How to Hide ActionBar/Toolbar While Scrolling Down in Webview

You can do this without any Java code using the design library's CoordinatorLayout and NestedScrollView, with app:layout_scrollFlags set on Toolbar. Here's how you do it.

<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.support.design.widget.AppBarLayout    android:id="@+id/appbar"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">    <android.support.v7.widget.Toolbar        android:id="@+id/toolbar"        android:layout_width="match_parent"        android:layout_height="?attr/actionBarSize"        android:background="?attr/colorPrimary"        app:layout_scrollFlags="scroll|enterAlways"        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" /></android.support.design.widget.AppBarLayout><android.support.v4.widget.NestedScrollView 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:layout_gravity="fill_vertical"   android:fillViewport="true"    app:layout_behavior="@string/appbar_scrolling_view_behavior">    <WebView        android:id="@+id/webview"        android:layout_width="match_parent"        android:layout_height="match_parent"/></android.support.v4.widget.NestedScrollView></android.support.design.widget.CoordinatorLayout>

You can play around with with different layout_scrollFlags and fitsSystemWindows behaviour once you get the hang of it.

Well I have implemented by CustomWebView and GestureDetector:

CustomWebView.java:

public class CustomWebView extends WebView {    private GestureDetector gestureDetector;    public CustomWebView(Context context) {        super(context);    }    public CustomWebView(Context context, AttributeSet attrs) {        super(context, attrs);    }    public CustomWebView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);    }    @Override    protected void onScrollChanged(int l, int t, int oldl, int oldt) {        super.onScrollChanged(l, t, oldl, oldt);    }    @Override    public boolean onTouchEvent(MotionEvent ev) {        return gestureDetector.onTouchEvent(ev) || super.onTouchEvent(ev);    }    public void setGestureDetector(GestureDetector gestureDetector) {        this.gestureDetector = gestureDetector;    }}

web_fragment.xml:

<?xml version="1.0" encoding="utf-8"?><LinearLayout 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:background="@android:color/transparent"    android:orientation="vertical">   <com.customview.CustomWebView            android:id="@+id/customWebView"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:focusable="true" /></LinearLayout>

CustomeGestureDetector clss for Gesture Detection (I have added in Fragment):

private class CustomeGestureDetector extends GestureDetector.SimpleOnGestureListener {        @Override        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {            if(e1 == null || e2 == null) return false;            if(e1.getPointerCount() > 1 || e2.getPointerCount() > 1) return false;            else {                try {                    if(e1.getY() - e2.getY() > 20 ) {                            // Hide Actionbar                        getSupportActionBar().hide();                        customWebView.invalidate();                       return false;                    }                    else if (e2.getY() - e1.getY() > 20 ) {                            // Show Actionbar                        getSupportActionBar().show();                        customWebView.invalidate();                       return false;                    }                } catch (Exception e) {                    customWebView.invalidate();                }                return false;            }        }    }

WebFragment.java:

private CustomWebView customWebView;customWebView= (CustomWebView) view.findViewById(R.id.customWebView);customWebView.setGestureDetector(new GestureDetector(new CustomeGestureDetector()));

It works fine for me, hope it would help you.

package com.keshav.hideactionbarandfooterexample;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.Toolbar;import android.util.Log;import android.view.View;import android.view.animation.AccelerateInterpolator;import android.view.animation.DecelerateInterpolator;import android.widget.FrameLayout;import android.widget.ImageButton;import java.util.ArrayList;import java.util.List;import adapters.RecyclerAdapter;import listners.HidingScrollListener;public class MainActivity extends AppCompatActivity {    private Toolbar mToolbar;    private Toolbar toolbar_bottom;    private ImageButton mFabButton;    @Override    protected void onCreate(Bundle savedInstanceState) {        setTheme(R.style.AppThemeRed);        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Log.e("keshav", "MainActivity called");        initToolbar();        mFabButton = (ImageButton) findViewById(R.id.fabButton);        initRecyclerView();    }    private void initToolbar() {        mToolbar = (Toolbar) findViewById(R.id.toolbar);        toolbar_bottom = (Toolbar) findViewById(R.id.toolbar_bottom);        setSupportActionBar(mToolbar);        setSupportActionBar(toolbar_bottom);        setTitle(getString(R.string.app_name));        mToolbar.setTitleTextColor(getResources().getColor(android.R.color.white));        toolbar_bottom.setTitleTextColor(getResources().getColor(android.R.color.white));        toolbar_bottom.setVisibility(View.GONE);    }    private void initRecyclerView() {        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerView);        recyclerView.setLayoutManager(new LinearLayoutManager(this));        RecyclerAdapter recyclerAdapter = new RecyclerAdapter(createItemList());        recyclerView.setAdapter(recyclerAdapter);        recyclerView.addOnScrollListener(new HidingScrollListener() {            @Override            public void onHide() {                hideViews();            }            @Override            public void onShow() {                showViews();            }        });    }    private void hideViews() {        // TODO (-mToolbar)  plus means  2 view above ho jaye or not visible to user        mToolbar.animate().translationY(-mToolbar.getHeight()).setInterpolator(new AccelerateInterpolator(2));        // TODO uncomment this Hide Footer in android when Scrolling        // TODO (+mToolbar)  plus means  2 view forward ho jaye or not visible to user        toolbar_bottom.animate().translationY(+toolbar_bottom.getHeight()).setInterpolator(new AccelerateInterpolator(2));        // TODO keshav Hide Also Floatng Button In Android        FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) mFabButton.getLayoutParams();        int fabBottomMargin = lp.bottomMargin;        mFabButton.animate().translationY(mFabButton.getHeight() + fabBottomMargin).setInterpolator(new AccelerateInterpolator(2)).start();        // TODO keshav Hide Also Floatng Button In Android    }    private void showViews() {        mToolbar.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2));        // TODO uncomment this Hide Footer in android when Scrolling        toolbar_bottom.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2));        mFabButton.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2)).start();    }    private List<String> createItemList() {        List<String> itemList = new ArrayList<>();        for (int i = 0; i < 20; i++) {            itemList.add("Item " + i);        }        return itemList;    }}=============================================             RecyclerAdapter=============================================package adapters;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import com.keshav.hideactionbarandfooterexample.R;import java.util.List;/** RecyclerView Adapter that allows to add a header view.* */public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {    private static final int TYPE_HEADER = 2;    private static final int TYPE_ITEM = 1;    private List<String> mItemList;    public RecyclerAdapter(List<String> itemList) {        mItemList = itemList;    }    @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        Context context = parent.getContext();        if (viewType == TYPE_ITEM) {            final View view = LayoutInflater.from(context).inflate(R.layout.recycler_item, parent, false);            return RecyclerItemViewHolder.newInstance(view);        } else if (viewType == TYPE_HEADER) {            final View view = LayoutInflater.from(context).inflate(R.layout.recycler_header, parent, false);            return new RecyclerHeaderViewHolder(view);        }        throw new RuntimeException("There is no type that matches the type " + viewType + " + make sure your using types correctly");    }    @Override    public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {        if (!isPositionHeader(position)) {            RecyclerItemViewHolder holder = (RecyclerItemViewHolder) viewHolder;            String itemText = mItemList.get(position - 1); // header            holder.setItemText(itemText);        }    }    public int getBasicItemCount() {        return mItemList == null ? 0 : mItemList.size();    }    @Override    public int getItemViewType(int position) {        if (isPositionHeader(position)) {            return TYPE_HEADER;        }        return TYPE_ITEM;    }    @Override    public int getItemCount() {        return getBasicItemCount() + 1; // header    }    private boolean isPositionHeader(int position) {        return position == 0;    }}=====================================================         RecyclerHeaderViewHolder=====================================================package adapters;import android.support.v7.widget.RecyclerView;import android.view.View;public class RecyclerHeaderViewHolder extends RecyclerView.ViewHolder {    public RecyclerHeaderViewHolder(View itemView) {        super(itemView);    }}=====================================================              RecyclerItemViewHolder=====================================================package adapters;import android.support.v7.widget.RecyclerView;import android.view.View;import android.widget.TextView;import com.keshav.hideactionbarandfooterexample.R;public class RecyclerItemViewHolder extends RecyclerView.ViewHolder {    private final TextView mItemTextView;    public RecyclerItemViewHolder(final View parent, TextView itemTextView) {        super(parent);        mItemTextView = itemTextView;    }    public static RecyclerItemViewHolder newInstance(View parent) {        TextView itemTextView = (TextView) parent.findViewById(R.id.itemTextView);        return new RecyclerItemViewHolder(parent, itemTextView);    }    public void setItemText(CharSequence text) {        mItemTextView.setText(text);    }}===================================================            activity_main.xml===================================================<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"                android:layout_width="match_parent"                android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView            android:id="@+id/recyclerView"            android:layout_width="match_parent"            android:layout_height="match_parent"/>    <android.support.v7.widget.Toolbar            android:id="@+id/toolbar"            android:layout_width="match_parent"            android:layout_height="?attr/actionBarSize"            android:background="?attr/colorPrimary"/>    <ImageButton            android:id="@+id/fabButton"            android:layout_width="56dp"            android:layout_height="56dp"            android:layout_gravity="bottom|right"            android:layout_marginBottom="16dp"            android:layout_marginRight="16dp"            android:background="@drawable/fab_bcg"            android:src="@drawable/ic_favorite_outline_white_24dp"            android:contentDescription="@string/fab_description"/>    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent">    <android.support.v7.widget.Toolbar        android:id="@+id/toolbar_bottom"        android:layout_width="match_parent"        android:layout_alignParentBottom="true"        android:layout_height="?attr/actionBarSize"        android:background="?attr/colorPrimary"/>    </RelativeLayout></FrameLayout>==================================================    recycle_header.xml in layout folder==================================================<?xml version="1.0" encoding="utf-8"?><View xmlns:android="http://schemas.android.com/apk/res/android"      android:layout_width="match_parent"      android:layout_height="?attr/actionBarSize"/>==================================================    recycle_item.xml in layout folder==================================================<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:card_view="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_gravity="center"    android:layout_margin="8dp"    card_view:cardCornerRadius="4dp">    <TextView        android:id="@+id/itemTextView"        android:layout_width="match_parent"        android:layout_height="?attr/listPreferredItemHeight"        android:gravity="center_vertical"        android:padding="8dp"        style="@style/Base.TextAppearance.AppCompat.Body2"/></android.support.v7.widget.CardView>=================================================                      styles.xml=================================================<resources>    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">    </style>    <style name="AppThemeRed" parent="AppTheme">        <item name="colorPrimary">@color/color_primary_red</item>        <item name="colorPrimaryDark">@color/color_primary_red_dark</item>    </style>    <style name="AppThemeGreen" parent="AppTheme">        <item name="colorPrimary">@color/color_primary_green</item>        <item name="colorPrimaryDark">@color/color_primary_green_dark</item>    </style>    <style name="AppThemeBlue" parent="AppTheme">        <item name="colorPrimary">@color/color_primary_blue</item>        <item name="colorPrimaryDark">@color/color_primary_blue_dark</item>        <item name="colorAccent">@color/color_accent_pink</item>    </style></resources>

build.gradle Dependency

  compile 'com.android.support:appcompat-v7:25.3.1'    compile 'com.android.support:recyclerview-v7:25.3.1'    compile 'com.android.support:cardview-v7:25.3.1'    compile 'com.android.support:design:25.3.1'