在studio中有些代碼沒有自動生成，有關于R的地方一直顯示紅色
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
LayoutInflater inflate = LayoutInflater.from(MainActivity.this);
View viewDialog = inflate.inflate(R.layout.new_cost_data, null);
final EditText title = (EditText) viewDialog.findViewById(R.id.et_cost_title);
final EditText money = (EditText) viewDialog.findViewById(R.id.et_cost_money);
final DatePicker date = (DatePicker) viewDialog.findViewById(R.id.dp_cost_date);
2017-04-30
先 Build -> ReBuild Project
再 Tools -> Android -> Sync Project