Button addWord appears and disappears as expected

app/src/main/AndroidManifest.xml

@@ -15,7 +15,9 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".ui.MainActivity" />
+        <activity
+            android:name=".ui.MainActivity"
+            android:windowSoftInputMode="adjustResize"/>
         <activity android:name=".ui.LogInActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

app/src/main/java/com/paktalin/vocabularynotebook/ui/NewWordFragment.kt

@@ -8,6 +8,7 @@ import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.ImageButton
 import com.paktalin.vocabularynotebook.R
 import kotlinx.android.synthetic.main.fragment_new_word.*
 
@@ -35,6 +36,7 @@ class NewWordFragment : Fragment() {
             etWord.text.clear()
             etTranslation.text.clear()
         }
+        activity!!.findViewById<ImageButton>(R.id.btnAddWord).setOnClickListener { addWord() }
     }
 
     private fun textWatcher(setEmpty: () -> Unit): TextWatcher {
@@ -58,11 +60,12 @@ class NewWordFragment : Fragment() {
 
     private fun showAddWordButton() {
         Log.d(TAG, "showAddWordButton")
-        //todo show add word button
+        activity!!.findViewById<ImageButton>(R.id.btnAddWord).visibility = View.VISIBLE
     }
 
     private fun hideAddWordButton() {
         Log.d(TAG, "hideAddWordButton")
+        activity!!.findViewById<ImageButton>(R.id.btnAddWord).visibility = View.GONE
     }
 
     private fun hideClearButton() {
@@ -73,7 +76,10 @@ class NewWordFragment : Fragment() {
     private fun showClearButton() {
         Log.d(TAG, "showClearButton")
         btnClear.visibility = View.VISIBLE
-        //todo add button click listener
+    }
+
+    private fun addWord() {
+        //todo get word data from edit texts and save it
     }
 
     companion object { private val TAG = "VN/" + NewWordFragment::class.java.simpleName }

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

@@ -9,10 +9,9 @@
 
     <include layout="@layout/img_background" />
 
-    <LinearLayout
+    <android.support.constraint.ConstraintLayout
         android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:orientation="vertical">
+        android:layout_height="match_parent">
 
         <fragment
             android:id="@+id/fragment_new_word"
@@ -32,9 +31,30 @@
             android:id="@+id/fragment_vocabulary"
             android:name="com.paktalin.vocabularynotebook.ui.VocabularyFragment"
             android:layout_width="match_parent"
-            android:layout_height="wrap_content" />
+            android:layout_height="wrap_content"
+            android:layout_marginEnd="8dp"
+            android:layout_marginLeft="8dp"
+            android:layout_marginRight="8dp"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="8dp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/fragment_new_word" />
+
+        <ImageButton
+            android:id="@+id/btnAddWord"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="8dp"
+            android:layout_marginEnd="8dp"
+            android:layout_marginRight="8dp"
+            android:background="@android:color/transparent"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            android:visibility="invisible"
+            app:srcCompat="@drawable/ic_done_icon" />
 
-    </LinearLayout>
+    </android.support.constraint.ConstraintLayout>
 
     <android.support.design.widget.NavigationView
         android:id="@+id/navigationView"

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

@@ -10,7 +10,6 @@
     <android.support.v7.widget.RecyclerView
         android:id="@+id/recyclerView"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_margin="8dp" />
+        android:layout_height="wrap_content"/>
 
 </FrameLayout>