How to Build Binary to Decimal Converter Android App in Android Studio?

Last Updated : 09 May, 2021

This app will convert a Binary Number into a Decimal Number. Some people may also have written a java program to convert a Binary Number into a Decimal Number, but while making an app let’s see how to do that.

Brief Go Through

We will start by creating a new project with an Empty Activity. After creating a project, we would add the drawable resource file which will be used to give a box-type shape or outline to the EditText. Then we would work with the XML file where we would be adding two Edit Texts, buttons, and TextViews. In the final, we will go to the MainActivity.java and create some functions which will work when the user will click on the buttons. Note that we are going to implement the application using Java language. A sample gif is given below to get an idea of what we are going to implement in this article.

Step by Step Implementation

Step 1: Create a New Project with an Empty Activity

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Java as the programming language.

Step 2: Adding a drawable resource file

Navigate to app/res/drawable and right-click on the drawable folder and go to New/Drawable Resource File.

Name the file as “edit_text_border” (you can name anything according to your wish but note that the letters should not be in the capital) and with the default settings, click on the ok button.

Step 3: Working with the drawable resource file

In the XML file of the drawable resource “edit_text_border.xml”, we will define the shape as a rectangle first. Then add a stroke to the shape which will make an outline around the shape. Under the same attribute, we will specify the width and color of the stroke. Finally, we will give a round shape in the corners by specifying the radius of the corners. Refer to the XML code below to understand the above lines:

XML

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle"> 
  
    <stroke
        android:width="2dp"
        android:color="@color/gfg_official"/> 
  
    <corners
        android:radius="20dp"/> 
  
</shape>

Step 4: Working with the activity_main.xml file

Navigate to the app/res/layout/activity_main.xml and add the below code to that file. In the activity_main.xml file, we have to add two EditText for Input and Output text to display, two buttons for submit which will submit the input and clear to reset it and I have added two TextView to show some text so that we can guide the user about how to use this app. Below is the code for the activity_main.xml file.

XML

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"> 
  
    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="200dp"
        android:layout_marginRight="8dp"
        android:background="@drawable/edit_text_border"
        android:digits="01"
        android:hint="Enter a Binary Number"
        android:inputType="numberDecimal"
        android:padding="10dp"
        android:textAlignment="center"
        android:textSize="20sp" /> 
  
    <Button
        android:id="@+id/submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/editText"
        android:layout_centerHorizontal="true"
        android:layout_margin="8dp"
        android:text="Submit"
        android:textAllCaps="false" /> 
  
    <EditText
        android:id="@+id/output"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/submit"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="40dp"
        android:layout_marginRight="8dp"
        android:background="@drawable/edit_text_border"
        android:hint="Answer will appear here"
        android:padding="10dp"
        android:textAlignment="center"
        android:textSize="20sp" /> 
  
    <Button
        android:id="@+id/reset"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/output"
        android:layout_centerHorizontal="true"
        android:layout_margin="8dp"
        android:text="Reset"
        android:textAllCaps="false" /> 
  
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/reset"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="50dp"
        android:text="⚫ Click on Submit Button after entering a Binary Number"
        android:textSize="15dp" /> 
  
    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/textView"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="10dp"
        android:text="⚫ Click on Reset Button to reset"
        android:textSize="15dp" /> 
  
</RelativeLayout>

After writing the code of the XML file for the app, the design will look something like this:

Step 5: Working with the ActivityMain.java file

Go to the MainActivity.java file and refer to the following code. Comments are added inside the code to understand the code in more detail.

Java

import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
  
import androidx.appcompat.app.AppCompatActivity; 
  
public class MainActivity extends AppCompatActivity { 
  
    @Override
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
  
        // Giving name to the variables for two EditTexts and two Buttons 
        // input is where the user will input the decimal number 
        // output is where the user will get the output in the form of binary number 
        // submit is the button created to submit the decimal number entered by the user 
        // clear is the button to clear the answer 
        EditText input, output; 
        Button submit, reset; 
  
        // Calling the EditText by id which we gave in xml file 
        input = (EditText) findViewById(R.id.editText); 
        output = (EditText) findViewById(R.id.output); 
  
        submit = (Button) findViewById(R.id.submit); 
  
        // It is set so that when the user clicks on submit button, the data 
        // gets send in the function created below which will convert it and then 
        // show the answer to the user in the output 
        submit.setOnClickListener(new View.OnClickListener() { 
            @Override
            public void onClick(View v) { 
  
                // Creating a string method argument 
                String string = input.getText().toString(); 
  
                // Here, we are parsing a string method  
                // argument into an integer object 
                int i = Integer.parseInt(string, 2); 
  
                // Converts and stores it in the form of string 
                String decimal = Integer.toString(i); 
  
                // It will show the output in the second edit text that we created 
                output.setText(decimal); 
            } 
        }); 
  
        // Here, we will define a function which will 
        // clear the whole text and reset it 
        reset = (Button) findViewById(R.id.reset); 
        reset.setOnClickListener(new View.OnClickListener() { 
            @Override
            public void onClick(View v) { 
                input.setText(""); 
                output.setText(""); 
            } 
        }); 
  
    } 
}