登录

#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");
}