android的线性布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

<LinearLayout
         android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
       android:orientation="horizontal"
      android:layout_weight="0.5">
        <TextView
        android:text="green"
        android:layout_gravity="center_horizontal"
        android:layout_width="wrap_content"
      android:layout_weight="1"
        android:layout_height="fill_parent"
        android:background="#00aa00"
        />
        
        <TextView
        android:text="blue"
        android:layout_gravity="center_horizontal"
        android:layout_width="wrap_content"
      android:layout_weight="1"
        android:layout_height="fill_parent"
        android:background="#0000aa"
        />
        
    </LinearLayout>
<LinearLayout
         android:id="@+id/textView2"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
       android:orientation="vertical"
      android:layout_weight="1">
        <TextView
        android:text="row one"
      
        android:layout_width="fill_parent"
      android:layout_weight="1"
        android:layout_height="wrap_content"
        android:background="#aa0000"
        />
        
        <TextView
        android:text="row two"
       
        android:layout_width="fill_parent"
      android:layout_weight="1"
        android:layout_height="wrap_content"
        android:background="#aaaa00"
        />
        
    </LinearLayout>
    
</LinearLayout>