ios - 如何将新的 NSMutableDictionary 保存到属性列表

Question

我这里有这个方法，每次我按保存时它都会运行:

-(void)setName:(NSString *)foodName andCarbs:(NSNumber *)carbAmount{
    [self.userFoodDictionary setObject:(NSString *)foodName forKey:(NSString *)foodName];
    NSString *value = [[NSString alloc] initWithFormat:@"%@ Value", foodName];
    [self.userFoodDictionary setObject:(NSNumber *)carbAmount forKey:(NSString *)value];
    [self.userFoodDictionary writeToFile:self.appDataPath atomically:YES];
}

根据我的理解，倒数第二行应该将 userFoodDictionary 属性保存到指定的属性列表路径。但这种情况似乎没有发生过一次。我重建应用程序。也许我创建新字典对象的方式不正确。有人可以解释为什么这不起作用吗？

Answer 1

写入Plist

- (NSString *)foodDataPlistFilePath
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"UserFoodData.plist"];

    return filePath;
}

...

-(void)setName:(NSString *)foodName andCarbs:(NSNumber *)carbAmount{
    [self.userFoodDictionary setObject:(NSString *)foodName forKey:(NSString *)foodName];
    NSString *value = [[NSString alloc] initWithFormat:@"%@ Value", foodName];
    [self.userFoodDictionary setObject:(NSNumber *)carbAmount forKey:(NSString *)value];
    NSString *filePath = [self foodDataPlistFilePath];
    [self.userFoodDictionary writeToFile:filePath atomically:YES];
}

初始化可变字典:

NSString *filePath = [self foodDataPlistFilePath];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath];
self.userFoodDictionary = [[NSMutableDictionary alloc] init];
if(fileExists){
    NSDictionary *foodData = [NSDictionary dictionaryWithContentsOfFile:filePath];
    [_userFoodDictionary setDictionary:foodData];
}