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Le Tutoriel de Android ImageSwitcher

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1- L'aperçu de ImageSwitcher

C'est l'image d'une l'application qui utilise ImageSwitcher:
  • TODO: More infos

2- Exemple avec Android ImageSwitcher

Créez un projet nommé AndroidImageSwitcher:
  • File > New Project > Empty Activity
Vous devez préparer quelques images afin de les utiliser dans des exemples ci- dessous:
image1.png
image2.png
image3.png
Copiez ces images dans le dossier drawable.
L'interface de l'application:
If you are interested in the steps to design the interface of this application, please see the appendix at the end of the article.
main_actvity.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">

    <ImageSwitcher
        android:id="@+id/imageSwitcher"
        android:layout_width="0dp"
        android:layout_height="279dp"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="27dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <LinearLayout
        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:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageSwitcher">

        <Space
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />

        <Button
            android:id="@+id/button_previous "
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:text="Previous" />

        <Button
            android:id="@+id/button_next"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:text="Next" />

        <Space
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />
    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.java

package org.o7planning.androidimageswitcher;

import android.os.Bundle;
import android.app.ActionBar.LayoutParams;
import android.graphics.Color;
import android.util.Log;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.ViewSwitcher.ViewFactory;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private ImageSwitcher imageSwitcher;
    private Button buttonPrevious;
    private Button buttonNext;

    private final String[] imageNames={"image1", "image2", "image3"};
    private int currentIndex;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        buttonPrevious = (Button) findViewById(R.id.button_previous);
        buttonNext = (Button) findViewById(R.id.button_next);

        imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);

        // Animation when switching to another image.
        Animation out= AnimationUtils.loadAnimation(this, android.R.anim.fade_out);
        Animation in= AnimationUtils.loadAnimation(this, android.R.anim.fade_in);

        // Set animation when switching images.
        imageSwitcher.setInAnimation(in);
        imageSwitcher.setOutAnimation(out);

        //
        imageSwitcher.setFactory(new ViewFactory() {

            // Returns the view to show Image
            // (Usually should use ImageView)
            @Override
            public View makeView() {
                ImageView imageView = new ImageView(getApplicationContext());

                imageView.setBackgroundColor(Color.LTGRAY);
                imageView.setScaleType(ImageView.ScaleType.CENTER);

                ImageSwitcher.LayoutParams params= new ImageSwitcher.LayoutParams(
                        LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
                imageView.setLayoutParams(params);
                return imageView;
            }
        });

        this.currentIndex=0;
        this.showImage(this.currentIndex);

        buttonPrevious.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                previousImage();
            }
        });

        buttonNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nextImage();
            }
        });
    }


    private void previousImage()  {
        if(currentIndex > 0) {
            currentIndex--;
        }else  {
            Toast.makeText(getApplicationContext(), "No Previous Image", Toast.LENGTH_SHORT).show();
            return;
        }
        this.showImage(currentIndex);
    }

    private void nextImage()  {
        if(currentIndex < this.imageNames.length-1) {
            currentIndex++;
        }else  {
            Toast.makeText(getApplicationContext(), "No Next Image", Toast.LENGTH_SHORT).show();
            return;
        }
        this.showImage(currentIndex);
    }


    private void showImage(int imgIndex)  {
        String imageName= this.imageNames[imgIndex];

        int resId= getDrawableResIdByName(imageName);
        if(resId!=  0) {
            this.imageSwitcher.setImageResource(resId);
        }
    }

    // Find Image ID corresponding to the name of the image (in the drawable folder).
    public int getDrawableResIdByName(String resName)  {
        String pkgName = this.getPackageName();
        // Return 0 if not found.
        int resID = this.getResources().getIdentifier(resName , "drawable", pkgName);
        Log.i("MyLog", "Res Name: " + resName + "==> Res ID = " + resID);
        return resID;
    }

}
L'exécution de l'application:

3- Appendix: Interface design

I don't know why ImageSwitcher is not available on design window of Android Studio 3.6.x, so you can't drag it into the interface. The best way is to add the following XML code to the activity_main.xml file and you will get ImageSwitcher on the interface.

<ImageSwitcher
        android:layout_width="100dp"
        android:layout_height="100dp" />
Set ID, Text for components on the interface.

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