removed hardcoded string, and add licece to some files.

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

@@ -8,6 +8,24 @@ import android.preference.PreferenceManager;
 import info.guardianproject.netcipher.NetCipher;
 import info.guardianproject.netcipher.proxy.OrbotHelper;
 
+/**
+ * Copyright (C) Hans-Christoph Steiner 2016 <hans@eds.org>
+ * App.java is part of NewPipe.
+ *
+ * NewPipe is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * NewPipe is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with NewPipe.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
 public class App extends Application {
 
     private static boolean useTor;

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

@@ -7,6 +7,24 @@ import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
 
+/**
+ * Copyright (C) Hans-Christoph Steiner 2016 <hans@eds.org>
+ * ExitActivity.java is part of NewPipe.
+ *
+ * NewPipe is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * NewPipe is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with NewPipe.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
 public class ExitActivity extends Activity {
 
     @SuppressLint("NewApi")

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

@@ -14,6 +14,22 @@ import java.util.Locale;
 
 /**
  * Created by chschtsch on 12/29/15.
+ *
+ * Copyright (C) Gregory Arkhipov 2015
+ * Localization.java is part of NewPipe.
+ *
+ * NewPipe is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * NewPipe is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with NewPipe.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 public class Localization {

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

@@ -7,6 +7,24 @@ import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
 
+/**
+ * Copyright (C) Hans-Christoph Steiner 2016 <hans@eds.org>
+ * PanicResponderActivity.java is part of NewPipe.
+ *
+ * NewPipe is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * NewPipe is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with NewPipe.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
 public class PanicResponderActivity extends Activity {
 
     public static final String PANIC_TRIGGER_ACTION = "info.guardianproject.panic.action.TRIGGER";

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

@@ -118,7 +118,8 @@ public class VideoItemListFragment extends ListFragment {
                 h.post(new Runnable() {
                     @Override
                     public void run() {
-                        Toast.makeText(getActivity(), "Network Error", Toast.LENGTH_SHORT).show();
+                        Toast.makeText(getActivity(), getString(R.string.networkError),
+                                Toast.LENGTH_SHORT).show();
                     }
                 });
             }
@@ -298,7 +299,8 @@ public class VideoItemListFragment extends ListFragment {
         super.onViewCreated(view, savedInstanceState);
         list = getListView();
         videoListAdapter = new VideoListAdapter(getActivity(), this);
-        footer = ((LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.paginate_footer, null, false);
+        footer = ((LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE))
+                .inflate(R.layout.paginate_footer, null, false);
 
 
         setListAdapter(videoListAdapter);
@@ -319,7 +321,8 @@ public class VideoItemListFragment extends ListFragment {
             }
 
             @Override
-            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
+            public void onScroll(AbsListView view, int firstVisibleItem,
+                                 int visibleItemCount, int totalItemCount) {
                 if (mode != PRESENT_VIDEOS_MODE
                         && list.getChildAt(0) != null
                         && list.getLastVisiblePosition() == list.getAdapter().getCount() - 1

app/src/main/res/values/strings.xml

@@ -56,6 +56,7 @@
     <string name="backgroundPlayerStartPlayingToast">Playing in background</string>
     <string name="c3sUrl" translatable="false">https://www.c3s.cc/</string>
     <string name="play">Play</string>
+    <string name="networkError">Network Error</string>
 
     <!-- Content descriptions (for better accessibility) -->
     <string name="itemThumbnailViewDescription">Video preview thumbnail</string>