为什么在片段中为relativelayout设置backgroundcolor时按钮会更改颜色？

Question

this is my fragment

<RelativeLayout
    android:layout_width="fill_parent"
    android:layout_height="135dp"
    android:background="@color/colorTerracota"
    android:padding="15dp"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true"
    android:layout_gravity="center">

    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/statetexas"
        android:id="@+id/btnTexas"
        android:width="100dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/stateyucatan"
        android:id="@+id/btnYucatan"
        android:width="100dp"
        android:layout_alignParentTop="true"
        android:layout_alignLeft="@+id/btnTexas"
        android:layout_alignStart="@+id/btnTexas" />


</RelativeLayout>

I wanted this see as it:

Answer 1

Set your buttons' background color in your XML file:

android:background:"#9E9E9E" // Your color

Their background is set by default to be transparent .

Answer 2

Create a background selector as below in drawable folder

drawable - selectablebackground.xml

   <?xml version="1.0" encoding="utf-8"?>
       <selector xmlns:android="http://schemas.android.com/apk/res/android">
       <item android:drawable="@color/grey_lightest" android:state_pressed="true"/>
       <item android:drawable="@color/grey_lightest" android:state_focused="true"/>
       <item android:drawable="@android:color/white"/>
    </selector>

Replace colors as you like for pressed and normal states. Set this as background to your button

android:background:"@drawable/selectablebackground"

This should work.