android:id="@+id/button2"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="@mipmap/ic_launcher"
android:text="蓝牙"
android:textAlignment="gravity">
让button中文本显示靠下居中android:gravity="bottom|center" 就可以了
android:gravity="bottom|center"
首先要知道你是什么布局,RelativeLayout?LinearLayout?ConstraintLayout?
将android:textAlignment="gravity"修改为android:gravity="bottom|center"
android:gravity="bottom|center"