cocoa - 如何将整数传递给模型类

我对此有点麻烦！我确实看过很多帖子，但是无法正常工作。以前，在我的应用程序中，我已经通过将数据分配给属性来设法在类之间传递数据。我不确定我在哪里出问题了，因此不胜感激。我知道以下代码不是很好，并且我正在寻找字典来提供帮助，但是目前，我想使其正常运行。

- (IBAction)checkAnswers:(id)sender
{
// The following if statements check user input and checks to see if it is the right answer.
// The .text parts are uitextfield properties and then shows an image of a tick if correct.
// It then assigns one to a variable and sums them up at the end (blag)
if ([eyepiece.text isEqualToString:@"Eyepiece"]) {
    UIImage *image = [UIImage imageNamed:@"Tick.png"];
    [eyepieceTick setImage:image];
    a = 1;
}

if ([focussingKnobs.text isEqualToString:@"Focussing knobs"]) {
    UIImage *image = [UIImage imageNamed:@"Tick.png"];
    [focussingTick setImage:image];

    b = 1;
}

if ([objectiveLens.text isEqualToString:@"Objective lenses"]) {
    UIImage *image = [UIImage imageNamed:@"Tick.png"];
    [objectiveTick setImage:image];
    c = 1;
}

if ([stage.text isEqualToString:@"Stage"]) {
    UIImage *image = [UIImage imageNamed:@"Tick.png"];
    [stageTick setImage:image];
    d = 1;
}
if ([mirror.text isEqualToString:@"Mirror"]) {
    UIImage *image = [UIImage imageNamed:@"Tick.png"];
    [mirrorTick setImage:image];
    e = 1;
}

blag = a + b + c + d + e;

// Here I update a label with the score

finalScore = [[NSString alloc] initWithFormat:@"%D", blag];
[score setText:finalScore];

// This is probably where I'm going wrong.  I'm allocating a model class called
// Level_3_Brain and trying to assign a new property in that class (cellsLevelThree)
// with the score.

// Level_3_Brain *level = [[Level_3_Brain alloc] init];
// level.cellsLevelThree = blag;

// Updated to
    [Level_3_Brain sharedInstanceOfLevel3].cellsLevelThree = blag;


// I then set them all back to zero so that the score doesn't go above 5
a = 0, b = 0, c = 0, d = 0, e = 0;
blag = 0;

}

我的模型类.h现在具有：

@interface Level_3_Brain : NSObject

+ (id)sharedInstanceOfLevel3;

@property (nonatomic) int cellsLevelThree;

@end

现在，我的.m的代码摘自Singleton文章：

@implementation Level_3_Brain
@synthesize cellsLevelThree;

static Level_3_Brain *sharedInstanceOfLevel3 = nil;

// Get the shared instance and create it if necessary.
+ (Level_3_Brain *)sharedInstanceOfLevel3 {
if (sharedInstanceOfLevel3 == nil)
{
sharedInstanceOfLevel3 = [[super allocWithZone:NULL] init];
}



return sharedInstanceOfLevel3;


}

// We can still have a regular init method, that will get called the first time the Singleton is used.

- (id)init
{
self = [super init];

if (self) {
    // Work your initialising magic here as you normally would
}

NSLog(@"%@", cellsLevelThree);

return self;
}

// Your dealloc method will never be called, as the singleton survives for the duration of your app.
// However, I like to include it so I know what memory I'm using (and incase, one day, I convert away from Singleton).
-(void)dealloc
{
// I'm never called!
// [super dealloc];
}

/ We don't want to allocate a new instance, so return the current one.
+ (id)allocWithZone:(NSZone*)zone {
return [self sharedInstanceOfLevel3];
}

// Equally, we don't want to generate multiple copies of the singleton.
- (id)copyWithZone:(NSZone *)zone {
return self;
}


@end

不幸的是，我现在收到错误“在类型为id的对象上找不到属性'cellsLevelThree'。请帮助！！

最佳答案

您在注释中正确标识了“出错”的位置：问题不在于您错误地设置了值，而是因为您在方法本地的全新实例上设置了该值，并且在退出该方法时立即被丢弃。

通常，应在应用程序启动时创建模型类，并在整个应用程序生命周期中保持可用。这通常使用singletons完成。

关于cocoa - 如何将整数传递给模型类，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/10121798/