06-按钮Button

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<Button
    android:id="@+id/btn_click"
    android:layout_width="200dp"
    android:layout_height="100dp"
    android:layout_gravity="center"
    android:gravity="center"
    android:background="@color/colorAccent"
    android:text="按钮"/>
</LinearLayout>