Google maps and coordinator layout

Question

I am trying to imitate the google maps layout. It's seems they use a coordinator layout with a map fragment. The problems are:

1 - I cant set a minimum value of bottom view (see picture 1 and 3).

2 - I need a maximimum of collapsed, I always want to show a part of the map (picture 2)

3 - If I collapse the map too much, the FAB and map disapears.

The code:

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <fragment
                android:id="@+id/map"
                android:name="com.google.android.gms.maps.SupportMapFragment"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layout_collapseMode="parallax"
                app:layout_scrollFlags="scroll|enterAlways" />

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

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

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

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_camera"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_margin="@dimen/activity_horizontal_margin"
        android:clickable="true"
        android:src="@drawable/ic_photo_camera_white"
        app:backgroundTint="@color/colorPrimary"
        app:fabSize="normal"
        app:layout_anchor="@+id/appbar"
        app:layout_anchorGravity="bottom|right|end" />
</android.support.design.widget.CoordinatorLayout>

Answer 1

For screenshot num 3, as a min height you could do something like this:

<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:layout_marginBottom="120dp">

For screenshot 5, use an empty toolbar to set the min height.

Take a look at the next sample:

<android.support.design.widget.CoordinatorLayout
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:fitsSystemWindows="true">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:fitsSystemWindows="true"
    android:id="@+id/appBar">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapse_toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"
        android:fitsSystemWindows="true">

        <fragment
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.MapFragment"
            android:layout_width="match_parent"
            android:layout_height="300dp"
            android:fitsSystemWindows="true"
            app:layout_collapseMode="parallax"
            app:layout_scrollFlags="scroll|enterAlways" />

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_collapseMode="pin"/>

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

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

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

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/fragment_container">

    </FrameLayout>

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

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="-60dp"
    android:layout_marginRight="16dp"
    android:src="@android:drawable/ic_dialog_email"
    app:layout_anchor="@id/appBar"
    app:layout_anchorGravity="bottom|right|end"  />

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