Android应用的LinearLayout中嵌套RelativeLayout的布局用法

想将Button和ListView分别放在屏幕的一左一右。
单纯使用android:gravity和android:layout_gravity不成功。
于是涉及到RelativeLayout。
关键为：android:layout_alignParentRight="true"，
android:layout_alignParentLeft="true"：

xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
  android:orientation = "vertical" android:layout_width = "fill_parent"
  android:layout_height = "wrap_content" android:gravity = "center_vertical" >

  < TextView
    android:id = "@+id/mTextView"
    android:layout_width = "fill_parent"
    android:layout_height = "wrap_content"
    android:text = "@string/hello" />

   < RelativeLayout
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content" android:gravity = "right"
    android:padding = "10dp" >
    < TextView
      android:id = "@+id/mTextView01"
      android:layout_alignParentLeft = "true"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content"
      android:text = "范例一" />
    < Button
      android:id = "@+id/mButton01"
      android:layout_alignParentRight = "true"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content"
      android:text = "发送" />
    RelativeLayout >

    < RelativeLayout
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content" android:gravity = "right"
    android:padding = "10dp" >
    < TextView
      android:id = "@+id/mTextView02"
      android:layout_alignParentLeft = "true"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content"
      android:text = "范例二" />
    < Button
      android:id = "@+id/mButton01"
      android:layout_alignParentRight = "true"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content"
      android:text = "发送" />
    RelativeLayout >
LinearLayout >

效果为：

PS：另附我的项目布局的一点经验

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

  < LinearLayout android:layout_width = "fill_parent"
    android:layout_height = "wrap_content"
    android:orientation = "horizontal"
    android:layout_marginLeft = "50px"
    android:layout_marginRight = "50px"
    android:layout_marginBottom = "15px"
    android:layout_gravity = "center"
    android:gravity = "center" >
    < TextView
      android:layout_width = "fill_parent"
      android:layout_height = "wrap_content"
      android:text = "性别"
      android:textSize = "18sp"
      android:layout_weight = "3" />
     < RadioGroup android:id = "@+id/radioGroup"
       android:contentDescription = "性别"
       android:layout_width = "fill_parent"
       android:layout_height = "wrap_content"
       android:orientation = "horizontal"
       android:layout_weight = "1" >

      < RadioButton android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:id = "@+id/radioMale"
        android:text = "男"
        android:checked = "true"
        android:layout_marginRight = "15px"
        android:textSize = "18sp" >
        RadioButton >
      < RadioButton android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:id = "@+id/radioFemale"
        android:text = "女"
        android:textSize = "18sp" >
        RadioButton >
     RadioGroup >
 LinearLayout >

LinearLayout >

 开始时RadioGroup的layout_width="wrap_content"，怎么设置权都达不到想要的效果。要改成fill_parent
RadioButton的尺寸比TextView大  所以显示时TextView在上方，设置LinearLayout中android:gravity="center">即可。

http://www.jb51.net/article/82360.htm