if (!cond1 ) {

            b1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {

                        audio_buongiorno.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {

                            @Override
                            public void onCompletion(MediaPlayer mp) {
                                b1.setBackgroundResource(android.R.drawable.btn_default);
                                b1.setText("Buongiorno Buonasera");
                                Log.v("cond","cond 1 stop "+cond1);
                                cond1 = false;

                            }

                        });
                        audio_buongiorno.start();

                        b1.setBackgroundColor(Color.RED);
                        b1.setText("Riproduzione in corso . . .");
                         cond1 = true;

                        Log.v("cond", "cond 1 " + cond1);
                    }

            });

    }

        if(cond1) {
            b1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    audio_buongiorno.stop();
                    b1.setBackgroundResource(android.R.drawable.btn_default);
                    b1.setText("Buongiorno Buonasera");

                    cond1 = false;
                    Log.v("cond", "cond 2 " + cond1);
                }
                });
        }