如何禁用CollapsingToolbar的折叠当滚动没有内容？

Question

  <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:id="@+id/appbar"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fitsSystemWindows="true"
                android:background="@android:color/white"
                android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

                <android.support.design.widget.CollapsingToolbarLayout
                    android:id="@+id/collapsing_toolbar"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:fitsSystemWindows="true"
                    app:contentScrim="?attr/colorPrimary"
                    app:expandedTitleMarginEnd="64dp"
                    app:expandedTitleMarginStart="48dp"
                    app:layout_scrollFlags="scroll|exitUntilCollapsed">

                    <fragment
                        android:id="@+id/pawfile_header"
                        android:name="com.lightbulb.pawesome.fragments.PawfileHeaderFragment"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_marginLeft="10dp"
                        android:layout_marginTop="10dp"
                        android:fitsSystemWindows="true"
                        app:layout_collapseMode="parallax" />

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

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

            <fragment
                android:id="@+id/pawfile_timeline"
                android:name="com.lightbulb.pawesome.user_timeline.PawesomeUserTimelineFragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:layout_behavior="@string/appbar_scrolling_view_behavior" />

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

UDPATE问题：

我已经完成了禁用和启用视图的折叠。我使用这行代码来禁用折叠：

AppBarLayout.LayoutParams appbarParams = (AppBarLayout.LayoutParams)     collapsingToolbar.getLayoutParams();
appbarParams.setScrollFlags(0);
collapsingToolbar.setLayoutParams(p);

Answer 1

AppBarLayout.LayoutParams p = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();
p.setScrollFlags(0);
toolbar.setLayoutParams(p);