Collapsing AppBarLayout not scrolling with TabLayout and NestedScrollView

Question

I have an issue with scrolling Collapsing AppBar, when I am trying to scroll it touching the AppBarLayout part. And also it sometimes scrolling not smoothly.

Here is short (1m 30s) video of issue: https://www.youtube.com/watch?v=n32N9Z4S3SA&feature=youtu.be

Here is link to simple project (only this issue on github): https://github.com/yozhik/Reviews/tree/master/app/src/main/java/com/ylet/sr/review

I'm using: com.android.support:appcompat-v7:27.1.1

There is issue on offsite: https://issuetracker.google.com/issues/37050152

How it is: https://www.youtube.com/watch?v=xWadOVEaTSY&feature=youtu.be

How it should be: https://www.youtube.com/watch?v=J8ITp6RusZo&feature=youtu.be

Does anybody know how to fix this issue you saw on video? I created absolutely simple layouts to avoid any side effects, but bug still reproduced. Thanks in advance.

Description:

CollapsingActivity - activity with Collapsing AppBarLayout. Which loads one or two fragments into "fragment_content_holder" and it has TabLayout to switch between fragments in view pager.

In activity method onCreate() - I'm just simulating request to server (loadData), and when some fake data is loaded - I am showing fragments in view pager, on first call - I am creating new TabMenuAdapter extends FragmentPagerAdapter, populate it with fragments and save links to instances. On the next call - I don't create fragments from scratch and just populate them with fresh data.

MenuFragment1, MenuFragment1 - two fragments. MenuFragment1 - has method public void setupData(SomeCustomData data), to set new data, not recreating fragment on network reconnect.

NetworkStateReceiver - listens to network change and send notifications.

TabMenuAdapter - just simple class to hold fragments.

Next is just copy/paste of code:

public class CollapsingActivity extends AppCompatActivity implements ChangeNetworkNotification {
    private static int dataReloadIteration = 0;
    private SomeCustomData dummyDataFromServer;

    @BindView(R.id.root_layout)
    CoordinatorLayout root_layout;

    @BindView(R.id.app_bar_layout)
    AppBarLayout app_bar_layout;

    @BindView(R.id.collapsing_toolbar_layout)
    CollapsingToolbarLayout collapsing_toolbar_layout;

    @BindView(R.id.view_pager_layout)
    ViewPager viewPager;

    @BindView(R.id.tab_layout)
    TabLayout tabLayout;

    @BindView(R.id.collapsing_data_1_txt)
    TextView collapsing_data_1_txt;

    private NetworkStateReceiver networkStateReceiver;
    private boolean isConnected;

    protected Fragment currentFragment;
    protected Fragment previousFragment;
    protected FragmentManager fragmentManager;

    private boolean dataLoading = false;
    private boolean isCreated = false;

    private MenuFragment1 menu1Fragment1;
    private MenuFragment2 menu1Fragment2;
    private TabMenuAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d("TEST", "CollapsingActivity.onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_collapsing);
        ButterKnife.bind(this);

        fragmentManager = getSupportFragmentManager();

        networkStateReceiver = new NetworkStateReceiver();
        networkStateReceiver.setNetworkReceiver(this);

        IntentFilter intentFilterForNetwork = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
        registerReceiver(networkStateReceiver, intentFilterForNetwork);

        initToolbar();
        loadData();
    }

    @Override
    protected void onStart() {
        Log.d("TEST", "CollapsingActivity.onStart");
        super.onStart();
        IntentFilter intentFilterForNetwork = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
        registerReceiver(networkStateReceiver, intentFilterForNetwork);
    }

    private void initToolbar() {
        Log.d("TEST", "CollapsingActivity.initToolbar");
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_layout);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowTitleEnabled(false);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    private void loadData() {
        Log.d("TEST", "CollapsingActivity.loadData");
        dataLoading = true;
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(CollapsingActivity.this, "Data loaded.", Toast.LENGTH_SHORT).show();
                        Log.d("TEST", "CollapsingActivity.Data loaded.");
                        dataReloadIteration++;
                        dummyDataFromServer = getDummyObjectFromServer();

                        collapsing_data_1_txt.setText(dummyDataFromServer.Name); //Set data from server in collapsing part of Activity

                        boolean showOneView = false;
                        if (showOneView) {
                            initSingleView();
                        } else {
                            if (!isCreated) {
                                initTabView();
                            } else {
                                menu1Fragment1.setupData(dummyDataFromServer);  //Set the data from server to fragment, not reloading it, just updating data
                            }
                        }
                        dataLoading = false;
                    }
                });
            }
        });
        t.start();
    }

    private SomeCustomData getDummyObjectFromServer() {
        SomeCustomData dto = new SomeCustomData();
        dto.Age = dataReloadIteration;
        dto.Name = "Name " + dataReloadIteration;
        return dto;
    }

    private void initSingleView() {
        Log.d("TEST", "CollapsingActivity.initSingleView");
        tabLayout.setVisibility(View.GONE);
        viewPager.setVisibility(View.GONE);
        showFragmentWithoutBackStack(R.id.fragment_content_holder, new MenuFragment1());
    }

    private void initTabView() {
        if (!isCreated) {
            Log.d("TEST", "CollapsingActivity.initTabView");
            tabLayout.setVisibility(View.VISIBLE);
            viewPager.setVisibility(View.VISIBLE);

            setupViewPager(viewPager);
            tabLayout.setupWithViewPager(viewPager);
            isCreated = true;
        }
    }

    private void setupViewPager(ViewPager viewPager) {
        Log.d("TEST", "CollapsingActivity.setupViewPager");
        menu1Fragment1 = MenuFragment1.newInstance(dummyDataFromServer);
        menu1Fragment2 = MenuFragment2.newInstance();

        adapter = new TabMenuAdapter(getSupportFragmentManager());
        adapter.addFragment(menu1Fragment1, "Menu 1");
        adapter.addFragment(menu1Fragment2, "Menu 2");
        viewPager.setAdapter(adapter);
    }

    @Override
    protected void onDestroy() {
        Log.d("TEST", "CollapsingActivity.onDestroy");
        super.onDestroy();
        unregisterReceiver(networkStateReceiver);
    }

    @Override
    public void networkStateIsChanged(boolean isConnected) {
        this.isConnected = isConnected;
        Log.d("TEST", "CollapsingActivity.networkStateIsChanged.isConnected: " + isConnected);
        if (isConnected) {
            Toast.makeText(CollapsingActivity.this, "Connection received.", Toast.LENGTH_SHORT).show();
            if (!dataLoading) {
                loadData();
            }
        } else {
            Toast.makeText(CollapsingActivity.this, "Connection lost.", Toast.LENGTH_SHORT).show();
        }
    }

    protected void showFragmentWithoutBackStack(int containerViewId, Fragment fragment) {
        Log.d("TEST", "CollapsingActivity.showFragmentWithoutBackStack");
        previousFragment = currentFragment;
        currentFragment = fragment;
        String fragmentTag = fragment.getClass().getSimpleName();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        if (previousFragment != null) {
            fragmentTransaction.remove(previousFragment);
        }
        fragmentTransaction.add(containerViewId, fragment, fragmentTag)
                .commitNowAllowingStateLoss();
    }
}

activity's layout:

<?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/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="false"
        android:background="@color/white"
        android:stateListAnimator="@drawable/appbar_shadow"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/green"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:title=""
            app:titleEnabled="false">

            <include
                layout="@layout/appbar_collapsing_part"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="?attr/actionBarSize"
                app:layout_scrollFlags="scroll|exitUntilCollapsed" />


            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar_layout"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@color/green"
                android:stateListAnimator="@drawable/appbar_shadow"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme.PopupOverlay"
                app:theme="@style/ToolbarMenuItemsBackGroundTheme">

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">

                    <TextView
                        android:id="@+id/title_txt"
                        android:layout_width="wrap_content"
                        android:layout_height="match_parent"
                        android:layout_alignParentStart="true"
                        android:layout_toStartOf="@+id/star_img"
                        android:ellipsize="end"
                        android:fontFamily="sans-serif-medium"
                        android:gravity="center_vertical"
                        android:maxLines="1"
                        android:textColor="@color/colorPrimaryDark"
                        android:textSize="19sp" />

                    <ImageView
                        android:id="@+id/star_img"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignParentEnd="true"
                        android:layout_centerInParent="true"
                        android:layout_gravity="center"
                        android:layout_marginEnd="24dp"
                        android:padding="10dp"
                        android:src="@drawable/ic_favorite_filled" />

                </RelativeLayout>

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

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

        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="wrap_content"
            android:layout_height="48dp"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:background="#45b0b2"
            android:visibility="gone"
            app:tabBackground="@drawable/backgr_blue_transparent_selector"
            app:tabGravity="center"
            app:tabIndicatorColor="@color/colorPrimaryDark"
            app:tabIndicatorHeight="2dp"
            app:tabMinWidth="500dp"
            app:tabMode="fixed"
            app:tabSelectedTextColor="@color/colorPrimaryDark"
            app:tabTextAppearance="@style/CustomTabLayout"
            app:tabTextColor="@color/green" />

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


    <FrameLayout
        android:id="@+id/fragment_content_holder"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/blue"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

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

Fragment 1:

public class MenuFragment1 extends Fragment {

    public SomeCustomData transferedDataFromActivity;
    private TextView data_1_txt;

    public static MenuFragment1 newInstance(SomeCustomData data) {
        Log.d("TEST", "MenuFragment1.newInstance");
        MenuFragment1 fragment = new MenuFragment1();

        Bundle args = new Bundle();
        args.putSerializable("DATA_FROM_ACTIVITY", data);
        fragment.setArguments(args);

        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("TEST", "MenuFragment1.onCreate");

        if (getArguments() != null) {
            this.transferedDataFromActivity = (SomeCustomData) getArguments().getSerializable("DATA_FROM_ACTIVITY");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.d("TEST", "MenuFragment1.onCreateView");
        View v = inflater.inflate(R.layout.menu_fragment_1, container, false);
        data_1_txt = (TextView) v.findViewById(R.id.data_1_txt);

        setupInOnCreateView();

        return v;
    }

    protected void setupInOnCreateView() {
        Log.d("TEST", "MenuFragment1.setupInOnCreateView");
        //initialization of all view elements of layout with data is happens here.
        setupData(transferedDataFromActivity);
    }

    public void setupData(SomeCustomData data) {
        Log.d("TEST", "MenuFragment1.setupData");
        this.transferedDataFromActivity = data;
        if (transferedDataFromActivity != null) {
            data_1_txt.setText(transferedDataFromActivity.Name);
        }
    }
}

Fragment 1 layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/green"
    android:orientation="vertical">

    <TextView
        android:id="@+id/data_1_txt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/yellow"
        android:text="Test"
        android:textSize="20sp" />

    <include layout="@layout/description_layout" />

</LinearLayout>

Fragment 2:

public class MenuFragment2 extends Fragment {

    public static MenuFragment2 newInstance() {
        Log.d("TEST", "MenuFragment2.newInstance");
        MenuFragment2 fragment = new MenuFragment2();
        return fragment;
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.d("TEST", "MenuFragment2.onCreateView");
        View v = inflater.inflate(R.layout.menu_fragment_2, container, false);

        setupInOnCreateView();

        return v;
    }

    protected void setupInOnCreateView() {
        Log.d("TEST", "MenuFragment2.setupInOnCreateView");
        //initialization of all view elements of layout with data is happens here.
    }
}

Fragment 2 layout:

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

<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/comments_scrollable_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:visibility="visible">

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

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:background="@color/yellow" />

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:background="@color/blue" />

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:background="@color/yellow" />

    </LinearLayout>


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

TabMenuAdapter:

public class TabMenuAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragments = new ArrayList<>();
    private final List<String> mFragmentTitles = new ArrayList<>();

    public TabMenuAdapter(FragmentManager fm) {
        super(fm);
    }

    public void addFragment(Fragment fragment, String title) {
        mFragments.add(fragment);
        mFragmentTitles.add(title);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitles.get(position);
    }

}

Answer 1

Try this

Activity layout

    <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    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:theme="@style/AppTheme.AppBarOverlay">

        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:title=""
            app:titleEnabled="false">

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="256dp"
                android:scaleType="fitXY"
                android:src="@drawable/abc"
                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/AppTheme.PopupOverlay" />
        </android.support.design.widget.CollapsingToolbarLayout>

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            app:layout_anchor="@id/appBar"
            app:tabGravity="fill"
            app:tabTextColor="#FFFFFF"
            app:tabSelectedTextColor="#ff00"
            app:tabMode="scrollable"
            app:layout_anchorGravity="bottom" />

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

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

Activity code

public class MainActivity extends AppCompatActivity {


    private Toolbar toolbar;
    private TabLayout tabLayout;
    private ViewPager viewPager;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);


    }
    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
        adapter.addFragment(new BlankFragment(), "TAB-ONE");
        adapter.addFragment(new BlankFragment(), "TAB-TWO");
        adapter.addFragment(new BlankFragment(), "TAB-THREE");
        viewPager.setAdapter(adapter);
    }




}

Fragment Code

public class BlankFragment extends Fragment {


    public BlankFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment



        return inflater.inflate(R.layout.fragment_blank, container, false);
    }

}

Fragment Layout

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

<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">


    <LinearLayout
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".BlankFragment">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:layout_margin="5dp"
            android:scaleType="centerCrop"
            android:src="@drawable/kid_goku" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:layout_margin="5dp"
            android:scaleType="centerCrop"
            android:src="@drawable/kid_goku" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:layout_margin="5dp"
            android:scaleType="centerCrop"
            android:src="@drawable/kid_goku" />

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

ViewPagerAdapter code

public class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragmentList.get(position);
    }

    @Override
    public int getCount() {
        return mFragmentList.size();
    }

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }

}

You can see the video here CollapsingToolbarLayout WITH TabLayout

You download the complete project from here CollapsingToolbarLayout WITH TabLayout

Answer 2

Try the below layout foryour activity

  <?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="false"
        android:background="@color/white"
        android:stateListAnimator="@drawable/appbar_shadow"
        android:theme="@style/AppTheme.AppBarOverlay"
        tools:targetApi="lollipop">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/green"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:title=""
            app:titleEnabled="false">

            <include
                layout="@layout/appbar_collapsing_part"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="?attr/actionBarSize"
                app:layout_scrollFlags="scroll|exitUntilCollapsed" />


            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar_layout"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@color/green"
                android:stateListAnimator="@drawable/appbar_shadow"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme.PopupOverlay"
                app:theme="@style/ToolbarMenuItemsBackGroundTheme"
                tools:targetApi="lollipop">

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">

                    <TextView
                        android:id="@+id/title_txt"
                        android:layout_width="wrap_content"
                        android:layout_height="match_parent"
                        android:layout_alignParentStart="true"
                        android:layout_toStartOf="@+id/star_img"
                        android:ellipsize="end"
                        android:fontFamily="sans-serif-medium"
                        android:gravity="center_vertical"
                        android:maxLines="1"
                        android:textColor="@color/colorPrimaryDark"
                        android:textSize="19sp" />

                    <ImageView
                        android:id="@+id/star_img"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignParentEnd="true"
                        android:layout_centerInParent="true"
                        android:layout_gravity="center"
                        android:layout_marginEnd="24dp"
                        android:padding="10dp"
                        android:src="@drawable/ic_favorite_filled" />

                </RelativeLayout>

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



        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="wrap_content"
            android:layout_height="48dp"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:background="#45b0b2"
            android:visibility="gone"
            app:tabBackground="@drawable/backgr_blue_transparent_selector"
            app:tabGravity="center"
            app:tabIndicatorColor="@color/colorPrimaryDark"
            app:tabIndicatorHeight="2dp"
            app:tabMinWidth="500dp"
            app:tabMode="fixed"
            app:tabSelectedTextColor="@color/colorPrimaryDark"
            app:tabTextAppearance="@style/CustomTabLayout"
            app:tabTextColor="@color/green" />
        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>


    <FrameLayout
        android:id="@+id/fragment_content_holder"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/black"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>

Answer 3

Try scrolling to top in the fragment in the view pager by calling scrollView.fullScroll(View.FOCUS_UP) whenever you click on a tab. If your fragment inside the viewpager is scrolled up then your scrolling should work correctly.