xml file of relative layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".MainActivity">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Log In "
        android:id="@+id/t1"
        android:gravity="center"
        android:textSize="30dp" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="username "
        android:id="@+id/t2"
        android:gravity="center"
        android:layout_below="@+id/t1"
        android:textSize="100px" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/t3"
        android:gravity="center"
        android:layout_below="@+id/t1"
        android:layout_toRightOf="@+id/t2" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="password "
        android:id="@+id/t4"
        android:gravity="center"
        android:layout_below="@+id/t2"
        android:textSize="100px" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/t5"
        android:gravity="center"
        android:layout_below="@+id/t3"
        android:layout_toRightOf="@+id/t4" />

    <Button
        android:id="@+id/b1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/t5"
        android:gravity="center"
        android:layout_toEndOf="@id/t4"
        android:text="Login" />
</RelativeLayout>