Add double-tap to edit task functionality via custom AlertDialog

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

@@ -0,0 +1,43 @@
+package com.embers.simpleto_do
+
+import android.app.AlertDialog
+import android.app.Dialog
+import android.content.DialogInterface
+import android.os.Bundle
+import android.text.InputType
+import android.util.Log
+import android.widget.EditText
+import androidx.fragment.app.DialogFragment
+import java.lang.IllegalStateException
+
+class EditTaskDialogFragment(private val dismissListener: OnDismissListener) : DialogFragment() {
+    private val TAG: String = this::class.java.name
+
+    interface OnDismissListener {
+        fun onDismiss(text: String, submitted: Boolean)
+    }
+
+    private var text: String = ""
+    private var submitted: Boolean = false
+
+    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+        return activity?.let {
+            val input = EditText(it)
+            input.inputType = InputType.TYPE_CLASS_TEXT
+
+            val builder = AlertDialog.Builder(it)
+            builder.setMessage(R.string.dialog_edit_task)
+                    .setView(input)
+                .setNegativeButton(R.string.dialog_negative) {_, _ ->}
+                .setPositiveButton(R.string.dialog_positive) {_, _ -> text = input.text.toString(); submitted = true}
+
+            builder.create()
+        } ?: throw IllegalStateException("Activity cannot be null")
+    }
+
+    override fun onDismiss(dialog: DialogInterface) {
+        super.onDismiss(dialog)
+
+        dismissListener.onDismiss(text, submitted)
+    }
+}

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

@@ -73,6 +73,24 @@ class MainActivity : AppCompatActivity() {
                 adapter.notifyItemRemoved(position)
                 saveData()
             }
+
+            override fun onDoubleClick(position: Int) {
+                // When double clicked and 'submit' is hit in the dialog, the text entered will be
+                val dismissListener = object : EditTaskDialogFragment.OnDismissListener {
+                    override fun onDismiss(text: String, submitted: Boolean) {
+                        // If the dialog was submitted
+                        if (submitted) {
+                            // Update data, inform adapter, save to file
+                            taskList[position] = text
+                            adapter.notifyItemChanged(position)
+                            saveData()
+                        }
+                    }
+                }
+
+                val editTaskDialog = EditTaskDialogFragment(dismissListener)
+                editTaskDialog.show(supportFragmentManager, "edit_task")
+            }
         }
 
         // Setup RecyclerView

app/src/main/res/values/strings.xml

@@ -2,4 +2,7 @@
     <string name="app_name">Simple To-do</string>
     <string name="button_text">Add</string>
     <string name="textbox_labelfor">Name of new To-do list item</string>
+    <string name="dialog_edit_task">Edit the name of this to-do task</string>
+    <string name="dialog_positive">SUBMIT</string>
+    <string name="dialog_negative">CANCEL</string>
 </resources>