activity_post.xml

<?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"
    android:layout_marginVertical="16dp"
    android:layout_marginHorizontal="16dp"
    tools:context=".PostActivity">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:hint="Tulis posting Anda..."
        android:id="@+id/postContent"
        android:gravity="start"/>
    <ProgressBar
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:id="@+id/progressBar"
        android:layout_toLeftOf="@+id/postButton"
        android:layout_below="@+id/postContent"
        android:layout_marginTop="6dp"
        android:layout_marginRight="12dp"
        android:visibility="invisible"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/postButton"
        android:text="Simpan"
        android:layout_below="@+id/postContent"
        android:layout_alignParentRight="true"
        android:background="@color/colorPrimary"
        android:textColor="@android:color/white"/>

</RelativeLayout>