setEabled(true)とsetEnabled(false)

setEnabledでtrueだとbuttonを押せる。

private Button startButton;
    private Button stopButton;
    private Button resetButton;

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

        startButton = (Button) findViewById(R.id.startButton);
        stopButton = (Button) findViewById(R.id.stopButton);
        resetButton = (Button) findViewById(R.id.resetButton);

        setButtonState(true,false,false);
    }

    public void setButtonState(boolean start, boolean stop, boolean reset){
        startButton.setEnabled(true);
        stopButton.setEnabled(false);
        resetButton.setEnabled(false);

    }