Android 自定义 TabActivity 的实例方法

系统自带的TabActivity的效果不甚理想。开发中对TabActivity自定义可能有两种：第一种：改变TAB行的位置，如放到页面下方。第二种：对TabHost图片的自定义。

一、改变Tab栏的位置

在TabActivity的oncreate方法中添加setContentView(R.layout.tab_host);

其中 Layout tab_host.xml 是从系统资源文件中抠出来之后略作修改。

系统原来的 tab_host.xml内容如下

<?xml version="1.0" encoding="utf-8"?>
<!--
/* //device/apps/common/assets/res/layout/tab_content.xml
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License"); 
** you may not use this file except in compliance with the License. 
** You may obtain a copy of the License at 
**
**     http://www.apache.org/licenses/LICENSE-2.0 
**
** Unless required by applicable law or agreed to in writing, software 
** distributed under the License is distributed on an "AS IS" BASIS, 
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
** See the License for the specific language governing permissions and 
** limitations under the License.
*/
-->
<TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost"
    android:layout_width="match_parent" android:layout_height="match_parent">
    <LinearLayout android:orientation="vertical"
        android:layout_width="match_parent" android:layout_height="match_parent">
        <TabWidget android:id="@android:id/tabs" android:layout_width="match_parent"
            android:layout_height="wrap_content" android:layout_weight="0" />
        <FrameLayout android:id="@android:id/tabcontent"
            android:layout_width="match_parent" android:layout_height="0dip"
            android:layout_weight="1"/>
    </LinearLayout>
</TabHost>

要实现TAB栏在页面下方，只需简单修改。

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost"
         android:layout_width="fill_parent" android:layout_height="fill_parent">
        <LinearLayout android:orientation="vertical"
        android:layout_width="fill_parent" android:layout_height="fill_parent">
                 <FrameLayout android:id="@android:id/tabcontent"
                 android:layout_width="fill_parent" android:layout_height="0dip"
            android:layout_weight="1"/>
       <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent"
                android:layout_height="wrap_content" android:layout_weight="0" />
         </LinearLayout>
 </TabHost>

二、自定义TAB的图片

系统自带的tab_indicator.xml内容如下

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2008 The Android Open Source Project
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="0dip"
    android:layout_height="64dip"
    android:layout_weight="1"
    android:layout_marginLeft="-3dip"
    android:layout_marginRight="-3dip"
    android:orientation="vertical"
    android:background="@android:drawable/tab_indicator">
    <ImageView android:id="@+id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
    />
    <TextView android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        style="?android:attr/tabWidgetStyle"
    />
</RelativeLayout>

可以看出，默认情况下，图标在文字上方，并且不能占到整个格，无法满足设计需要。因此可以重写该Layout。

编写tab_in.xml

<?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="wrap_content"
     android:layout_height="64dip"
     android:orientation="vertical"
     >
</RelativeLayout>

View view1 = inflater.inflate(R.layout.tab_in, null);;
        View view2 = inflater.inflate(R.layout.tab_in, null);;
        View view3 = inflater.inflate(R.layout.tab_in, null);;

        view1 .setBackgroundResource(R.drawable.record_upload_button_stateful);
        view2 .setBackgroundResource(R.drawable.record_download_button_stateful);
        view3 .setBackgroundResource(R.drawable.record_receive_button_stateful);
tabHost.addTab(tabHost
                .newTabSpec("view1")
                .setIndicator(view1)              
          );
        tabHost.addTab(tabHost
                .newTabSpec("view2")
                .setIndicator(view2)
        );

        tabHost.addTab(tabHost
                .newTabSpec("view3")
                .setIndicator(view3)
             );