Android Studio – Error when trying to use a PieChart (hellocharts) on an Activity

I’m trying to use the external library "hellocharts" in my project. I have linked the library to my project already, but when the activity that has the chart starts, the whole app crash with the exception: "Error inflating class lecho.lib.hellocharts.view.PieChartView".

I don’t know what the problem can be. The java class (when I use the Charts) don’t seem to have that problem (it doesn’t get compile errors of not finding the library).

Here it is the .xml file of the activity

    <?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <HorizontalScrollView
        android:id="@+id/horizontalScrollView"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent">

            <Button
                android:id="@+id/Dia"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:layout_marginBottom="8dp"
                android:text="Dia" />

            <Button
                android:id="@+id/Semana"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:text="Semana" />

            <Button
                android:id="@+id/Mes"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:text="Mes" />

            <Button
                android:id="@+id/Temporizador"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:text="Temp" />

            <Button
                android:id="@+id/Estadisticas"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:text="Stats" />

            <Button
                android:id="@+id/Tienda"
                style="@android:style/Widget.Button"
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:text="Tienda" />
        </LinearLayout>
    </HorizontalScrollView>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <lecho.lib.hellocharts.view.PieChartView
            android:id="@+id/graphic_pie_chart"
            android:layout_width="match_parent"
            android:layout_height="500dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.826" />

        <TextView
            android:id="@+id/tv_asignatura"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="28sp"
            android:textStyle="bold"
            android:layout_gravity="center"
            app:layout_constraintBottom_toTopOf="@+id/graphic_pie_chart"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@+id/graphic_pie_chart"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.3" />

        <TextView
            android:id="@+id/tv_tiempo"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="20sp"
            android:layout_gravity="center"
            app:layout_constraintBottom_toTopOf="@+id/graphic_pie_chart"
            app:layout_constraintEnd_toEndOf="@+id/tv_asignatura"
            app:layout_constraintStart_toStartOf="@+id/tv_asignatura"
            app:layout_constraintTop_toBottomOf="@+id/tv_asignatura"
            app:layout_constraintVertical_bias="0.45" />

    </androidx.constraintlayout.widget.ConstraintLayout>



</LinearLayout>

And here it is the gradle files

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 31

    defaultConfig {
        applicationId "es.ucm"
        minSdkVersion 26
        targetSdkVersion 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.4.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    implementation 'com.github.lecho:hellocharts-library:1.5.8@aar'
}

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.2.2"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
        jcenter()// Warning: this repository is going to shut down soon

    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}