和老師的代碼一樣咋效果不一樣呢?

activity_main.xml

<RelativeLayout?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"
????tools:context=".MainActivity"?>
??<include?layout="@layout/common_title"/>
????<TextView
????????android:layout_width="match_parent"
????????android:layout_height="wrap_content"
????????android:text="正文內(nèi)容"
????????android:textSize="18dp"
?????????/>
</RelativeLayout>

common_title.xml

<?xml?version="1.0"?encoding="utf-8"?>
<RelativeLayout?xmlns:android="http://schemas.android.com/apk/res/android"
????android:layout_width="match_parent"
????android:layout_height="wrap_content"?
????android:background="#000"
????android:paddingTop="10dp"
????android:paddingBottom="10dp"
????>
????<TextView
????????android:id="@+id/textView_Left_Common_Title"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:layout_alignParentLeft="true"
????????android:layout_marginLeft="10dp"
????????android:layout_centerVertical="true"
????????android:textColor="#fff"
????????android:textSize="14sp"
????????android:text="返回"?/>
????<TextView
????????android:id="@+id/TextView_Context_Common_Title"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:layout_centerInParent="true"
????????android:text="布局優(yōu)化"
????????android:textColor="#fff"
????????android:textSize="18sp"?/>
????<TextView
????????android:id="@+id/TextView_Right_Common_Title"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:layout_alignParentRight="true"
????????android:layout_centerVertical="true"
????????android:layout_marginRight="10dp"
????????android:text="功能"
????????android:textColor="#fff"
????????android:textSize="14sp"?/>
</RelativeLayout>