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iOS —— 天气预报仿写总结

网友: 技术文档 2025-07-26 20:00:06

在iOS中，最常见的网络请求方式是NSURLSession，它是苹果推荐的现代API，简单安全且易于拓展。

一次完整的网络请求流程：

  1. 构造 NSURL 对象

  2. 创建 NSURLSessionDataTask

  3. 发起请求（resume）

  4. 在回调中解析数据

  5. 回到主线程更新 UI

下面，我们用一个简单的程序来试一下。

NSString *city = @\"Beijing\";NSString *apiKey = @\"你的API密钥\";NSString *urlString = [NSString stringWithFormat:@\"https://api.weatherapi.com/v1/current.json?key=%@&q=%@&lang=zh\", apiKey, city];urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];NSURL *url = [NSURL URLWithString:urlString];NSURLSessionDataTask *task = [[NSURLSession sharedSession] dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { if (error) { NSLog(@\"请求失败：%@\", error.localizedDescription); return; } NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil]; NSLog(@\"天气数据：%@\", json); dispatch_async(dispatch_get_main_queue(), ^{ // 更新 UI });}];[task resume];

首页

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleAddCityNotification:) name:@\"AddNewCityNotification\" object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleDeleteCityNotification:) name:@\"DeleteCityNotification\" object:nil];

接收两个通知，一个是搜索页面的城市，另一个是详情页面的删除指令。

 

-(void) handleAddCityNotification:(NSNotification *)notification { NSDictionary *userInfo = [notification userInfo]; NSString *newCity = userInfo[@\"cityName\"]; BOOL exists = NO; for (NSDictionary *city in self.cityData) { if ([city[@\"name\"] isEqualToString:newCity]) { exists = YES; break; } } if (!exists) { [self.cityData addObject:@{@\"name\": newCity}]; [self createUrl]; }}- (void)handleDeleteCityNotification:(NSNotification *)notification { NSDictionary *userInfo = [notification userInfo]; NSString *cityName = userInfo[@\"cityName\"]; // 从城市列表中删除该城市 NSMutableArray *citiesToRemove = [NSMutableArray array]; for (NSDictionary *city in self.cityData) { if ([city[@\"name\"] isEqualToString:cityName]) { [citiesToRemove addObject:city]; } } [self.cityData removeObjectsInArray:citiesToRemove]; [self.tableView reloadData];}

这个页面要执行两个操作： 点击加号添加城市，删除城市。

这里给出我的网络请求代码： 

- (void)createUrl { if (self.cityData.count == 0) return; dispatch_group_t group = dispatch_group_create(); NSURLSession *session = [NSURLSession sharedSession]; NSMutableArray *tempDicArray = [NSMutableArray array]; NSLog(@\"1\"); for (NSDictionary *city in self.cityData) { dispatch_group_enter(group); NSString *cityName = city[@\"name\"]; NSString *urlString = [NSString stringWithFormat:@\"https://api.weatherapi.com/v1/current.json?key=2db0265c1d084416b9275428252207&q=%@&lang=zh \", cityName]; urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]]; NSURL *url = [NSURL URLWithString:urlString]; NSURLSessionDataTask *task = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { if (error) { NSLog(@\"错错错！！ %@: %@\", city, error.localizedDescription); dispatch_group_leave(group); return; } if (data) {  NSError *jsonError;  //解析数据  NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:0 error:&jsonError];  if (jsonError) { NSLog(@\"JSON解析失败: %@\", jsonError.localizedDescription);  } else { NSLog(@\"API响应: %@\", dic); // 检查是否有错误  if (dic[@\"error\"]) {  NSLog(@\"API返回错误: %@\", dic[@\"error\"][@\"message\"]);  } else { @synchronized (tempDicArray) { //赋值到tempDicArray [tempDicArray addObject:dic]; NSLog(@\"成功添加城市: %@\", cityName); }  } } } else { NSLog(@\"无响应数据\"); } dispatch_group_leave(group); }]; [task resume];}  dispatch_group_notify(group, dispatch_get_main_queue(), ^{ NSLog(@\"所有请求完成，获取到%ld个城市数据\", tempDicArray.count); //最终到dicArray self.dicArray = tempDicArray; [self.tableView reloadData]; });}
// 添加支持滑动删除- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { return YES;}

搜索页面

-(void) addCityToMain:(NSDictionary *)cityInfo { NSString *cityName = cityInfo[@\"name\"]; NSDictionary *userInfo = @{@\"cityName\": cityName}; [[NSNotificationCenter defaultCenter] postNotificationName:@\"AddNewCityNotification\" object:nil userInfo:userInfo]; // 关闭添加页面// [self dismissViewControllerAnimated:YES completion:nil];}
//选中哪个就传给主页- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [tableView deselectRowAtIndexPath:indexPath animated:YES]; if (indexPath.row < self.searchResults.count) { NSDictionary *city = self.searchResults[indexPath.row]; DetailViewController *detailVC = [[DetailViewController alloc] init]; detailVC.cityName = city[@\"name\"]; detailVC.canAddCity = YES; UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:detailVC]; nav.modalPresentationStyle = UIModalPresentationFullScreen; [self presentViewController:nav animated:YES completion:nil]; }}

当我们点击其中一行时，我们会跳转到该城市

城市详细天气

给出我的每小时天气预报代码

- (void)setupHourlyForecastData { NSArray *forecastDays = self.weatherData[@\"forecast\"][@\"forecastday\"]; if (forecastDays.count == 0) return; //WeatherAPI 返回的 forecast 结构中，每天包含一个 hour 数组（24 小时）。为了支持“跨天展示”，你先拼接所有天的小时数组 // 拼接所有 forecastday 的 hour 数据 NSMutableArray *allHours = [NSMutableArray array]; for (NSDictionary *day in forecastDays) { NSArray *hours = day[@\"hour\"]; if (hours) [allHours addObjectsFromArray:hours]; } if (allHours.count == 0) return; UIView *hourlyCard = [self.contentView viewWithTag:1000]; UIScrollView *scrollView = [hourlyCard viewWithTag:1001]; if (!scrollView) return; CGFloat itemWidth = 60; CGFloat spacing = 10; //当前小时 NSDate *now = [NSDate date]; NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; formatter.dateFormat = @\"yyyy-MM-dd HH\"; NSString *nowHourString = [formatter stringFromDate:now]; NSInteger startIndex = 0; //找出当前时间匹配的小时 for (int i = 0; i < allHours.count; i++) { NSString *hourString = [allHours[i][@\"time\"] substringToIndex:13]; if ([hourString isEqualToString:nowHourString]) { startIndex = i; break; } } //主要是防止数组越界 NSInteger count = MIN(24, allHours.count - startIndex); //给7个格子赋值 for (int i = 0; i < count; i++) { NSDictionary *hour = allHours[startIndex + i]; NSString *time = [hour[@\"time\"] substringFromIndex:11]; NSString *temp = [NSString stringWithFormat:@\"%.0f°\", [hour[@\"temp_c\"] floatValue]]; NSString *iconUrl = [NSString stringWithFormat:@\"https:%@\", hour[@\"condition\"][@\"icon\"]]; UIView *hourView = [[UIView alloc] initWithFrame:CGRectMake(i * (itemWidth + spacing), 0, itemWidth, 70)]; UILabel *timeLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, itemWidth, 20)]; timeLabel.text = time; timeLabel.font = [UIFont systemFontOfSize:12]; timeLabel.textColor = [UIColor whiteColor]; timeLabel.textAlignment = NSTextAlignmentCenter; [hourView addSubview:timeLabel]; UIImageView *icon = [[UIImageView alloc] initWithFrame:CGRectMake(10, 20, 40, 30)]; icon.contentMode = UIViewContentModeScaleAspectFit; [hourView addSubview:icon]; [self loadIcon:iconUrl forImageView:icon]; UILabel *tempLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 50, itemWidth, 20)]; tempLabel.text = temp; tempLabel.font = [UIFont systemFontOfSize:12]; tempLabel.textColor = [UIColor whiteColor]; tempLabel.textAlignment = NSTextAlignmentCenter; [hourView addSubview:tempLabel]; [scrollView addSubview:hourView]; } scrollView.contentSize = CGSizeMake((itemWidth + spacing) * count, 70);}//每小时天气

同时，我下面的每部分都以卡片形式呈现

//卡片- (UIView *)createCardViewWithFrame:(CGRect)frame { UIView *card = [[UIView alloc] initWithFrame:frame]; card.backgroundColor = [UIColor colorWithWhite:1 alpha:0.2]; card.layer.cornerRadius = 20; card.layer.borderWidth = 1; card.layer.borderColor = [UIColor colorWithWhite:1 alpha:0.3].CGColor; return card;}//卡片标题- (UILabel *)createSectionTitleLabel:(NSString *)title frame:(CGRect)frame { UILabel *label = [[UILabel alloc] initWithFrame:frame]; label.text = title; label.font = [UIFont systemFontOfSize:20 weight:UIFontWeightBold]; label.textColor = [UIColor whiteColor]; return label;}

我的背景可以根据天气不同自动切换，代码如下：

- (void)setBackgroundBasedOnWeather { if (!self.weatherData) return; NSDictionary *current = self.weatherData[@\"current\"]; NSDictionary *condition = current[@\"condition\"]; NSInteger code = [condition[@\"code\"] integerValue]; NSString *bgImageName; // 晴天 if (code == 1000) { bgImageName = @\"pic1.jpg\"; } // 多云或阴天 else if (code >= 1003 && code = 1063 && code = 1150 && code = 1240 && code = 1066 && code = 1114 && code = 1273 && code <= 1282) { bgImageName = @\"pic5.jpg\"; } // 默认 else { bgImageName = @\"pic1.jpg\"; } self.backgroundImageView.image = [UIImage imageNamed:bgImageName];}
//日期字符串转换为周几- (NSString *)formatDate:(NSString *)dateString { NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init]; inputFormatter.dateFormat = @\"yyyy-MM-dd\"; NSDate *date = [inputFormatter dateFromString:dateString]; NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init]; outputFormatter.locale = [NSLocale localeWithLocaleIdentifier:@\"zh_CN\"]; outputFormatter.dateFormat = @\"EEE\"; return [outputFormatter stringFromDate:date];}

详情页的删除按钮：

- (void)deleteCity { if (self.cityName) { NSDictionary *userInfo = @{@\"cityName\": self.cityName}; [[NSNotificationCenter defaultCenter] postNotificationName:@\"DeleteCityNotification\" object:nil  userInfo:userInfo]; [self dismissViewControllerAnimated:YES completion:nil]; }}

关于多个城市横向滑动查看详情，我使用了UIPageController。

- (id)init { self = [super initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll  navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil]; return self;}

这段代码实现了页面的横向滑动效果。

// MainVC.m- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [tableView deselectRowAtIndexPath:indexPath animated:YES]; NSMutableArray *cityNames = [NSMutableArray array]; for (NSDictionary *city in self.cityData) { [cityNames addObject:city[@\"name\"]]; } CitiesDetailViewController *containerVC = [[CitiesDetailViewController alloc] init]; containerVC.cityNames = cityNames; containerVC.initialIndex = indexPath.section; containerVC.modalPresentationStyle = UIModalPresentationFullScreen; [self presentViewController:containerVC animated:YES completion:nil];}
// CitiesDetailViewController.m- (void)viewDidLoad { [super viewDidLoad]; self.delegate = self; self.dataSource = self; self.cities = self.cityNames;  // 城市名列表由外部传入 self.currentIndex = self.initialIndex; // 初始城市索引也由外部设置 DetailViewController *initialVC = [self detailViewControllerForIndex:self.initialIndex]; [self setViewControllers:@[initialVC] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
#pragma mark - Page View Controller Data Source// 获取前一个VC- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController { //下标 NSInteger index = [(DetailViewController *)viewController index]; //不是第一个就去上一个 if (index > 0) { return [self detailViewControllerForIndex:index - 1]; } return nil;}//获取后一个VC- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController { NSInteger index = [(DetailViewController *)viewController index]; if (index < self.cities.count - 1) { return [self detailViewControllerForIndex:index + 1]; } return nil;}//进入指定页面- (DetailViewController *)detailViewControllerForIndex:(NSInteger)index { if (index = self.cities.count) return nil; DetailViewController *detailVC = [[DetailViewController alloc] init]; detailVC.cityName = self.cities[index]; detailVC.index = index; detailVC.canAddCity = NO; return detailVC;}- (void)deleteCurrentCity { if (self.cities.count == 0) { [self dismissViewControllerAnimated:YES completion:nil]; return; } // 获取当前显示的视图控制器 DetailViewController *currentVC = (DetailViewController *)self.viewControllers.firstObject; NSInteger currentIndex = currentVC.index; // 防止索引越界 if (currentIndex >= self.cities.count) { [self dismissViewControllerAnimated:YES completion:nil]; return; } NSString *cityName = self.cities[currentIndex]; // 发送删除通知 NSDictionary *userInfo = @{@\"cityName\": cityName}; [[NSNotificationCenter defaultCenter] postNotificationName:@\"DeleteCityNotification\" object:nil userInfo:userInfo]; // 从数据源中删除 NSMutableArray *mutableCities = [self.cities mutableCopy]; [mutableCities removeObjectAtIndex:currentIndex]; self.cities = [mutableCities copy]; // 如果删除后没有城市了，关闭页面 if (self.cities.count == 0) { [self dismissViewControllerAnimated:YES completion:nil]; return; } // 计算新的当前索引 NSInteger newIndex; if (currentIndex >= self.cities.count) { newIndex = self.cities.count - 1; } else { newIndex = currentIndex; } // 确定导航方向：如果删除的是最后一个，则向前翻一页，否则保持当前页 UIPageViewControllerNavigationDirection direction = UIPageViewControllerNavigationDirectionForward; if (newIndex < currentIndex) { direction = UIPageViewControllerNavigationDirectionReverse; } // 获取新的视图控制器 DetailViewController *newVC = [self detailViewControllerForIndex:newIndex]; if (newVC) { [self setViewControllers:@[newVC] direction:direction animated:YEScompletion:nil]; self.currentIndex = newIndex; }}
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