iOS中UDP的使用

//
//  ViewController.m
//  UDPDemo
//
//  Created by qianfeng01 on 15-8-13.
//  Copyright (c) 2015年 zg. All rights reserved.
//

#import "ViewController.h"
#import "AsyncUdpSocket.h"
#import "ZCScreenShot.h"
#define STU 1

@interface ViewController ()<AsyncUdpSocketDelegate>
{
    //建立socket
    AsyncUdpSocket *sendSocket;
    AsyncUdpSocket *serverSocket;
    
    //教师端须要一个label，每隔1秒，改变一下数字
    UILabel *numberLabel;
    
    //学生端。须要一个imageView,显示教师端发送过来的数据
    UIImageView *imageView;
    //须要一个宏定义来区分学生端和教师端，一键转换
    
}
@property (nonatomic,strong) NSMutableArray *ipArray;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    /**
     *  程序分为学生端和教师端。教师端负责对全部接入程序的学生发送截图图片，学生端接受数据的时候。在imageview上显示
      
        学生端程序启动的时候，须要向教师端发送一个数据。也就是签到，这样教师端能够获得学生端的IP地址。进行数据转发
     
        须要的是：截屏函数仅仅对普通的ui有效。可是无法获取到视频截屏，假设要进行视频截屏。须要使用opengl来获取GL的信息，再进行渲染
     */
    self.ipArray = [NSMutableArray arrayWithCapacity:0];
    [self createView];
    [self createSocket];
    
    if (STU) {
        //假设是学生，程序启动向教师端发送一个数据
        [sendSocket sendData:[@"签到！

" dataUsingEncoding:NSUTF8StringEncoding] toHost:@"10.8.155.36" port:5678 withTimeout:-1 tag:100];
    }else{
        [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(timerClick) userInfo:nil repeats:YES];
    }
}

- (void)timerClick{
    
    if (self.ipArray.count == 0) {
        return;
    }
    
    //设置label的背景颜色
    float r = arc4random()%256/255.0;
    float g = arc4random()%256/255.0;
    float b = arc4random()%256/255.0;
    numberLabel.backgroundColor = [UIColor colorWithRed:r green:g blue:b alpha:1];
    numberLabel.text = @"抽烟不？跟我一块儿吧";
    numberLabel.font = [UIFont boldSystemFontOfSize:40];
    
    
    //截取屏幕
    
    //第一个參数是截取图片的范围，第二个參数是截取的那一层
    UIImage *image = [ZCScreenShot beginImageContext:self.view.frame View:self.view];
    
    //遍历转发
    for (NSString *ip in self.ipArray) {
        [sendSocket sendData:UIImageJPEGRepresentation(image, 0.1) toHost:ip port:5678 withTimeout:-1 tag:100];
    }
    
}

- (void)createSocket{
    //不论是学生端。还是教师端,都须要发送和接受，学生端发送一个签到给教师端，教师端发送图片给学生端
    sendSocket = [[AsyncUdpSocket alloc]initWithDelegate:self];
    serverSocket = [[AsyncUdpSocket alloc]initWithDelegate:self];
    
    
    //服务端绑定port
    [serverSocket bindToPort:5678 error:nil];
    //持续观察
    [serverSocket receiveWithTimeout:-1 tag:100];
    
}

- (void)createView{
    if (STU) {
        //学生端
        imageView = [[UIImageView alloc]initWithFrame:self.view.frame];
        [self.view addSubview:imageView];
    }else{
        //教师端
        numberLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, 200, 300)];
        numberLabel.center = self.view.center;
        numberLabel.textAlignment =NSTextAlignmentCenter;
        [self.view addSubview:numberLabel];
    }
}


#pragma mark -- AsyncUdpSocketDelegate
-(void)onUdpSocket:(AsyncUdpSocket *)sock didSendDataWithTag:(long)tag{
    //发送完毕
}

- (BOOL)onUdpSocket:(AsyncUdpSocket *)sock didReceiveData:(NSData *)data withTag:(long)tag fromHost:(NSString *)host port:(UInt16)port{
    //接受数据
    
    
    //教师端接受学生的ip
    
    //学生端接受教师的图片
    if (STU) {
        if (imageView) {
            imageView.image = [UIImage imageWithData:data];
        }
        imageView.image = [UIImage imageWithData:data];
    }else{
        //记录学生IP，须要一个数组，对新的数据进行追加，对旧的数据忽略
        if (![self.ipArray containsObject:host]) {
            [self.ipArray addObject:host];
        }
    }
    //
    [sock receiveWithTimeout:-1 tag:100];
    return YES;
}
@end