Activity prime

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context="com.example.user.main.prime">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        android:orientation="horizontal">


        <TextView
            android:id="@+id/t1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="num:"
            android:textSize="30dp"/>
        <EditText
            android:id="@+id/e1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
    </LinearLayout>

    <Button
        android:id="@+id/b5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="Check for prime" />


</LinearLayout>