ConstraintLayout布局做item,调整条目间距

外层套一个LinearLayout控制，android:layout_marginTop="100dp"放到约束布局中

<?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="300px"
   >
    <androidx.constraintlayout.widget.ConstraintLayout
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/frameLayout2"
        android:layout_marginTop="100dp"
        android:background="@drawable/backg_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
            </androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>