Full source code to Add two numbers from EditText
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"
android:padding="16dp"
tools:context="tech.codingigpoint.additionexample.MainActivity">
<EditText
android:id="@+id/edittext_number_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number" />
<EditText
android:id="@+id/edittext_number_2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_below="@+id/edittext_number_1"
android:inputType="number" />
<TextView
android:id="@+id/textview_result"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/edittext_number_2"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:text="0"
android:textColor="@android:color/black"
android:textSize="50sp" />
<Button
android:id="@+id/button_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="add" />
</RelativeLayout>
MainActivity.java
package tech.codinginpoint.additionexample;
import android.support.v7.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 mEditText1;
private EditText mEditText2;
private TextView mTextViewResult;
private Button mButtonAdd;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mEditText1 = findViewById(R.id.edittext_number_1);
mEditText2 = findViewById(R.id.edittext_number_2);
mTextViewResult = findViewById(R.id.textview_result);
mButtonAdd = findViewById(R.id.button_add);
mButtonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mEditText1.getText().toString().length() == 0) {
mEditText1.setText("0");
}
if (mEditText2.getText().toString().length() == 0) {
mEditText2.setText("0");
}
int num1 = Integer.parseInt(mEditText1.getText().toString());
int num2 = Integer.parseInt(mEditText2.getText().toString());
int sum = num1 + num2;
mTextViewResult.setText(String.valueOf(sum));
}
});
}
}