Android 圆形按钮实现

<Button
android:id="@+id/btn_5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/general_consulting"
android:textColor="@color/white"
android:textSize="@dimen/text_size18"
android:background="@drawable/bg_special_disease_circle"/>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    
    <item>
        <shape android:shape="oval" >
            <corners android:radius="@dimen/size90"/>
            <solid android:color="@color/white" />
            <size android:width="170dp" android:height="170dp"/>
        </shape>
    </item>
    
    <item android:bottom="8dp" android:right="8dp" android:top="8dp" android:left="8dp" >
        <selector xmlns:android="http://schemas.android.com/apk/res/android">
            <item android:state_pressed="true">
                <shape android:shape="oval" >
                    <corners android:radius="@dimen/size90"/>
                    <solid android:color="#e66b4f" />
                    <size android:width="162dp" android:height="162dp"/>
                </shape>
            </item>
            
            <item>
                <shape android:shape="oval" >
                    <corners android:radius="@dimen/size90"/>
                    <solid android:color="#f3876f" />
                    <size android:width="162dp" android:height="162dp"/>
                </shape>
            </item>
        
        </selector>
    </item>
    
</layer-list>