Youtube Video in WebView doesn’t load

Now it works, with a combination of some things:

public class Videos extends Activity {

private WebView mWebView;
private String extra;

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

    extra = getIntent().getStringExtra("VideosId");        
    mWebView = (WebView) findViewById(R.id.videos_webview); 
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.getSettings().setPluginsEnabled(true);

    final Activity activity = this;
    mWebView.setWebChromeClient(new WebChromeClient() {
      public void onProgressChanged(WebView view, int progress) {
        // Activities and WebViews measure progress with different scales.
        // The progress meter will automatically disappear when we reach 100%
        activity.setProgress(progress * 1000);
      }
    });

    mWebView.setWebViewClient(new MyOwnWebViewClient());   


    mWebView.loadUrl("file:///android_asset/Videos/"+extra+".htm");     
    mWebView.setWebViewClient(new MyOwnWebViewClient());      
}

//Ermöglicht das Zurücknavigieren im Browser mittels Back-Button
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
        mWebView.goBack();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

And these entries in the manifest:

    <uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>

<application android:icon="@drawable/icon" android:label="@string/app_name" android:hardwareAccelerated = "true">

But I don’t know, which one are at least necessary. Further, it’s not possible to skip parts of the video, I have to watch it in one turn. Anyone knows a solution?

And MyOwnWebViewClient:

import android.webkit.WebView;
import android.webkit.WebViewClient;
//Enables the possibility for the User to navigate in the WebView and prevents,
//that the Standard-Browser is invoked

public class MyOwnWebViewClient extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;
    }

}