Change button text and action - android development

Question

I'm having trouble figuring out how to change the text and action of a button. What I want to do is have a button with the text "play" and when clicked it will play a song and change the text to "pause". then when you click it again, it will pause the song and change the text to "play".

I know how to use the mediaplayer (the coding) and just don't know how to code the button that way:

so far I have:

final Button testButton = (Button) findViewById(R.id.button1);
testButton.setText("Play");
testButton.setOnClickListener( new View.OnClickListener() {

@Override
public void onClick (View v) {
mPlayer.start();
testButton.setText("Pause");