How to hide ToolBar when I scrolling content up?

This is the best scenario to make use of CoordinatorLayout in your app. CoordinatorLayout is a super-powered FrameLayout which has got a lot of nifty animation tricks upon its sleeves.

The Design library introduces CoordinatorLayout, a layout which provides an additional level of control over touch events between child views, something which many of the components in the Design library take advantage of.

You can start with this and this tutorial.

you have to do many changes in your both layout. first use CoordinatorLayout in activity_main.XML like below(change theme as per your requirement).

<?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/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

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

    <include layout="@layout/content_main" />

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

in content_main.XML use android.support.v4.widget.NestedScrollView instead of ScrollView.

also use app:layout_behavior="@string/appbar_scrolling_view_behavior" inside android.support.v4.widget.NestedScrollView like below.

<android.support.v4.widget.NestedScrollView
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        xmlns:android="http://schemas.android.com/apk/res/android" 
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

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

            <TextView
                android:id="@+id/textone"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="hello world jheds sdjhs jds sjbs skjs ksjs kksjs ksj sdd dskd js sk "
                android:textSize="25dp"
                android:textStyle="bold" />

            /// Add your other code here

            </LinearLayout>

    </android.support.v4.widget.NestedScrollView>