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iOS版本PM2.5空氣質量監控儀

來源：程序員人生發布時間：2015-03-27 08:41:42 閱讀次數：3252次

前言

鑒于柴靜版《天穹之下》的火爆，也許更多的人會關心環境，空氣質量等環保因素，參考某學院的Swift版本的PM2.5的獲得，本人自己寫個Objective-C版本的。

基本原理

從服務器獲得當前的空氣質量數據，氣象中心開放接口，亞洲空氣質量實時監控，參照人家的教程使用亞洲空氣質量監控。
本地解析數據，獲得PM2.5數值，進行顯示。

具體實現

NSNumber *str;

-(void) loadData{
self.msgText.text = @"loading....";
NSURL *url = [NSURL URLWithString:@"http://aqicn.org/publishingdata/json"];
NSString *post=@"postData";
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
[request setHTTPBody:postData];
[request setTimeoutInterval:10.0];

//GCD實現異步接口通訊與UI更新的同步
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [NSURLConnection sendAsynchronousRequest:request
        queue:queue
        completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
        if (error) {
            NSLog(@"Httperror:%@%d", error.localizedDescription,error.code);
        }else{
            NSInteger responseCode = [(NSHTTPURLResponse *)response statusCode];
            NSString *responseString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"HttpResponseCode:%d", responseCode);
            NSLog(@"HttpResponseBody %@",responseString);
            NSData *resData = [[NSData alloc] initWithData:[responseString dataUsingEncoding:NSUTF8StringEncoding]];
            NSDictionary *resultDic = [NSJSONSerialization JSONObjectWithData:resData options:NSJSONReadingMutableLeaves error:nil];
            NSLog(@"resultDic=%@", resultDic);

            arr = [[resultDic valueForKey:@"pollutants"] valueForKey:@"value"];
            str = [[arr objectAtIndex:0] objectAtIndex:0];
            NSLog(@"PM2.5=%@", [[arr objectAtIndex:0] objectAtIndex:0]);
        }
    }];
        dispatch_async(dispatch_get_main_queue(),^{
    self.msgText.text = str.stringValue;
        });
    });
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self loadData];
// start reloadData
}
- (IBAction)reloadData:(id)sender {
NSLog(@"Button Clicked");
[self loadData];
NSLog(@"Button Clicked");
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}