Как добавить индикатор выполнения в веб-представление YouTube в Android Studio

Question

Я хотел добавить ссылку на YouTube в свое веб-представление в Android Studio. Поэтому я добавил несколько настроек (то есть полноэкранное включение).Поэтому далее я хочу добавить индикатор прогресса в процентах к моему веб-представлению. Я пытался, но безрезультатно ... Как включить индикатор выполнения (в процентах) в моем веб-представлении. Индикатор выполнения должен скрываться после загрузки URL-адреса.Спасибо

Вот мой MainActivity.java

public class MyActivity extends Activity {
    private WebView webView;
    private FrameLayout customViewContainer;
    private WebChromeClient.CustomViewCallback customViewCallback;
    private View mCustomView;
    private myWebChromeClient mWebChromeClient;
    private myWebViewClient mWebViewClient;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        customViewContainer = (FrameLayout) findViewById(R.id.customViewContainer);
        webView = (WebView) findViewById(R.id.webView);

        mWebViewClient = new myWebViewClient();
        webView.setWebViewClient(mWebViewClient);

        mWebChromeClient = new myWebChromeClient();
        webView.setWebChromeClient(mWebChromeClient);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setAppCacheEnabled(true);
        webView.getSettings().setBuiltInZoomControls(true);
        webView.getSettings().setSaveFormData(true);
        webView.loadUrl("https://www.youtube.com/user/ThatWasEpic11/videos");
    }

    public boolean inCustomView() {
        return (mCustomView != null);
    }

    public void hideCustomView() {
        mWebChromeClient.onHideCustomView();
    }

    @Override
    protected void onPause() {
        super.onPause();    //To change body of overridden methods use File | Settings | File Templates.
        webView.onPause();
    }

    @Override
    protected void onResume() {
        super.onResume();    //To change body of overridden methods use File | Settings | File Templates.
        webView.onResume();
    }

    @Override
    protected void onStop() {
        super.onStop();    //To change body of overridden methods use File | Settings | File Templates.
        if (inCustomView()) {
            hideCustomView();
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {

            if (inCustomView()) {
                hideCustomView();
                return true;
            }

            if ((mCustomView == null) && webView.canGoBack()) {
                webView.goBack();
                return true;
            }
        }
        return super.onKeyDown(keyCode, event);
    }

    class myWebChromeClient extends WebChromeClient {
        private Bitmap mDefaultVideoPoster;
        private View mVideoProgressView;

        @Override
        public void onShowCustomView(View view, int requestedOrientation, CustomViewCallback callback) {
           onShowCustomView(view, callback);    //To change body of overridden methods use File | Settings | File Templates.
        }

        @Override
        public void onShowCustomView(View view,CustomViewCallback callback) {

            // if a view already exists then immediately terminate the new one
            if (mCustomView != null) {
                callback.onCustomViewHidden();
                return;
            }
            mCustomView = view;
            webView.setVisibility(View.GONE);
            customViewContainer.setVisibility(View.VISIBLE);
            customViewContainer.addView(view);
            customViewCallback = callback;
        }

        @Override
        public View getVideoLoadingProgressView() {

            if (mVideoProgressView == null) {
                LayoutInflater inflater = LayoutInflater.from(MyActivity.this);
                mVideoProgressView = inflater.inflate(R.layout.video_progress, null);
            }
            return mVideoProgressView;
        }

        @Override
        public void onHideCustomView() {
            super.onHideCustomView();    //To change body of overridden methods use File | Settings | File Templates.
            if (mCustomView == null)
                return;

            webView.setVisibility(View.VISIBLE);
            customViewContainer.setVisibility(View.GONE);

            // Hide the custom view.
            mCustomView.setVisibility(View.GONE);

            // Remove the custom view from its container.
            customViewContainer.removeView(mCustomView);
            customViewCallback.onCustomViewHidden();

            mCustomView = null;
        }
    }

    class myWebViewClient extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            return super.shouldOverrideUrlLoading(view, url);    //To change body of overridden methods use File | Settings | File Templates.
        }
    }
 @Override
public void onBackPressed() {
    if (mCustomViewContainer != null)
        mWebChromeClient.onHideCustomView();
    else if (myWebView.canGoBack())
        myWebView.goBack();
    else
        super.onBackPressed();
}

}

Вот Activity_main.xml

<LinearLayout
    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:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:id="@+id/liProgressContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_centerInParent="true"
        android:layout_alignParentTop="true">

        <ProgressBar
            android:id="@+id/progress"
            style="@style/Widget.AppCompat.ProgressBar.Horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#FFFFFF" />

        <TextView
            android:id="@+id/tvLoadingPercentage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#FFFFFF" />

    </LinearLayout>



    <WebView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/webView"
        android:layout_gravity="center"
        />
    <FrameLayout
        android:id="@+id/customViewContainer"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:visibility="gone"
        />

    <com.google.android.gms.ads.AdView
        xmlns:ads="http://schemas.android.com/apk/res-auto"
        android:id="@+id/adView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true"
        ads:adSize="BANNER"
        ads:adUnitId="ca-app-pub-3940256099942544/6300978111">
    </com.google.android.gms.ads.AdView>
</LinearLayout>