How to set the value of TextView in Custom Dialog in Android

Question

I want to set the value of TextView in custom dialog box after I clicked in one of the fragments in Activity. Dialog was running fine with custom text view after it is being called. The problem is that it always shows NullPointerException when I tried to call changeMessageText("Hello") function.

ProgressDialogFragment.java

public class ProgressDialogFragment extends DialogFragment {

        private TextView txtMessage;
        private AlertDialog.Builder mBuilder;

        public static ProgressDialogFragment newInstance(AlertDialog.Builder builder){
            ProgressDialogFragment progressDialogFragment = new ProgressDialogFragment();
            progressDialogFragment.mBuilder = builder;
            return progressDialogFragment;
        }

        @Nullable
        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {

            View view = getLayoutInflater(savedInstanceState).inflate(R.layout.dialog_progress, null);
            txtMessage = (TextView) view.findViewById(R.id.txtMessage);

            changeMessageText("Hello World by default"); // this one works

            mBuilder.setView(view);

            return mBuilder.create();

        }
        public void changeMessageText(String text){
            txtMessage.setText(text);
        }
}

Sample Code after the button Clicked

AlertDialog.Builder builder = new AlertDialog.Builder(this);
ProgressDialogFragment progressDialogFragment = ProgressDialogFragment.newInstance(builder);
progressDialogFragment.show(getSupportFragmentManager(),"progress_dialog");
// dialog box shows until the following function is called.

progressDialogFragment.changeMessageText("Hello");

Answer 1

When progressDialogFragment.changeMessageText("Hello"); called, txtMessage is not created yet.

1) Add private String message; to ProgressDialogFragment .

2) Change changeMessageText

public void changeMessageText(String text){
    message = text;
    if(txtMessage != null){
        txtMessage.setText(text);
   }            
}

3) add after mBuilder.setView(view);

if(message!=null && !message.isEmpty()){
    txtMessage.setText(message);
}

4) Remove changeMessageText("Hello World by default"); in onCreateDialog

And. It Doesn't Work for Me.

View view = getLayoutInflater(savedInstanceState).inflate(R.layout.dialog_progress, null);

I change it.

LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.dialog_progress, null);

Hope it will help you.