To-do Creation Functionality

- Also made the button disable itself until text is entered.

app/src/main/java/com/embers/simpleto_do/MainActivity.kt

@@ -1,24 +1,53 @@
 package com.embers.simpleto_do
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.view.KeyEvent
+import android.view.View
 import android.widget.Button
+import android.widget.EditText
+import androidx.appcompat.app.AppCompatActivity
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 
 class MainActivity : AppCompatActivity() {
-    val taskList = mutableListOf<String>()
+    private val taskList = mutableListOf<String>()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
-        findViewById<Button>(R.id.button).setOnClickListener {
-        }
+        // Button is by default disabled (no text in textbox)
+        val button = findViewById<Button>(R.id.button)
+        button.isEnabled = false
 
+        // Setup RecyclerView
+        val editText = findViewById<EditText>(R.id.editTodoText)
         val recyclerView = findViewById<RecyclerView>(R.id.recyclerView)
         val adapter = TaskItemAdapter(taskList)
         recyclerView.adapter = adapter
         recyclerView.layoutManager = LinearLayoutManager(this)
+
+        // Disable add task button when text is not inside EditText
+        findViewById<EditText>(R.id.editTodoText).setOnKeyListener(View.OnKeyListener { v, keyCode, event ->
+            // Read only event after the action has been processed in the textbox
+            if (event.action == KeyEvent.ACTION_UP)
+                button.isEnabled = editText.text.isNotBlank()
+
+            false
+        })
+
+        findViewById<Button>(R.id.button).setOnClickListener {
+            // Check that the task name has text in it
+            if (editText.text.isBlank()) return@setOnClickListener
+
+            // Add task name to task list
+            taskList.add(editText.text.toString())
+
+            // Clear text box
+            editText.text.clear()
+
+            // Notify the adapter that data has changed
+            adapter.notifyItemInserted(taskList.size - 1)
+        }
     }
 }