child_guard/app/src/main/java/com/example/childguard/QRFragment.java

package com.example.childguard;

import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;

import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.browser.customtabs.CustomTabsIntent;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;
import com.journeyapps.barcodescanner.ScanContract;
import com.journeyapps.barcodescanner.ScanOptions;

import java.util.Objects;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link QRFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class QRFragment extends Fragment {
    //QRコードから受け取ったURLの受け渡しの宣言
//   OnDataPass dataPass;
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public QRFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment QRFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static QRFragment newInstance(String param1, String param2) {
        QRFragment fragment = new QRFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }


    }

    private final ActivityResultLauncher<ScanOptions> fragmentLauncher = registerForActivityResult(new ScanContract(),
            result -> {
                String contents = result.getContents();
                if (contents == null) {
                    Toast.makeText(getContext(), "QRコードが読み取れませんでした", Toast.LENGTH_LONG).show();
                } else if (!contents.contains("https://practicefirestore1-8808c.web.app/")) {
                    Toast.makeText(getContext(), "Chiled Guardに対応するQRコードではありません", Toast.LENGTH_LONG).show();
                } else {
                    //URLの表示
                    Toast.makeText(getContext(), contents, Toast.LENGTH_SHORT).show();
                    //ブラウザを起動し、URL先のサイトを開く
                    CustomTabsIntent.Builder builder = new CustomTabsIntent.Builder();
                    CustomTabsIntent customTabsIntent = builder.build();
                    customTabsIntent.launchUrl(requireContext(), Uri.parse(contents));
                }

                getParentFragmentManager().popBackStack();
            });

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_qr, container, false);


        Log.d("QRFragment", "onClick: called");
        //QRリーダ起動
        fragmentLauncher.launch(new ScanOptions());

        return view;
    }
    //画面遷移メソッド
    private void replaceFragment(Fragment fragment) {
        // フラグメントマネージャーの取得
        FragmentManager manager = getParentFragmentManager(); // アクティビティではgetSupportFragmentManager()?
        // フラグメントトランザクションの開始
        FragmentTransaction transaction = manager.beginTransaction();
        // レイアウトをfragmentに置き換え（追加）
        transaction.replace(R.id.fragmentContainerView, fragment);
        // 置き換えのトランザクションをバックスタックに保存する
        transaction.addToBackStack(null);
        // フラグメントトランザクションをコミット
        transaction.commit();
    }
}