My app in Android Studio does not run, it throws " java.lang.RuntimeException: Unable to instantiate activity"

Im new in android development and im having some problem with my app, im building a simple IMC calculator in Android Studio, it has 2 activities, one is the main activity where you put all the values (age, height, weight...) and then another one that gives you the result taking as reference that values. I saw in other questions that the main problem could be in the manifest, here is my manifest.

Manifest:

`<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">

<application
    android:allowBackup="true"
    android:dataExtractionRules="@xml/data_extraction_rules"
    android:fullBackupContent="@xml/backup_rules"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.CalculoIMC"
    tools:targetApi="34">
    <activity
        android:name=".SeeResults"
        android:exported="false"
        android:parentActivityName = "com.example.calculoimc.MainActivity"
  />
    <activity android:name="com.example.calculoimc.MainActivity"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>`

MainActivity (Variables are in spanish):

package com.example.calculoimc;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {



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


    public void sendData (View v) {
        Intent i = new Intent(this,SeeResults.class);
        String [] info  = new String[4];
        info [0] = name;
        info [1] = edadN;
        info [2] = alturaN;
        info [3] = pesoN;
        i.putExtra("data",info);
        startActivity(i);
    }
    EditText nombreApellidos = findViewById(R.id.NombreApellidos);
    EditText edad = findViewById(R.id.Edad);
    EditText altura = findViewById(R.id.altura);
    EditText peso = findViewById(R.id.peso);

    /*DATOS*/
    String name = nombreApellidos.getText().toString().replace("Nombre" , "");
    String edadN = edad.getText().toString().replace("Edad","");
    String alturaN = altura.getText().toString().replace("Altura","");
    String pesoN = peso.getText().toString().replace("Peso","");

}

The exact error is : java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.calculoimc/com.example.calculoimc.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference

I saw in another post that i have to check the activities in the manifest, I tried checking the activities in the manifest and all of them are declared there correctly, i dont know what to do exactly, i would be grateful if somebody can help me, thanks

Ok, i already solved it, it was pretty simple, the problem was the final part of the code:

EditText nombreApellidos = findViewById(R.id.NombreApellidos);
EditText edad = findViewById(R.id.Edad);
EditText altura = findViewById(R.id.altura);
EditText peso = findViewById(R.id.peso);
/*DATOS*/
String name = nombreApellidos.getText().toString().replace("Nombre" , "");
String edadN = edad.getText().toString().replace("Edad","");
String alturaN = altura.getText().toString().replace("Altura","");
String pesoN = peso.getText().toString().replace("Peso","");

I put the variables in the method "sendData" and then worked without any problem.

Solution:

package com.example.calculoimc;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void sendData (View v) {
EditText nombreApellidos = findViewById(R.id.NombreApellidos);
EditText edad = findViewById(R.id.Edad);
EditText altura = findViewById(R.id.altura);
EditText peso = findViewById(R.id.peso);
/*DATOS*/
String name = nombreApellidos.getText().toString().replace("Nombre" , "");
String edadN = edad.getText().toString().replace("Edad","");
String alturaN = altura.getText().toString().replace("Altura","");
String pesoN = peso.getText().toString().replace("Peso","");
Intent i = new Intent(this,SeeResults.class);
String [] info  = new String[4];
info [0] = name;
info [1] = edadN;
info [2] = alturaN;
info [3] = pesoN;
i.putExtra("data",info);
startActivity(i);
}
}