I have a method that after taking permission from user stores the user’s phone number into a variable and then shows it in a textView but the problem is the phone number is not being stored in the variable I am not able to understand why can somebody please help me.

Here’s the code of MainActivity.java file I am using/trying:

package com.example.androidapp;

import android.content.pm.PackageManager;
import android.os.Bundle;
import android.telephony.SubscriptionManager;
import android.util.Log;
import android.view.View;
import android.widget.TextView;

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class MainActivity extends AppCompatActivity {
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            textView = findViewById(R.id.textView);
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.READ_PHONE_NUMBERS}, PackageManager.PERMISSION_GRANTED);
            return insets;
        });
    }

    public void buttonGethoneNumber(View view) {
        SubscriptionManager subscriptionManager = (SubscriptionManager) getSystemService(TELEPHONY_SUBSCRIPTION_SERVICE);
        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.READ_PHONE_NUMBERS) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.

            return;
        }
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.TIRAMISU) {
            String phoneNumber = subscriptionManager.getPhoneNumber(SubscriptionManager.DEFAULT_SUBSCRIPTION_ID);
            textView.setText(phoneNumber);
            Log.d("MainActivity", "Value of textView: " + phoneNumber);
        }

    }
}

I want someone to check this code that what’s the ptoblem in it is thus the right approach and what I need to do right to get the phone number of the device my phone is running in.