Criação de Button em XML e Estilo

ButtonShape

<!-- O shape do botão deve ir na pasta "Drawable" -->
 
<?xml version= "1.0" encoding ="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
 
    <item android:state_pressed= "true"> <!-- se o botão estiver pressionado -->
        <shape android:shape="rectangle" >
            <corners
                android:radius="14dip" /> <!-- bordas arredondadas -->
            <stroke
                android:width="1dip"
                android:color="#0b496c" /> <!-- contorno -->
            <gradient
                android:angle="270"
                android:startColor="#0B496C"
                android:endColor="#5189a9" /> <!-- fundo (gradiente) -->
        </shape>     
    </item >
   
    <item android:state_focused= "true"> <!-- se o botão estiver com foco -->
        <shape android:shape="rectangle" >
            <corners
                android:radius="14dip" />
            <stroke
                android:width="1dip"
                android:color="#0b496c" />
            <solid
                android:color="#5d96c3" />
        </shape>     
    </item >
   
    <item >
        <shape android:shape="rectangle"   >
             <corners
                 android:radius="14dip" />
             <stroke
                 android:width="1dip"
                 android:color="#0b496c" />
             <gradient
                 android:angle="-90"
                 android:startColor="#5189a9"
                 android:endColor="#266B93" />           
         </shape>
     </item >
 
</selector>

ButtonStyle

<!-- O style vai no arquivo de estilos "Res > Values > Styles" -->
 
<style name="nomeEstiloBotao" parent ="@android:style/Widget.Button">
        <item name= "android:textStyle">bold</item >
        <item name= "android:textColor">#FFFFFF</item >
        <item name= "android:gravity">center</item >
        <item name= "android:shadowColor">#000000</item >
        <item name= "android:shadowDx">1</item > 
        <item name= "android:shadowDy">1</item > 
        <item name= "android:shadowRadius">0.6</item > 
        <item name= "android:background">@drawable/ButtonShape </item> <!-- aqui é chamado o shape criado anteriomente -->
        <item name= "android:padding">10dip</item >
</style >

Layout

<!-- No layout onde voce deseja inserir o botão, o mesmo deve ser chamado no atributo "Style" -->
 
<Button
	android:id="@+id/btn_entrar"
        style= "@style/nomeEstiloBotao" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/texto"
        android:textSize="40sp" />