An Android app that scans a receipt and calculates how much an individual should pay/tip
An Android app (written in Kotlin) that scans a receipt and calculates how much an individual should pay/tip. Let’s imagine for a moment how easy will it be to use this app as opposed to everyone having to calculate its share. The very first advantage is the fact that there will be no mistakes and we must be realistic, more often than not, splitting the bill results in a lot of mistakes. We either forgot to add a product or we even forgot that we have consumed it or virtually we mistype a number when we try to calculate and just with a simple mistake like that, everything goes south. This app makes it everything easy for us, which I believe is just the primary scope of day-to-day technology.
Once the app will have every feature ready, it will be published on Android Store and be available to the public.
We monitorized our backlog creation using Trello. It can be found here.
Basically, the user can either opt for scanning a receipt or create a checklist. If he chose to scan an receipt, he will be asked to chose a photo from the drice or use a photo from the gallery. Either way, the scanner will build a list containing the products (name and price). The user can modify this checklist should it contain any mistakes by adding/deleting a product or clearing the list. These operations can be done by pressing the buttons having the same names. Alongside with the name of the product and the price, the checklist also contains a checkbox which allows the user to select that product. After the checklist is finalised, each buyer will select the products that he consumed by pressing the checkbox of the product. When he finishes, he will press ‘Done’ button and the total sum will appear on the screen. After he finishes, he will press delete and everything that he consumed and paid will be deleted. The next user takes the phone and begin the same process by selecting his products from the remaining ones.
As a following implementation, the developers will add a new column called quantity which will let the individual select how many products of this kind he has consumed. His part will be subtracted from the total after he presses ‘Done’ button. Another idea is to enable split option as a product could have been shared by multiple individual and once paid, it should be subtracted from the total. As a final step, we would like to merge everything and update the app so as to calculate how much should everyone pay and then invites the user to pay his share using a credit card. This thing can be implemented in accordance with restaurant’s personnel. If the bill will come in this form instead of as a receipt on a paper. The consumer will not need to scan the receipt and then calculate. The restaurant’s personnel should bring the bill in this format and the user should select their products and pay them using a credit card. Just like that the weiter’s job gets easier because nobody will ask for a separate bill which is a daunting job when you have a lot of customers. Needless to say, the consumers will be deprived of having to calculate a lot in order to see how much he has to pay and the risk of making a mistake is virtually inexistent.
When the app is installed, the user will see the three pictures which presents the app’s basic features. The app has also a navigation drawer whose purpose is to redirect the user to either the homepage, the Scanner or the Checklist. The homepage invites the user to select one of the app’s functions (Load scanner or Open Checklist).
Installation Pages design - consists of three pictures aiming to present the app’s functionalities.These apeears only the first time the app is installed. Every page has two buttons (Skip and Next) which can be found in activity_slider.xml.
welcome_slider1.xml
- ImageView <br>- TextView - Welcome - <br>- TextView - Ever felt tired of keeping track of the receipt? -
welcome_slider2.xml
welcome_slider3.xml
Welcome Page design - appears every time the app is opened
- ImageView <br>- ProgressBar - <br>
Home Page design -
- ImageView <br>- Twp Buttons (Load Scanner and Open Checklist) - <br>
Navigation drawer
- NavigationView implemented by Android <br>- ImageView <br>- Two TextViews for username and passward <br>
Scanner page
content_main_drawer.xml
- ImageView (here will appear the image) <br>- Twp Buttons (Select image - takes the user to the gallery in order to select an image and Recognise Text - scans the image that was selected) - <br>- EditText (here will appear the text - names and prices of the products-) <br>
Chose an image option
After the image was chosen
Chose an image option
Text recognition function
Transform image into checklist
Checklist - activity_checklist.xml - a relative Layout which contains:
ListView - dynamic list which contains the added items resulted from scanning and/or added through the Checklist
Select an item using the checkbox
Calculating the total sum by pressing Done
Deleting an item by pressing Delete
Adding an item
Item added
Clearing the list by pressing Clear
Branches: https://github.com/AndraRaco/App-Receipt-Scanner/branches
Commits: https://github.com/AndraRaco/App-Receipt-Scanner/commits
Splash
Slider
Code for Next Button
btnNext.setOnClickListener(View.OnClickListener {if (viewPager.getCurrentItem() + 1 < layouts.size) {viewPager.setCurrentItem(viewPager.getCurrentItem() + 1)} else {//go to main activity//launcherManager.setFirstLaunch(false);startActivity(Intent(applicationContext, MainDrawer::class.java))}})
Code for Skip Button
btnSkip.setOnClickListener(View.OnClickListener {startActivity(Intent(applicationContext,MainDrawer::class.java))})
These functions can be found in Slider.kt file.
HomeFragment
elements:
openchecklistpart
code:
openchecklistpart.setOnClickListener {var intent = Intent(view.context,ChecklistActivity::class.java)startActivity(intent)}
openscanpart
code:
openscanpart.setOnClickListener {var intent = Intent(view.context,MainTextRecognizer::class.java)startActivity(intent)}
These functions can be found in GallertActivity.kt file.
GalleryActivity
behaviour: the user selects an image, either from the camera or from the gallery or from a google drive account
override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)//BUTTON CLICKimg_pick_btn.setOnClickListener {//check runtime permissionif (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {//permission deniedval permissions = arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE);//show popup to request runtime permissionrequestPermissions(permissions, PERMISSION_CODE);} else {//permission already grantedpickImageFromGallery();}} else {//system OS is < MarshmallowpickImageFromGallery();}}}
Functions used:
}
//Intent to pick imageval intent = Intent(Intent.ACTION_PICK)intent.type = "image/*"startActivityForResult(intent, IMAGE_PICK_CODE)
- Select an image
override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)//BUTTON CLICKimg_pick_btn.setOnClickListener {//check runtime permissionif (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {//permission deniedval permissions = arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE);//show popup to request runtime permissionrequestPermissions(permissions, PERMISSION_CODE);} else {//permission already grantedpickImageFromGallery();}} else {//system OS is < MarshmallowpickImageFromGallery();}}}
These functions can be found in **GallertActivity.kt** file.- MainTextRecognizer- info: the app activity that scans a given image- type: AppCompatActivity- behaviour: the user selects an image, either from the camera or from the gallery, then, using google's firebase ml ocr algorithms, the image is processed as text and saved as a listFunctions used:- Select an image
fun selectImage(v: View) {
val intent = Intent()
intent.type = “image/*”
intent.action = Intent.ACTION_GET_CONTENT
startActivityForResult(Intent.createChooser(intent, “Select Picture”), 1)
}
- Scanning the text
fun startRecognizing(v: View) {
if (imageView.drawable != null) {
editText.setText(“”)
v.isEnabled = false
val bitmap = (imageView.drawable as BitmapDrawable).bitmap
val image = FirebaseVisionImage.fromBitmap(bitmap)
val detector = FirebaseVision.getInstance().onDeviceTextRecognizer
detector.processImage(image).addOnSuccessListener { firebaseVisionText ->v.isEnabled = trueprocessResultText(firebaseVisionText)var toCheckList: List<String?> // list to send to checklist activitytoCheckList = ArrayList(50)var products: List<Pair<Double, String>> // auxiliary list to make tochecklistproducts = processResultText(firebaseVisionText)for (x in products)toCheckList.add(x.first.toString() + ',' + x.second)// pass the products array to checklist for mergingval Checklist = Intent(this, ChecklistActivity::class.java)Checklist.putExtra("Products", toCheckList)startActivity(Checklist)}.addOnFailureListener {v.isEnabled = trueeditText.setText("Failed")}} else {Toast.makeText(this, "Select an Image First", Toast.LENGTH_LONG).show()}}
Other functions:- Function for Processing the text
private fun processResultText(resultText: FirebaseVisionText): List<Pair<Double, String>> {var products: List<Pair<Double, String>>products = ArrayList(50)if (resultText.textBlocks.size == 0) {editText.setText("No Text Found")return products}for (block in resultText.textBlocks) {val blockText = block.texteditText.append(blockText + "\n")}val tuples = getTuples(editText.text.toString())products = getTuples(editText.text.toString())editText.setText("")for (t in tuples) {editText.append(t.toString() + "\n")}return products}
- Function for extracting the price and name of the products
// returns a list of pairs (price, product_name), given the text of the receipt
fun getTuples(text: String): List
var products = mutableListOf
var produs_crt = 0
var pret_crt = 0
var nume_crt = 0
var started =
false // all the text from the upper part of the receipt is unnecessary and it should be skipped
val lines = text.split(“\n”)
for (line in lines) {
if (“total” == line.toLowerCase(Locale.getDefault())
|| “*” in line.toLowerCase(Locale.getDefault())
) {
break
}
if ("x " in line.toLowerCase(Locale.getDefault())) {val trimmedLine = line.drop(line.toLowerCase(Locale.getDefault()).indexOf("x ") + 2)if (trimmedLine.isEmpty()) {continue}val words = trimmedLine.split(' ')if (words.isNotEmpty()) {if (words[0].toDoubleOrNull() != null) {val nr = words[0].toDouble()if (pret_crt == produs_crt) {products.add(Pair(nr, ""))produs_crt += 1pret_crt += 1} else {products[pret_crt] = Pair(nr, products[pret_crt].second)pret_crt += 1}started = true}}} else if (started&& !line[0].isDigit()&& "discount" !in line.toLowerCase(Locale.getDefault())&& "total" !in line.toLowerCase(Locale.getDefault())&& "lei" != line.toLowerCase(Locale.getDefault())&& "lel" != line.toLowerCase(Locale.getDefault())) { // the text recognizer might confuse i for lif (nume_crt == produs_crt) {products.add(Pair(0.toDouble(), line))produs_crt += 1nume_crt += 1} else {products[nume_crt] = Pair(products[nume_crt].first, line)nume_crt += 1}}}return products}
These functions can be found in **MainTextRecogniser.kt** file.- ChecklistActivity- info: app activity that creates a checklist for easy recipie management- type: AppCompatActivity- behaviour: adds items from userimput as a pair < name, price >, stores them in a list and calculates the total of the selected itemsFunctions used:- Add function which functions by pressing Add button
// Adding the items to the list when the add button is pressed
add.setOnClickListener {
addRow()
}
// Adding a new row to the CheckListfun addRow() {// Create product with name and praceval name = editText.text.toString()val price = et_price.text.toString().toDouble()val p = Product(name, price)// Add product to the list of ProductsitemList.add(p)// Notify the attached observers that the underlying data has been changed and// the listView should refresh itself(listView.adapter as ProductAdapter).notifyDataSetChanged()// After adding the item, the edit texts for name and for price will be clearededitText.text.clear()et_price.text.clear()}
- Clear function which functions by pressing Clear button
// Delete the all rows form the listViewclear.setOnClickListener {clearRows()}
// Delete the all rows form the listViewfun clearRows() {itemList.clear()// Notify the attached observers that the underlying data has been changed and// the listView should refresh itself(listView.adapter as ProductAdapter).notifyDataSetChanged()}
- Delete function which functions by pressing Delete button
// Selecting and Deleting the items from the list when the delete button is presseddelete.setOnClickListener {deleteRow()}
// Delete the selected rows form the listViewfun deleteRow() {val position: SparseBooleanArray =listView.checkedItemPositions // Map with indices of the items from listView// and true/false if the item is checked/ is not checkedval count = listView.count // size of the listViewvar item = count - 1 // index for the list// Removing the selected itemswhile (item >= 0) {if (position.get(item)) {itemList.removeAt(item)}item--}position.clear()// Notify the attached observers that the underlying data has been changed and// the listView should refresh itself(listView.adapter as ProductAdapter).notifyDataSetChanged()}
- Calculate sum function which functions by pressing Done button
// Calculate how much has the person to paycalculate.setOnClickListener {var sum = calculatePriceToPay()// Show a text with the sumandroid.widget.Toast.makeText(this,"You have to pay $sum",android.widget.Toast.LENGTH_SHORT).show()}
// Calculate how much the user has to payfun calculatePriceToPay(): Double {val position: SparseBooleanArray =listView.checkedItemPositions // Map with indices of the items from listView// and true/false if the item is checked/ is not checkedval count = listView.count // Size of the listViewvar pricesOfProducts: ArrayList<Double> = ArrayList<Double>()// Select the products that are checkedvar item = count - 1while (item >= 0) {if (position.get(item)) {pricesOfProducts.add(itemList[item].price)}item--}// Calculate the sum of the selected productsreturn sumAux(pricesOfProducts)}
These functions can be found in **ChecklistActivity.kt** file.## Build toolsOur project is developed using Andorid Studio IDE that has a Gradle-based building tool. When we want to build our project in an APK, so that we can give it to our users to install the application and use it, we go to:and click Build APK. Then, in the folder our project is in, it generates 2 files:One of the file, "app-debug.apk", is the apk that will install our application, the other one, "output.json", is a message that tells us if the apk was generated succesfully or not. We then transfer the APK to our mobile device and run it to install the application.## Testing protocols and their results### Describing the code used for Unit Testing## [Tests demo](https://github.com/AndraRaco/App-Receipt-Scanner/blob/master/Docs/tests_demo.mp4)**1. Test if the product ("mere", 4.5) can be added**
@Test
fun user_add_product_correct() {
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“mere”))
onView(withId(R.id.et_price)).perform(typeText(“4.5”))
var sizeBeforeAdd =rule.activity.getItemListSize() // Size of the Checklist before inserting a new element// Click on add buttononView(withId(R.id.add)).perform(click())var sizeAfterAdd =rule.activity.getItemListSize() // Size of the Checklist after inserting a new element// Check if the product was added, the size after add should be equal with the initial size + oneAssert.assertEquals("The product was not insert in the CheckList",(sizeBeforeAdd + 1).toDouble(), sizeAfterAdd.toDouble(), 0.0)}
**2. Test if the product ("mere", "ciocolata") can be added**
@Test
fun user_add_product_wrong() {
// Product name and price
var nameProduct = “mere”
var priceProduct = “ciocolata”
// Write product information in typeTextsonView(withId(R.id.editText)).perform(typeText(nameProduct))onView(withId(R.id.et_price)).perform(typeText(priceProduct))var ok: Boolean = true // Check whether the input was correct or notif (priceProduct.toDoubleOrNull() == null) // if price is not doubleok = falseif (priceProduct == "" || nameProduct == "") // if price or name is not writtenok = false// Check if the product was added, the size after add should be equal with the initial size + oneAssert.assertTrue("The product was not insert in the CheckList", ok)}
**3. Test if the user can delete product from the CheckList**
@Test
fun user_add_and_delete_product_correct() {
// Add 2 products to the CheckList
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“mere”))
onView(withId(R.id.et_price)).perform(typeText(“4.5”))
// Click on add button
onView(withId(R.id.add)).perform(click())
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“pere”))
onView(withId(R.id.et_price)).perform(typeText(“5.0”))
// Click on add button
onView(withId(R.id.add)).perform(click())
var sizeBeforeDelete =rule.activity.getItemListSize() // Size of the Checklist before deleting an element// Select "mere" from listonView(withText("mere")).perform(click())// Delete selected products from CheckListonView(withId(R.id.delete)).perform(click())var sizeAfterDelete =rule.activity.getItemListSize() // Size of the Checklist after deleting an element// Check if the product was added, the size after add should be equal with the initial size + oneAssert.assertEquals("The product was not deleted from the CheckList",(sizeBeforeDelete - 1).toDouble(), sizeAfterDelete.toDouble(), 0.0)}
**4. Test if the user can clear the CheckLsit**
@Test
fun user_add_and_clear_product_correct() {
// Add 2 products to the CheckList
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“mere”))
onView(withId(R.id.et_price)).perform(typeText(“4.5”))
// Click on add button
onView(withId(R.id.add)).perform(click())
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“pere”))
onView(withId(R.id.et_price)).perform(typeText(“5.0”))
// Click on add button
onView(withId(R.id.add)).perform(click())
// Click on clear buttononView(withId(R.id.clear)).perform(click())var sizeAfterClear =rule.activity.getItemListSize() // Size of the Checklist after deleting an element// Check if the product was added, the size after add should be equal with the initial size + oneAssert.assertEquals("The product was not deleted from the CheckList",0.0, sizeAfterClear.toDouble(), 0.0)}
**5. Test if the sum of the selected items is calculated correctly**
@Test
fun user_calculate_correct() {
// Add 2 products to the CheckList
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“mere”))
onView(withId(R.id.et_price)).perform(typeText(“4.5”))
// Click on add button
onView(withId(R.id.add)).perform(click())
// Write product information in typeTexts
onView(withId(R.id.editText)).perform(typeText(“pere”))
onView(withId(R.id.et_price)).perform(typeText(“5.0”))
// Click on add button
onView(withId(R.id.add)).perform(click())
// Select "mere" from listonView(withText("mere")).perform(click())// Select "pere" from listonView(withText("pere")).perform(click())var correctSum: Double = 4.5 + 5.0// How much has the user to pay for selected itemsvar sum = rule.activity.calculatePriceToPay()// Check if the product was added, the size after add should be equal with the initial size + oneAssert.assertEquals("The sum is wrong",correctSum, sum, 0.0)}
```
Unit Testing Results:
