我的Spinner.java文件:
package com.easybooks.android.test;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import java.util.ArrayList;
import java.util.List;
public class Spinner extends AppCompatActivity {
    private Spinner mySpinner;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_spinner);
        findViews();
    }
    private void findViews(){
        mySpinner=(Spinner) findViewById(R.id.spinner);//此处为出错代码
        List<String> list=new ArrayList<String>();
        list.add("博士");
        list.add("硕士");
        list.add("学士");
        ArrayAdapter<String> adapter1=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
        adapter1.setDropDownViewResource(android.R.layout.simple_spinner_item);
        mySpinner.setAdapter(adapter1);//此处也有出错代码
    }
}
我的activity_spinner.xml文件为:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.easybooks.android.test.Spinner">
<Spinner
    android:layout_width="300dp"
    android:layout_height="wrap_content"
    android:id="@+id/spinner"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"/>
</RelativeLayout>有哪位大佬能帮帮我?