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Fragment Does Not Appear In Android

I recently learned about Fragments in Android and was building a notepad application to practice them.
Idea: The idea behind the app is simple. I press the button to add a new note. A CardView Viewgroup turns visible. The fragment will be housed within this CardView.
Problem: When I press the button to add a new note, the fragment does not pop up.
MainActivity.java
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.util.Objects;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private CardView fragmentCardView;
private Button newNoteButton;
private FragmentManager fragmentManager = getSupportFragmentManager();
private FragmentTransaction fragmentTransaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setActionBar();
newNoteButton = findViewById(R.id.new_note_button);
fragmentCardView = findViewById(R.id.fragment_cardView);
}
void setActionBar(){
Objects.requireNonNull(getSupportActionBar()).setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
getSupportActionBar().setDisplayShowCustomEnabled(true);
getSupportActionBar().setCustomView(R.layout.layout_custom_action_bar);
}
void showCreateNoteFragment(){
CreateNoteFragment createNoteFragment = CreateNoteFragment.newInstance();
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.fragment_cardView, createNoteFragment);
fragmentTransaction.commit();
fragmentCardView.setVisibility(View.VISIBLE);
}
#Override
public void onClick(View v) {
if (v == newNoteButton)
showCreateNoteFragment();
}
}
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="#F2F2F2"
tools:context=".MainActivity">
<ListView
android:id="#+id/notes_listView"
android:layout_width="match_parent"
android:layout_height="667dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<Button
android:id="#+id/new_note_button"
android:layout_width="350dp"
android:layout_height="50dp"
android:layout_marginTop="27dp"
android:fontFamily="#font/nunito_bold"
android:text="#string/new_note_button_string"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/notes_listView"/>
<androidx.cardview.widget.CardView
android:id="#+id/fragment_cardView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="100dp"
android:layout_marginBottom="100dp"
android:layout_marginStart="25dp"
android:layout_marginEnd="25dp"
android:visibility="invisible"/>
</androidx.constraintlayout.widget.ConstraintLayout>
CreateNoteFragment.java
package com.example.notepadapplication;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
public class CreateNoteFragment extends Fragment implements View.OnClickListener {
private EditText inputEditText;
public CreateNoteFragment() {
// Required empty public constructor
}
static CreateNoteFragment newInstance(){
return new CreateNoteFragment();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_create_note, container, false);
inputEditText = rootView.findViewById(R.id.input_editText);
Button saveButton = rootView.findViewById(R.id.save_button);
saveButton.setOnClickListener(this);
return rootView;
}
#Override
public void onClick(View v) {
String saveButtonText = inputEditText.getText().toString();
}
}
fragment_create_note.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_marginTop="100dp"
android:layout_marginBottom="100dp"
android:layout_marginStart="25dp"
android:layout_marginEnd="25dp"
android:background="#F2F2F2"
tools:context=".CreateNoteFragment">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/header_textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="#string/display_fragment_header_string"
android:layout_marginTop="10dp"
android:textAlignment="center"
android:textSize="20sp"
android:fontFamily="#font/nunito_bold"/>
<View
android:id="#+id/divider_view"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="5dp"
android:layout_marginStart="15dp"
android:layout_marginEnd="15dp"
android:layout_below="#id/header_textView"
android:background="#000000" />
<EditText
android:id="#+id/input_editText"
android:layout_width="match_parent"
android:layout_height="475dp"
android:layout_below="#id/divider_view"
android:layout_alignParentStart="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="20dp"
android:layout_marginStart="5dp"
android:layout_marginEnd="5dp"
android:padding="10dp"
android:inputType="textMultiLine"
android:gravity="top"
android:background="#FFFFFF"
tools:ignore="Autofill,LabelFor,TextFields" />
<Button
android:id="#+id/save_button"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="10dp"
android:text="#string/save_button_string"
android:fontFamily="#font/nunito_bold"/>
</RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
Could anyone check why the fragment isn't popping up? Thanks for the help, guys.
P.S.: I think that the application might become a little bloated because of all the ViewGroups that I'm using. If you guys have a better way to design this, by all means, I would love any input.

When I press the button to add a new note, the fragment does not pop up.
This is expected since your button doesn't know what to do when pressed.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setActionBar();
newNoteButton = findViewById(R.id.new_note_button);
// Button will call activity's onClick whenever it's clicked
newNoteButton.setOnClickListener(this);
fragmentCardView = findViewById(R.id.fragment_cardView);
}

Problems in Android FirebaseRecyclerView Implementing A Search Users Function

I'm looking to implement a search function. When it runs, logcat is telling me:
E/RecyclerView: No adapter attached; skipping layout.
I have searched SO and the net and the answers tell me that I need to set the adapter and the linear layout manager. As you will see with my code, I set both. Alex Mamo's (#AlexMamo) work on here seems to point me in the right direction but I'm still getting the error.
My Activity
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;
import com.MyApp.Objects.ParticipantsObject;
import com.MyApp.R;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
public class ParticipantsActivity extends AppCompatActivity {
private EditText mSearchField;
private ImageButton mSearchBtn;
private RecyclerView mResultList;
private DatabaseReference mUserDatabase;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_neighbors);
mUserDatabase = FirebaseDatabase.getInstance().getReference().child("Users").child("Participants");
mSearchField = (EditText) findViewById(R.id.search_field);
mSearchBtn = (ImageButton) findViewById(R.id.search_btn);
mResultList = (RecyclerView) findViewById(R.id.result_list);
mResultList.setHasFixedSize(true);
mResultList.setLayoutManager(new LinearLayoutManager(this));
mSearchBtn.setOnClickListener(view -> {
String searchText = mSearchField.getText().toString();
firebaseUserSearch(searchText);
});
}
private void firebaseUserSearch(String searchText) {
Toast.makeText(ParticipantsActivity.this, "Started Search", Toast.LENGTH_LONG).show();
Query firebaseSearchQuery = mUserDatabase.orderByChild("name").startAt(searchText);
FirebaseRecyclerOptions<ParticipantsObject> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<ParticipantsObject>()
.setQuery(firebaseSearchQuery, ParticipantsObject.class)
.build();
class UserHolder extends RecyclerView.ViewHolder {
private TextView imageThumbTextView, nameTextView
UserHolder(View itemView) {
super(itemView);
imageThumbTextView = itemView.findViewById(R.id.profile_image);
nameTextView = itemView.findViewById(R.id.name_text);
}
void setUsers(ParticipantsObject participantsObject) {
String imageThumb = driverObject.getThumb_image();
imageThumbTextView.setText(imageThumb);
String name = participantsObject.getName();
nameTextView.setText(name);
}
}
FirebaseRecyclerAdapter<ParticipantsObject, UserHolder> firebaseRecyclerAdapter;
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<ParticipantsObject, UserHolder>(firebaseRecyclerOptions) {
#Override
protected void onBindViewHolder(#NonNull UserHolder userHolder, int position, #NonNull ParticipantsObject participantsObject) {
userHolder.setUsers(participantsObject);
}
#Override
public UserHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_layout, parent, false);
return new UserHolder(view);
}
};
mResultList.setAdapter(firebaseRecyclerAdapter);
firebaseRecyclerAdapter.startListening();
}
}
My Activity XML file
<?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"
android:background="#ffffff"
tools:context="com.MyApp.ParticipantsActivity">
<TextView
android:id="#+id/heading_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="30dp"
android:text="Firebase Search"
android:textColor="#555555"
android:textSize="24sp" />
<EditText
android:id="#+id/search_field"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignStart="#+id/heading_label"
android:layout_below="#+id/heading_label"
android:layout_marginRight="20dp"
android:layout_marginTop="20dp"
android:layout_toStartOf="#+id/search_btn"
android:background="#drawable/search_layout"
android:ems="10"
android:hint="Search here"
android:inputType="textPersonName"
android:paddingBottom="10dp"
android:paddingLeft="20dp"
android:paddingRight="20dp"
android:paddingTop="10dp"
android:textColor="#999999"
android:textSize="16sp" />
<ImageButton
android:id="#+id/search_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/search_field"
android:layout_alignParentEnd="true"
android:layout_alignTop="#+id/search_field"
android:layout_marginRight="30dp"
android:background="#android:color/background_light"
app:srcCompat="#mipmap/search_button" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/result_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/search_field"
android:layout_marginTop="50dp">
</androidx.recyclerview.widget.RecyclerView>
</RelativeLayout>
My list layout
<?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"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/profile_image"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="20dp"
app:srcCompat="#mipmap/ic_default_user" />
<TextView
android:id="#+id/name_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginStart="14dp"
android:layout_marginLeft="20dp"
android:layout_marginTop="50dp"
android:layout_marginEnd="213dp"
android:layout_marginRight="20dp"
android:layout_toEndOf="#+id/profile_image"
android:text="Username"
android:textColor="#555555"
android:textSize="16sp" />
</RelativeLayout>
Any ideas or advice would be much appreciated.

Your code is setting the adapter only after a button is pushed. Because you didn't set it before the first time the RecyclerView needed to render itself on screen, it's going to warn you about that with the message you see in the log. The RecyclerView must have an adapter attached at the time of rendering in order for it to display anything.

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);
}
}

Fragment transaction from activity not working

So i have a main activity that commits the transaction of a fragment that inflates the activity with an image view just like a main cover, and with the button "Sign up" that takes you to the signUp activity. However, all of that does work like it shoulds, the transaction works and the inflater does too, but the problem comes when:
I am trying to call a fragment (signUpForm) from the activity (signUp). The root of the problem is that the fragment transaction to signUpForm is not working because the toast programmed on it is not showing, so it does not even get to the inflater.
signUp class:
package com.example.joshumberto.workcon;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;
public class signUp extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_up);
getSupportFragmentManager().beginTransaction()
.add(R.id.sign_up_container, new signUpForm(), "signUpForm").commit();
}
}
activity_sign_up.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:id="#+id/sign_up_container"
tools:context=".signUp" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="look, i should have inflated companions"
/>
</LinearLayout>
signUpForm class (only pasting the oncreate method, other things aren't needed):
package com.example.joshumberto.workcon;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;
public class signUpForm extends Fragment implements View.OnClickListener {
EditText correo;
EditText telefono;
Button continuar;
public signUpForm(){
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setHasOptionsMenu(true);
}
public View OnCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Toast.makeText(
getActivity(),
"i am supposued to be created!!",
Toast.LENGTH_LONG).show();
View v = inflater.inflate(R.layout.fragment_sign_up_form, container, false);
correo = (EditText) v.findViewById(R.id.txt_usuario_correo);
telefono = (EditText) v.findViewById(R.id.txt_usuario_telefono);
continuar = (Button) v.findViewById(R.id.btn_registro_continuar);
continuar.setOnClickListener(this);
return v;
}
fragment_sign_up_form.xml (just button,textview and edit texts to inflate activity)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:background="#color/colorSignUpBackground"
tools:context=".signUp"
android:id="#+id/sign_up_form" >
<!--<include android:id="#+id/toolbar"
layout="#layout/toolbar" />-->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Registro"
android:fontFamily="sans-serif-smallcaps"
android:textSize="#dimen/titulo_txt"
android:id="#+id/textView"
android:layout_gravity="center_horizontal"
android:layout_marginTop="#dimen/margin_top_standar" />
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/txt_usuario_correo"
android:layout_marginTop="#dimen/margin_top_login_btn"
android:hint="Correo"
android:gravity="center"
android:layout_gravity="center_horizontal" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/txt_usuario_contrasena"
android:layout_marginTop="#dimen/margin_top_login_btn"
android:hint="Contrasena"
android:gravity="center"
android:layout_gravity="center_horizontal" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/txt_usuario_telefono"
android:layout_marginTop="#dimen/margin_top_login_btn"
android:hint="Telefono"
android:gravity="center"
android:layout_gravity="center_horizontal" />
</LinearLayout>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Continuar"
android:id="#+id/btn_registro_continuar"
android:layout_gravity="center_horizontal" />
<!--<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/miLista"
></ListView>-->
Ideas? Thanks.

You should try replace() method instead of add(). like this.
getSupportFragmentManager().beginTransaction().replace(R.id.sign_up_container, new signUpForm(), "signUpForm").commit();

RuntimeException: Unable to start activity ComponentInfo: java.lang.NullPointerException Fatal exception

Hi i'm new to android programming and i'm having this issue where i'm sure that my code should work but doesn't.
This is my MainActivity.java:
package com.example.evo;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
public class MainActivity extends Activity {
ImageButton imageButton2;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.open);
imageButton2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(), SecondScreenActivity.class);
}
} );
}
}
This is my SeconScreenActirity.java
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageButton;
public class SecondScreenActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.high_score);
}
}
This is my highscore.xml layout file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/yedi"
android:orientation="vertical" >
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="220dp"
android:text="high scores"
android:textColor="#FA5882" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="200dp"
android:layout_marginTop="29dp"
android:text="Evrim"
android:textColor="#00FFFF" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="320dp"
android:layout_marginTop="-17dp"
android:text="1528"
android:textColor="#CC2EFA" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="200dp"
android:layout_marginTop="20dp"
android:text="Selin"
android:textColor="#00FFFF" />
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="320dp"
android:layout_marginTop="-17dp"
android:text="1016"
android:textColor="#CC2EFA" />
<TextView
android:id="#+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="200dp"
android:layout_marginTop="11dp"
android:text="Muhammed"
android:textColor="#00FFFF" />
<TextView
android:id="#+id/textView7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="320dp"
android:layout_marginTop="-17dp"
android:text="800"
android:textColor="#CC2EFA" />
<ImageButton
android:id="#+id/imageButton1"
android:layout_width="72dp"
android:layout_height="0dp"
android:layout_marginTop="80dp"
android:layout_weight="0.16"
android:src="#drawable/abc_ic_ab_back_holo_light"
android:contentDescription="#string/todo"/>
</LinearLayout>
This is my open.xml where i have my imageButton2
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/son"
android:paddingBottom="#dimen/activity_horizontal_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_horizontal_margin"
android:screenOrientation="landscape"
tools:context="com.example.kkk.MainActivity$PlaceholderFragment" >
<ImageButton
android:id="#+id/imageButton2"
android:layout_width="100dp"
android:layout_height="30dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="#drawable/highscore" android:contentDescription="#string/todo"/>
<ImageButton
android:id="#+id/imageButton1"
android:layout_width="100dp"
android:layout_height="30dp"
android:layout_above="#+id/imageButton2"
android:layout_alignLeft="#+id/imageButton2"
android:src="#drawable/play" android:contentDescription="#string/todo"/>
<ImageButton
android:id="#+id/imageButton4"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:layout_below="#+id/imageButton3"
android:layout_centerHorizontal="true"
android:src="#drawable/exit" android:contentDescription="#string/todo"/>
<ImageButton
android:id="#+id/imageButton3"
android:layout_width="100dp"
android:layout_height="30dp"
android:layout_alignLeft="#+id/imageButton2"
android:layout_below="#+id/imageButton2"
android:src="#drawable/aboutt" android:contentDescription="#string/todo"/>
</RelativeLayout>
I also updated my AndroidManifest.xml to add SeconScreenActivity.java
And i'm getting this
java.lang.RuntimeException: Unable to start activity
ComponentInfo java.lang.NullPointerException
errors please plase help!

You never initialize your imageButton element in your first activity.
So you get the NullPointerException when trying to assign to it the click listener.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.open);
//or whatever the id is for the image button in the open layout
imageButton2 = (ImageButton) findViewById(R.id.imageButton2);
imageButton2.setOnClickListener(new View.OnClickListener() {

You missed to take reference of ImageButton from open layout:
imageButton2 = (ImageButton) findViewById(R.id.<ImageButtonIdInOpenXml);

Just add below line
imageButton2 = (ImageButton)findViewById(R.id.imageButton1);
after
setContentView(R.layout.open);
Your are getting error because view ImageButton is not initialized