我目前正在为我的A Level计算机科学控制评估工作开发一名Scout Manager。我正在使用Android Studio，Java，XML和MySQL，但以前都没有使用过。
我目前正在尝试计算活动/夏令营的食品估计成本，以及保存用餐计划，但是尽管满足if语句的所有条件，但仍未执行。
以下是声明：
//Calculating the cost of all food, as well as creating records for the food available on the event.
double TotalFoodCost=0;
if (providingfood==true)
{
if (sessiontype=="Event"){
Cursor FoodItem = DatabaseHandler.getRandomLunch();
//Ensures that the necessary meal is actually in the database
if (FoodItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
Integer foodID = FoodItem.getInt(FoodItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
Integer mealNo=1;
double FoodPricePerPerson = FoodItem.getDouble(FoodItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
Integer eventmealid = createEventMealId();
//Creates a record containing the meal and event ids
eventMealDetails eventmeal= new eventMealDetails(eventmealid, id, foodID,
1);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost+(properfoodpriceperperson*noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any lunches, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
}
else if (sessiontype=="Camp"){
//Getting necessary variables ready
Cursor FirstItem;
Integer foodID;
Integer mealNo;
double FoodPricePerPerson;
Integer eventmealid;
eventMealDetails eventmeal;
int noofdaysleft=noofdays;
//First meal
FirstItem=DatabaseHandler.getRandomDinner();
//Ensures that the necessary meal is actually in the database
if (FirstItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
foodID = FirstItem.getInt(FirstItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
mealNo = 1;
FoodPricePerPerson = FirstItem.getDouble(FirstItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
//Creates a record containing the meal and event ids
eventmealid = createEventMealId();
eventmeal = new eventMealDetails(eventmealid, id, foodID, mealNo);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost+(properfoodpriceperperson * noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any dinners, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
//Rest of meals
do{
Cursor breakfastItem=DatabaseHandler.getRandomBreakfast();
//Ensures that the necessary meal is actually in the database
if (breakfastItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
foodID = breakfastItem.getInt(breakfastItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
mealNo = mealNo + 1;
FoodPricePerPerson = breakfastItem.getDouble(breakfastItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
//Creates a record containing the meal and event ids
eventmealid = createEventMealId();
eventmeal = new eventMealDetails(eventmealid, id, foodID, mealNo);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost + (properfoodpriceperperson * noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any breakfasts, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
Cursor lunchItem=DatabaseHandler.getRandomLunch();
//Ensures that the necessary meal is actually in the database
if (lunchItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
lunchItem = DatabaseHandler.getRandomDinner();
foodID = lunchItem.getInt(lunchItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
mealNo = mealNo + 1;
FoodPricePerPerson = lunchItem.getDouble(lunchItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
//Creates a record containing the meal and event ids
eventmealid = createEventMealId();
eventmeal = new eventMealDetails(eventmealid, id, foodID, mealNo);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost + (properfoodpriceperperson * noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any lunches, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
Cursor dinnerItem=DatabaseHandler.getRandomDinner();
//Ensures that the necessary meal is actually in the database
if (breakfastItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
foodID = dinnerItem.getInt(dinnerItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
mealNo = mealNo + 1;
FoodPricePerPerson = dinnerItem.getDouble(dinnerItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
//Creates a record containing the meal and event ids
eventmealid = createEventMealId();
eventmeal = new eventMealDetails(eventmealid, id, foodID, mealNo);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost + (properfoodpriceperperson * noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any dinners, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
noofdaysleft=noofdaysleft-1;
}while (noofdaysleft>0);
//Last Meal
Cursor breakfastItem=DatabaseHandler.getRandomBreakfast();
if (breakfastItem.moveToFirst()) {
//Gets a random food, works out the cost for the number of people.
foodID = breakfastItem.getInt(breakfastItem.getColumnIndex(
DatabaseHandler.COLUMN_MNAME));
mealNo = mealNo + 1;
FoodPricePerPerson = breakfastItem.getDouble(breakfastItem.getColumnIndex(
DatabaseHandler.COLUMN_FCOST));
//Creates a record containing the meal and event ids
eventmealid = createEventMealId();
eventmeal = new eventMealDetails(eventmealid, id, foodID, mealNo);
DatabaseHandler.createEventMeal(eventmeal);
//Rounds the food price per person, as the database will not always store decimals correctly.
BigDecimal bigdecimalfoodpriceperperson=new BigDecimal(FoodPricePerPerson);
BigDecimal bigdecimalproperfoodpriceperperson=((bigdecimalfoodpriceperperson.setScale(2,bigdecimalfoodpriceperperson.ROUND_DOWN)));
double properfoodpriceperperson=bigdecimalproperfoodpriceperperson.doubleValue();
TotalFoodCost = TotalFoodCost + (properfoodpriceperperson * noOfPeople);
}
else
{
Toast.makeText(
context,
"Error - you have not added any breakfasts, therefore food " +
"cannot be added.",
Toast.LENGTH_SHORT
).show();
return;
}
}
}
我确保提供的食物是真实的，已经将Eventtype和Camp设置为sessiontype，但仍然没有任何反应-甚至没有错误消息，或者吐司说什么也找不到。
任何帮助将不胜感激。另外，我对这些语言，此IDE和此站点还很陌生，因此，如果需要更多信息，请随时询问，以便我改善问题。
谢谢。