implemented optimised version of YoutubeExtractor.getVideoId().

new version uses a regular expression instead of creating a HashMap and looping over them.
Needs testing before pushing to origin

app/src/main/java/org/schabi/newpipe/VideoItemDetailActivity.java

@@ -67,8 +67,7 @@ public class VideoItemDetailActivity extends AppCompatActivity {
                         arguments.putInt(VideoItemDetailFragment.STREAMING_SERVICE, i);
                         try {
                             currentStreamingService = i;
-                            extractor = ServiceList.getService(i)
-                                    .getExtractorInstance();
+                            extractor = ServiceList.getService(i).getExtractorInstance();
                         } catch (Exception e) {
                             e.printStackTrace();
                         }

app/src/main/java/org/schabi/newpipe/youtube/YoutubeExtractor.java

@@ -130,6 +130,26 @@ public class YoutubeExtractor implements Extractor {
         }
     }
 
+    @Override
+    public String getVideoId(String videoUrl) {
+        //https://www.youtube.com/watch?v=laF2D3QyAFQ
+        String id;
+        Pattern pat;
+        if(videoUrl.contains("youtube")) {
+            pat = Pattern.compile("youtube\\.com/watch\\?v=([a-zA-Z0-9_]{11})");
+        }
+        else if(videoUrl.contains("youtu.be")) {
+            pat = Pattern.compile("youtu\\.be/([a-zA-Z0-9_]{11})");
+        }
+        else {
+            Log.e(TAG, "Error could not parse url: " + videoUrl);
+            return "";
+        }
+        Matcher mat = pat.matcher(videoUrl);
+        id = mat.group(1);
+        return (id == null ? "" : id);
+    }
+/*
     @Override
     public String getVideoId(String videoUrl) {
         try {
@@ -165,7 +185,7 @@ public class YoutubeExtractor implements Extractor {
         }
         return null;
     }
-
+*/
     @Override
     public String getVideoUrl(String videoId) {
         return "https://www.youtube.com/watch?v=" + videoId;