iOS开发——post异步网络请求封装

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import "Reachability.h"

@interface HttpHelper : NSObject

+ (BOOL)NetWorkIsOK;//检查网络是否可用
+ (void)post:(NSString *)Url RequestParams:(NSDictionary *)params FinishBlock:(void (^)(NSURLResponse *response, NSData *data, NSError *connectionError)) block;//post请求封装

@end

//  HttpHelper.m
#import "HttpHelper.h"

@implementation HttpHelper

//这个函数是判断网络是否可用的函数（wifi或者蜂窝数据可用，都返回YES）
+ (BOOL)NetWorkIsOK{
    if(
       ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus]
       != NotReachable)
       &&
       ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus]
       != NotReachable)
       ){
        return YES;
    }else{
        return NO;
    }
}

//post异步请求封装函数
+ (void)post:(NSString *)URL RequestParams:(NSDictionary *)params FinishBlock:(void (^)(NSURLResponse *response, NSData *data, NSError *connectionError)) block{
    //把传进来的URL字符串转变为URL地址
    NSURL *url = [NSURL URLWithString:URL];
    //请求初始化，可以在这针对缓存，超时做出一些设置
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestReloadIgnoringCacheData
                                                       timeoutInterval:20];
    //解析请求参数，用NSDictionary来存参数，通过自定义的函数parseParams把它解析成一个post格式的字符串
    NSString *parseParamsResult = [self parseParams:params];
    NSData *postData = [parseParamsResult dataUsingEncoding:NSUTF8StringEncoding];
    
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:postData];
    
    //创建一个新的队列（开启新线程）
    NSOperationQueue *queue = [NSOperationQueue new];
    //发送异步请求，请求完以后返回的数据，通过completionHandler参数来调用
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:queue
                           completionHandler:block];
//    return result;
}

//把NSDictionary解析成post格式的NSString字符串
+ (NSString *)parseParams:(NSDictionary *)params{
    NSString *keyValueFormat;
    NSMutableString *result = [NSMutableString new];
    //实例化一个key枚举器用来存放dictionary的key
    NSEnumerator *keyEnum = [params keyEnumerator];
    id key;
    while (key = [keyEnum nextObject]) {
        keyValueFormat = [NSString stringWithFormat:@"%@=%@&",key,[params valueForKey:key]];
        [result appendString:keyValueFormat];
        NSLog(@"post()方法参数解析结果：%@",result);
    }
    return result;
}

@end

- (void)login{ 
    NSString *url = @"127.0.0.1/login.php";
    NSString *userName = @"admin";
    NSString *password =  @"root";
    //加入参数
    NSMutableDictionary *params = [NSMutableDictionary new];
    [params setValue:userName forKey:@"phone"];
    [params setValue:password forKey:@"password"];
    //有网络才发送请求
    if([HttpHelper NetWorkIsOK]){
     //发送请求，并且得到返回的数据
    [HttpHelper post:url RequestParams:params FinishBlock:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
    　　//传回来的数据存在，则执行改回调甘薯
    　　if(data){
    　　//子线程通知主线程更新UI，selector中是要执行的函数，data是传给这个函数的参数
    　　//login_callBack就处理返回来的消息，这里就简单的输出，登录成功
     　　[self performSelectorOnMainThread:@selector(login_callBack:) withObject:data waitUntilDone:YES];
     　　}else{
     　　    NSLog(@"无效的数据");
     　　}    
     　　}];
　　}
}

//登录的回调函数，首先判断接收的值是不是能登录。若不能，则提示用户。若能登录，则处理segue来跳转界面
- (void)login_callBack:(id)value{
        NSLog(@"登录成功");
}