How to edit a TextView in a fragment from MainActivity - android-studio

Question

I have a textview in a fragment that I want to edit in MainActivity.java (The parent activity). I've tried many methods such as creating a function in the fragment code:
public class HomeFragment extends Fragment {
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_home, container, false);
return root;
}
public void status(String txt){
TextView textView = getView().findViewById(R.id.status_message);
textView.setText(txt);
}
}
and calling it in MainActivity like so:
public class MainActivity extends AppCompatActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
HomeFragment fragment = new HomeFragment();
fragment.status("Test");
}
}
But this results in the app crashing. How can I fix this? I am using the Bottom Navigation Activity Template.

Answer 1

Best thing I would advice is to create your fragment instance in your main activity like this:
public class MainActivity extends AppCompatActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
HomeFragment fragment =
HomeFragment.createInstance("Test");
}
}
And then in your fragment:
public class HomeFragment extends Fragment {
private string text;
public View onCreateView(#NonNull LayoutInflater
inflater, ViewGroup container, Bundle
savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_home,
container, false);
TextView textView =
root.findViewById(R.id.status_message);
return root;
}
public static HomeFragment createInstance(String text)
{
HomeFragment f =new HomeFragment ();
Bundle bundle=new Bundle();
bundle.putString("key", text);
f.set arguments(bundle);
return f;
}
#Override
public void onCreate(#Nullable Bundle
savedInstanceState)
{
super.onCreate(savedInstanceState);
if (getArguments != null) {
text= getArguments.getString("key");
status(text);
}
}
public void status(String txt){
textView.setText(txt);
}
}
Hopes this helps

Answer 2

Fixed this by accessing MainActivity from the fragment rather than accessing Fragment from MainActivity. Instead of changing the textview from MainActivity, send the string you want to put in the textview through a method and change the textview in the fragment.
MainActivity.java
public class MainActivity extends AppCompatActivity{
String text;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public String sendData(){
return text;
}
}
HomeFragment.java
public class HomeFragment extends Fragment {
TextView tv;
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_home, container, false);
tv = root.findViewById(R.id.textview);
MainActivity ma = (MainActivity)getActivity();
tv.setText(ma.sendData());
return root;
}
}