I am a beginner trying to make a click listener for a button in java, can you help me?

I am trying to compile my code in Android Studio, code is here:

choice1.setOnClickListener(new View.OnClickListener(){
        public void onClick(View view)
        {
            if(choice1.getText().equals(result))
                showToastMessage(true);
            else
                showToastMessage(false);
        }
    });

Android Studio is saying that all of the lines are illegal and won't run in the android emulator because it cannot be compiled. Can someone help me with what is going wrong?

EDIT: Here is the code that I am using in this specific instance:

public class FullscreenActivity extends AppCompatActivity {
    private String result = "New York";
    private Button choice1 = (Button)findViewById(R.id.choice1);
    private Button choice2 = (Button)findViewById(R.id.choice2);
    private Button choice3 = (Button)findViewById(R.id.choice3);

    @Override protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fullscreen);
    }

    choice1.setOnClickListener(new View.OnClickListener(){
        public void onClick(View view)
        {
            if(choice1.getText().equals(result))
                showToastMessage(true);
            else
                showToastMessage(false);
        }
    });

    choice2.setOnClickListener(new View.OnClickListener(){
        public void onClick(View view) {
            if(choice2.getText().equals(result))
                showToastMessage(true);
            else
                showToastMessage(false);
        }
    });

    choice3.setOnClickListener(new View.OnClickListener(){
        public void onClick(View view) {
            if(choice3.getText().equals(result))
                showToastMessage(true);
            else
                showToastMessage(false);
        }
    });
}

    private void showToastMessage(boolean showToastMessage)
    {
            if(showToastMessage)
                Toast.makeText(this, "Correct", toast.LENGTH_SHORT).show();
            else
                Toast.makeText(this, "Wrong", Toast.LENGTH_SHORT).show();
    }

It's just that I don't know if the code I am learning is old, I made a mistake or whatever the case may be, I just want to learn it as best I can, hence why I'm asking. Thanks to everyone who has replied! <3

You have to put a click listener in one of the lifecycle callback. If it is an activity,
move the code to onCreate() method.

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.filters); 
choice1.setOnClickListener(new View.OnClickListener(){
public void onClick(View view)
{
if(choice1.getText().equals(result))
showToastMessage(true);
else
showToastMessage(false);
}
});
}

if it's a fragment, put it in onViewCreated().