我正在制作化学反应的测验应用程序。该应用程序向用户提供问题，用户在两个单独的文本字段中键入反应物和产品。
我有一个数据类，其中包含所有可能的测验问题。然后，根据特定参数，数据类从可能的问题池中选择一定数量的问题，并将它们混合成一个数组quizQuestions。
我还有一个视图控制器quizController。对于每个问题，都会加载quizController的新实例。 vc需要数据来知道要显示哪个问题，正确答案是什么等等。
这是我在数据和vc之间进行通信的原始解决方案。
我创建了一个数据类实例data。
我为第一个问题创建了vc1，并将data设置为vc1的属性，并将其标记设置为1，以便从数据中加载第一个问题。
在用户回答第一个问题后，我使用vc2的方法创建了一个新的视图控制器vc1，使标记比最后一个vc更多，以便加载第二个问题，并将data从vc1的属性传递给vc2。
然后我重复其他问题。
然而，这不是很好的设计，我正在寻找更好的解决方案。我不认为我可以使用类方法，因为data应该包含一组随机问题。下面我有数据类的代码。
// the data class as it is now, designed for instance methods
- (id)init {
self = [super init];
if (self) {
//Questions of the same type belong to a "ROW" (Reaction of Week)
//individual questions
// Items in array: (1)Question, (2)Reactants, (3)Products, (4)Elements for keyboard
NSArray *R1Q1 = [[NSArray alloc] initWithObjects:@"Methanol is burned completely in air", @"2CH₃OH(l) + 3O₂(g)", @"2CO₂(g) + 4H₂O", @"C,H,O", nil];
NSArray *R1Q2 = [[NSArray alloc] initWithObjects:@"Ammonia is burned in excess oxygen gas", @"4NH₃(g) + 7H₂O(l)", @"4NO₂(g) + 6H₂O(l)", @"N,H,O", nil];
NSArray *R1Q3 = [[NSArray alloc] initWithObjects:@"Hydrogen sulfide gas is burned in excess oxygen gas", @"2H₂S(g) + 3O₂(g)", @"CO₂(g) + 2SO₂(g)", @"H,S,O", nil];
NSArray *R2Q1 = [[NSArray alloc] initWithObjects:@"Solid potassium is added to a flask of oxygen gas", @"K(s) + O₂(g)", @"KO₂(s)", @"K,O", nil];
NSArray *R2Q2 = [[NSArray alloc] initWithObjects:@"Sodium metal is dropped into a flask of pure water", @"2Na(s) + H₂O(l)", @"2Na⁺(aq) + 2OH⁻(aq) + H₂(g)", @"Na,H,O", nil];
NSArray *R2Q3 = [[NSArray alloc] initWithObjects:@"A piece of lithium is heated strongly in oxygen", @"4Li(s) + O₂(g)", @"2Li₂O(s)", @"Li,O", nil];
NSArray *R3Q1 = [[NSArray alloc] initWithObjects:@"Solutions of potassium chloride and silver nitrate are mixed", @"Ag⁺(aq) + Cl⁻(aq)", @"AgCl(s)", @"K,Cl,Ag,N,O", nil];
NSArray *R3Q2 = [[NSArray alloc] initWithObjects:@"Solutions of iron(III) nitrate and sodium hydroxide are mixed", @"Fe³⁺(aq) + 3OH⁻(aq)", @"Fe(OH)₃(s)", @"Fe,N,O,Na,H", nil];
NSArray *R3Q3 = [[NSArray alloc] initWithObjects:@"Solutions of nickel iodide and barium hydroxide are mixed", @"Ni²⁺(aq) + 2OH⁻(aq)", @"Ni(OH)₂(s)", @"Ni,I,Ba,OH", nil];
// add rest
//organize questions into groups
row1 = [[NSArray alloc] initWithObjects:R1Q1, R1Q2, R1Q3, nil];
row2 = [[NSArray alloc] initWithObjects:R2Q1, R2Q2, R2Q3, nil];
row3 = [[NSArray alloc] initWithObjects:R3Q1, R3Q2, R3Q3, nil];
//add rest
// array containing all questions
allRows = [[NSMutableArray alloc] initWithObjects:row1, row2, row3, nil];
//in a real situation, needs to be given to class dynamically
self.maxRowNumber = 3;
self.questionsPerRow = 2;
}
return self;
}
- (void)selectQuestions {
self.quizQuestions = [[NSMutableArray alloc] init];
for (int j = 0; j<self.maxRowNumber; j++) {
//shuffle each row
NSMutableArray *row = [NSMutableArray arrayWithArray:[allRows objectAtIndex:j]];
[row shuffle];
//add questions from each row
for (int k = 0; k<self.questionsPerRow; k++)
[quizQuestions addObject:[row objectAtIndex:k]];
}
[quizQuestions shuffle];
}
查看控制器代码摘录
# pragma mark Cell Setup
//1st cell in tableview
- (void) setUpEquationCell: (UITableView *) tableView {
equationCell = (EquationCell *) [tableView dequeueReusableCellWithIdentifier:@"equationCell"];
if (equationCell == nil) {
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"EquationCell" owner:self options:nil];
equationCell = (EquationCell*) [nib objectAtIndex:0];
[equationCell.leftButton addTarget:self action:@selector(addDissociateCell) forControlEvents:UIControlEventTouchUpInside];
[equationCell.rightButton addTarget:self action:@selector(addBalanceCell) forControlEvents:UIControlEventTouchUpInside];
}
}
- (void) setUpBalanceCell: (UITableView *) tableView {
//2nd cell in tableview
balanceCell = (BalanceCell *) [tableView dequeueReusableCellWithIdentifier:@"balanceCell"];
if (balanceCell == nil) {
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"BalanceCell" owner:self options:nil];
balanceCell = (BalanceCell*) [nib objectAtIndex:0];
// stores data from equation cell into model
for (FormulaLabel *label in equationCell.leftView.equationOrder)
[leftData.equation addObject:label.text];
for (FormulaLabel *label in equationCell.rightView.equationOrder)
[rightData.equation addObject:label.text];
[leftData setUpBalancedEquation];
[rightData setUpBalancedEquation];
[self setUpView:balanceCell.leftView fromArray:leftData.equation toArray:leftBalanceItems];
[self setUpView:balanceCell.rightView fromArray:rightData.equation toArray:rightBalanceItems];
[self addBalanceTapMethodInArray:leftBalanceItems Data:leftData];
[self addBalanceTapMethodInArray:rightBalanceItems Data:rightData];
}
}
- (void) setUpDissociateCell: (UITableView *) tableView {
dissCell = (DissociateCell *) [tableView dequeueReusableCellWithIdentifier:@"dissCell"];
if (dissCell == nil) {
NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"DissociateCell" owner:self options:nil];
dissCell = (DissociateCell*) [nib objectAtIndex:0];
leftData.disEquation = [[NSMutableArray alloc] init];
rightData.disEquation = [[NSMutableArray alloc] init];
// stores data from equation cell into model
for (FormulaLabel *label in equationCell.leftView.equationOrder)
[leftData.disEquation addObject:label.text];
for (FormulaLabel *label in equationCell.rightView.equationOrder)
[rightData.disEquation addObject:label.text];
[self setUpView:dissCell.leftView fromArray:leftData.disEquation toArray:leftDisItems];
[self setUpView:dissCell.rightView fromArray:rightData.disEquation toArray:rightDisItems];
[self addDissTapToArray:leftDisItems fromData:leftData inView:dissCell.leftView];
[self addDissTapToArray:rightDisItems fromData:rightData inView:dissCell.rightView];
[dissCell.dissociateButton addTarget:self action:@selector(dissociate) forControlEvents:UIControlEventTouchUpInside];
}
[dissCell.rightButton addTarget:self action:@selector(addBalanceCell) forControlEvents:UIControlEventTouchUpInside];
}
- (void)addDissociateCell {
[cellOrder addObject:@"dissociateCell"];
[table reloadData];
NSIndexPath *myIndexPath = [NSIndexPath indexPathForRow:0 inSection:([cellOrder count]-1)];
[table scrollToRowAtIndexPath:myIndexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
- (void) addDissTapToArray:(NSMutableArray*)viewOrder fromData:(EquationData*)data inView:(UIView*)view {
NSString *leftOrRight;
if (view == dissCell.leftView)
leftOrRight = @"left";
else
leftOrRight = @"right";
for (int j=0; j < [viewOrder count]; j++) {
if (j%2==0) {
UIView *formulaView = [viewOrder objectAtIndex:j];
//dissociate method
FalseTarget *target = [[FalseTarget alloc] initWithVC:self leftOrRightView:leftOrRight];
UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:target action:@selector(dissTap:)];
[formulaView addGestureRecognizer:tap];
// cancelling method
FalseTarget *target2 = [[FalseTarget alloc] initWithVC:self Data:data ViewList:viewOrder view:view];
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:target2 action:@selector(dissLongTap:)];
[formulaView addGestureRecognizer:longPress];
}
}
}
- (void)addCompoundToLabel:(UIGestureRecognizer *)recognizer leftOrRight:(NSString*)leftRight{
if( [recognizer state] == UIGestureRecognizerStateEnded ) {
FormulaLabel* label = (FormulaLabel*)[recognizer view];
dissIndex = label.tag;
dissCell.unDissociated.text = label.text;
currentDissCellView = leftRight;
}
}
- (void)dissociate {
EquationData *data;
NSMutableArray *viewOrder;
UIView *view;
if ([currentDissCellView isEqualToString:@"left"]) {
data = leftData;
viewOrder = leftDisItems;
view = dissCell.leftView;
}
else {
data = rightData;
viewOrder = rightDisItems;
view = dissCell.rightView;
}
FormulaLabel *c1 = [dissCell.leftTextField.equationOrder objectAtIndex:0];
FormulaLabel *c2 = [dissCell.rightTextField.equationOrder objectAtIndex:0];
[data updateDisEquationAtIndex:dissIndex withCompound1:c1.text Compound2:c2.text];
for (UIView *view in viewOrder)
[view removeFromSuperview];
[viewOrder removeAllObjects];
[self setUpView:view fromArray:data.disEquation toArray:viewOrder];
[self addDissTapToArray:viewOrder fromData:data inView:view];
}
- (void) cancelIons:(id)sender fromData:(EquationData *)data inView:(UIView *)view withViewList:(NSMutableArray *)viewlist {
if( [sender state] == UIGestureRecognizerStateEnded ) {
FormulaLabel* label = (FormulaLabel*)[sender view];
int index = label.tag;
[data.disEquation removeObjectAtIndex:index];
for (UIView *formulaView in viewlist)
[formulaView removeFromSuperview];
[viewlist removeAllObjects];
[self setUpView:view fromArray:data.disEquation toArray:viewlist];
[self addDissTapToArray:viewlist fromData:data inView:view];
}
}
- (void)addBalanceCell {
[cellOrder addObject:@"balanceCell"];
[table reloadData];
NSIndexPath *myIndexPath = [NSIndexPath indexPathForRow:0 inSection:([cellOrder count]-1)];
[table scrollToRowAtIndexPath:myIndexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
leftBalanceItems = [[NSMutableArray alloc] init];
rightBalanceItems = [[NSMutableArray alloc] init];
}
- (void) addBalanceTapMethodInArray:(NSMutableArray *)balanceItems Data:(EquationData *)data {
FalseTarget *target = [[FalseTarget alloc] initWithVC:self Data:data ViewList:balanceItems view:nil];
for (UIView *view in balanceItems) {
UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:target action:@selector(tap:)];
[view addGestureRecognizer:tap];
}
}
- (void)updateBalanceLabelofSender:(UIGestureRecognizer*)sender fromData:(EquationData *)data inArray:(NSMutableArray *)balanceItems {
FormulaLabel* label = (FormulaLabel*)[sender view];
int oldWidth = label.frame.size.width;
label.text = [data updateBalancedatIndex:label.tag];
[label sizeToFit];
int newWidth = label.frame.size.width;
int difference = newWidth - oldWidth;
int labelIndex = label.tag * 2;
for (int j = 0; j<[balanceItems count]; j++) {
// adjusts coordinate of all views to the right of tapped item
if (j > labelIndex){
UIView *item = [balanceItems objectAtIndex:j];
item.frame = CGRectMake(item.frame.origin.x + difference, item.frame.origin.y, item.frame.size.width, item.frame.size.height);
}
}
}
- (void)setUpView:(UIView *)view fromArray:(NSMutableArray *)equationData toArray:(NSMutableArray *)balanceItems {
int labelCount = 0; //label #
int startingPoint = 5; //x vaiue where first label starts
for (NSString *equationText in equationData) {
//add text
FormulaLabel *tempLabel = [[FormulaLabel alloc] initWithFrame:CGRectMake(startingPoint, 2, 10, 22)];
tempLabel.text = equationText;
[tempLabel sizeToFit];
[view addSubview:tempLabel];
tempLabel.tag = labelCount;
[balanceItems addObject:tempLabel];
//set location of '+'
startingPoint = tempLabel.frame.origin.x + tempLabel.frame.size.width + 3;
if (labelCount != [equationData count]-1) { //not the last label
UILabel *plus = [[[UILabel alloc] initWithFrame:CGRectMake(startingPoint, 5, 10, 10)]autorelease];
plus.text = @"+";
plus.font = [UIFont systemFontOfSize:13];
[plus sizeToFit];
[view addSubview:plus];
startingPoint = plus.frame.origin.x + plus.frame.size.width + 3;
[balanceItems addObject:plus];
}
labelCount ++;
[tempLabel release];
}
}
答案 0 :(得分：0)
我不会这样做，因为你强迫UIViewController知道数据模型（同时使它成为它的属性）。我会做的是一个类，使用类方法（而不是对象方法）将创建数据源。您仍然需要以某种方式保留UIViewController中的数据，但我认为NSArray或NSDictionary足够好：
-(void)viewDidLoad{
[superViewDidLoad];
myArray = [MyModel createDataSourceForTag:myTag];
}
答案 1 :(得分：0)
我想你应该选择模型结构。
<强> 1。模型：模型代表实体。在你的情况下，我可以创建两个实体Round，Question
@interface Round: NSObject {
NSUInteger *roundId; // 1, 2 = if it is required to check then this mi
NSArray *questions; // Array that contains objects for Question entity
}
@interface Question:NSObject {
NSString *questionText;
NSString *options1Text;
NSString *options2Text;
NSString *options3Text;
}
@interface DataManager:NSObject {
NSArray *rounds; // Array that contains object for Round entity
}
+(void)sharedInstance;
<强> 2。 DataManger ：DataManager将管理您的实体对象。此数据管理器将是sharedInstance类。因此，在初始化管理器时，将创建实体并插入数据。
第3。 ViewController：现在在视图控制器中，您可以直接使用sharedInstace，如下所示：
[[DataManager sharedInstance] rounds]
您可以轻松获取用于创建sharedInstance类的代码。
现在，您可以在整个应用程序的任何位置使用此轮次。 所以它很容易访问。例如，如果您需要第1轮第2个问题第3个选项，那么以相同的方式编写代码
第1轮
Round *r = [[[DataManager sharedInstance] rounds] objectAtIndex:0];
问题2
Question *q = [[r questions] objectAtIndex:1];
问题文本和选项3
NSLog(@"questionText : %@ 3rd Option: %@", q.questionText, q.option3Text)
享受编码：）
答案 2 :(得分：0)
为什么不能将一个带有question-property的视图控制器类用于重载属性的setter方法以将UI更新为新数据：
在QuestionViewController.h文件中：
@property (retain, nonatomic) Question* myQuestionData;
-(void) setMyQuestionData:(Question*)newData {
[myQuestionData autorelease];
myQuestionData = [newData retain];
[self updateUIElements];
}