Documentation of the Codebase

app/src/main/java/com/vob/scanit/PDFProcessing.kt

@@ -17,24 +17,24 @@ import java.io.*
 import java.util.*
 import kotlin.collections.ArrayList
 
+/* The following class enables us to generate, compress and save PDF documents*/
 public class PDFProcessing(context: Context) {
 
     lateinit var pdfDocument: PdfDocument
     val context = context
 
-
+    /*makePDF() is used to create a new PDF document, start a page, write content to it and save the document*/
     public fun makePDF(bitmap: Bitmap, filename: String) {
-        pdfDocument = PdfDocument()
-
+        pdfDocument = PdfDocument()  //create a new PDF document
 
         val compressedBitmap = compressBitmap(bitmap)
         val pageInfo: PdfDocument.PageInfo = PdfDocument.PageInfo.Builder(compressedBitmap.width, compressedBitmap.height, 1).create()
-        val page: PdfDocument.Page = pdfDocument.startPage(pageInfo)
+        val page: PdfDocument.Page = pdfDocument.startPage(pageInfo) //start a page
         val canvas: Canvas = page.getCanvas()
         val paint = Paint()
         paint.setColor(Color.parseColor("#FFFFFF"))
         canvas.drawBitmap(compressedBitmap, 0.0f, 0.0f, null)
-        pdfDocument.finishPage(page)
+        pdfDocument.finishPage(page)  //finish the page
         //if (fileName.getText().toString().isEmpty()) {
         //    Toast.makeText(context, "You need to enter file name as follow\nyour_fileName.pdf", Toast.LENGTH_SHORT).show()
         //}
@@ -44,13 +44,14 @@ public class PDFProcessing(context: Context) {
             saveFileToScopedStorage(filename)
         }
 
-        else
+        else  //if filename does not have .pdf extension, we append it with the extension before calling save method
         {
             //saveFile("$filename.pdf")
             saveFileToScopedStorage("$filename.pdf")
         }
     }
 
+    /*The following function compresses the document to a standard size*/
     private fun compressBitmap(bitmap: Bitmap): Bitmap {
         val originalHeight = bitmap.height
         val originalWidth = bitmap.width
@@ -73,14 +74,13 @@ public class PDFProcessing(context: Context) {
         return compressedBitmap
     }
 
-
+    /* saveFile() writes the PDF document to the output stream */
     fun saveFile(filename: String) {
         if (pdfDocument == null) {
             return
         }
         val root = File(Environment.getExternalStorageDirectory().absolutePath, "Scanner")
 
-
         var isDirectoryCreated: Boolean = root.exists()
         if (!isDirectoryCreated) {
             isDirectoryCreated = root.mkdir()
@@ -104,6 +104,8 @@ public class PDFProcessing(context: Context) {
         return true
     }
 
+    /* The following function saves the PDF file. It uses the ContentValues class to store a
+    *  set of values that the ContentResolver can process. The put() method adds a value to the set */
 //    fun queryScopedStorage() : ArrayList<PdfDocument> {
 //        val projection = arrayOf(
 //                MediaStore.MediaColumns.DISPLAY_NAME,

app/src/main/java/com/vob/scanit/ThemeConfig.kt

@@ -4,6 +4,9 @@ import android.content.Context
 import android.content.res.Configuration
 import androidx.appcompat.app.AppCompatDelegate
 
+/*This kotlin file defines the themes for the app, which allows the user to toggle between system theme,
+* light theme and dark theme*/
+
 fun currentSystemTheme(context: Context):Int{
     return when(context.resources.configuration.uiMode.and(Configuration.UI_MODE_NIGHT_MASK)){
         Configuration.UI_MODE_NIGHT_NO -> 1

app/src/main/java/com/vob/scanit/adapters/DocumentListAdapter.kt

@@ -8,28 +8,38 @@ import androidx.recyclerview.widget.RecyclerView
 import com.vob.scanit.R
 import java.io.File
 
+/* DocumentListAdapter class extends RecyclerView.Adapter, and overrides the methods needed for the
+*  Adapter to work. */
 class DocumentListAdapter(private val documentList: ArrayList<File>):
 RecyclerView.Adapter<DocumentListAdapter.DocumentViewHolder>()
 {
+    /* DocumentViewHolder class extends RecyclerView.ViewHolder. It is used to represent the items in
+       our list and display them. */
     class DocumentViewHolder(var view: View): RecyclerView.ViewHolder(view) {}
 
+    /* The following method updates the list of documents and informs the listener*/
     fun updateDocumentList(newDocumentList: List<File>) {
         documentList.clear()
         documentList.addAll(newDocumentList)
         notifyDataSetChanged()
     }
 
+    /*The following method is called when the Adapter is created and is used to initialise the ViewHolder.
+    * LayoutInflater class is used to convert the xml file(adapter_pdf) to a view*/
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DocumentViewHolder {
         val inflater = LayoutInflater.from(parent.context)
         val view = inflater.inflate(R.layout.adapter_pdf, parent, false)
         return DocumentViewHolder(view)
     }
 
+    /* The function onBindViewHolder() is called for each ViewHolder and is used to bind it to the Adapter.
+    *  We pass the data to our ViewHolder using this function*/
     override fun onBindViewHolder(holder: DocumentViewHolder, position: Int) {
         val filename = holder.view.findViewById<TextView>(R.id.filename_TV)
         filename.text = documentList.get(position).name
     }
 
+    /* getItemCount() method returns the number of items in the list that we want to display */
     override fun getItemCount(): Int {
         return documentList.size
     }

app/src/main/java/com/vob/scanit/adapters/PDFAdapter.java

@@ -31,6 +31,7 @@
 import java.util.Locale;
 import java.util.logging.Handler;
 
+/* PDFAdapter class extends ArrayAdapter, specifying the type of data the adapter must display*/
 public class PDFAdapter extends ArrayAdapter<File> {
 
     Context context;
@@ -40,6 +41,8 @@ public class PDFAdapter extends ArrayAdapter<File> {
     private ImageView options_btn;
     Activity activity;
 
+    /*Defining a constructor that takes in arguments used to initialise the class variables
+    * This is required for inflating and adding data to our view */
     public PDFAdapter(Context context, ArrayList<File> fileList, Activity activity) {
         super(context, R.layout.adapter_pdf, fileList);
         this.context = context;
@@ -48,11 +51,13 @@ public PDFAdapter(Context context, ArrayList<File> fileList, Activity activity)
         this.searchList.addAll(this.fileList);
     }
 
+    /*The following method returns the view type of the item at position*/
     @Override
     public int getItemViewType(int position) {
         return position;
     }
 
+    /*The following method returns the number of different types of views*/
     @Override
     public int getViewTypeCount() {
         if (fileList.size() > 0)
@@ -61,6 +66,8 @@ public int getViewTypeCount() {
             return 1;
     }
 
+    /* We override the method getView() that is called when the items are created and populated with data
+    *  In this method, the view gets inflated if the view is new (check for null) */
     @NonNull
     @Override
     public View getView(int position, @Nullable View view, @NonNull ViewGroup parent) {
@@ -90,6 +97,11 @@ public void onClick(View v) {
         return view;
     }
 
+    /* In the following method, we find the file searched for by the user.
+       We convert the text we receive into the lowercase characters of the language in the region
+       where the app is being used(using Locale.getDefault()).
+       Using notifyDataSetChanged(), we can notify the listeners attached to our adapter about the
+       changes in the underlying data, so that any view reflecting this data can be refreshed accordingly*/
     public void filter(String characterText) {
         characterText = characterText.toLowerCase(Locale.getDefault());
         fileList.clear();
@@ -110,6 +122,7 @@ public void filter(String characterText) {
         notifyDataSetChanged();
     }
 
+    /* We define a ViewHolder class to be used with our Adapter */
     public class ViewHolder
     {
         TextView filename;

app/src/main/java/com/vob/scanit/adapters/PdfAdapterRv.kt

@@ -15,24 +15,31 @@ import java.io.File
 import java.util.*
 import kotlin.collections.ArrayList
 
+/* PdfAdapterRv class extends RecyclerView.Adapter and takes in arguments and a listener,
+   along with overriding the methods needed for the Adapter to work. */
+
 class PdfAdapterRv(private val context: Context, private val activity: Activity,
                    private val fileList: ArrayList<File>,private val pdfInterface: PdfAdapterInterface) :
         RecyclerView.Adapter<PdfAdapterRv.PdfAdapterViewHolder>(){
 
     private val searchList: ArrayList<File> = ArrayList()
 
+    /* PdfAdapterViewHolder contains all the elements that gets displayed in the recycler view */
     inner class PdfAdapterViewHolder(itemView: View):RecyclerView.ViewHolder(itemView){
 
         val fileName: TextView = itemView.findViewById(R.id.filename_TV)
         val optionsBtn: ImageView = itemView.findViewById(R.id.options_btn)
 
     }
 
+    /* Informs the activity when the item gets clicked  */
     interface PdfAdapterInterface{
         fun onItemClicked(position: Int)
         fun onItemLongClicked(position: Int)
     }
 
+    /*onCreateViewHolder() is called when the Adapter is created and returns an instance of the
+      PdfAdapterViewHolder. In this function, we handle the onClick event by displaying a toast message*/
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PdfAdapterViewHolder {
         val viewHolder = PdfAdapterViewHolder(
                 LayoutInflater.from(context).inflate(R.layout.adapter_pdf, parent, false))
@@ -44,22 +51,29 @@ class PdfAdapterRv(private val context: Context, private val activity: Activity,
         return viewHolder
     }
 
+    /*onBindViewHolder() is called for each ViewHolder and used to define the actions on it */
     override fun onBindViewHolder(holder: PdfAdapterViewHolder, position: Int) {
         holder.fileName.text = fileList[position].name
 
-        holder.itemView.setOnClickListener{
+        holder.itemView.setOnClickListener {
             pdfInterface.onItemClicked(position)
         }
-        holder.itemView.setOnLongClickListener{
+        holder.itemView.setOnLongClickListener {
             pdfInterface.onItemLongClicked(position)
             true
         }
     }
 
+    /* getItemCount() method returns the number of items in the list that we want to display */
     override fun getItemCount(): Int {
         return fileList.size
     }
 
+    /* In the following method, we find the file searched for by the user.
+       We convert the text we receive into the lowercase characters of the language in the region
+       where the app is being used (using Locale.getDefault()).
+       Using notifyDataSetChanged(), we can notify the listener attached to our adapter about the
+       changes in the underlying data, so that any view reflecting this data can be refreshed accordingly */
     fun filter(characterText: String) {
         var characterText = characterText
         characterText = characterText.toLowerCase(Locale.getDefault())

app/src/main/java/com/vob/scanit/model/Documents.kt

@@ -3,6 +3,7 @@ package com.vob.scanit.model
 import android.net.Uri
 import java.util.*
 
+/* We define a data class and specify the arguments to be passed into its constructor */
 data class Documents(
         val id: Long,
         val displayName: String,