When I declare String s (string obtained from edittext) globally intents stop working why?

package com.example.intents;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
TextView textView=findViewById(R.id.editTextTextPersonName);
String s=textView.getText().toString();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public void mail(View v){
    Intent i=new Intent(Intent.ACTION_SENDTO);
    i.setData(Uri.parse("mailto:"+s));
    startActivity(i);
}public void dial(View v){


    Intent i=new Intent(Intent.ACTION_DIAL);
    i.setData(Uri.parse("tel:"+s));
    startActivity(i);
}public void search(View v){

    Intent i=new Intent(Intent.ACTION_VIEW);
    i.setData(Uri.parse("https://"+s));
    startActivity(i);
}

}