使用包含工具栏布局和一个片段创建布局

Question

设计很简单，但不知道导致错误的原因。

 <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:layout_gravity="top">

                <include
                    android:id="@+id/toolbar"
                    layout="@layout/toolbar" />
            </LinearLayout>

            <include layout="@layout/activity_main"/>



        <fragment
            android:id="@+id/fragmented1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="top"
            app:layout="@layout/search_box"
            tools:layout="@layout/search_box" />

    </LinearLayout>

    public class MainActivity extends AppCompatActivity {

        RelativeLayout search;
        TextView textView;
        ImageView close_btn,filter_cars;
        Intent intent;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            search=(RelativeLayout) findViewById(R.id.searchingcars);
            textView=(TextView) findViewById(R.id.searchcars1);
            close_btn=(ImageView) findViewById(R.id.search_close_btn);
    //        filter_cars=(ImageView) findViewById(R.id.filter);
     /*       filter_cars.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    intent=new Intent(this,Filtercars.java);
                    startActivity(intent);
                }
            });*/
            close_btn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    search.setVisibility(View.GONE);
                }
            });
            textView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                     search.setVisibility(View.VISIBLE);
                }
            });
        }
    }

错误：无法启动活动ComponentInfo {in.mega.sliderdrawer/in.mega.sliderdrawer.MainActivity}：java.lang.NullPointerException：尝试调用虚方法＆＃39; void android.widget.ImageView.setOnClickListener（android.view） .View $ OnClickListener）＆＃39;在空对象引用上