center"
android:singleLine="true"
android:text="@string/nav_title_one"
android:textColor="@color/nav_text_color_selec"
android:textSize="@dimen/list_cat_size"
android:clickable="true"/>

<TextView
android:id="@+id/news_tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:drawableTop="@drawable/goverment_main_btn"
android:gravity="center"
android:singleLine="true"
android:text="@string/nav_title_two"
android:textColor="@color/nav_text_color_selec"
android:textSize="@dimen/list_cat_size"
android:clickable="true" />

<TextView
android:id="@+id/news_tv3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:drawableTop="@drawable/community_main_btn"
android:gravity="center"
android:singleLine="true"
android:text="@string/nav_title_three"
android:textColor="@color/nav_text_color_selec"
android:textSize="@dimen/list_cat_size" />

<TextView
android:id="@+id/news_tv4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:drawableTop="@drawable/search_main_btn"
android:gravity="center"
android:singleLine="true"
android:text="@string/nav_title_four"
android:textColor="@color/nav_text_color_selec"
android:textSize="@dimen/list_cat_size" />
</LinearLayout>

</RelativeLayout>
[/sourcecode]
写好了布局文件和对应的属性值之后，我在模拟器中查看效果，只看到如下页面：