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Why doesn't the replace function for fragments work?

I'm trying to open a Fragment from a Activity by using the fragmentManager.replace() function, but it doesn't do anything and the Logcat tells me nothing either. I have tried using both FragmentContainerView and FrameLayout inside my activity_main.xml, and even using the activity's ConstraintLayout ID to host the Fragment, but to no avail.
Here are the codes for my Activity that should open the fragment, and the fragment code itself:
OsActivity.java
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import com.leonardomaito.autocommobile.fragments.NewOsFragment;
import autocommobile.R;
public class OsActivity extends AppCompatActivity {
NewOsFragment newOsFragment = new NewOsFragment();
private View v;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_os);
}
public void createNewOs(View view) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.setReorderingAllowed(true);
fragmentTransaction.replace(R.id.osFragmentContainer, newOsFragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
}
NewOsFragment.java
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import autocommobile.R;
public class NewOsFragment extends Fragment {
private Button btOsNext;
private Button btOsCancel;
private Fragment nextOs = new Fragment();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_new_os, container, false);
btOsNext = view.findViewById(R.id.btNextOs);
btOsCancel = view.findViewById(R.id.btCancelNewOs);
return view;
}
public void nextOsStep(View view) {
FragmentTransaction fragmentManager = getActivity()
.getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_new_os, nextOs);
}
}
ActivityOs.xml
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/activity_os"
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:layout_marginBottom="0dp"
android:background="#color/white"
tools:context="com.leonardomaito.autocommobile.activities.OsActivity">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/osFragmentContainer"
android:name="com.leonardomaito.autocommobile.fragments.NewOsFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:layout="#layout/fragment_new_os">
</androidx.fragment.app.FragmentContainerView>
<include
android:id="#+id/include"
layout="#layout/layout_header_search" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/glRecyclerLimit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_begin="124dp" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerViewOs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="650dp"
app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#+id/glRecyclerLimit"
app:layout_constraintVertical_bias="0.0"
tools:listitem="#layout/layout_os_item" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/btNewOs"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="Inserir OS"
android:onClick="createNewOs"
android:src="#drawable/custom_plus_icon"
app:backgroundTint="#color/autocom_blue"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.98"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#+id/glRecyclerLimit"
app:layout_constraintVertical_bias="0.988"
app:rippleColor="#color/autocom_blue" />
</androidx.constraintlayout.widget.ConstraintLayout>
fragment_new_os.xml
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/fragment_new_os"
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"
tools:context="com.leonardomaito.autocommobile.fragments.NewOsFragment">
<TextView
android:id="#+id/tvServiceOrder"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:text="Ordem de Serviço"
android:textColor="#color/autocom_blue"
android:textSize="30sp"
app:layout_constraintBottom_toTopOf="#+id/viewHorizontalBar"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<View
android:id="#+id/viewHorizontalBar"
android:layout_width="match_parent"
android:layout_height="3dp"
android:layout_marginTop="32dp"
android:background="#color/autocom_blue"
app:layout_constraintBottom_toTopOf="#+id/glViewBottom"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/glViewBottom"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_begin="57dp" />
<TextView
android:id="#+id/tvCliente"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="136dp"
android:text="Cliente"
android:textColor="#color/autocom_blue"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.084"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/viewHorizontalBar" />
<EditText
android:id="#+id/etClientInput"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:background="#drawable/custom_border"
android:drawableStart="#drawable/custom_search_icon"
android:ems="17"
android:importantForAutofill="no"
android:inputType="text"
android:minHeight="48dp"
android:textColor="#color/autocom_blue"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.49"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvCliente" />
<TextView
android:id="#+id/tvAddress"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="48dp"
android:text="Endereço"
android:textColor="#color/autocom_blue"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.094"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/etClientInput" />
<EditText
android:id="#+id/etAddressInput"
android:enabled="false"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:background="#drawable/custom_border"
android:ems="17"
android:inputType="text"
android:minHeight="48dp"
android:textColor="#color/autocom_blue"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.49"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvAddress"
android:importantForAutofill="no" />
<TextView
android:id="#+id/tvTelephone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="52dp"
android:text="Telefone"
android:textColor="#color/autocom_blue"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.091"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/etAddressInput" />
<EditText
android:id="#+id/etTelephoneInput"
android:enabled="false"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:background="#drawable/custom_border"
android:ems="17"
android:inputType="text"
android:minHeight="48dp"
android:textColor="#color/autocom_blue"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.49"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvTelephone"
android:importantForAutofill="no" />
<android.widget.Button
android:id="#+id/btNextOs"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="64dp"
android:background="#drawable/custom_button"
android:minWidth="125dp"
android:onClick="nextOsStep"
android:text="Avançar"
android:textColor="#color/white"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/etTelephoneInput"
app:layout_constraintVertical_bias="0.155" />
</androidx.constraintlayout.widget.ConstraintLayout>
Shouldn't the replace function be opening my fragment on top of my activity? Is there something I'm doing wrong? The majority of other posts adressing this situation seemed to use .add instead of .replace, and were fixed by doing so.

SeekBar not working while used in pop up window java android studio

Hi I've been trying to make a pop up window which presents a trackable seekbar as a part of a school project, both parts of the code work alone but when put together the seekbar progress is not tracked (you can move the seekbar but the number won't change), Help would be very appreciated!
MainActivity.java
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.PopupWindow;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void onButtonShowPopupWindowClick(View view) {
// inflate the layout of the popup window
LayoutInflater inflater = (LayoutInflater)
getSystemService(LAYOUT_INFLATER_SERVICE);
View popupView = inflater.inflate(R.layout.activity_pop_up, null);
// create the popup window
int width = LinearLayout.LayoutParams.MATCH_PARENT;
int height = 500;
boolean focusable = true; // lets taps outside the popup also dismiss it
final PopupWindow popupWindow = new PopupWindow(popupView, width, height, focusable);
// show the popup window
// which view you pass in doesn't matter, it is only used for the window token
popupWindow.showAtLocation(view, Gravity.BOTTOM, 0, 0);
// dismiss the popup window when touched
popupView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
popupWindow.dismiss();
return true;
}
});
}
}
activity_main.xml
<?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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onButtonShowPopupWindowClick"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.368" />
</androidx.constraintlayout.widget.ConstraintLayout>
popUp.java
package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ProgressBar;
import android.widget.SeekBar;
import android.widget.TextView;
public class popUp extends AppCompatActivity {
private TextView textView;
private SeekBar seekBar;
private ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textView);
seekBar = (SeekBar) findViewById(R.id.seekBar);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
progressBar.setProgress(progress);
textView.setText("" + progress + "$");
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
});
}
}
activity_pop_up.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="right">
<Button
android:id="#+id/bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="confirm"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.06"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.01999998" />
<SeekBar
android:id="#+id/seekBar"
android:layout_width="250dp"
android:layout_height="55dp"
android:progress="0"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.78"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.01999998" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="#+id/textView3"
android:layout_width="154dp"
android:layout_height="45dp"
android:gravity="center"
android:text="amount:"
android:textSize="30dp"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.110000014" />
<TextView
android:id="#+id/textView"
android:layout_width="214dp"
android:layout_height="44dp"
android:text="0"
android:textSize="30dp"
android:gravity="center"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.75"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.110000014" />
</LinearLayout>
<ProgressBar
android:id="#+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#id/seekBar"
android:layout_alignParentStart="true"
android:layout_marginBottom="21dp" />
</LinearLayout>

How do I create a fragment template(class with variables and methods, layout) for multiple fragments with the same content?

On the main screen I have 7 buttons (days) and a fragment.
For every day of the week I wanted to generate a fragment with some EditTexts and a ListView, but creating 7 fragments with the same layout and almost the same class content seems too repetitive.
I only did it for Monday and Tuesday.
The only difference between MondayFragment and TuesdayFragment is that in TuesdayFragment I renamed the variable mondayTV to tuesdayTV and in layout I changed the ids of the submit button and the ListView. Also the key for Bundle is different. I don't think it's worth posting it since it's so similar to MondayFragment.
I want to know if it's possible to create a fragment template and use it to generate a fragment for every button of the activity given this code I wrote. There is still a lot to work on when it comes to functionality but I can't get this idea out of my head.
MainActivity.java
package com.example.dietmanagement;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
public Button monday, tuesday, wednesday, thursday, friday, saturday, sunday;
final MondayFragment mondayFragment = new MondayFragment();
final TuesdayFragment tuesdayFragment = new TuesdayFragment();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/*Intent i = getIntent();
String current_user = i.getStringExtra("current_user");
TextView current_user_txtview = findViewById(R.id.current_user);
current_user_txtview.setText("Welcome, " + current_user);*/
monday = (Button)findViewById(R.id.monday_btn);
tuesday = (Button)findViewById(R.id.tuesday_btn);
wednesday = (Button)findViewById(R.id.wednesday_btn);
thursday = (Button)findViewById(R.id.thursday_btn);
friday = (Button)findViewById(R.id.friday_btn);
saturday = (Button)findViewById(R.id.saturday_btn);
sunday = (Button)findViewById(R.id.sunday_btn);
monday.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openFragment(mondayFragment);
getDay(mondayFragment, "monday", (String) monday.getContentDescription());
}
});
tuesday.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
openFragment(tuesdayFragment);
getDay(tuesdayFragment, "tuesday", (String) tuesday.getContentDescription());
}
});
}
private void openFragment(final Fragment fragment){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.daysfragment, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
public void getDay(final Fragment fragment, String key, String value)
{
Bundle bnd = new Bundle();
bnd.putString(key, value);
fragment.setArguments(bnd);
}
}
Activity_main.xml
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/background_green"
tools:context=".MainActivity">
<Button
android:id="#+id/tuesday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:contentDescription="#string/tuesday_context"
android:text="#string/tuesday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.194"
app:layout_constraintStart_toEndOf="#+id/monday_btn"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.017" />
<TextView
android:id="#+id/main_title"
android:layout_width="147dp"
android:layout_height="93dp"
android:fontFamily="sans-serif-medium"
android:text="#string/welcome_label"
android:textColor="#FFFFFF"
android:textSize="70sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.414"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.049" />
<Button
android:id="#+id/monday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:contentDescription="#string/monday_context"
android:text="#string/monday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.16"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.017" />
<Button
android:id="#+id/thursday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:text="#string/thursday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.018"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.172" />
<Button
android:id="#+id/sunday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:text="#string/sunday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="28sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.786"
app:layout_constraintStart_toEndOf="#+id/saturday_btn"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.172" />
<Button
android:id="#+id/saturday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:text="#string/saturday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="28sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.225"
app:layout_constraintStart_toEndOf="#+id/friday_btn"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.172" />
<Button
android:id="#+id/friday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:text="#string/friday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.137"
app:layout_constraintStart_toEndOf="#+id/thursday_btn"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.172" />
<Button
android:id="#+id/wednesday_btn"
android:layout_width="70dp"
android:layout_height="70dp"
android:background="#drawable/button_states"
android:text="#string/wednesday"
android:textAllCaps="false"
android:textColor="#color/white"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.369"
app:layout_constraintStart_toEndOf="#+id/tuesday_btn"
app:layout_constraintTop_toBottomOf="#+id/main_title"
app:layout_constraintVertical_bias="0.017" />
<ImageView
android:id="#+id/logo"
android:layout_width="52dp"
android:layout_height="58dp"
android:layout_marginStart="8dp"
android:layout_marginTop="52dp"
android:contentDescription="#string/app_name"
app:layout_constraintStart_toEndOf="#+id/main_title"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_logo" />
<TextView
android:id="#+id/current_user"
android:layout_width="362dp"
android:layout_height="27dp"
android:text="#string/current_user"
android:textAlignment="viewEnd"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="#+id/main_title"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.938"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.318" />
<FrameLayout
android:id="#+id/daysfragment"
android:layout_width="match_parent"
android:layout_height="460dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
MondayFragment.java
package com.example.dietmanagement;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MondayFragment extends Fragment {
public TextView mondayTV;
public ArrayList<String> hour_food;
public ArrayAdapter<String> listViewAdapter;
public ListView listView;
public EditText input_meal;
public EditText input_time;
public Button submit;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_monday, container, false);
mondayTV = (TextView) v.findViewById(R.id.day);
Bundle bndMon = getArguments();
String day = bndMon.getString("monday");
mondayTV.setText(day);
hour_food = new ArrayList<String>();
listViewAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, hour_food);
listView = (ListView)v.findViewById(R.id.monday_list_item);
listView.setAdapter(listViewAdapter);
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
hour_food.remove(position);
Toast.makeText(getActivity(), "Meal Removed", Toast.LENGTH_SHORT).show();
listViewAdapter.notifyDataSetChanged();
return true;
}
});
input_meal = v.findViewById(R.id.input_meal);
input_time = v.findViewById(R.id.input_time);
submit = (Button) v.findViewById(R.id.submit_food_btn);
submit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(TextUtils.isEmpty(input_time.getText())) {
Toast.makeText(getActivity(), "Empty time input", Toast.LENGTH_SHORT).show();
} else if(TextUtils.isEmpty(input_meal.getText())){
Toast.makeText(getActivity(), "Empty meal input", Toast.LENGTH_SHORT).show();
}
else
{
hour_food.add(String.format("%s - %s", input_meal.getText().toString(), input_time.getText().toString()));
listViewAdapter.notifyDataSetChanged();
input_meal.setText("");
input_time.setText("");
}
}
});
return v;
}
}
fragment_monday.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/background_green"
tools:context=".MondayFragment">
<TextView
android:id="#+id/day"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:text="#string/day" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<EditText
android:id="#+id/input_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:autofillHints="#string/time"
android:hint="#string/time"
android:inputType="time" />
<EditText
android:id="#+id/input_meal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:autofillHints="#string/meal"
android:hint="#string/meal"
android:inputType="textAutoCorrect|textCapSentences" />
</LinearLayout>
<Button
android:id="#+id/submit_food_btn_monday"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/submit"
android:background="#color/white"
android:textColor="#color/background_green"
android:layout_gravity="end"
android:layout_marginTop="10dp"/>
<ListView
android:id="#+id/monday_list_item"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>
strings.xml

Create DayFragment and layout only for one day. Pass extra information for Fragment and handle situations for different days with that extra information (in your case it looks like only String from bundle is different).
fragment_day.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/background_green">
<TextView
android:id="#+id/day"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:text="#string/day" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<EditText
android:id="#+id/input_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:autofillHints="#string/time"
android:hint="#string/time"
android:inputType="time" />
<EditText
android:id="#+id/input_meal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:autofillHints="#string/meal"
android:hint="#string/meal"
android:inputType="textAutoCorrect|textCapSentences" />
</LinearLayout>
<Button
android:id="#+id/submit_food_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/submit"
android:background="#color/white"
android:textColor="#color/background_green"
android:layout_gravity="end"
android:layout_marginTop="10dp"/>
<ListView
android:id="#+id/list_item"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
DayFragment.java
public class DayFragment extends Fragment {
private TextView dayTV;
private ArrayList<String> hour_food;
private ArrayAdapter<String> listViewAdapter;
private ListView listView;
private EditText input_meal;
private EditText input_time;
private Button submit;
private String text;
public DayFragment(String text) {
this.text = text;
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_day, container, false);
dayTV = v.findViewById(R.id.day);
dayTV.setText(text);
hour_food = new ArrayList<>();
listViewAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, hour_food);
listView = v.findViewById(R.id.list_item);
listView.setAdapter(listViewAdapter);
listView.setOnItemLongClickListener((parent, view, position, id) -> {
hour_food.remove(position);
Toast.makeText(getActivity(), "Meal Removed", Toast.LENGTH_SHORT).show();
listViewAdapter.notifyDataSetChanged();
return true;
});
input_meal = v.findViewById(R.id.input_meal);
input_time = v.findViewById(R.id.input_time);
submit = v.findViewById(R.id.submit_food_btn);
submit.setOnClickListener(v1 -> {
if (TextUtils.isEmpty(input_time.getText())) {
Toast.makeText(getActivity(), "Empty time input", Toast.LENGTH_SHORT).show();
} else if (TextUtils.isEmpty(input_meal.getText())) {
Toast.makeText(getActivity(), "Empty meal input", Toast.LENGTH_SHORT).show();
} else {
hour_food.add(String.format("%s - %s", input_meal.getText().toString(), input_time.getText().toString()));
listViewAdapter.notifyDataSetChanged();
input_meal.setText("");
input_time.setText("");
}
});
return v;
}
}
Use constructor for passing information.
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button monday = findViewById(R.id.monday_btn),
tuesday = findViewById(R.id.tuesday_btn),
wednesday = findViewById(R.id.wednesday_btn),
thursday = findViewById(R.id.thursday_btn),
friday = findViewById(R.id.friday_btn),
saturday = findViewById(R.id.saturday_btn),
sunday = findViewById(R.id.sunday_btn);
openFragment(monday);
openFragment(tuesday);
openFragment(wednesday);
openFragment(thursday);
openFragment(friday);
openFragment(saturday);
openFragment(sunday);
}
private void openFragment(Button btn) {
btn.setOnClickListener(v -> {
String contentDescription = btn.getContentDescription().toString();
getSupportFragmentManager().beginTransaction()
.replace(R.id.daysfragment, new DayFragment(contentDescription))
.addToBackStack(null)
.commit();
});
}
}
In MainActivity openFragment() method takes a Button parameter and with that Button and sets onClickListener to that Button. When you click any Button it gets content description from that Button and passing it to Fragment and opens that Fragment with that content description.

How do I get rid of the extra spacing that is appearing at the top of my Android app?

I'm building a homepage for an Android app for one of my college classes. My group is using Android Studio. I've got the layout that I was but I have this random extra space at the top above where it says Welcome.
I cannot figure out how to get rid of that random spacing at the top and it's pushing the rest of my objects down (reports list disappears below nav bar)
Here's my fragment_home.xml
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<EditText
android:id="#+id/editText"
android:layout_width="365dp"
android:layout_height="wrap_content"
android:text="#string/home_welcome"
android:textAlignment="center"
android:textSize="20pt"
app:layout_constraintBottom_toTopOf="#+id/text_appts"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/text_appts"
android:layout_width="365dp"
android:layout_height="55dp"
android:ems="10"
android:text="#string/title_appointments"
android:textSize="14pt"
app:layout_constraintBottom_toTopOf="#+id/recycler_appts"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/editText" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_appts"
android:layout_width="360dp"
android:layout_height="125dp"
app:layout_constraintBottom_toTopOf="#+id/text_chats"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.484"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/text_appts"
app:layout_constraintVertical_bias="0.226" />
<EditText
android:id="#+id/text_chats"
android:layout_width="365dp"
android:layout_height="55dp"
android:ems="10"
android:text="#string/title_chats"
android:textSize="14pt"
app:layout_constraintBottom_toTopOf="#+id/recycler_chats"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/recycler_appts" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_chats"
android:layout_width="360dp"
android:layout_height="125dp"
app:layout_constraintBottom_toTopOf="#+id/text_reports"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.484"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/text_chats"
app:layout_constraintVertical_bias="0.226" />
<EditText
android:id="#+id/text_reports"
android:layout_width="365dp"
android:layout_height="55dp"
android:ems="10"
android:text="#string/title_reports"
android:textSize="14pt"
app:layout_constraintBottom_toTopOf="#+id/recycler_reports"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/recycler_chats" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_reports"
android:layout_width="360dp"
android:layout_height="125dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.424"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/text_reports"
app:layout_constraintVertical_bias="0.226" />
</androidx.constraintlayout.widget.ConstraintLayout>
Here's my HomeFragment.java
package com.example.telemedicine.ui.home;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.Nullable;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProviders;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.example.telemedicine.R;
import com.example.telemedicine.ui.utilities.RecyclerItem;
public class HomeFragment extends Fragment {
private HomeViewModel homeViewModel;
private RecyclerView recyclerView_appt, recyclerView_chat, recyclerView_report;
private RecyclerView.Adapter mAdapter_appt, mAdapter_chat, mAdapter_report;
private RecyclerView.LayoutManager layoutManager_appt, layoutManager_chat, layoutManager_report;
private String[] apptData = {"Physical - 9/29 # 10:00am", "Vaccination - 10/4 # 1:30pm", "Check-Up - 10/19 # 9:00am"};
private String[] chatData = {"Dr. Jane Smith", "Dr. Hayden Lee", "Dr. Michael Dean"};
private String[] reportData = {"Blood Work 9/10", "Vaccination Summary 9/1", "Physical 8/23"};
//Activity activity = (Activity)getContext();
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
homeViewModel =
ViewModelProviders.of(this).get(HomeViewModel.class);
View root = inflater.inflate(R.layout.fragment_home, container, false);
final TextView textView = root.findViewById(R.id.editText);
homeViewModel.getText().observe(this, new Observer<String>() {
#Override
public void onChanged(#Nullable String s) {
textView.setText(s);
}
});
recyclerView_appt = (RecyclerView)root.findViewById(R.id.recycler_appts);
layoutManager_appt = new LinearLayoutManager(this.getActivity());
recyclerView_appt.setLayoutManager(layoutManager_appt);
mAdapter_appt = new RecyclerItem(apptData);
recyclerView_appt.setAdapter(mAdapter_appt);
recyclerView_chat = (RecyclerView)root.findViewById(R.id.recycler_chats);
layoutManager_chat = new LinearLayoutManager(this.getActivity());
recyclerView_chat.setLayoutManager(layoutManager_chat);
mAdapter_chat = new RecyclerItem(chatData);
recyclerView_chat.setAdapter(mAdapter_chat);
recyclerView_report = (RecyclerView)root.findViewById(R.id.recycler_reports);
layoutManager_report = new LinearLayoutManager(this.getActivity());
recyclerView_report.setLayoutManager(layoutManager_report);
mAdapter_report = new RecyclerItem(reportData);
recyclerView_report.setAdapter(mAdapter_report);
return root;
}
}
Here's my HomeViewModel.java
package com.example.telemedicine.ui.home;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;
public class HomeViewModel extends ViewModel {
private MutableLiveData<String> mText;
public HomeViewModel() {
mText = new MutableLiveData<>();
}
public LiveData<String> getText() {
return mText;
}
}
And my activity_main.xml
<?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"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorBackground"
android:paddingTop="?attr/actionBarSize">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/bottom_nav_menu" />
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:layout_constraintBottom_toTopOf="#id/nav_view"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="#navigation/mobile_navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>
I don't know what other files to include but hopefully the problem is in those four files. I've tried so many things to get rid of that spacing, but I cannot figure out how to get rid of it.
Thanks in advance!!

In your activity_main.xml file, try removing the android:paddingTop="?attr/actionBarSize" line in the ConstraintLayout since there is no actionBar.

in your activity_main.xml change 'fragment' (nav_host_fragment) layout_width and layout_height to 0dp. that is the correct form of using constraints.
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:defaultNavHost="true"
app:layout_constraintBottom_toTopOf="#id/nav_view"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="#navigation/mobile_navigation" />

Android Studio error when adding ImageView in fragment

1- I have a fragment which has 2 EditText and 1 Button (below the code is)
<android.support.constraint.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"
tools:context="com.example.junior_yao.fragmentfrombeginning.Top_Fragment"
tools:layout_editor_absoluteY="81dp"
tools:layout_editor_absoluteX="0dp">
<EditText
android:id="#+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="information"
android:inputType="text|textShortMessage"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="16dp"
app:layout_constraintHorizontal_bias="0.503" />
<EditText
android:id="#+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="information"
android:inputType="textPersonName"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="#+id/editText1"
android:layout_marginLeft="0dp"
app:layout_constraintLeft_toLeftOf="#+id/editText1"
android:layout_marginTop="23dp"
app:layout_constraintTop_toBottomOf="#+id/editText1"
app:layout_constraintHorizontal_bias="0.0" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Send Info"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="#+id/editText1"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="#+id/editText1"
android:layout_marginTop="32dp"
app:layout_constraintTop_toBottomOf="#+id/editText2"
app:layout_constraintHorizontal_bias="0.495" />
</android.support.constraint.ConstraintLayout>
2- I have another fragment which has one Image View and 2 TextView
<android.support.constraint.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"
tools:context="com.example.junior_yao.fragmentfrombeginning.Down_Fragment"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/androidtest"
tools:layout_constraintTop_creator="1"
tools:layout_constraintLeft_creator="1"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginLeft="0dp"
android:layout_marginTop="0dp"
android:id="#+id/imageView" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text2"
android:textSize="25dp"
android:textColor="#7FFF00"
tools:layout_constraintRight_creator="1"
tools:layout_constraintBottom_creator="1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
tools:layout_constraintLeft_creator="1"
android:layout_marginBottom="30dp"
app:layout_constraintLeft_toLeftOf="parent" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text1"
android:textSize="25dp"
android:textColor="#7FFF00"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="44dp" />
</android.support.constraint.ConstraintLayout>
On the 3rd part I add those 2 fragment in main activity layout
3 - if I add the first fragment only (I got no Error )
4 - Here the issue
If I add the 2nd fragment the app does not start , please help me to figure it out
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:context="com.example.junior_yao.fragmentfrombeginning.MainActivity">
<fragment
android:id="#+id/fragment"
android:name="com.example.junior_yao.fragmentfrombeginning.Top_Fragment"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
/>
<fragment
android:id="#+id/fragment12"
android:name="com.example.junior_yao.fragmentfrombeginning.Down_Fragment"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
/>
</RelativeLayout>

You need to add more information so you can be helped, the java code where the fragments are being called and created and the logcat as well to help solve the problem, the XML design code is not helpful.

here the java code for the 1st fragment
package com.example.junior_yao.fragmentfrombeginning;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Top_Fragment extends Fragment {
public Top_Fragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_top, container, false);
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
}
The java code for the 2nd fragment
package com.example.junior_yao.fragmentfrombeginning;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Down_Fragment extends Fragment {
public Down_Fragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_down, container, false);
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
}
Now the java code of the main Activity
package com.example.junior_yao.fragmentfrombeginning;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}