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Tutoriel Android RatingBar

  1. Android RatingBar
  2. RatingBar Styles
  3. RatingBar Events
  4. Exemple de RatingBar

1. Android RatingBar

Sous Android, RatingBar est un contrôle d'interface utilisateur (User Interface Control) permettant de recevoir les avis des utilisateurs. RatingBar est un descendant de ProgressBar qui hérite donc les fonctions de ProgressBar. Il permet aussi d'afficher une note globale (moyenne) de tous les utilisateurs. En termes d'interface, RatingBar se compose des étoiles et les utilisateurs en sélectionnent une pour donner une note, la première étoile correspond à la note la plus faible et la dernière correspond à la note la plus élevée.
Ci-dessous la structure d'un RatingBar:
android:numStars
L'attribut android:numStars permet de définir le nombre d'étoiles affichées sur RatingBar. Sa valeur par défaut est 5.
android:numStars
<!-- numStars default is 5 -->
<RatingBar
    android:id="@+id/ratingBar21"
    android:rating="3.5"
    android:stepSize="0.1" ... />

<!-- numStars = 7 -->
<RatingBar
    android:id="@+id/ratingBar22"
    android:numStars="7"
    android:rating="5.7"
    android:stepSize="0.1" ... />
android:rating, android:stepSize
android:rating: Une valeur indiquant la note de l'utilisateur ou la valeur moyenne de toutes les évaluations des utilisateurs. Cela se situe entre (0,numStars].
La valeur par défaut de l'attribut android:stepSize est 0.5, ce qui signifie que RatingBar n'affiche que les notes (ou les avis d'utilisateurs) avec les valeurs 0, 0.5, 1, 1.5, 2, etc. Quand la valeur de l'attribut android:stepSite est modifié en 0.1, RatingBar peut afficher des valeurs 0, 0.1, 0.2, 0.3, 0.4, 0.5, etc.
android:stepSize
<!-- android.stepSize = "0.5" (Default) -->
<RatingBar
    android:id="@+id/ratingBar31"
    android:rating="2.7" ... />

<!-- android.stepSize = "0.1" -->
<RatingBar
    android:id="@+id/ratingBar32"
    android:rating="2.7"
    android:stepSize="0.1" ... />
android:isIndicator
L'attribut android:isIndicator = "true" est utilisé quand vous ne voulez pas permettre aux utilisateurs de laisser une note avec RatingBar. Par exemple, vous prévoyez d'avoir une RatingBar pour afficher uniquement une note globale (moyenne). Par défaut, la valeur de l'attribut est false.
<!-- android:isIndicator = "false" (Default) -->
<RatingBar
    android:id="@+id/ratingBar51"
    android:rating="2" ... />

<!-- android:isIndicator = "true" (Readonly RatingBar) -->
<RatingBar
    android:id="@+id/ratingBar52"
    android:isIndicator="true"
    android:rating="4.5" ... />

2. RatingBar Styles

L'attribut style est une option de RatingBar permettant de définir le style pour RatingBar. Vous pouvez utiliser certains styles disponibles dans la bibliothèque d'Android.
La bibliothèque d'Android fournit certains styles pour RatingBar, pourtant, beaucoup d'entre eux se ressemblent. Ainsi, il est difficile de faire la différence. Ci-dessous un exemple avec certains styles sympas:
  • style="@style/Widget.AppCompat.RatingBar.Indicator"
  • style="@android:style/Widget.DeviceDefault.Light.RatingBar.Small"
  • style="@android:style/Widget.RatingBar"
  • style="@android:style/Widget.Holo.RatingBar"
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView41"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="(Default)"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <RatingBar
        android:id="@+id/ratingBar41"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:rating="2.7"
        android:stepSize="0.1"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView41" />

    <TextView
        android:id="@+id/textView42"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="AppCompat.RatingBar.Indicator"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ratingBar41" />

    <RatingBar
        android:id="@+id/ratingBar42"
        style="@style/Widget.AppCompat.RatingBar.Indicator"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:rating="4.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView42" />

    <TextView
        android:id="@+id/textView43"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Widget.DeviceDefault.Light.RatingBar.Small"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ratingBar42" />

    <RatingBar
        android:id="@+id/ratingBar43"
        style="@android:style/Widget.DeviceDefault.Light.RatingBar.Small"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:rating="2.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView43" />

    <TextView
        android:id="@+id/textView44"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Widget.RatingBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ratingBar43" />

    <RatingBar
        android:id="@+id/ratingBar44"
        style="@android:style/Widget.RatingBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:rating="3"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView44" />

    <TextView
        android:id="@+id/textView45"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Widget.Holo.RatingBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ratingBar44" />

    <RatingBar
        android:id="@+id/ratingBa45"
        style="@android:style/Widget.Holo.RatingBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:rating="3.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView45" />

</androidx.constraintlayout.widget.ConstraintLayout>

3. RatingBar Events

Il y a certains évènements relatifs à une RatingBar, ci-dessous ceux les plus utilisés:
  • setOnClickListener(View.OnClickListener);
  • setOnRatingBarChangeListener(RatingBar.OnRatingBarChangeListener);
On Click Event:
L'évènement se produit quand l'utilisateur clique (click) sur RatingBar. Cela donne le même effet quand l'utilisateur clique sur un Button.
ratingBar.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
         RatingBar rb = (RatingBar) v;
         float rating = rb.getRating();
         
         // Your code ...
    }
});
On RatingBar Changed Event
L'évènement se produit quand la valeur de rating change en raison d'une action de l'utilisateur ou sous l'effet de la méthode ratingBar.setRating(newRating), etc.
ratingBar.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener() {
    @Override
    public void onRatingChanged(RatingBar ratingBar, float newRating, boolean fromUser) {
         // Your code
    }
});

4. Exemple de RatingBar

OK, prendre un exemple simple en utilisant RatingBar. Dans cet exemple, la première RatingBar reçoit les avis d'utilisateurs. La seconde RatingBar affiche une note globale (moyenne) de tous les utilisateurs.
Dans Android Studio, créer un nouveau projet:
  • File > New > New Project > Empty Activity
    • Name: RatingBarExample
    • Package name: org.o7planning.ratingbarexample
    • Language: Java
Voici l'interface de l'application:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Give your Rating:"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <RatingBar
        android:id="@+id/ratingBar_yours"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <TextView
        android:id="@+id/textView_yourCurrentRating"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Your current Rating:"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ratingBar_yours" />

    <Button
        android:id="@+id/button_submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Submit"
        android:textAllCaps="false"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.52"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView_yourCurrentRating" />

    <TextView
        android:id="@+id/textView_ratingCount"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Rating Count: 0"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button_submit" />

    <TextView
        android:id="@+id/textView_sumAllRating"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Sum of all Rating: 0"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView_ratingCount" />

    <TextView
        android:id="@+id/textView_averageAllRating"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:text="Average value of all Rating: 0"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView_sumAllRating" />

    <RatingBar
        android:id="@+id/ratingBar_all"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:isIndicator="true"
        android:stepSize="0.1"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView_averageAllRating" />

</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.java
package com.example.ratingbarexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RatingBar;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private RatingBar ratingBarYours;
    private RatingBar ratingBarAll;

    private Button buttonSubmit;

    private TextView textViewYourCurrentRating;
    private TextView textViewRatingCount;
    private TextView textViewSumAllRating;
    private TextView textViewAverageAllRating;

    private List<Float> allRatings = new ArrayList<Float>();

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

        //
        this.buttonSubmit = (Button) this.findViewById(R.id.button_submit);
        this.ratingBarYours = (RatingBar) this.findViewById(R.id.ratingBar_yours);
        this.ratingBarAll = (RatingBar) this.findViewById(R.id.ratingBar_all);

        this.textViewYourCurrentRating = (TextView) this.findViewById(R.id.textView_yourCurrentRating);
        this.textViewRatingCount= (TextView) this.findViewById(R.id.textView_ratingCount);
        this.textViewSumAllRating= (TextView) this.findViewById(R.id.textView_sumAllRating);
        this.textViewAverageAllRating= (TextView) this.findViewById(R.id.textView_averageAllRating);

        this.ratingBarYours.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener() {
            @Override
            public void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser) {
                textViewYourCurrentRating.setText("Your current Rating: " + rating);
            }
        });
        this.buttonSubmit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                doSubmit();
            }
        });
    }

    private void doSubmit()  {
        float rating = this.ratingBarYours.getRating();
        this.allRatings.add(rating);

        int ratingCount = this.allRatings.size();
        float ratingSum = 0f;
        for(Float r: this.allRatings)  {
            ratingSum += r;
        }
        float averageRating = ratingSum / ratingCount;


        this.textViewRatingCount.setText("Rating Count: " + ratingCount);
        this.textViewSumAllRating.setText("Sum off all Rating: " + ratingSum);
        this.textViewAverageAllRating.setText("Average value off all Rating: " + averageRating);

        float ratingAll = this.ratingBarAll.getNumStars() * averageRating / this.ratingBarYours.getNumStars() ;
        this.ratingBarAll.setRating(ratingAll);
    }

}

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