How to disable scrolling of NestedScrollView&CollapsingToolbarLayout, for example when there is no more content below?

What can I do in order to make the scrolling stop when there is no more content to show at the bottom?

Firstly, as I have commented below, the scrolling you said in your question is not of the NestedScrollView. It belongs to the CollapsingToolbarLayout. The NestedScrollView's scroll event only happens when CollapsingToolbarLayout fully collapsed, and of course it will stop scrolling when when there is no more content inside it (bottom reached). For the CollapsingToolbarLayout, it will collapse to its Toolbar's layout_height (as in the xml file, you will find "?attr/actionBarSize"). The following image will demonstrate that, pay attention to the red rectangular that is the toolbar (I set its background)

BNK's image

So to have a solution for your #1, you need to calculate the height of NestedScrollView, then if it's smaller than screen height, we fix the toolbar's height.

In short, you can update activity_detail.xml as the following:

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_content"
    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="@dimen/detail_backdrop_height"
        android:fitsSystemWindows="true"
        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:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="false"
                android:scaleType="centerCrop"
                app:layout_collapseMode="parallax" />

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

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

    </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">

        <LinearLayout
            android:id="@+id/linearLayout1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_margin="@dimen/card_margin">

                <LinearLayout
                    style="@style/Widget.CardContent"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Info"
                        android:textAppearance="@style/TextAppearance.AppCompat.Title" />

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="@string/cheese_ipsum" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

        </LinearLayout>

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

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

And CheeseDetailActivity.java:

public class CheeseDetailActivity extends AppCompatActivity {

    public static final String EXTRA_NAME = "cheese_name";
    private final Context mContext = this;
    private int screenHeight;
    private int linearLayoutHeight;
    private int toolbarHeight_org;
    private int toolbarHeight;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detail);

        Intent intent = getIntent();
        final String cheeseName = intent.getStringExtra(EXTRA_NAME);

        screenHeight = getScreenHeight(this);

        TypedValue typedValue = new TypedValue();
        getTheme().resolveAttribute(R.attr.colorPrimary, typedValue, true);
        final int colorPrimary = typedValue.data;

        final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        AppBarLayout appbar = (AppBarLayout) findViewById(R.id.appbar);
        final CoordinatorLayout.LayoutParams appbarLayoutParams = (CoordinatorLayout.LayoutParams)appbar.getLayoutParams();

        final ViewGroup.LayoutParams toolbarLayoutParams = toolbar.getLayoutParams();
        if (toolbarLayoutParams != null) {
            toolbarHeight_org = toolbarLayoutParams.height;
            toolbarHeight = toolbarLayoutParams.height;
        }

        final CollapsingToolbarLayout collapsingToolbar =
                (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
        collapsingToolbar.setTitle(cheeseName);

        collapsingToolbar.setContentScrimColor(colorPrimary);
        collapsingToolbar.setExpandedTitleTextAppearance(R.style.ExpandedTitleTextAppearance);
        //collapsingToolbar.setCollapsedTitleTextAppearance(R.style.CollapsedTitleTextAppearance);

        final LinearLayout linearLayout = (LinearLayout) findViewById(R.id.linearLayout1);
        ViewTreeObserver observer = linearLayout.getViewTreeObserver();
        observer.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                linearLayoutHeight = linearLayout.getHeight();
                if (linearLayoutHeight + toolbarHeight < screenHeight) {
                    if (toolbarLayoutParams != null) {
                        toolbarLayoutParams.height = screenHeight - linearLayoutHeight - 20;
                        if (toolbarLayoutParams.height < toolbarHeight_org) {
                            toolbarLayoutParams.height = toolbarHeight_org;
                        }

                        int extended_text_size = (int) getResources().getDimension(R.dimen.expanded_text_size);

                        if (appbarLayoutParams.height - toolbarLayoutParams.height <= extended_text_size) {
                            int value = appbarLayoutParams.height - toolbarLayoutParams.height;
                            if (value < 0) {
                                appbarLayoutParams.height = toolbarLayoutParams.height - value + extended_text_size * 3;
                            } else {
                                appbarLayoutParams.height = toolbarLayoutParams.height + extended_text_size * 3;
                            }
                            if (appbarLayoutParams.height >= screenHeight) {
                                appbarLayoutParams.height = screenHeight;
                            }
                        }

                        // collapsingToolbar.setContentScrimColor(getResources().getColor(android.R.color.transparent));
                        if (toolbarLayoutParams.height > toolbarHeight_org) {
                            collapsingToolbar.setContentScrimColor(ContextCompat.getColor(mContext, android.R.color.transparent));
                        }
                    }
                }
                // Removes the listener if possible
                ViewTreeObserver viewTreeObserver = linearLayout.getViewTreeObserver();
                if (viewTreeObserver.isAlive()) {
                    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
                        linearLayout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                    } else {
                        linearLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                    }
                }
            }
        });

        loadBackdrop();
        appbar.setExpanded(true);
    }

    private int getScreenHeight(Context context) {
        int measuredHeight;
        Point size = new Point();
        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
            wm.getDefaultDisplay().getSize(size);
            measuredHeight = size.y;
        } else {
            Display d = wm.getDefaultDisplay();
            measuredHeight = d.getHeight();
        }

        return measuredHeight;
    }

    private void loadBackdrop() {
        final ImageView imageView = (ImageView) findViewById(R.id.backdrop);
        Glide.with(this).load(Cheeses.getRandomCheeseDrawable()).centerCrop().into(imageView);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.sample_actions, menu);
        return true;
    }
}

Here's the result:

BNK's screenshot

With Cheesesquare sample, I have customized this project and uploaded to My GitHub. I agree that it still has some problems, however, at least it can be a solution for your 1st issue.

Please take a look. Hope it helps!