Floating Action Button + Coordinator Layot + Position and placing issue

Question

Floating Action Button inside coordinator layout is not getting placed on Right|Bottom. Even cannot resolve. Might be there is an issue regarding layout_anchor but don't know what is the problem.

Here is there code:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mDrawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.CoordinatorLayout
        android:id="@+id/coordinator"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <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="@android:color/background_light"
                app:layout_scrollFlags="enterAlways|scroll" />

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

        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="This is sample Text" />
        </android.support.v4.widget.NestedScrollView>

        <android.support.design.widget.FloatingActionButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="16dp"
            app:layout_anchor="@id/coordinator"
            app:layout_anchorGravity="bottom|right|end"
            app:layout_behavior="@string/fab_onscroll_behavior" />

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

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@color/colorAccent"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/nav_menu" />


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

Can anyone help me to resolve this issues? What is the reason why it is not getting on bottom right side?

Answer 1

just add FAB button in RelativeLayout like below this may help

    <?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mDrawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.CoordinatorLayout
        android:id="@+id/coordinator"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <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="@android:color/background_light"
                app:layout_scrollFlags="enterAlways|scroll" />

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

        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="This is sample Text" />
        </android.support.v4.widget.NestedScrollView>

       // try this
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.design.widget.FloatingActionButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="16dp"
            android:layout_alignParentBottom="true"
            android:layout_alignParentEnd="true"/>
    </RelativeLayout>

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

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@color/colorAccent"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/nav_menu" />


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

Answer 2

Your FloatingActionButton should be like this:

<android.support.design.widget.FloatingActionButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="16dp"
    android:layout_gravity="bottom|end" />

You don't need to use anchor to place it inside the CoordinatorLayout. Anchor and AnchorGravity only used for anchor the view to another sibling view.