No error in code. But while launching the app says, Unfortunately app has stopped

Question

I am developed simple android application including some simple adding calculation function. After the Run emulator display that kind error. More time wasted to find that error in android application. No error in code. But while launching the app says, Unfortunately app has stopped.

Error- Screen Shot

My Code as Follows

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".MainActivity"
    tools:layout_editor_absoluteY="81dp">

    <TextView
        android:id="@+id/textView_answer"
        android:layout_width="100dp"
        android:layout_height="25dp"
        android:layout_marginLeft="130dp"
        android:layout_marginTop="300dp"
        android:text="0"
        android:textSize="20dp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/textView_first_no"
        android:layout_width="150dp"
        android:layout_height="25dp"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="50dp"
        android:text="First number"
        android:textSize="20dp" />

    <TextView
        android:id="@+id/textView_second_no"
        android:layout_width="150dp"
        android:layout_height="25dp"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="100dp"
        android:text="Second number"
        android:textSize="20dp" />

    <EditText
        android:id="@+id/editText_first_no"
        android:layout_width="150dp"
        android:layout_height="40dp"
        android:layout_marginLeft="200dp"
        android:layout_marginTop="40dp"
        android:inputType="number"
        tools:ignore="MissingConstraints" />

    <EditText
        android:id="@+id/editText_second_no"
        android:layout_width="150dp"
        android:layout_height="40dp"
        android:layout_marginLeft="200dp"
        android:layout_marginTop="90dp"
        android:inputType="number"
        tools:ignore="MissingConstraints" />


</RelativeLayout>

MainActivity.java

package com.example.marks;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {

    EditText number1;
    EditText number2;
    Button Add_button;
    TextView result;

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

        number1 = (EditText) findViewById(R.id.editText_first_no);
        number2 = (EditText) findViewById(R.id.editText_second_no);
        result = (TextView) findViewById(R.id.textView_answer);

        Add_button.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                double num1 = Double.parseDouble(number1.getText().toString());
                double num2 = Double.parseDouble(number2.getText().toString());

                double sum = num1 + num2;

                result.setText(Double.toString(sum));
            }
        });
    }
}

@Sergey Glotov nothing says logcat. sure. but xml file view some warnings. — InsidelPit, May 26 '20 at 07:46
You're just missing those logs, then, somehow, because you were at least getting a `NullPointerException` at some point, if not still. — Mike M., May 26 '20 at 07:48

score 3 · Answer 1 · answered May 26 '20 at 07:19

3

Where the button (Add_button) on your xml file. The error is because the button is not defined yet.

answered May 26 '20 at 07:19

Youcef Bachadel

31
3

after button was added. but error is same – InsidelPit May 26 '20 at 07:34
You should alsow initialize it by add_button =findviewbyid... – Youcef Bachadel May 26 '20 at 09:09
Button Add_button = findViewById(R.id.submit); – Youcef Bachadel May 26 '20 at 09:14

No error in code. But while launching the app says, Unfortunately app has stopped

1 Answers1