Dans ce guide technique, nous explorerons comment implémenter une interface utilisateur basée sur des fragments dans une application Android, en utilisant un RadioGroup pour naviguer entre différentes sections. L'exemple montre comment initialiser, remplacer et gérer des fragments avec des transactions.

1. MainActivity.java

package com.example.fragmentapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedState) {
        super.onCreate(savedState);
        setContentView(R.layout.main_layout);
    }

    public void onNavigateToDemo(View view) {
        Intent navIntent = new Intent(this, DemoActivity.class);
        startActivity(navIntent);
    }
}

2. DemoActivity.java

package com.example.fragmentapp;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
import android.widget.RadioGroup;

public class DemoActivity extends Activity {

    private FragmentManager manager;
    private FragmentTransaction transaction;
    private RadioGroup menuGroup;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.demo_layout);
        menuGroup = findViewById(R.id.navigation_group);

        manager = getFragmentManager();
        transaction = manager.beginTransaction();
        transaction.add(R.id.content_container, new MessageFragment());
        transaction.commit();

        menuGroup.setOnCheckedChangeListener((group, checkedId) -> {
            Fragment selectedFragment;
            if (checkedId == R.id.option_messages) {
                selectedFragment = new MessageFragment();
            } else if (checkedId == R.id.option_contacts) {
                selectedFragment = new ContactFragment();
            } else {
                selectedFragment = new ExploreFragment();
            }
            transaction = manager.beginTransaction();
            transaction.replace(R.id.content_container, selectedFragment);
            transaction.addToBackStack(null);
            transaction.commit();
        });
    }
}

3. MessageFragment.java

package com.example.fragmentapp;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

public class MessageFragment extends Fragment {

    private Button actionButton;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_message, container, false);
        actionButton = rootView.findViewById(R.id.action_btn);
        actionButton.setOnClickListener(v -> {
            Toast.makeText(getActivity(), "Action effectuée", Toast.LENGTH_SHORT).show();
        });
        return rootView;
    }
}

4. ContactFragment.java

package com.example.fragmentapp;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class ContactFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_contact, container, false);
    }
}

5. ExploreFragment.java

package com.example.fragmentapp;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class ExploreFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_explore, container, false);
    }
}

6. main_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Exemple de FrameLayout"
        android:onClick="onFrameExample"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Démo avec Fragments"
        android:onClick="onNavigateToDemo"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Layout Grid"
        android:onClick="onGridExample"
        />
</LinearLayout>

7. demo_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <FrameLayout
        android:id="@+id/content_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/navigation_bar" />

    <LinearLayout
        android:id="@+id/navigation_bar"
        android:layout_alignParentBottom="true"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <RadioGroup
            android:id="@+id/navigation_group"
            android:checkedButton="@id/option_messages"
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <RadioButton
                android:id="@+id/option_messages"
                android:text="Messages"
                android:drawableTop="@mipmap/ic_launcher"
                android:clickable="true"
                android:button="@null"
                android:gravity="center"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="wrap_content" />

            <RadioButton
                android:id="@+id/option_contacts"
                android:text="Contacts"
                android:drawableTop="@mipmap/ic_launcher"
                android:clickable="true"
                android:button="@null"
                android:gravity="center"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="wrap_content" />

            <RadioButton
                android:id="@+id/option_explore"
                android:text="Explorer"
                android:drawableTop="@mipmap/ic_launcher"
                android:clickable="true"
                android:button="@null"
                android:gravity="center"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="wrap_content" />

            <RadioButton
                android:id="@+id/option_profile"
                android:text="Profil"
                android:drawableTop="@mipmap/ic_launcher"
                android:clickable="true"
                android:button="@null"
                android:gravity="center"
                android:layout_width="0dp"
                android:layout_weight="1"
                android:layout_height="wrap_content" />
        </RadioGroup>
    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@android:color/darker_gray"
        android:layout_above="@id/navigation_bar" />
</RelativeLayout>

8. fragment_message.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="28sp"
        android:text="Section Messages" />

    <Button
        android:id="@+id/action_btn"
        android:text="Cliquer ici"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

9. frgament_contact.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize="28sp"
        android:textColor="@android:color/holo_red_dark"
        android:text="Liste des Contacts" />
</LinearLayout>

10. fragment_explore.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize="28sp"
        android:textColor="@android:color/holo_green_light"
        android:text="Découvrir du Contenu" />
</FrameLayout>