tank-server/app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/coordinatorLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="150dp"
            android:scaleType="centerCrop"
            android:src="@drawable/header" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:background="@color/colorPrimaryLight"
            android:gravity="center"
            android:orientation="vertical">

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/textViewIpAccess"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="http://000.000.000.000:"
                    android:textColor="@android:color/white"
                    android:textSize="20sp"
                    android:textStyle="bold" />

                <EditText
                    android:id="@+id/editTextPort"
                    android:layout_width="60dp"
                    android:layout_height="wrap_content"
                    android:gravity="center"
                    android:hint="8080"
                    android:inputType="numberDecimal"
                    android:maxLength="4"
                    android:text="8080"
                    android:textColor="@android:color/white"
                    android:textSize="20sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <TextView
                android:id="@+id/textViewMessage"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="50dp"
                android:layout_marginRight="50dp"
                android:layout_marginTop="50dp"
                android:gravity="center"
                android:text="@string/message"
                android:textColor="@android:color/white"
                android:textSize="18sp"
                android:visibility="invisible" />

        </LinearLayout>

    </LinearLayout>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/floatingActionButtonOnOff"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end|bottom"
        android:layout_margin="16dp"
        android:elevation="4dp"
        android:src="@drawable/on_btn"
        app:backgroundTint="@color/colorRed" />

    <Button
        android:id="@+id/open_hotspot"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button" />

    <TextView
        android:id="@+id/open_hotspot_msg"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="TextView" />

</android.support.design.widget.CoordinatorLayout>