How to implement showing youtube video in webview from version 4.4.4?

Question

YouTube

The application required a built-in browser. The bottom line is to display various videos in the "Help" section (not only youtube - so there is no point in using the youtube api.). No autoplay is needed. Just open the link in a browser and let the user decide to watch/not watch.
In the Manifesto

<?xml version="1.0" encoding="utf-8"?>
    <application
           ...
            android:hardwareAccelerated="true"
          ...>
    </application>

MainActivity

public class MainActivity extends Activity {

    private WebView webView;
    private FrameLayout customViewContainer;
    private WebChromeClient.CustomViewCallback customViewCallback;
    private View mCustomView;
    private myWebChromeClient mWebChromeClient;
    private myWebViewClient mWebViewClient;

    @SuppressLint("SetJavaScriptEnabled")

    @SuppressWarnings("deprecation")
    public static void clearCookies(Context context)
    {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
            CookieManager.getInstance().removeAllCookies(null);
            CookieManager.getInstance().flush();
        } else
        {
            CookieSyncManager cookieSyncMngr=CookieSyncManager.createInstance(context);
            cookieSyncMngr.startSync();
            CookieManager cookieManager=CookieManager.getInstance();
            cookieManager.removeAllCookie();
            cookieManager.removeSessionCookie();
            cookieSyncMngr.stopSync();
            cookieSyncMngr.sync();
        }
    }
    @Override
    @JavascriptInterface
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        customViewContainer = (FrameLayout) findViewById(R.id.customViewContainer);
        webView = (WebView) findViewById(R.id.webView);

        webView.clearCache(true);
        webView.clearHistory();

        clearCookies(this);

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

        mWebChromeClient = new myWebChromeClient();
        webView.setWebChromeClient(mWebChromeClient);

        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
        webView.getSettings().setSupportMultipleWindows(true);
        webView.getSettings().setBuiltInZoomControls(true);
        webView.getSettings().setSupportZoom(true);
        webView.getSettings().setDomStorageEnabled(true);
        webView.getSettings().setPluginState(WebSettings.PluginState.ON);

        if (savedInstanceState == null)
        {
            webView.loadUrl("https://www.youtube.com/watch?v=7mOduxyaZp4");

        } else {
            webView.restoreState(savedInstanceState);
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState )
    {
        super.onSaveInstanceState(outState);
        webView.saveState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState)
    {
        super.onRestoreInstanceState(savedInstanceState);
        webView.restoreState(savedInstanceState);
    }

    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 {
        @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 void onHideCustomView() {
            super.onHideCustomView();   
            if (mCustomView == null)
                return;

            webView.setVisibility(View.VISIBLE);
            customViewContainer.setVisibility(View.GONE);
            mCustomView.setVisibility(View.GONE);
            customViewContainer.removeView(mCustomView);
            customViewCallback.onCustomViewHidden();

            mCustomView = null;
        }
    }

    class myWebViewClient extends WebViewClient {

        private String mUrl;
        private final long LOADING_ERROR_TIMEOUT = TimeUnit.SECONDS.toMillis(45);
        private WeakReference<WebView> mReference;
        private boolean mLoadingFinished = false;
        private boolean mLoadingError = false;
        private long mLoadingStartTime = 0;

        // Helps to handle case when onReceivedError get called before onPageStarted
        // Problem cached on Nexus 7; Android 5
        private String mOnErrorUrl;


        private String removeLastSlash(String url) {
            while (url.endsWith("/")) {
                url = url.substring(0, url.length() - 1);
            }
            return url;
        }

        private boolean startsWith(String str, String prefix) {
            return str != null && prefix != null && str.startsWith(prefix);
        }

        private final Runnable mPageLoadingTimeoutHandlerTask = new Runnable() {
            @Override
            public void run() {
                mUrl = null;
                mLoadingFinished = true;
                long loadingTime = System.currentTimeMillis() - mLoadingStartTime;
                if (mReference != null) {
                    WebView webView = mReference.get();
                    if (webView != null) {
                        webView.stopLoading();
                    }
                }

            }
        };

        @Override
        public void onReceivedError(WebView view, int errorCode, String description, String url) {
            if (mUrl != null && !mLoadingError) {
                mLoadingError = true;
            } else {
                mOnErrorUrl = removeLastSlash(url);
            }
        }


        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            url = removeLastSlash(url);
            if (!startsWith(url, mUrl) && !mLoadingFinished) {

                mUrl = null;
                onPageStarted(view, url, null);
            }
            return false;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favIcon) {
            url = removeLastSlash(url);
            if (startsWith(url, mOnErrorUrl)) {
                mUrl = url;
                mLoadingError = true;
                mLoadingFinished = false;
                onPageFinished(view, url);
            }
            if (mUrl == null) {
                mUrl = url;
                mLoadingError = false;
                mLoadingFinished = false;
                mLoadingStartTime = System.currentTimeMillis();
                view.removeCallbacks(mPageLoadingTimeoutHandlerTask);
                view.postDelayed(mPageLoadingTimeoutHandlerTask, LOADING_ERROR_TIMEOUT);
                mReference = new WeakReference<>(view);
            }
        }

        public void onData(String value) {
            //.. do something with the data
        }

        @JavascriptInterface
        @Override
        public void onPageFinished(final WebView view, String url) {

            url = removeLastSlash(url);

            if (startsWith(url, mUrl) && !mLoadingFinished) {
                mLoadingFinished = true;
                view.removeCallbacks(mPageLoadingTimeoutHandlerTask);

                mOnErrorUrl = null;
                mUrl = null;
                Log.e("UA",view.getSettings().getUserAgentString());

            } else if (mUrl == null) {
                // On some devices (e.g. Lg Nexus 5) onPageStarted sometimes not called at all
                // The only way I found to fix it is to reset WebViewClient
                view.setWebViewClient(new myWebViewClient());
                mLoadingFinished = true;
            }
        }
    }

}

in versions higher than 4.4.4 after clicking on play I get this
And tries to download to infinity
Thank you!

Answer 1

UPDATE. Most likely it all depends on the input format of the video on youtube. If the video is mp4, then there are no problems. If m4v - it will not be displayed. Why so - I do not know, I'm not strong in this matter. There may still be formats that will not be able to work out