Bottom Align Floating Action Button

For RelativeLayout:

<com.google.android.material.floatingactionbutton.FloatingActionButton    android:id="@+id/fab"    android:layout_alignParentBottom="true"    android:layout_alignParentRight="true"    ... />

For CoordinatorLayout, you should use android:layout_gravity="end|bottom"

For ConstraintLayout:

<com.google.android.material.floatingactionbutton.FloatingActionButton    android:id="@+id/fab"    app:layout_constraintBottom_toBottomOf="parent"    app:layout_constraintEnd_toEndOf="parent"    ... />

See this answer for more information.

Layout should be RelativeLayout. Try the next code:

<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"><LinearLayout    android:id="@+id/ly_list_form"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical">    <ListView        android:id="@+id/list_forms"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:dividerHeight="1dp" /></LinearLayout><LinearLayout    android:id="@+id/ly_bar_bottom"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:layout_alignParentBottom="true"    android:gravity="right"    android:orientation="horizontal">    <android.support.design.widget.FloatingActionButton        android:id="@+id/button_addc"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="bottom|end"        android:layout_margin="28dp"        android:src="@drawable/ic_add"        app:borderWidth="0dp"        app:elevation="6dp"        app:pressedTranslationZ="12dp" /></LinearLayout>

It appears that FloatingActionButton isn't positioned correctly inside a RelativeLayout.

I changed RelativeLayout to FrameLayout, and problem solved!Hope it helps!

<ListView    android:id="@+id/mylist"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_margin="5dp"    android:divider="@android:color/transparent"    android:dividerHeight="1.0sp" /><android.support.design.widget.FloatingActionButton    android:id="@+id/fab"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="right|bottom"    android:src="@drawable/ic_add_white_48dp"    app:backgroundTint="@color/spg_rosa"    app:borderWidth="0dp"    app:elevation="8dp"    app:fabSize="normal" /></FrameLayout>