Android Studio – Android Studio- Display one string if a button is pressed with no text in the textbox and another when text is inputted

I am incredibly new to Android Studio and was hoping to get some assistance.
For some reason, this code is only displaying the ("Hi, " +name) portion. I am not sure what I am doing wrong or how to get the ("You must enter a name") portion to show when there is no text that has been inputted. We are needing to incorporate a SayHello() function into this and I am not sure if I am doing it properly…
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package com.example.assignment5_2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    EditText nameText;
    TextView textGreeting;
    Button buttonSayHello;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        nameText = (EditText) findViewById(R.id.nameText);
        textGreeting = (TextView) findViewById(R.id.textGreeting);
        buttonSayHello = (Button) findViewById(R.id.buttonSayHello);

        buttonSayHello.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                SayHello();
            }

            public void SayHello() {
                String name = nameText.getText().toString();
                if (name != null) {
                    textGreeting.setText("Hi, " + name);
                } else {
                    textGreeting.setText("You must enter a name");
                    buttonSayHello.setEnabled(name.isEmpty());
                }

            }
        });
    }
}