对话框的三个按钮的显示方法实现

Log.d(getClass().toString(),"initDevice is start!!!");AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);builder.setTitle("工学1号馆");builder.setIcon(R.drawable.ic_launcher);builder.setMessage("浏览wuyudong的博客?");builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {    }});builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {        dialog.cancel();    }});builder.setNeutralButton("扫描", new DialogInterface.OnClickListener() {    @Override    public void onClick(DialogInterface dialog, int which) {    }});AlertDialog dialog = builder.create();dialog.show();