Слова CheckBox и CheckedTextView не отображаются

Я сделал файл макета xml для всплывающего окна. В макете я установил два CheckedTextViews. Я вижу тексты на превью. Но когда я устанавливаю и активирую его на AVD и мобильном телефоне, я не вижу его текстов. Это довольно простой код. Но я не знаю, что с ним не так.

Я заменяю CheckedTextView на CheckBox. Но это все еще не работает.

popup.xml:

<?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:layout_width = "300dp"
    android:layout_height = "150dp" 
    android:background = "@color/colorWhite">

    <android.support.constraint.Guideline
        android:id = "@+id/guideline28"
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:orientation = "horizontal"
        app:layout_constraintGuide_begin = "0dp"                                              
        app:layout_constraintGuide_percent = "0.6"/>

    <android.support.constraint.Guideline
        android:id = "@+id/guideline22"
        android:layout_width = "wrap_content"
        android:layout_height = "wrap_content"
        android:orientation = "horizontal"
        app:layout_constraintGuide_begin = "0dp"
        app:layout_constraintGuide_percent = "0.2"/>

    <android.support.constraint.ConstraintLayout
        android:id = "@+id/constraintLayout6"
        android:layout_marginStart = "8dp" 
        android:layout_width = "0dp"
        android:layout_height = "0dp"
        app:layout_constraintBottom_toTopOf = "@+id/guideline22" 
        app:layout_constraintEnd_toEndOf = "parent"
        app:layout_constraintTop_toTopOf = "parent" 
        app:layout_constraintStart_toStartOf = "parent">

        <!-- this is the CheckedTextView -->
        <CheckedTextView
            android:id = "@+id/checkedTextView2"
            android:text = "@string/week"
            android:layout_width = "0dp"
            android:layout_height = "wrap_content"
            android:textAppearance = "?android:attr/textAppearanceListItemSmall"
            android:checkMark = "?android:attr/listChoiceIndicatorMultiple" 
            android:layout_marginEnd = "8dp"
            android:layout_marginStart = "8dp"
            android:visibility = "visible"
            app:layout_constraintTop_toTopOf = "@+id/checkedTextView3"
            app:layout_constraintBottom_toBottomOf = "@+id/checkedTextView3"
            app:layout_constraintEnd_toStartOf = "@+id/guideline23" 
            app:layout_constraintStart_toStartOf = "parent"/>

        <CheckedTextView
            android:id = "@+id/checkedTextView3" 
            android:text = "@string/weekend"
            android:layout_width = "0dp"
            android:layout_height = "wrap_content"
            android:layout_marginStart = "8dp" 
            android:layout_marginEnd = "8dp"
            app:layout_constraintStart_toStartOf = "@+id/guideline23"
            app:layout_constraintEnd_toEndOf = "parent"
            app:layout_constraintTop_toTopOf = "parent"
            app:layout_constraintBottom_toBottomOf = "parent"/>

        <android.support.constraint.Guideline
            android:id = "@+id/guideline23"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:orientation = "vertical"
            app:layout_constraintGuide_begin = "0dp"
            app:layout_constraintGuide_percent = "0.5"/>

    </android.support.constraint.ConstraintLayout>

    <android.support.constraint.ConstraintLayout
        android:layout_width = "0dp"
        android:layout_height = "wrap_content" 
        android:layout_marginEnd = "8dp"
        app:layout_constraintEnd_toEndOf = "parent"
        app:layout_constraintStart_toStartOf = "parent"
        android:layout_marginStart = "8dp"
        app:layout_constraintBottom_toTopOf = "@+id/guideline28"
        app:layout_constraintTop_toBottomOf = "@+id/constraintLayout6" android:id = "@+id/constraintLayout7">

        <Button
            android:id = "@+id/button16"
            android:text = "@string/monday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line"
            app:layout_constraintStart_toStartOf = "parent" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button17" 
            app:layout_constraintTop_toTopOf = "@+id/button17"
            app:layout_constraintBottom_toBottomOf = "@+id/button17"/>

        <Button
            android:id = "@+id/button17"
            android:text = "@string/tuesday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button16" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button18" 
            app:layout_constraintTop_toTopOf = "@+id/button18"
            app:layout_constraintBottom_toBottomOf = "@+id/button18"/>

        <Button
            android:text = "@string/wednesday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:id = "@+id/button18"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button17" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button14" 
            app:layout_constraintTop_toTopOf = "@+id/button14"
            app:layout_constraintBottom_toBottomOf = "@+id/button14"/>

        <Button
            android:id = "@+id/button14"
            android:text = "@string/thursday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button18" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button15" 
            app:layout_constraintTop_toTopOf = "@+id/button15"
            app:layout_constraintBottom_toBottomOf = "@+id/button15"/>

        <Button
            android:id = "@+id/button15"
            android:text = "@string/friday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button14" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button13" 
            app:layout_constraintTop_toTopOf = "@+id/button13"
            app:layout_constraintBottom_toBottomOf = "@+id/button13"/>

        <Button
            android:id = "@+id/button13"
            android:text = "@string/saturday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button15" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toStartOf = "@+id/button6" 
            app:layout_constraintTop_toTopOf = "@+id/button6"
            app:layout_constraintBottom_toBottomOf = "@+id/button6"/>

        <Button
            android:id = "@+id/button6"
            android:text = "@string/sunday"
            android:layout_width = "30dp"
            android:layout_height = "50dp"
            android:textColor = "@color/colorRed"
            android:background = "@drawable/style_button_red_line" 
            app:layout_constraintStart_toEndOf = "@+id/button13" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toEndOf = "parent"
            app:layout_constraintTop_toTopOf = "parent"
            app:layout_constraintBottom_toBottomOf = "parent"/>

    </android.support.constraint.ConstraintLayout>

    <android.support.constraint.ConstraintLayout
        android:layout_width = "0dp"
        android:layout_height = "0dp"
        app:layout_constraintTop_toBottomOf = "@id/guideline28" 
        app:layout_constraintStart_toStartOf = "parent"
        app:layout_constraintEnd_toEndOf = "parent"
        app:layout_constraintBottom_toBottomOf = "parent">

        <android.support.constraint.Guideline
            android:id = "@+id/guideline29"
            android:layout_width = "wrap_content"
            android:layout_height = "wrap_content"
            android:orientation = "vertical"
            app:layout_constraintGuide_begin = "0dp"
            app:layout_constraintGuide_percent = "0.5"/>

        <Button
            android:id = "@+id/btn_cancel" 
            android:text = "@string/cancel"
            android:layout_width = "0dp"
            android:layout_height = "0dp"
            app:layout_constraintStart_toStartOf = "parent"
            app:layout_constraintHorizontal_bias = "0.5" 
            app:layout_constraintEnd_toStartOf = "@+id/btn_ok"
            app:layout_constraintTop_toTopOf = "parent"
            app:layout_constraintBottom_toBottomOf = "parent"
            android:background = "@drawable/style_button_gray_line" 
            android:elevation = "10dp"/>

        <Button
            android:id = "@+id/btn_ok"
            android:text = "@string/ok"
            android:layout_width = "0dp"
            android:layout_height = "0dp"
            app:layout_constraintStart_toEndOf = "@+id/btn_cancel" 
            app:layout_constraintHorizontal_bias = "0.5"
            app:layout_constraintEnd_toEndOf = "parent" 
            app:layout_constraintTop_toTopOf = "parent"
            app:layout_constraintBottom_toBottomOf = "parent" 
            android:background = "@drawable/style_button_gray_line"
            android:elevation = "10dp"/>

    </android.support.constraint.ConstraintLayout>

</android.support.constraint.ConstraintLayout>

PopupActivity.java:

import android.app.Activity;
import android.os.Bundle;
import android.view.Window;

public class PopupActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.popup);
    }

}

Manifest.xml:

<activity
    android:name = ".PopupActivity"
    android:theme = "@android:style/Theme.Dialog" />