Develop Reference

Nested Spinner Android Design Issues ConstraintLayout

I'm working with spinner for the first time, and I don't understand why the second spinner doesn't look exactly like the first one even though they were created practically the same (the only difference is the data). These are nested.
The design implemented it with "constraint layout"
<Spinner
android:id="#+id/spCategorie"
android:layout_width="0dp"
android:layout_height="28dp"
android:layout_marginStart="10dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="32dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toEndOf="#+id/categorieText"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/categorieText"
android:layout_width="73dp"
android:layout_height="28dp"
android:layout_marginStart="16dp"
android:layout_marginTop="32dp"
android:text="Categorie:"
android:textAlignment="viewStart"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Spinner
android:id="#+id/spProduct"
android:layout_width="0dp"
android:layout_height="28dp"
android:layout_marginStart="10dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="32dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/productText"
app:layout_constraintTop_toBottomOf="#+id/spCategorie" />
This is how it looks in the emulator
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, productsCat);
arrayAdapter.setDropDownViewResource(R.layout.support_simple_spinner_dropdown_item);
categorie.setAdapter(arrayAdapter);
categorie.setOnItemSelectedListener(new SpinnersEvents());
product.setOnItemSelectedListener(new SpinnersEvents());
private class SpinnersEvents implements AdapterView.OnItemSelectedListener {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (parent.getId() == R.id.spCategorie){
String[] productsName = getProductName(productsCat[position]);
ArrayAdapter<String> arrayAdapterChild = new ArrayAdapter<String>(getBaseContext(),R.layout.support_simple_spinner_dropdown_item, productsName);
arrayAdapterChild.setDropDownViewResource(R.layout.support_simple_spinner_dropdown_item);
product.setAdapter(arrayAdapterChild);
}else{
price.setText(String.valueOf(tempList.get(position).getPrice()));
imgPrd.setImageResource(tempList.get(position).getImage());
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
}

Please try this in your code may help you, you can also set wrapcontent in spinner or increase the size to view text proper
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
tools:ignore="MissingConstraints">
<TextView
android:id="#+id/categorieText"
android:layout_width="73dp"
android:layout_height="28dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:layout_marginBottom="10dp"
android:gravity="center"
android:text="Categorie:"
android:textAlignment="viewStart"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:ignore="RtlCompat" />
<Spinner
android:id="#+id/spCategorie"
android:layout_width="0dp"
android:layout_height="28dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:layout_marginBottom="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toEndOf="#+id/categorieText"/>
<TextView
android:id="#+id/productText"
android:layout_width="73dp"
android:layout_height="28dp"
android:layout_marginTop="32dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:layout_marginBottom="10dp"
android:text="Product:"
android:textAlignment="viewStart"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/categorieText"/>
<Spinner
android:id="#+id/spproduct"
android:layout_width="0dp"
android:layout_height="28dp"
android:layout_marginTop="32dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:layout_marginBottom="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintTop_toBottomOf="#+id/spCategorie"
app:layout_constraintStart_toEndOf="#+id/categorieText"/>
</androidx.constraintlayout.widget.ConstraintLayout>

The solution was in the code, not in the layout.
The second spinner must be:
ArrayAdapter<String> arrayAdapterChild = new ArrayAdapter<String>(MainActivity.this,R.layout.support_simple_spinner_dropdown_item, productsName);
instead:
ArrayAdapter<String> arrayAdapterChild = new ArrayAdapter<String>(getBaseContext(),R.layout.support_simple_spinner_dropdown_item, productsName);
In this case, calling the getBaseContext() method generated that particular problem.
Sorry for the confusion.

NullPointerException Java android studio setMovementMethod(LinkMovementMethod.getInstance())

I'm still new with coding but I have a project with android studio right now. What I wanted to do was to add hyperlinks in a page. I've followed the steps and tutorials to do this very carefully but I can't seem to find the problem. In my Logcat it says
PID: 17644 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setMovementMethod(android.text.method.MovementMethod)' on a null object reference
but I don't understand how it was caused. I have read some similar problems stating the findByViewId might be wrong but I don't think that is the case for my problem but I would love to be wrong. Here is my code. Any help is much appreciated.
public class LearnFragment extends Fragment {
private Button search;
private TextView faq_link_1, faq_link_2, faq_link_3, faq_link_4, faq_link_5;
EditText editSearch;
public LearnFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View viewRoot = inflater.inflate(R.layout.fragment_account, container, false);
faq_link_1 = (TextView) viewRoot.findViewById(R.id.faq1);
faq_link_2 = (TextView) viewRoot.findViewById(R.id.faq2);
faq_link_3 = (TextView) viewRoot.findViewById(R.id.faq3);
faq_link_4 = (TextView) viewRoot.findViewById(R.id.faq4);
faq_link_5 = (TextView) viewRoot.findViewById(R.id.faq5);
faq_link_1.setMovementMethod(LinkMovementMethod.getInstance());
faq_link_2.setMovementMethod(LinkMovementMethod.getInstance());
faq_link_3.setMovementMethod(LinkMovementMethod.getInstance());
faq_link_4.setMovementMethod(LinkMovementMethod.getInstance());
and this is the xml file
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".boundary.LearnFragment">
<AutoCompleteTextView
android:id="#+id/search_bar"
android:layout_width="0dp"
android:layout_height="44dp"
android:layout_marginStart="16dp"
android:layout_marginTop="28dp"
android:hint="Search..."
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintEnd_toStartOf="#+id/b_search"
app:layout_constraintHorizontal_bias="0.158"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/b_search"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="28dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="14dp"
android:layout_weight="1"
android:text="Search"
app:layout_constraintBottom_toTopOf="#+id/textView2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/search_bar"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/faq1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="37dp"
android:text="#string/link_period_pain"
android:textSize="23sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView2"
android:linksClickable="true"/>
<TextView
android:id="#+id/faq2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="27dp"
android:text="#string/menstrual_cramp_link"
android:textSize="23sp"
app:layout_constraintBottom_toTopOf="#+id/faq3"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/faq1"
android:linksClickable="true" />
<TextView
android:id="#+id/faq3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="32dp"
android:text="#string/late_period_link"
android:textSize="23sp"
app:layout_constraintBottom_toTopOf="#+id/faq4"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/faq2"
android:linksClickable="true" />
<TextView
android:id="#+id/faq4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="30dp"
android:text="#string/cervical_screening_link"
android:textSize="23sp"
app:layout_constraintBottom_toTopOf="#+id/faq5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/faq3"
android:linksClickable="true" />
<TextView
android:id="#+id/faq5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="35dp"
android:text="#string/pap_smear_link"
android:textSize="23sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/faq4"
android:linksClickable="true" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="13dp"
android:text="Not looking what you're looking for? Use the search bar to find out more!"
android:textSize="23sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/search_bar" />
</androidx.constraintlayout.widget.ConstraintLayout>

Fragment is not added to the back stack when replaced

Above is the path I follow until I reach the BeginnerFragment.
Above is the hierarchy of activity / fragments
Current Situation
In my application I have a Bottom Navigation, and in each fragment of the navigation, I have two tabs.
The Problem
My problem is that when I'm at BeginnerFragment and I press the cell back button, it returns to the StatusFragment.
I expected it to return to EducationHomeFragment, as I added it to BackStack, according to the codes below.
EducationFragment
public class EducationFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View root = inflater.inflate(R.layout.fragment_education, container, false);
// Instanciando o Fragmento de página inicial da Educação
EducationHomeFragment educationHomeFragment = new EducationHomeFragment();
getActivity().getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, educationHomeFragment).addToBackStack(null).commit();
return root;
}
}
fragment_education
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/fragment_container"
tools:context=".education.EducationFragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
EducationHomeFragment
public class EducationHomeFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View root = inflater.inflate(R.layout.fragment_education_home, container, false);
CardView beginnerFreelance = root.findViewById(R.id.cardview_beginner_skills);
beginnerFreelance.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
BeginnerFragment fragment = new BeginnerFragment();
getActivity().getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_container , fragment)
.addToBackStack(null)
.commit();
}
});
return root;
}
}
fragment_education_home
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/fragment_education_home_container"
tools:context=".education.EducationHomeFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#EEE"
>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/text_academic_education"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:text="#string/academic_education"
android:textColor="#color/colorPrimaryDark"
app:fontFamily="#font/exo_2_semibold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_advanced_skills" />
<TextView
android:id="#+id/title_courses_available"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="12dp"
android:text="#string/general_courses"
android:textColor="#color/colorPrimaryDark"
app:fontFamily="#font/exo_2_semibold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_qualifications" />
<androidx.cardview.widget.CardView
android:id="#+id/cardview_doctoral_courses"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
android:layout_marginBottom="20dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_master_courses">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView39"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/doctoral_courses"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_master_courses"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_specialization_courses">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView38"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/master_courses"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_specialization_courses"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_higher_courses">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_doctoral_courses"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/specialization_courses"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_higher_courses"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/text_academic_education">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_master_courses"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/higher_level_courses"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_advanced_skills"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_intermediate_skills">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_specialization_courses"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/advanced"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_study_status"
android:layout_width="match_parent"
android:layout_height="85dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/default_cardview_mgtop"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/image_study_status"
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_marginTop="10dp"
android:tint="#color/colorPrimary"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/outline_menu_book_24" />
<TextView
android:id="#+id/text_study_status"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="#string/not_studying"
android:textColor="#color/colorPrimaryDark"
app:fontFamily="#font/exo_2_semibold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/image_study_status" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_qualifications"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/default_cardview_mgtop"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_study_status">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="12dp"
android:paddingBottom="12dp">
<TextView
android:id="#+id/title_obtained_qualifications"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/qualifications_obtained"
android:textColor="#color/colorPrimaryDark"
app:fontFamily="#font/exo_2_semibold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/obtained_qualification_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="#string/no_course_completed"
app:fontFamily="#font/exo_2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_obtained_qualifications" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_beginner_skills"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_courses_available">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_basic_courses"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/beginner"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/cardview_intermediate_skills"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="#dimen/default_cardview_mgsides"
android:layout_marginTop="#dimen/cardview_list_margin"
android:layout_marginRight="#dimen/default_cardview_mgsides"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cardview_beginner_skills">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_higher_courses"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/intermediate"
app:fontFamily="#font/exo_2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
Why isn't FragmentEducationHome being added to the stack? I want to return to FragmentEducationHome when I click on the BeginnerFragment back button.

This is not a direct answer to the question.
But Google suggests to use Jetpack Navigation approach.
Which will be single Activity and multiple fragments.
Google Code Labs Link
This avoids lot of bipolarate code , were we had to handle backstack, keeping fragment count etc...
At first anyone will feel bit difficult to start with, but in a while , you can grasp and move on to new approach which is suggestible.
Nav_graph avoids programmers responsibility to add/ remove fragments
Allows passing data (raw data or data classes with Parcelable) from one fragment to another
Moving from one child nav graph to another
And much more...
I would suggest you do checkout this once starting with a new trial/project
EDIT
Even though one activity is suggested, we may have more than one Activity and its corresponding child fragment graphs if required. This purely depends on the requirement. In my last project we started with single activity concept. But as the app complexity increased, it was decided to move for two activity and its corresponding child frags.
With respect to Clean Code Architecture this is easily adaptable as well...
Good luck!

Please refer to this question:
Override onBackPressed() into your activity and call this in order to remove current fragment from backstack, since you add it.
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportFragmentManager().popBackStackImmediate()
} else {
finish();
}

Make sure R.id.fragment_container lives in the parent activity xml (not the fragment xml) and in EducationHomeFragment use .add instead of .replace to add BeginnerFragment to the back stack

You already replace current container fragment by BeginnerFragment, so you can't back to previous fragment. Try to use add(id, fragment, tag) and addToBackStack(tag). Hope help you.

Why is my layout not filling the screen in landscape mode?

I have the following layout for a video player:
video_view.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.google.android.exoplayer2.ui.AspectRatioFrameLayout
android:id="#+id/aspectRatioLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center">
<SurfaceView
android:id="#+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ImageView
android:id="#+id/posterImage"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:contentDescription="#string/poster_image_description" />
<com.google.android.exoplayer2.ui.SubtitleView
android:id="#+id/subtitleView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<com.google.android.exoplayer2.ui.PlayerControlView
android:id="#+id/nativeControls"
android:layout_width="match_parent"
android:layout_height="match_parent">
</com.google.android.exoplayer2.ui.PlayerControlView>
<com.sdk.adapters.controls.ControlBar
android:id="#+id/controls"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</com.sdk.adapters.controls.ControlBar>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/messageOverlay"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="#80000000">
<TextView
android:id="#+id/messageOverlayText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="#string/message_overlay"
android:textColor="#android:color/white"
android:textSize="30sp" />
</FrameLayout>
</FrameLayout>
</com.google.android.exoplayer2.ui.AspectRatioFrameLayout>
</FrameLayout>
The ControlBar is defined as:
control_bar_view.xml
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#80000000">
<!-- BEGIN: Strut -->
<View
android:id="#+id/exitPlaceholder"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintWidth_percent="0.1" />
<!-- END: Strut -->
<TextView
android:id="#+id/broadcastName"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:text="#string/broadcast_name"
android:textColor="#ffffff"
android:textSize="18sp"
app:layout_constraintEnd_toStartOf="#id/castButton"
app:layout_constraintStart_toEndOf="#id/exitPlaceholder"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/siteName"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:text="#string/site_name"
android:textColor="#ffffff"
android:textSize="18sp"
app:layout_constraintEnd_toStartOf="#id/castButton"
app:layout_constraintStart_toEndOf="#id/exitPlaceholder"
app:layout_constraintTop_toBottomOf="#id/broadcastName" />
<ImageButton
android:id="#+id/castButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="10dp"
android:contentDescription="#string/send_to_google_chromecast"
android:visibility="invisible"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toStartOf="#id/airplayButton"
app:layout_constraintHeight_percent="0.1"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/airplayButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="10dp"
android:contentDescription="#string/send_to_apple_airplay"
android:visibility="invisible"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toStartOf="#id/optionsButton"
app:layout_constraintHeight_percent="0.1"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/optionsButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="10dp"
android:background="#android:color/transparent"
android:contentDescription="#string/fullscreen"
android:scaleType="fitStart"
android:src="#drawable/closed_caption_gray"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.1"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/skipBackButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#android:color/transparent"
android:contentDescription="#string/skip_back_button"
android:scaleType="fitStart"
android:src="#drawable/back_30"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toStartOf="#id/playPauseToggle"
app:layout_constraintHeight_percent="0.20"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/playPauseToggle"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#android:color/transparent"
android:contentDescription="#string/play_button"
android:scaleType="fitStart"
android:src="#drawable/play"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toStartOf="#id/skipForwardButton"
app:layout_constraintHeight_percent="0.25"
app:layout_constraintStart_toEndOf="#id/skipBackButton"
app:layout_constraintTop_toTopOf="parent" />
<ImageButton
android:id="#+id/skipForwardButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#android:color/transparent"
android:contentDescription="#string/skip_forward_button"
android:scaleType="fitStart"
android:src="#drawable/forward_30"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.20"
app:layout_constraintStart_toEndOf="#id/playPauseToggle"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/currentTime"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_margin="10dp"
android:text="#string/null_time"
android:textColor="#ffffff"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="#id/seekBar"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/remainingTime"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_margin="10dp"
android:text="#string/null_time"
android:textColor="#ffffff"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="#id/seekBar"
app:layout_constraintEnd_toEndOf="parent" />
<SeekBar
android:id="#+id/seekBar"
android:layout_width="0dp"
android:layout_height="0dp"
android:progress="50"
android:progressDrawable="#drawable/seek_bar"
android:thumb="#drawable/seek_thumb"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#id/fullscreenButton"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#id/fullscreenButton"
app:layout_constraintVertical_bias="0.0" />
<ImageButton
android:id="#+id/fullscreenButton"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="10dp"
android:background="#android:color/transparent"
android:contentDescription="#string/fullscreen"
android:scaleType="fitStart"
android:src="#drawable/fullscreen"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintDimensionRatio="1:1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.1" />
</androidx.constraintlayout.widget.ConstraintLayout>
In the layout editor in Android Studio, this looks good:
However when I run an actual app, the ControlBar (and only the ControlBar) isn't filling the screen! Everything else stretches to fill the screen perfectly:
What am I doing wrong?
If it helps, the ControlBar is a custom View which extends ConstraintLayout. Here's what the initialization code looks like:
ControlBar.java
public class ControlBar extends ConstraintLayout
{
private BFPlayer player;
private TextView broadcastName;
// ... references for the various subviews ...
private ImageButton fullscreenButton;
public ControlBar ( Context context )
{
super(context);
init(context);
}
public ControlBar ( Context context, AttributeSet attrs )
{
super(context, attrs);
init(context);
}
public ControlBar ( Context context, AttributeSet attrs, int defStyleAttr )
{
super(context, attrs, defStyleAttr);
init(context);
}
private void init ( Context context )
{
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.bf_control_bar_view, null);
addView(view);
broadcastName = findViewById(R.id.broadcastName);
// ... grab references to the various buttons ...
fullscreenButton = findViewById(R.id.fullscreenButton);
// ... set up listeners for the various buttons ...
}
// ... The rest of the class ...
}
What am I doing wrong? I'm sure it's something simple, but I've been staring for a minute and can't figure it out. (Note: I'm pretty new to Android development, and not very experienced. My job has me changing platforms and programming languages very often)

You're not telling it what the parent is when you inflate your View, so it doesn't apply the LayoutParams correctly:
View view = inflater.inflate(R.layout.bf_control_bar_view, null);
addView(view);
Instead, tell it to inflate directly into the parent:
View view = inflater.inflate(R.layout.bf_control_bar_view, this);

Error in data Binding in Android

activity_main.xml
<data class="LoginDataBinding">
<variable
name="login"
type="com.example.itstym.logina.LoginViewModel" />
<variable
name="ModelClickListener"
type="com.example.itstym.logina.interface.ClickListener" />
</data>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:textStyle="bold"
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Welcome, Back"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Medium"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="24dp"/>
<EditText
app:error="#{login.errorEmail}"
android:hint="#{login.emailHint}"
android:text="#{login.userEmailAddress}"
android:id="#+id/user_email_address"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:ems="10"
android:inputType="textEmailAddress"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
android:layout_marginTop="24dp"
app:layout_constraintTop_toBottomOf="#+id/textView"
android:layout_marginStart="8dp"/>
<EditText
app:error="#{login.errorPassword}"
android:text="#{login.userPassword}"
android:hint="#{login.passwordHint}"
android:id="#+id/user_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:ems="10"
android:inputType="textPassword"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/user_email_address"/>
<Button
android:onClick="#{(v)->ModelClickListener.onSubmitButtonClick()}"
android:text="#{login.loginButtonText}"
android:id="#+id/login_submit"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
app:layout_constraintTop_toBottomOf="#+id/user_password"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"/>
</android.support.constraint.ConstraintLayout>
MainActivity.java
public class SampleActivity extends AppCompatActivity {
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final LoginDataBinding loginDataBinding= DataBindingUtil.setContentView(this,R.layout.activity_main);
LoginViewModel viewModel = new LoginViewModel("Enter Email Address","Enter password","Login");
loginDataBinding.setLogin(viewModel);
loginDataBinding.setModelClickListener(new ClickListener() {
#Override
public void onClick() {
Toast.makeText(getApplicationContext(), loginDataBinding.getLogin().getUserEmailAddress(), Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(), loginDataBinding.getLogin().getUserPassword(), Toast.LENGTH_SHORT).show();
}
});
}
}
But I am getting the error unresolved reference for setModelClickListener() but the setLogin() works perfertly normal.
One more thing why the DataBindingUtil.setContentView(this,R.layout.activity_main); return the LoginDataBinding instead of MainActivityBinding?