Button is hiding in nested scrollview with collapsing toolbar

Question

I am using collapsing toolbar with nested ScrollView in Registration fragment, But the register button at the bottom is not fully displaying for the first time when I click on some edit text and opens keyboard if I scroll to bottom then the button is fully visible.

The image is attached below.

Before opening keyboard

when keyboard opens

After keyboard closed

Here is the xml code.

<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="10dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="10dp"
        android:orientation="vertical">

            <android.support.design.widget.TextInputLayout
                style="@style/StyledTilEditText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/stemiIcon"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp">

                <EditText
                    android:id="@+id/et_reg_name"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Name"
                    android:imeOptions="actionNext"
                    android:inputType="textPersonName" />
            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                style="@style/StyledTilEditText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/stemiIcon"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp">

                <EditText
                    android:id="@+id/et_reg_phone"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Phone"
                    android:imeOptions="actionNext"
                    android:inputType="phone" />
            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                style="@style/StyledTilEditText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/stemiIcon"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp">

                <EditText
                    android:id="@+id/et_reg_dob"
                    style="@style/StyledTilEditText"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:clickable="true"
                    android:cursorVisible="false"
                    android:editable="false"
                    android:hint="Date of birth"
                    android:imeOptions="actionNext"
                    android:inputType="none"
                    android:longClickable="false" />
            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                style="@style/StyledTilEditText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/stemiIcon"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp">

                <EditText
                    android:id="@+id/et_reg_email"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Email"
                    android:imeOptions="actionNext"
                    android:inputType="textEmailAddress" />
            </android.support.design.widget.TextInputLayout>

            <android.support.design.widget.TextInputLayout
                style="@style/StyledTilEditText"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/stemiIcon"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp">

                <EditText
                    android:id="@+id/et_reg_password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:hint="Password"
                    android:imeOptions="actionNext"
                    android:inputType="textPassword" />
            </android.support.design.widget.TextInputLayout>

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="10dp"
                android:layout_marginStart="10dp"
                android:layout_marginTop="15dp"
                android:text="Gender"
                android:textColor="@color/text_line" />

            <com.agiliztech.stepout2play.customviews.AnswerTemplateView
                android:id="@+id/answerLayout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/have_diabetes"
                android:layout_margin="10dp"
                app:clickedColor="@color/selected_gender"
                app:colorView="@color/color_white"
                app:textBackground="@drawable/text_border_with_color"
                app:textColor="@color/selected_gender">

            </com.agiliztech.stepout2play.customviews.AnswerTemplateView>

        <Button
            android:id="@+id/bt_reg_register"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@color/btn_color"
            android:text="REGISTER"
            android:textColor="@color/color_white" />
    </LinearLayout>


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

Answer 1

Set height to match_parent and add android:fillViewport element

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="10dp"
    android:fillViewport="true"/>
    ...
    ...
</android.support.v4.widget.NestedScrollView>