Successfull Build in Android Studio still crashes on Device

Question

I'm pretty much a beginner still and I've tried to make an App to ease my work in the Lab. It's just some basic calculation. I want to make an App that is compatible to the most devices, in case its useful information. Even though the App seems to Build successfully, as soon as it starts on my Device it just crashes immediatelly. Files used are listed below. I tried all the hints Android Studio gave me with no result. App still crashed.

Would be very thankful for some hints and constructive feeback!

---

Main Activity.java

package com.e.concalc;

import androidx.appcompat.app.AppCompatActivity; 
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {


private EditText protein_sp;
private EditText salt_sp;
private EditText protein_st;
private EditText salt_st;
private EditText volume_sp;

private TextView tv_resultH2O;
private TextView tv_resultSalt;
private TextView tv_resultProtein;

private Button button1;

public MainActivity(TextView tv_resultH2O, TextView tv_resultSalt, TextView tv_resultProtein, Button button1) {
    this.tv_resultH2O = tv_resultH2O;
    this.tv_resultSalt = tv_resultSalt;
    this.tv_resultProtein = tv_resultProtein;
    this.button1 = button1;
}

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

    protein_sp = findViewById(R.id.edit1);
    protein_st = findViewById(R.id.edit2);
    salt_sp = findViewById(R.id.edit3);
    salt_st = findViewById(R.id.edit4);
    volume_sp = findViewById(R.id.edit5);



    button1.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            makeCalculations();
        }
    });
}


private void makeCalculations() {
    double p_sp = Double.valueOf(protein_sp.getText().toString());
    double p_st = Double.valueOf(protein_st.getText().toString());
    double s_sp = Double.valueOf(salt_sp.getText().toString());
    double s_st = Double.valueOf(salt_st.getText().toString());
    double v_sp = Double.valueOf(volume_sp.getText().toString());

    double resultH2O;
    double resultSalt;
    double resultProtein;

    resultProtein = p_sp * v_sp / p_st;
    resultSalt = s_sp * v_sp / s_st;
    resultH2O = v_sp - resultProtein - resultSalt;



    tv_resultH2O.setText(Double.toString(resultH2O));
    tv_resultSalt.setText(Double.toString(resultSalt));
    tv_resultProtein.setText(Double.toString(resultProtein));
    }
}

---

activity_main.xml - Layout

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">



<TextView
    android:id="@+id/text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/Protein1"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintHorizontal_bias="0.133"
    app:layout_constraintVertical_bias="0.070" />

<TextView
    android:id="@+id/text2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/Protein2"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.77"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.070" />


<TextView
    android:id="@+id/text4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/Salt1"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toStartOf="@+id/text2"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.21" />

<TextView
    android:id="@+id/text3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/Salt2"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toStartOf="@+id/text1"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.21" />

<TextView
    android:id="@+id/text5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/SampleVolume"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toStartOf="@+id/text3"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.35" />


<EditText
    android:id="@+id/edit1"
    android:layout_width="100dp"
    android:layout_height="40dp"
    android:textSize="15sp"
    android:inputType="number"
    android:hint="@string/hint"
    app:layout_constraintStart_toStartOf="@+id/text1"
    app:layout_constraintTop_toBottomOf="@+id/text1"
    android:importantForAutofill="no" />

<EditText
    android:id="@id/edit2"
    android:layout_width="100dp"
    android:layout_height="40dp"
    android:textSize="15sp"
    android:inputType="number"
    android:hint="@string/hint"
    app:layout_constraintStart_toStartOf="@+id/text2"
    app:layout_constraintTop_toBottomOf="@+id/text2"
    android:importantForAutofill="no" />

<EditText
    android:id="@id/edit4"
    android:layout_width="100dp"
    android:layout_height="40dp"
    android:textSize="15sp"
    android:inputType="number"
    android:hint="@string/hint"
    app:layout_constraintStart_toStartOf="@+id/text4"
    app:layout_constraintTop_toBottomOf="@+id/text4"
    android:importantForAutofill="no" />

<EditText
    android:id="@id/edit3"
    android:layout_width="100dp"
    android:layout_height="40dp"
    android:textSize="15sp"
    android:inputType="number"
    android:hint="@string/hint"
    app:layout_constraintStart_toStartOf="@+id/text3"
    app:layout_constraintTop_toBottomOf="@+id/text3"
    android:importantForAutofill="no" />

<EditText
    android:id="@+id/edit5"
    android:layout_width="100dp"
    android:layout_height="40dp"
    android:textSize="15sp"
    android:inputType="number"
    android:hint="@string/hint"
    app:layout_constraintStart_toStartOf="@+id/text5"
    app:layout_constraintTop_toBottomOf="@+id/text5"
    android:importantForAutofill="no" />

<Button
    android:id="@+id/button1"
    android:layout_width="120dp"
    android:layout_height="40dp"
    android:layout_marginBottom="128dp"
    android:text="@string/button1"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.158"
    app:layout_constraintStart_toStartOf="parent" />


<Button
    android:id="@+id/button2"
    android:layout_width="120dp"
    android:layout_height="40dp"
    android:layout_marginStart="51dp"
    android:layout_marginLeft="51dp"
    android:text="@string/button2"
    app:layout_constraintBottom_toBottomOf="@+id/button1"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.745"
    app:layout_constraintStart_toEndOf="@+id/button1"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@+id/button1" />


<TextView
    android:id="@+id/tv_resultH2O"
    android:layout_width="100dp"
    android:layout_height="50dp"
    android:layout_centerInParent="true"

    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintHorizontal_bias="0.1"
    app:layout_constraintVertical_bias="0.6"/>


<TextView
    android:id="@+id/tv_resultSalt"
    android:layout_width="100dp"
    android:layout_height="50dp"
    android:layout_centerInParent="true"
    android:textAppearance="?android:attr/textAppearanceLarge"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintVertical_bias="0.6"/>

<TextView
    android:id="@+id/tv_resultProtein"
    android:layout_width="100dp"
    android:layout_height="50dp"
    android:layout_centerInParent="true"
    android:textAppearance="?android:attr/textAppearanceLarge"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintHorizontal_bias="0.9"
    app:layout_constraintVertical_bias="0.6"/>
</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

Remove your custom constructor.

Activities must have a no-argument constructor that Android uses to create your class and when you define any override then the no-argument constructor is no longer automatically created for you in Java...

Answer 2

You forgot to findViewById the button1.So in onCreate method, before button1.setOnClickListener.... add this line:

button1 = findViewById(R.id.button1);