如何从nsobject类传递nsarray来查看控制器类？ [英] How to pass nsarray from an nsobject class to view controller class?

问题描述

我是客观的新手。我正在尝试创建一个天气应用程序。我从开放的天气图解析数据。我已将解析后的数据存储到数组中。现在想要从其他类访问数组值，但获取空值。





有谁可以帮助我？在此先感谢。



我尝试过：



这里是我的nsobject类我存储数据并尝试将其发送到viewcontroller。



- （void）getCurrentWeather：（NSString *）查询

{

NSString * const BASE_URL_STRING = @http://api.openweathermap.org/data/2.5/weather?q=;

NSString * const API_KEY = @& APPID = 35e37cecbd835f3949f6d67cb25b0706;



NSString * weatherURLText = [NSString stringWithFormat：@％@％@％@，

BASE_URL_STRING，query，API_KEY];

NSURL * weatherURL = [NSURL URLWithString：weatherURLText];



dispatch_async（kBgQueue，^ {

NSData * data = [NSData dataWithContentsOfURL：weatherURL];

[self performSelectorOnMainThread：@selector（fetchedData :) withObject：data waitUntilDone：YES];



}）;

}





- （无效）fetchedData：（NSData *）responseData {



NSError *错误;

NSDictionary * json = [NSJSONSerialization JSONObjectWithData：responseData options：kNilOptions错误：& error];



NSString * cityName = [json objectForKey：@name];



int currentTempCelsius =（int）[[[json objectForKey：@main] objectForKey：@temp] intValue] - ZERO_CELSIUS_IN_KELVIN;

int maxTemp =（int）[[[json objectForKey ：@main] objectForKey：@temp_max] intValue] - ZERO_CELSIUS_IN_KELVIN;

int minTemp =（int）[[[json objectForKey：@main] objectForKey：@temp_min] intValue] - ZERO_CELSIUS_IN_KELVIN;

NSString * weatherDescription = [[[json objectForKey：@weather] objectAtIndex：0] objectForKey：@description];



weatherArray = [[NSMutableArray alloc] initWithObjects：cit yName，weatherDescription，

[NSString stringWithFormat：@％d，currentTempCelsius]，

[NSString stringWithFormat：@％d，maxTemp]，

[NSString stringWithFormat：@％d，minTemp]，nil];





我有NSObject.h文件as-



@interface WeatherData：NSObject





@property（ nonatomic）NSString * weatherDescription;

@property（强，非原子）NSString * currentTemp;

@property（nonatomic）int maxTempCelsius;

@ property（nonatomic）int minTempCelsius;

@property（nonatomic，retain）NSMutableArray * weatherArray;



- （void）getCurrentWeather：（NSString *）查询;



@end



在我的视图控制器中 -



.h文件：



@property（非原子，保留）NSMutableArray * weatherResultArray;



.m档案：



- （无效）searchButtonClicked：（UIButton *）发件人

{



[self.view endEditing：YES];

WeatherData * weather = [[WeatherData alloc] init];

[weather getCurrentWeather：_textField.text];

self.weatherResultArray = weather.weatherArray;



//temperatureLabel.text = [NSString stringWithFormat：@％d°，weather.currentTempCelsius];

}



我只想在UILable中显示结果。

解决方案

是的，你得到null因为你的weatherArray没有分配和初始化任何地方。
ViewDidload（）中的
尝试分配如下数组：

 _ weatherArray = [[NSMutableArray alloc] INIT]; 

I am new to objective c. I am trying to create a weather app. where i parsed data from open weather map. I have stored the parsed data to an array. now want to access the array value from other class but getting null value.


Can anyone help me? Thanks in advance.

What I have tried:

here is my nsobject class where i am storing data and trying to send that to viewcontroller.

- (void)getCurrentWeather:(NSString *)query
{
NSString *const BASE_URL_STRING = @"http://api.openweathermap.org/data/2.5/weather?q=";
NSString *const API_KEY = @"&APPID=35e37cecbd835f3949f6d67cb25b0706";

NSString *weatherURLText = [NSString stringWithFormat:@"%@%@%@",
BASE_URL_STRING, query,API_KEY];
NSURL *weatherURL = [NSURL URLWithString:weatherURLText];

dispatch_async(kBgQueue, ^{
NSData* data = [NSData dataWithContentsOfURL:weatherURL];
[self performSelectorOnMainThread:@selector(fetchedData:)withObject:data waitUntilDone:YES];

});
}


- (void)fetchedData:(NSData *)responseData {

NSError* error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];

NSString* cityName = [json objectForKey:@"name"];

int currentTempCelsius = (int)[[[json objectForKey:@"main"] objectForKey:@"temp"] intValue] - ZERO_CELSIUS_IN_KELVIN;
int maxTemp = (int)[[[json objectForKey:@"main"] objectForKey:@"temp_max"] intValue] - ZERO_CELSIUS_IN_KELVIN;
int minTemp = (int)[[[json objectForKey:@"main"] objectForKey:@"temp_min"] intValue] - ZERO_CELSIUS_IN_KELVIN;
NSString *weatherDescription = [[[json objectForKey:@"weather"] objectAtIndex:0] objectForKey:@"description"];

weatherArray = [[NSMutableArray alloc] initWithObjects:cityName, weatherDescription,
[NSString stringWithFormat:@"%d", currentTempCelsius],
[NSString stringWithFormat:@"%d", maxTemp],
[NSString stringWithFormat:@"%d", minTemp],nil];


I have NSObject.h file as-

@interface WeatherData : NSObject


@property (nonatomic) NSString *weatherDescription;
@property (strong, nonatomic) NSString *currentTemp;
@property (nonatomic) int maxTempCelsius;
@property (nonatomic) int minTempCelsius;
@property (nonatomic, retain) NSMutableArray *weatherArray;

- (void)getCurrentWeather:(NSString *)query;

@end

In my view controller -

.h file:

@property (nonatomic, retain) NSMutableArray *weatherResultArray;

.m file:

-(void)searchButtonClicked:(UIButton*)sender
{

[self.view endEditing:YES];
WeatherData *weather = [[WeatherData alloc] init];
[weather getCurrentWeather:_textField.text];
self.weatherResultArray = weather.weatherArray;

//temperatureLabel.text = [NSString stringWithFormat:@"%d°",weather.currentTempCelsius];
}

I just want to show the results in UILable.

解决方案

Yes , you are getting null because your weatherArray has not allocate and initialize any where .
in ViewDidload() try to allocate the array like :

_weatherArray = [[NSMutableArray alloc]init];

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