diff --git a/.idea/.name b/.idea/.name
new file mode 100644
index 0000000..d51122f
--- /dev/null
+++ b/.idea/.name
@@ -0,0 +1 @@
+AndroidFundamentalsMai2021
\ No newline at end of file
diff --git a/app/src/main/java/com/magdamiu/androidfundamentalsmai2021/MainActivity.java b/app/src/main/java/com/magdamiu/androidfundamentalsmai2021/MainActivity.java
index ab7184b..7c6f37e 100644
--- a/app/src/main/java/com/magdamiu/androidfundamentalsmai2021/MainActivity.java
+++ b/app/src/main/java/com/magdamiu/androidfundamentalsmai2021/MainActivity.java
@@ -3,7 +3,9 @@
 import androidx.appcompat.app.AppCompatActivity;
 
 import android.os.Bundle;
+import android.text.TextUtils;
 import android.util.Log;
+import android.util.Patterns;
 import android.view.View;
 import android.webkit.WebView;
 import android.widget.AdapterView;
@@ -21,6 +23,8 @@ public class MainActivity extends AppCompatActivity {
     private static final String ANDROID_URL = "https://developer.android.com/";
 
     private EditText editTextName;
+    private EditText editTextEmail;
+    private EditText editTextPhone;
     private Button buttonDisplayGreetings;
     private TextView textViewGreetings;
 
@@ -33,20 +37,22 @@ public class MainActivity extends AppCompatActivity {
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        /*setContentView(R.layout.activity_main);*/
-        /*setContentView(R.layout.sample);*/
-        // setContentView(R.layout.scrollview_sample);
-        // setContentView(R.layout.webview_sample);
+        /* setContentView(R.layout.activity_main);
+        setContentView(R.layout.sample);
+        setContentView(R.layout.code_challenge_c2);
+        setContentView(R.layout.scrollview_sample);
+        setContentView(R.layout.webview_sample);
         setContentView(R.layout.spinner_sample);
+        setContentView(R.layout.code_challenge2_c3); */
+        setContentView(R.layout.code_challenge1_c3);
 
-        setAndroidVersions();
+        /* setAndroidVersions();
         initialiseSpinnerAdapter();
         setSpinnerAdapter();
-        handlingSpinnerListener();
+        handlingSpinnerListener(); */
 
-        //loadUrl();
-
-        // initViews();
+        // loadUrl();
+        initViews();
         displayLogs();
     }
 
@@ -60,6 +66,7 @@ private void setAndroidVersions() {
         androidVersions.add("kitkat");
     }
 
+
     // step 2: initialise adapter for our spinner
     // ArrayAdapter is a default adapter
     private void initialiseSpinnerAdapter() {
@@ -89,6 +96,7 @@ public void onNothingSelected(AdapterView<?> adapterView) {
         });
     }
 
+
     // webview load url
     private void loadUrl() {
         webView = findViewById(R.id.webViewSample);
@@ -96,11 +104,14 @@ private void loadUrl() {
         webView.loadUrl(ANDROID_URL);
     }
 
+
     // init views for implementing a first simple form
     private void initViews() {
         editTextName = findViewById(R.id.editTextName);
         buttonDisplayGreetings = findViewById(R.id.buttonDisplayGreetings);
         textViewGreetings = findViewById(R.id.textViewGreetings);
+        editTextEmail = findViewById(R.id.editTextEmail);
+        editTextPhone = findViewById(R.id.editTextPhone);
     }
 
     private void displayLogs() {
@@ -128,4 +139,28 @@ public void displayGreetingsOnClick(View view) {
             Toast.makeText(MainActivity.this, getString(R.string.error_insert_name), Toast.LENGTH_LONG).show();
         }
     }
+
+    // Course 3: Code Challenge 1
+    public static boolean isValidEmail(CharSequence target) {
+        return (!TextUtils.isEmpty(target) && Patterns.EMAIL_ADDRESS.matcher(target).matches());
+    }
+
+    public static boolean isValidPhone(CharSequence phone) {
+        return (!TextUtils.isEmpty(phone) && Patterns.PHONE.matcher(phone).matches());
+    }
+
+    public void displaySubmitOnClick(View view) {
+        String inputName = editTextEmail.getText().toString();
+        if (!isValidEmail(inputName)) {
+            editTextEmail.setError(getString(R.string.error_insert_email));
+            Toast.makeText(MainActivity.this, getString(R.string.error_insert_email),
+                    Toast.LENGTH_LONG).show();
+        }
+        inputName = editTextPhone.getText().toString();
+        if (!isValidPhone(inputName)) {
+            editTextPhone.setError(getString(R.string.error_insert_phone));
+            Toast.makeText(MainActivity.this, getString(R.string.error_insert_phone),
+                    Toast.LENGTH_LONG).show();
+        }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/res/drawable/paint.png b/app/src/main/res/drawable/paint.png
new file mode 100644
index 0000000..a6a6092
Binary files /dev/null and b/app/src/main/res/drawable/paint.png differ
diff --git a/app/src/main/res/layout/code_challenge1_c3.xml b/app/src/main/res/layout/code_challenge1_c3.xml
new file mode 100644
index 0000000..5d1cdab
--- /dev/null
+++ b/app/src/main/res/layout/code_challenge1_c3.xml
@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="@dimen/dp_16">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:background="@color/white"
+        android:text="@string/login"
+        android:textColor="@color/orange_FC987E"
+        android:textSize="@dimen/sp_32"
+        android:textStyle="bold" />
+
+    <EditText
+        android:id="@+id/editTextEmail"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:autofillHints="@string/email"
+        android:hint="@string/email"
+        android:inputType="textEmailAddress" />
+
+    <EditText
+        android:id="@+id/editTextPhone"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:autofillHints="@string/phone"
+        android:hint="@string/phone"
+        android:inputType="phone" />
+
+    <CheckBox
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:checked="false"
+        android:text="@string/i_accept_t_amp_c" />
+
+    <Button
+        android:id="@+id/buttonSubmit"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:onClick="displaySubmitOnClick"
+        android:text="@string/submit"
+        android:textColor="@color/white" />
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/code_challenge2_c3.xml b/app/src/main/res/layout/code_challenge2_c3.xml
new file mode 100644
index 0000000..042d336
--- /dev/null
+++ b/app/src/main/res/layout/code_challenge2_c3.xml
@@ -0,0 +1,115 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:fillViewport="true">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:padding="@dimen/medium_space">
+
+        <RelativeLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content">
+
+            <View
+                android:layout_width="@dimen/dp_64"
+                android:layout_height="@dimen/dp_64"
+                android:layout_alignParentStart="true"
+                android:background="@color/purple_200" />
+
+            <View
+                android:layout_width="@dimen/dp_64"
+                android:layout_height="@dimen/dp_64"
+                android:layout_alignParentEnd="true"
+                android:background="@color/teal_700" />
+
+            <View
+                android:id="@+id/viewCentre"
+                android:layout_width="@dimen/dp_64"
+                android:layout_height="@dimen/dp_64"
+                android:layout_centerHorizontal="true"
+                android:background="@color/green_A2C89C" />
+
+            <View
+                android:layout_width="@dimen/dp_64"
+                android:layout_height="@dimen/dp_64"
+                android:layout_toEndOf="@id/viewCentre"
+                android:background="@color/orange_FC987E" />
+
+        </RelativeLayout>
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_space"
+            android:text="@string/scroll_view_text" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_space"
+            android:text="@string/scroll_view_text" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_space"
+            android:text="@string/scroll_view_text" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_space"
+            android:text="@string/scroll_view_text" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_space"
+            android:text="@string/scroll_view_text" />
+
+        <FrameLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/dp_64"
+            android:layout_marginBottom="@dimen/dp_64">
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="@dimen/dp_128"
+                android:layout_gravity="center"
+                android:layout_marginStart="@dimen/dp_8"
+                android:layout_marginEnd="@dimen/dp_8"
+                android:background="@color/purple_9B2FAE" />
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="@dimen/dp_64"
+                android:layout_gravity="center"
+                android:layout_marginStart="@dimen/dp_16"
+                android:layout_marginEnd="@dimen/dp_16"
+                android:background="@color/teal_7CCBC5" />
+
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="@dimen/dp_32"
+                android:layout_gravity="center"
+                android:layout_marginStart="@dimen/dp_24"
+                android:layout_marginEnd="@dimen/dp_24"
+                android:background="@color/yellow_FBC962" />
+
+        </FrameLayout>
+
+        <Spinner
+            android:id="@+id/spinnerAndroidVersions"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/dp_64"
+            android:layout_marginBottom="@dimen/dp_64" />
+
+    </LinearLayout>
+
+</ScrollView>
\ No newline at end of file
diff --git a/app/src/main/res/layout/code_challenge_c2.xml b/app/src/main/res/layout/code_challenge_c2.xml
new file mode 100644
index 0000000..4463d56
--- /dev/null
+++ b/app/src/main/res/layout/code_challenge_c2.xml
@@ -0,0 +1,168 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/dp_150">
+
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:background="@color/orange_FC987E"
+            android:gravity="center"
+            android:padding="@dimen/dp_17"
+            android:text="@string/this_is_an_orange_textview"
+            android:textAlignment="center"
+            android:textColor="@color/white" />
+
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:background="@color/green_CDEDD7"
+            android:gravity="center"
+            android:text="@string/this_is_a_green_textview"
+            android:textAlignment="center"
+            android:textColor="@color/black" />
+
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:background="@color/blue_7BCCC6"
+            android:gravity="center"
+            android:text="@string/this_is_a_blue_textview"
+            android:textAlignment="center"
+            android:textColor="@color/white" />
+    </LinearLayout>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/dp_150">
+
+        <Button
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_margin="@dimen/dp_5"
+            android:layout_weight="1"
+            android:backgroundTint="@color/blue_7BCCC6"
+            android:text="@string/this_is_a_button"
+            android:textColor="@color/black" />
+
+        <ImageView
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_weight="1"
+            android:scaleType="fitCenter"
+            android:contentDescription="@string/paint_image"
+            android:src="@drawable/paint" />
+
+        <Button
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:layout_margin="@dimen/dp_5"
+            android:layout_weight="1"
+            android:backgroundTint="@color/green_A2C89C"
+            android:gravity="center"
+            android:text="@string/this_is_a_green_button"
+            android:textColor="@color/black" />
+    </LinearLayout>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/dp_120"
+        android:background="@color/yellow_FBC962"
+        android:orientation="vertical"
+        android:paddingTop="@dimen/dp_20"
+        android:paddingBottom="@dimen/dp_20">
+
+        <EditText
+            android:layout_width="match_parent"
+            android:layout_height="@dimen/dp_0"
+            android:layout_weight="1"
+            android:autofillHints="@string/edit_this"
+            android:hint="@string/this_is_an_edittext"
+            android:inputType="textCapWords"
+            android:textColor="@color/purple_700" />
+
+        <EditText
+            android:layout_width="match_parent"
+            android:layout_height="@dimen/dp_0"
+            android:layout_weight="1"
+            android:autofillHints="@string/edit_this"
+            android:hint="@string/this_is_a_new_edittext"
+            android:inputType="textCapWords"
+            android:textColor="@color/purple_700" />
+
+    </LinearLayout>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/blue_7BCCC6"
+        android:orientation="vertical">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="@dimen/dp_50">
+
+            <CheckBox
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_marginStart="@dimen/dp_10"
+                android:layout_weight="1"
+                android:checked="false"
+                android:text="@string/notify_me"
+                android:textSize="@dimen/sp_20" />
+
+            <androidx.appcompat.widget.SwitchCompat
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_weight="1"
+                android:text="@string/auto_backup"
+                android:textSize="@dimen/sp_16" />
+        </LinearLayout>
+
+        <View
+            android:layout_width="match_parent"
+            android:layout_height="@dimen/dp_2"
+            android:background="@color/purple_200" />
+
+        <RatingBar
+            style="@style/Widget.AppCompat.RatingBar.Small"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/dp_15"
+            android:layout_marginBottom="@dimen/dp_15"
+            android:isIndicator="false"
+            android:numStars="5"
+            android:progressTint="@color/pink_FC4481"
+            android:rating="4" />
+
+        <View
+            android:layout_width="match_parent"
+            android:layout_height="@dimen/dp_2"
+            android:background="@color/purple_200" />
+
+        <RadioGroup
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content">
+
+            <RadioButton
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/yes" />
+
+            <RadioButton
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/no" />
+        </RadioGroup>
+
+    </LinearLayout>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index d8ce349..1c3127d 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -8,4 +8,12 @@
     <color name="black">#FF000000</color>
     <color name="white">#FFFFFFFF</color>
     <color name="red">#ff3412</color>
+    <color name="orange_FC987E">#FC987E</color>
+    <color name="green_CDEDD7">#CDEDD7</color>
+    <color name="blue_7BCCC6">#7BCCC6</color>
+    <color name="green_A2C89C">#A2C89C</color>
+    <color name="yellow_FBC962">#FBC962</color>
+    <color name="pink_FC4481">#FC4481</color>
+    <color name="purple_9B2FAE">#9B2FAE</color>
+    <color name="teal_7CCBC5">#7CCBC5</color>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/dimens.xml b/app/src/main/res/values/dimens.xml
index e8b2c28..7e0a65a 100644
--- a/app/src/main/res/values/dimens.xml
+++ b/app/src/main/res/values/dimens.xml
@@ -2,6 +2,25 @@
 <resources>
     <dimen name="medium_text">23sp</dimen>
     <dimen name="medium_space">16dp</dimen>
+    <dimen name="dp_5">5dp</dimen>
+    <dimen name="dp_150">150dp</dimen>
+    <dimen name="dp_17">17dp</dimen>
+    <dimen name="dp_120">120dp</dimen>
+    <dimen name="dp_0">0dp</dimen>
+    <dimen name="dp_50">50dp</dimen>
+    <dimen name="dp_10">10dp</dimen>
+    <dimen name="sp_20">20sp</dimen>
+    <dimen name="sp_16">16sp</dimen>
+    <dimen name="dp_2">2dp</dimen>
+    <dimen name="dp_15">15dp</dimen>
+    <dimen name="dp_20">20dp</dimen>
+    <dimen name="dp_128">128dp</dimen>
+    <dimen name="dp_64">64dp</dimen>
+    <dimen name="dp_8">8dp</dimen>
+    <dimen name="dp_16">16dp</dimen>
+    <dimen name="dp_24">24dp</dimen>
+    <dimen name="dp_32">32dp</dimen>
+    <dimen name="sp_32">32sp</dimen>
     <dimen name="space_128">128dp</dimen>
     <dimen name="space_64">64dp</dimen>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 0f8b9c3..df1a6be 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -12,6 +12,26 @@
     <string name="please_add_your_name_here">Please add your name here</string>
     <string name="greetings">Greetings :)</string>
     <string name="error_insert_name">Please insert a name</string>
+    <string name="error_insert_email">Fill the input with a valid email address</string>
+    <string name="error_insert_phone">Fill the input with a valid phone number</string>
+    <string name="this_is_an_orange_textview">This is an orange TextView</string>
+    <string name="this_is_a_green_textview">This is a green TextView</string>
+    <string name="this_is_a_blue_textview">This is a blue TextView</string>
+    <string name="this_is_a_button">this is a button</string>
+    <string name="this_is_an_edittext">This is an EditText</string>
+    <string name="this_is_a_new_edittext">This is a new EditText</string>
+    <string name="notify_me">Notify me :)</string>
+    <string name="auto_backup">Auto backup</string>
+    <string name="this_is_a_green_button">This is a green button</string>
+    <string name="edit_this">edit this...</string>
+    <string name="paint_image">paint image</string>
+    <string name="text_on_the_left">text on the left</string>
+    <string name="scroll_view_text">ScrollView: A view group that allows the view hierarchy placed within it to be scrolled. Scroll view may have only one direct child placed within it. To add multiple views within the scroll view, make the direct child you add a view group, for example LinearLayout, and place additional views within that LinearLayout.</string>
+    <string name="login">LOGIN</string>
+    <string name="email">Email</string>
+    <string name="phone">Phone</string>
+    <string name="i_accept_t_amp_c"><![CDATA[I accept T&C]]></string>
+    <string name="submit">SUBMIT</string>
     <string name="textview_3">TextView 3</string>
     <string name="textview_2">TextView 2</string>
     <string name="textview_1">TextView 1</string>