链接文件资源失败

这是导致错误的 Java 文件

package com.example.daksh.timetable;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Button mon_but,tue_but,wed_but,thur_but,fri_but;
        mon_but = (Button)findViewById(R.id.mon);
        tue_but = (Button)findViewById(R.id.tue);
        wed_but = (Button)findViewById(R.id.wed);
        thur_but = (Button)findViewById(R.id.thur);
        fri_but = (Button)findViewById(R.id.fri);
        final ImageView main_Image = (ImageView) findViewById(R.id.day);
        final int[] dayarray = {R.drawable.monday,R.drawable.tuesday,R.drawable.wednesday,R.drawable.thursday, R.drawable.friday};

        mon_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                main_Image.setImageResource(dayarray[0]);
            }

        });
        tue_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                main_Image.setImageResource(dayarray[1]);
            }
        });
        wed_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                main_Image.setImageResource(dayarray[2]);
            }
        });
        thur_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                main_Image.setImageResource(dayarray[3]);
            }
        });
        fri_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                main_Image.setImageResource(dayarray[4]);
            }
       });
   }
}

我所遇到的错误如下：

信息：Gradle 任务 [clean, :app:assembleDebug] C:\Projects\TimeTable\app\src\main\res\layout\activity_main.xml 错误：error: resource android:attr/colorSwitchThumbNormal 是私有的。 错误：resource android:attr/colorSwitchThumbNormal 是私有的。 C:\Projects\TimeTable\app\src\main\res\layout-land\activity_main.xml 错误：error: resource android:attr/colorSwitchThumbNormal 是私有的。 错误：resource android:attr/colorSwitchThumbNormal 是私有的。 错误：无法链接文件资源。 错误：java.util.concurrent.ExecutionException: java.util.concurrent.ExecutionException: com.android.tools.aapt2.Aapt2Exception: AAPT2 error: check logs for details 错误：java.util.concurrent.ExecutionException: com.android.tools.aapt2.Aapt2Exception: AAPT2 error: check logs for details 错误：com.android.tools.aapt2.Aapt2Exception: AAPT2 error: check logs for details 错误：执行任务 ':app:processDebugResources' 失败。 未能执行 aapt 信息：BUILD FAILED in 9s 信息：9 个错误 信息：0 个警告 信息：请查看控制台以获取完整输出

这是 Activity_main.xml 文件

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/background"
    android:paddingBottom="16dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="16dp"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/day"
        android:layout_width="0dp"
        android:layout_height="0dp"

        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:contentDescription="TODO"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintHorizontal_bias="0.519"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/guideline2"
        app:layout_constraintVertical_bias="0.472"
        app:srcCompat="@drawable/monday" />

    <TextView
        android:id="@+id/textView"
        style="@style/Widget.AppCompat.TextView.SpinnerItem"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:fontFamily="serif"
        android:text="@string/message"
        android:textColor="?android:attr/colorSwitchThumbNormal"
        android:textSize="18sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/mon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="50dp"
        android:text="@string/monday"
        app:layout_constraintBottom_toTopOf="@+id/tue"
        app:layout_constraintStart_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/tue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginStart="16dp"
        android:text="@string/tuesday"
        app:layout_constraintBottom_toTopOf="@+id/wed"
        app:layout_constraintStart_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintTop_toBottomOf="@id/mon" />

    <Button
        android:id="@+id/wed"
        android:layout_width="88dp"
        android:layout_height="48dp"
        android:layout_marginBottom="16dp"
        android:layout_marginStart="16dp"
        android:text="@string/wednesday"
        app:layout_constraintBottom_toTopOf="@+id/thur"
        app:layout_constraintStart_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintTop_toBottomOf="@id/tue" />

    <Button
        android:id="@+id/thur"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginStart="16dp"
        android:text="@string/thursday"
        app:layout_constraintBottom_toTopOf="@+id/fri"
        app:layout_constraintStart_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintTop_toBottomOf="@id/wed" />

    <Button
        android:id="@+id/fri"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginStart="16dp"
        android:text="@string/friday"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="@+id/guideline_dayselection"
        app:layout_constraintTop_toBottomOf="@id/thur" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline_dayselection"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_end="196dp" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintGuide_percent="0.15339233" />


</android.support.constraint.ConstraintLayout>