activity_maps.xml

<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">

        <fragment
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.SupportMapFragment"
            android:layout_width="383dp"
            android:layout_height="435dp"
            android:layout_column="0"
            android:layout_row="2"
            tools:context="com.example.student.myapplication123.MapsActivity"
            android:layout_marginRight="0dp"
            app:layout_constraintRight_toRightOf="parent"
            android:layout_marginLeft="0dp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginTop="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            android:layout_marginBottom="0dp"
            app:layout_constraintVertical_bias="1.0"
            app:layout_constraintHorizontal_bias="0.4"
            tools:layout_editor_absoluteY="76dp" />

    <Button
        android:id="@+id/button2"
        android:layout_width="113dp"
        android:layout_height="51dp"
        android:layout_marginBottom="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="84dp"
        android:layout_marginTop="8dp"
        android:onClick="Culick"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.642"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.018" />

        <EditText
            android:id="@+id/editText"
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:layout_column="0"
            android:layout_row="1"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="100"
            android:textSize="26sp"
            android:layout_marginLeft="8dp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginTop="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            android:layout_marginBottom="8dp"
            app:layout_constraintVertical_bias="0.018"
            android:layout_marginRight="8dp"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintHorizontal_bias="0.029" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:textSize="26sp"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="8dp"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintHorizontal_bias="0.911"
        app:layout_constraintVertical_bias="0.04" />
</android.support.constraint.ConstraintLayout>