Removie redundant backgound style in home page. and fix a potential bug.

frontend/Movie_Pigeon/app/src/main/java/org/example/team_pigeon/movie_pigeon/RecommendationFragment.java

@@ -1,13 +1,11 @@
 package org.example.team_pigeon.movie_pigeon;
 
-import android.app.ProgressDialog;
 import android.content.Intent;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.support.v4.app.Fragment;
 import android.util.DisplayMetrics;
 import android.util.Log;
-import android.view.Display;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -25,7 +23,6 @@
 import org.example.team_pigeon.movie_pigeon.models.MovieWithCount;
 
 import java.io.IOException;
-import java.io.Serializable;
 import java.util.ArrayList;
 
 import okhttp3.OkHttpClient;
@@ -57,6 +54,7 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
         searchView = (SearchView) view.findViewById(R.id.search_view);
         nowShowingGrid = (GridView) view.findViewById(R.id.grid_now_showing);
         recommendedGrid = (GridView) view.findViewById(R.id.grid_recommended);
+        nowShowingMovieList = new ArrayList<>();
         nowShowingTask = new Task();
         nowShowingTask.execute("nowshowing");
         searchView.setSubmitButtonEnabled(true);

frontend/Movie_Pigeon/app/src/main/res/drawable/tab_menu_background.xml

@@ -1,10 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:state_selected="true">
-        <shape>
-            <solid android:color="@color/text_selected" />
-        </shape>
-    </item>
     <item>
         <shape>
             <solid android:color="@color/transparent" />