Autocompletion List is added to the Username field.

app/src/main/java/com/training/simpleloginform/MainActivity.java

@@ -2,26 +2,39 @@
 
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
+import android.text.Editable;
+import android.text.TextWatcher;
 import android.view.View;
+import android.widget.ArrayAdapter;
+import android.widget.AutoCompleteTextView;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
 
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
 /**
  * Assignment add validation to edit text fields
- *
+ * <p>
  * if an edit text is empty, show a toast that says "edit text cannot be empty", where edit text can be username or password
- *
  */
-public class MainActivity extends AppCompatActivity implements View.OnClickListener {
+public class MainActivity extends AppCompatActivity implements View.OnClickListener, TextWatcher {
 
-    private EditText usernameEditText;
+    private AutoCompleteTextView usernameEditText;
     private EditText passwordEditText;
     private Button submitButton;
     private TextView usernameDetailsTextView;
     private TextView passwordDetailsTextView;
     private Button resetButton;
 
+    Names names = new Names();
+
+    List<String> namesList = new ArrayList<>();
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -35,10 +48,17 @@ protected void onCreate(Bundle savedInstanceState) {
         submitButton = findViewById(R.id.submit_button);
         resetButton = findViewById(R.id.reset_button);
 
+        namesList.addAll(names.getNames());
+
+            usernameEditText.addTextChangedListener(this);
+            usernameEditText.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, namesList));
+
         submitButton.setOnClickListener(this);
         resetButton.setOnClickListener(this);
+
     }
 
+
     @Override
     public void onClick(View view) {
         switch (view.getId()) {
@@ -48,11 +68,42 @@ public void onClick(View view) {
 
                 usernameDetailsTextView.setText(username);
                 passwordDetailsTextView.setText(password);
+
+                    if(!namesList.contains(username)){
+                        namesList.add(username);
+                    }
+
+
                 break;
             case R.id.reset_button:
-                usernameEditText.setText("");
-                passwordEditText.setText("");
+                setResetButton();
                 break;
         }
     }
+
+    public void setResetButton() {
+        usernameEditText.setText("");
+        passwordEditText.setText("");
+        usernameDetailsTextView.setText("");
+        passwordDetailsTextView.setText("");
+
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+
+        usernameEditText.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, namesList));
+
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+
+
+    }
 }

app/src/main/java/com/training/simpleloginform/Names.java

@@ -0,0 +1,22 @@
+package com.training.simpleloginform;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Names {
+
+    List<String> names = new ArrayList<>();
+
+    public List<String> getNames() {
+
+        names.add("Desmond");
+        names.add("Dean");
+        names.add("Sidd");
+        names.add("Nahi");
+        names.add("Iliana");
+        names.add("Sulekha");
+        names.add("Damian");
+
+        return names;
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -20,12 +20,13 @@
             android:textColor="@android:color/holo_green_dark"
             android:textStyle="bold" />
 
-        <EditText
+        <AutoCompleteTextView
             android:id="@+id/user_name_edit_text"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_marginStart="@dimen/general_margin"
-            android:hint="@string/username_edit_text_hint" />
+            android:hint="@string/username_edit_text_hint"
+            android:completionThreshold="1"/>
 
     </LinearLayout>
 
@@ -55,17 +56,17 @@
 
     <LinearLayout
         android:layout_width="match_parent"
-        android:layout_height="match_parent"
+        android:layout_height="wrap_content"
         android:orientation="horizontal">
 
         <Button
             android:id="@+id/submit_button"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_weight="1"
+            android:layout_marginLeft="@dimen/general_margin"
             android:layout_marginTop="@dimen/general_margin"
             android:layout_marginRight="@dimen/general_margin"
-            android:layout_marginLeft="@dimen/general_margin"
+            android:layout_weight="1"
             android:background="@android:color/holo_green_dark"
             android:text="@string/submit_button_string"
             android:textStyle="bold" />