Android | App to Add Two Numbers - GeeksforGeeks

22 Sep, 2021
Below are the steps for Creating a Simple Android Application to Add Two Numbers
STEP-1: First of all go to the xml file
STEP-2: Now go to the text and write the code for adding 3 textview,2 textedit and Button and Assign ID to each component. Assign margin top, left, right for the location.
STEP-3: Now, open up the activity java file.
STEP-4: Declare few variables and the values entered in the Text Views can be read by using an id which we have set in the XML code above.
STEP-5: Add the click listener to the Add button.
STEP-6: When the Add button has been clicked, add the values and store it into the sum variable.
STEP-7: To show the output in the result text view, set the sum in the textview.
Complete code of layout xml file and java file is given below.
activity_main.xml
MainActivity.java
<!--The activity_main.xml is a layout file an XML-based layout is a file that defines the different widgets to be used in the UI and the relations between those widgets and their containers. -->    <?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">      <!-- Text view for result view-->    <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" />      <!--take the input first number-->    <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" />    <!-- for message input first number-->    <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" />      <!--view message -->    <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" />      <!-- take input for second number -->      <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" />      <!-- button for run add logic and view result -->      <Button        android:id="@+id/add_button"        android:layout_width="100dp"        android:layout_height="50dp"        android:layout_marginLeft="110dp"        android:layout_marginTop="200dp"        android:text="ADD" />  </RelativeLayout>
// Each new activity has its own layout and Java files, // here we build the logic for adding two number   package org.geeksforgeeks.addtwonumbers;  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 {      // define the global variable      // variable number1, number2 for input input number    // Add_button, result textView      EditText number1;    EditText number2;    Button Add_button;    TextView result;    int ans=0;      @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);          // by ID we can use each component which id is assign in xml file        number1=(EditText) findViewById(R.id.editText_first_no);        number2=(EditText) findViewById(R.id.editText_second_no);        Add_button=(Button) findViewById(R.id.add_button);        result = (TextView) findViewById(R.id.textView_answer);          // Add_button add clicklistener        Add_button.setOnClickListener(new View.OnClickListener() {              public void onClick(View v) {                  // num1 or num2 double type                // get data which is in edittext, convert it to string                // using parse Double convert it to Double type                double num1 = Double.parseDouble(number1.getText().toString());                double num2 = Double.parseDouble(number2.getText().toString());                // add both number and store it to sum                double sum = num1 + num2;                // set it ot result textview                result.setText(Double.toString(sum));            }        });    }}
After Complete layout xml file it will be shown as given below
Output:
Note: Similarly, Android App to subtract, multiply and divide numbers can be made by making minor changes in the Java and XML code.
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