Le Tutoriel de Android SeekBar

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Tutoriels de programmation Android

Qu'est-ce que SeekBar?
Exemple de SeekBar
Personnaliser SeekBar
Appendix: Interface design

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1- Qu'est-ce que SeekBar?

Un SeekBar est une extension de ProgressBar qui ajoute un pouce extensible. L'utilisateur peut toucher le pouce et faire glisser vers la gauche ou vers la droite pour régler la progression en cours ou utiliser les touches fléchées. Vous pouvez placer des widgets focalisables à gauche ou à droite d'un SeekBar malgré que celui est découragé.

Ci- dessous sont quelques exemples de SeekBar:

2- Exemple de SeekBar

Créez un nouveau projet nommé SeekBarDemo.

File > New > New Project > Empty Activity
- Name: SeekBarDemo
- Package name: org.o7planning.seekbardemo
- Language: Java

The interface of the application is quite simple, it is similar to the illustration below, if you are interested in the interface design steps, please see the appendix at the end of the article.

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">

    <SeekBar
        android:id="@+id/seekBar"
        android:layout_width="0dp"
        android:layout_height="27dp"
        android:layout_marginStart="19dp"
        android:layout_marginLeft="19dp"
        android:layout_marginTop="43dp"
        android:layout_marginEnd="21dp"
        android:layout_marginRight="21dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="24dp"
        android:layout_marginStart="22dp"
        android:layout_marginLeft="22dp"
        android:layout_marginTop="34dp"
        android:layout_marginEnd="21dp"
        android:layout_marginRight="21dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/seekBar" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="1dp"
        android:layout_marginLeft="1dp"
        android:layout_marginTop="50dp"
        android:layout_marginEnd="1dp"
        android:layout_marginRight="1dp"
        android:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView">

        <Button
            android:id="@+id/button_decrease"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="-" />

        <Button
            android:id="@+id/button_increase"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="+" />
    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java


package org.o7planning.seekbardemo;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private SeekBar seekBar;
    private TextView textView;
    private Button buttonDecrease;
    private Button buttonIncrease;

    private static int DELTA_VALUE = 5;

    private static final String LOGTAG = "SeekBarDemo";


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

        //
        this.seekBar = (SeekBar) findViewById(R.id.seekBar );
        this.textView = (TextView) findViewById(R.id.textView);


        this.buttonDecrease= (Button) findViewById(R.id.button_decrease);
        this.buttonIncrease= (Button) findViewById(R.id.button_increase);

        this.seekBar.setMax(100);
        this.seekBar.setProgress(15);

        this.textView.setText("Progress: " + seekBar.getProgress() + "/" + seekBar.getMax());
        //
        this.seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            int progress = 0;

            // When Progress value changed.
            @Override
            public void onProgressChanged(SeekBar seekBar, int progressValue, boolean fromUser) {
                progress = progressValue;
                textView.setText("Progress: " + progressValue + "/" + seekBar.getMax());
                Log.i(LOGTAG, "Changing seekbar's progress");
                Toast.makeText(getApplicationContext(), "Changing seekbar's progress", Toast.LENGTH_SHORT).show();
            }

            // Notification that the user has started a touch gesture.
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                Log.i(LOGTAG, "Started tracking seekbar");
                Toast.makeText(getApplicationContext(), "Started tracking seekbar", Toast.LENGTH_SHORT).show();
            }

            // Notification that the user has finished a touch gesture
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                textView.setText("Progress: " + progress + "/" + seekBar.getMax());
                Log.i(LOGTAG, "Stopped tracking seekbar");
                Toast.makeText(getApplicationContext(), "Stopped tracking seekbar", Toast.LENGTH_SHORT).show();

            }
        });

        this.buttonDecrease.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                decreateProgress();
            }
        });

        this.buttonIncrease.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                increateProgress();
            }
        });
    }


    private void decreateProgress()  {
        int progress= this.seekBar.getProgress();
        if(progress - DELTA_VALUE < 0)  {
            this.seekBar.setProgress(0);
        } else  {
            this.seekBar.setProgress(progress - DELTA_VALUE);
        }
        textView.setText("Progress: " + seekBar.getProgress()+ "/" + seekBar.getMax());
    }

    private void increateProgress()  {
        int progress= this.seekBar.getProgress();
        if(progress + DELTA_VALUE > this.seekBar.getMax())  {
            this.seekBar.setProgress(0);
        }else {
            this.seekBar.setProgress(progress + DELTA_VALUE);
        }
        textView.setText("Progress: " + seekBar.getProgress()+ "/" + seekBar.getMax());
    }

}

Exécutez l'application: