layout

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.esteban.myapplication.MainActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="215dp"
        android:layout_height="43dp"
        android:ems="10"
        android:inputType="text"
        android:text="Alimento"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="100dp"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Buscar"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="220dp"
        android:layout_marginLeft="100dp"
        app:layout_constraintLeft_toLeftOf="parent" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="215dp"
        android:layout_height="42dp"
        android:ems="10"
        android:inputType="text"
        android:text="Cantidad"
        android:layout_marginLeft="100dp"
        app:layout_constraintLeft_toLeftOf="parent"
        android:layout_marginRight="100dp"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="150dp" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_marginLeft="150dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="200dp" />
</android.support.constraint.ConstraintLayout>