Android Studio: How to change a button's text onClick

Question

I am very new to Android. I am trying to make a simple tic tac toe game. I have 9 buttons set up evenly across the screen with gray lines between. I just need the buttons to say either 'X' or '0' when pressed. How do you change the buttons text when you click it? I should be able to figure out the logic on whether it should be an X or an O once I can actually figure out how to change the button text.

Solution

You can try something like this: (You need to fill in your button id.)

public class MainActivity extends Activity implements View.OnClickListener {
private Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = (Button) findViewById(R.id.yourbuttonid);
        btn.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        btn.setText("X");
    }
}

If you want to do this with multiple buttons you need to check which button is clicked, like this:

@Override
public void onClick(View v) {
    if(v.getId() == R.id.yourbuttonid) {
        btn.setText("X");
    }else if(v.getId() == R.id.yourbuttonid2){
        btn2.setText("X");
    }
}

Hope that solves your problem. If you have any questions, feel free to ask ;)