android studio navigtion not woring when movieng with fragments in java - android-studio

Question

so i wanted to creat a footer navigtion on the main activity and a fragment view above it
but now when i try to use the normal navigtion with the navigtion grafh it just crashes.
mainActivity java code:
package com.example.mywatchlist;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button homeBtn = findViewById(R.id.homeBtn);
Button profileBtn = findViewById(R.id.profileBtn);
Button socialBtn = findViewById(R.id.theSocialSearchBtn);
Button contentBtn = findViewById(R.id.contentContentSearchBtn);
homeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
homeFragment home = new homeFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.fragmentContainerView,home).commit();
}
});
profileBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
userProfileFragment profile = new userProfileFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.fragmentContainerView,profile).commit();
}
});
socialBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
socialSearchFragment social = new socialSearchFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.fragmentContainerView,social).commit();
}
});
contentBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
contentSearchFragment contentSearch = new contentSearchFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.fragmentContainerView,contentSearch).commit();
}
});
}
}
main activity.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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/fragmentContainerView"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="632dp"
app:defaultNavHost="true"
app:navGraph="#navigation/navigation" />
<LinearLayout
android:id="#+id/footer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<Button
android:id="#+id/homeBtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="Go to\nHome"
android:textSize="12dp" />
<Button
android:id="#+id/profileBtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="My\nProfile"
android:textSize="12dp" />
<Button
android:id="#+id/theSocialSearchBtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="Search for\nPeople"
android:textSize="12dp" />
<Button
android:id="#+id/contentContentSearchBtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="Search for\nContent"
android:textSize="12dp" />
</LinearLayout>
</LinearLayout>
and now it crashes when i try to move in this fragment:
fragment to move from java code:
package com.example.mywatchlist;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.navigation.Navigation;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
/**
* A simple {#link Fragment} subclass.
* Use the {#link contentSearchFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class contentSearchFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
public contentSearchFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment contentSearchFragment.
*/
// TODO: Rename and change types and number of parameters
public static contentSearchFragment newInstance(String param1, String param2) {
contentSearchFragment fragment = new contentSearchFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_content_search,container, false);
// Inflate the layout for this fragment
Button searchBtn = view.findViewById(R.id.contentContentSearchBtn);
searchBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Navigation.findNavController(view).navigate(R.id.action_contentSearchFragment_to_contentFragment);
}
});
return view;
}
}
and this is the 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"
tools:context=".contentSearchFragment" >
<TextView
android:id="#+id/contentSearchTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#C4FF80"
android:gravity="center"
android:text="Content search"
android:textSize="30dp" />
<Button
android:id="#+id/contentSearchAddNewContent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add new content" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FFEB3B"
android:orientation="horizontal">
<EditText
android:id="#+id/contentSearchBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#C8C8C8"
android:ems="10"
android:hint="Search for content"
android:inputType="textPersonName"
android:minHeight="48dp" />
<Button
android:id="#+id/contentContentSearchBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Search" />
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="502dp">
<TextView
android:id="#+id/contentSearchData"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="test\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntesttest\ntest\ntest\ntest\ntest\ntest\XXXXXXXXXXXXXXXXXXntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\ntest\nXXXXXXXXXXXXXXXXX test\ntest\nXXXXXXXXXXXXXXXX\ntest\ntest\ntest\ntest\ntest" />
</ScrollView>
</LinearLayout>
and this is the navigtion xml:
<?xml version="1.0" encoding="utf-8"?>
<navigation 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/navigation"
app:startDestination="#id/startFragment">
<fragment
android:id="#+id/startFragment"
android:name="com.example.mywatchlist.startFragment"
android:label="fragment_start"
tools:layout="#layout/fragment_start" >
<action
android:id="#+id/action_startFragment_to_logInFragment"
app:destination="#id/logInFragment" />
<action
android:id="#+id/action_startFragment_to_registerFragment"
app:destination="#id/registerFragment" />
</fragment>
<fragment
android:id="#+id/logInFragment"
android:name="com.example.mywatchlist.logInFragment"
android:label="fragment_log_in"
tools:layout="#layout/fragment_log_in" >
<action
android:id="#+id/action_logInFragment_to_homeFragment"
app:destination="#id/homeFragment" />
</fragment>
<fragment
android:id="#+id/registerFragment"
android:name="com.example.mywatchlist.registerFragment"
android:label="fragment_register"
tools:layout="#layout/fragment_register" >
<action
android:id="#+id/action_registerFragment_to_homeFragment"
app:destination="#id/homeFragment" />
</fragment>
<fragment
android:id="#+id/homeFragment"
android:name="com.example.mywatchlist.homeFragment"
android:label="fragment_home"
tools:layout="#layout/fragment_home" />
<fragment
android:id="#+id/userProfileFragment"
android:name="com.example.mywatchlist.userProfileFragment"
android:label="fragment_user_profile"
tools:layout="#layout/fragment_user_profile" />
<fragment
android:id="#+id/contentFragment"
android:name="com.example.mywatchlist.contentFragment"
android:label="fragment_content"
tools:layout="#layout/fragment_content" />
<fragment
android:id="#+id/contentSearchFragment"
android:name="com.example.mywatchlist.contentSearchFragment"
android:label="fragment_content_search"
tools:layout="#layout/fragment_content_search" >
<action
android:id="#+id/action_contentSearchFragment_to_contentFragment"
app:destination="#id/contentFragment" />
</fragment>
<fragment
android:id="#+id/socialSearchFragment"
android:name="com.example.mywatchlist.socialSearchFragment"
android:label="fragment_social_search"
tools:layout="#layout/fragment_social_search" >
<action
android:id="#+id/action_socialSearchFragment_to_userProfileFragment"
app:destination="#id/userProfileFragment" />
</fragment>
</navigation>
crashing:
--------- beginning of crash
2022-07-01 14:32:49.986 25363-25363/com.example.mywatchlist E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mywatchlist, PID: 25363
java.lang.IllegalStateException: View com.google.android.material.button.MaterialButton{3bedc11 VFED..C.. ...P.... 921,5-1440,173 #7f080237 app:id/contentContentSearchBtn} does not have a NavController set
at androidx.navigation.Navigation.findNavController(Navigation.kt:71)
at com.example.mywatchlist.contentSearchFragment$1.onClick(contentSearchFragment.java:73)
at android.view.View.performClick(View.java:7448)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1194)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2022-07-01 14:32:50.027 25363-25363/com.example.mywatchlist I/Process: Sending signal. PID: 25363 SIG: 9
thank you to all the helpers

Answer 1

can you please share the crashing error? It's hard to figure out the error. If you can also add how to reproduce the crash it can be very helpful

Answer 2

You forgot to initialize NavHostFragent
so kindly Initiliaze In your OnCreate
NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager()
.findFragmentById(R.id. fragmentContainerView);
NavController navController = navHostFragment.getNavController();
and for the navigate one fragment to another fragment use navigate
homeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {navController.navigate(R.id. action_startFragment_to_registerFragment
}
});)