Using:
compile 'com.android.support:design:23.0.0' compile 'com.android.support:appcompat-v7:23.0.0' compile 'com.android.support:cardview-v7:23.0.0' compile 'com.android.support:recyclerview-v7:23.0.0' With the project Cheesesquare updated.
Into the detail of cheese, I remove 2 cards (to have only one). Is there a way to prevent the collapsing of the toolbar that show a blank space?
To implement such behaviour in Cheesesquare example just modify android:layout_height param of the NestedScrollView to wrap_content. It will prevent scrolling by content if it is small enough to fit on the screen.
And to prevent scrolling by CollapsingToolbarLayout you should programmatically set layout_scrollFlags parameter to the AppBarLayout.LayoutParams.SCROLL_FLAG_SNAP value.
Here described how you can do this.
app:layout_scrollFlags="snap" to the CollapsingToolbarLayout tag
wrap_content resolves the problem. The layout has AppBarLayout and NestedScrollView.You can use below code for this:
public static void stopScroll() { AppBarLayout.LayoutParams toolbarLayoutParams = (AppBarLayout.LayoutParams) collapsingToolbar.getLayoutParams(); toolbarLayoutParams.setScrollFlags(0); collapsingToolbar.setLayoutParams(toolbarLayoutParams); CoordinatorLayout.LayoutParams appBarLayoutParams = (CoordinatorLayout.LayoutParams) appbar.getLayoutParams(); appBarLayoutParams.setBehavior(null); appbar.setLayoutParams(appBarLayoutParams); } public static void startScroll() { AppBarLayout.LayoutParams toolbarLayoutParams = (AppBarLayout.LayoutParams) collapsingToolbar.getLayoutParams(); toolbarLayoutParams.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS); collapsingToolbar.setLayoutParams(toolbarLayoutParams); CoordinatorLayout.LayoutParams appBarLayoutParams = (CoordinatorLayout.LayoutParams) appbar.getLayoutParams(); appBarLayoutParams.setBehavior(new AppBarLayout.Behavior()); appbar.setLayoutParams(appBarLayoutParams); } 
A data-binding solution inspired by @Vishal's answer
<com.google.android.material.appbar.AppBarLayout> <com.google.android.material.appbar.CollapsingToolbarLayout app:enableCollapsingScroll="@{listItems.size > 0}" ... /> </com.google.android.material.appbar.AppBarLayout> @BindingAdapter("app:enableCollapsingScroll") fun setCollapsingToolbarLayoutScrollEnabled(collapsingToolbarLayout: CollapsingToolbarLayout, enabled: Boolean?) { val lp = collapsingToolbarLayout.layoutParams as AppBarLayout.LayoutParams if (enabled.orFalse()) { lp.scrollFlags = AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL or AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED } else { lp.scrollFlags = AppBarLayout.LayoutParams.SCROLL_FLAG_SNAP } collapsingToolbarLayout.layoutParams = lp } In xml I have used property
app:layout_scrollFlags="snap" in <android.support.design.widget.CollapsingToolbarLayout
and following in the activity
toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); toolbar.setTitle(null); toolbar.setCollapsible(false); It is working now.
AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) activityUserGroupProfleBinding.collapsingToolbarLayout.getLayoutParams(); if (logic) { params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED); } else { params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SNAP); } activityUserGroupProfleBinding.collapsingToolbarLayout.setLayoutParams(params); Here is my working code, to initially collapes the bar:
AppBarLayout _appbar = (AppBarLayout) findViewById(R.id.appbar); _appbar.setExpanded(false); here is the layout xml
<android.support.design.widget.AppBarLayout android:id="@+id/appbar" android:layout_width="match_parent" android:layout_height="@dimen/detail_backdrop_height" android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" android:fitsSystemWindows="true"> <android.support.design.widget.CollapsingToolbarLayout android:id="@+id/collapsing_toolbar" android:layout_width="match_parent" android:layout_height="match_parent" app:layout_scrollFlags="scroll|exitUntilCollapsed" android:fitsSystemWindows="true" app:contentScrim="?attr/colorPrimary" app:expandedTitleMarginStart="48dp" app:expandedTitleMarginEnd="64dp"> <android.support.v7.widget.Toolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" app:popupTheme="@style/ThemeOverlay.AppCompat.Light" app:layout_collapseMode="pin" /> </android.support.design.widget.CollapsingToolbarLayout> </android.support.design.widget.AppBarLayout> the reference is: AppBarLayout.setExpanded(boolean)
