<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <LinearLayout
        android:layout_marginTop="40dp"
        android:gravity="center"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <ImageView
            android:id="@+id/btn1"
            android:layout_weight="1"
            android:layout_width="80dp"
            android:layout_height="80dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:src="@drawable/btn_stat"
            />
        <ImageView
            android:id="@+id/btn2"
            android:layout_weight="1"
            android:layout_width="80dp"
            android:layout_height="80dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:src="@drawable/btn_empty"
            />

        <ImageView
            android:id="@+id/btn3"
            android:layout_weight="1"
            android:layout_width="80dp"
            android:layout_height="80dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:src="@drawable/btn_empty"
            />
        <ImageView
            android:id="@+id/btn4"
            android:layout_weight="1"
            android:layout_width="80dp"
            android:layout_height="80dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:src="@drawable/btn_plus"
            />
    </LinearLayout>

</layout>