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1、文字的宽高
/*
text:文字
font:文字的字体
maxsize:文字的最大宽高
*/
- (CGSize)sizeWithText:(NSString *)text andFont:(NSFont *)font andMaxSize:(CGSize)maxsize{
NSDictionary * dict = @{NSFontAttributeName : font};
return [text boundingRectWithSize:maxsize options:NSStringDrawingUsesLineFragmentOrigin attributes:dict context:nil].size;
}
2、多线程的简单使用
NSOperationQueue *queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc]
initWithTarget:self
selector:nil)
object:nil];
[queue addOperation:operation];
/***********************************GCD**************************************************/
//一次性执行
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
//code be executed once
});
//延迟调用
double delayInSeconds = 2.0;
dispatch_time_t timer = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds *NSEC_PER_SEC);
dispatch_after(timer, dispatch_get_main_queue(), ^{
//code be executed once after delay
});
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
//code be executed once after delay
});
//自定义queque
dispatch_queue_t fun = dispatch_queue_create("funfun", NULL);
dispatch_async(fun, ^{
// your code
});
MRC 需要释放
//dispatch_release(fun);
//GCD组 同时进行多个任务，任务完成之后再主线程执行其他任务
dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group, dispatch_get_global_queue(0, 0), ^{
//your code
});
dispatch_group_async(group, dispatch_get_global_queue(0, 0), ^{
//your code
});
dispatch_group_notify(group, dispatch_get_main_queue(), ^{
//your code
});
//多线程的线程安全
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{
// 线程锁
NSLock *lock = [[NSLock alloc] init];
[lock lock];
//your code
[lock unlock];
});
dispatch_async(queue, ^{
NSLock *lock = [[NSLock alloc] init];
[lock lock];
//your code
[lock unlock];
});
3、简单的倒计时效果
- (void)viewDidLoad {
[super viewDidLoad];
[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerMethod:) userInfo:nil repeats:YES];
}
- (void)timerMethod:(NSTimer *)timer
{
//创建一个NSCalendar对象
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *Boom = [[NSDateComponents alloc] init];
Boom.year = 2015;
Boom.month = 7;
Boom.day = 8;
Boom.hour = 13;
Boom.minute = 59;
Boom.second = 30;
//把目标时间装载入date
NSDate *date = [calendar dateFromComponents:Boom];
//得到当前时间
NSDate *currentDate = [NSDate date];
//用来得到具体的时差
unsigned int flags = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
NSDateComponents *rub = [cal components:flags fromDate:currentDate toDate:date options:0];
_Boom.text = [NSString stringWithFormat:@"??????%ld：%ld：%ld", d.hour, d.minute, d.second];
}
4、基本的网络请求
一、同步GET
// 1.将网址初始化成一个OC字符串对象
NSString *urlStr = [NSString stringWithFormat:@"%@?wewe=%@", @"111", @"222"];
// 2.如果网址中存在中文,进行URLEncodeNSString *newUrlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];// 3.构建网络URL对象, NSURLNSURL *url = [NSURL URLWithString:newUrlStr];// 4.创建网络请求NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:10];// 5.创建同步链接NSURLResponse *response = nil;NSError *error = nil;NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];// 1.将网址初始化成一个OC字符串对象
NSString *urlStr = [NSString stringWithFormat:@"%@?wewe=%@", @"111", @"222"];
// 2.如果网址中存在中文,进行URLEncodeNSString *newUrlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];// 3.构建网络URL对象, NSURLNSURL *url = [NSURL URLWithString:newUrlStr];// 4.创建网络请求NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:10];[NSURLConnection sendAsynchronousRequest:requst queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) { //your code }]// 异步连接（形式2）// 服务器接收到请求时- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{}// 当收到服务器返回的数据时触发, 返回的可能是资源片段，需要拼接资源片段- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{}// 当服务器返回所有数据时触发, 数据返回完毕- (void)connectionDidFinishLoading:(NSURLConnection *)connection{}// 请求数据失败时触发- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{ NSLog(@"%@", error);}// 1.将网址初始化成一个OC字符串对象
NSString *urlStr = [NSString stringWithFormat:@"%@?wewe=%@", @"111", @"222"];
// 2.如果网址中存在中文,进行URLEncodeNSString *newUrlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];// 3.构建网络URL对象, NSURLNSURL *url = [NSURL URLWithString:newUrlStr];// 4.创建请求NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];// 5.创建参数字符串对象NSString *parmStr = @"method=album.channel.get&appKey=myKey&format=json&channel=t&pageNo=1&pageSize=10";// 6.将字符串转为NSData对象NSData *pramData = [parmStr dataUsingEncoding:NSUTF8StringEncoding];// 7.设置请求体// 8.设置请求方式[request setHTTPMethod:@"POST"]; // 9.创建同步链接 NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];// 1.将网址初始化成一个OC字符串对象
NSString *urlStr = [NSString stringWithFormat:@"%@?wewe=%@", @"111", @"222"];
// 2.如果网址中存在中文,进行URLEncodeNSString *newUrlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];// 3.构建网络URL对象, NSURLNSURL *url = [NSURL URLWithString:newUrlStr];// 4.创建请求NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];// 5.创建参数字符串对象NSString *parmStr = @"method=album.channel.get&appKey=myKey&format=json&channel=t&pageNo=1&pageSize=10";// 6.将字符串转为NSData对象NSData *pramData = [parmStr dataUsingEncoding:NSUTF8StringEncoding];// 7.设置请求体[request setHTTPBody:pramData];// 8.设置请求方式[request setHTTPMethod:@"POST"];// 9.创建异步连接（形式2）[NSURLConnection connectionWithRequest:request delegate:self];GET请求和POST请求的区别：
1. GET请求的接口会包含参数部分，参数会作为网址的一部分，服务器地址与参数之间通过 ? 来间隔。POST请求会将服务器地址与参数分开，请求接口中只有服务器地址，而参数会作为请求的一部分，提交后台服务器。
2. GET请求参数会出现在接口中，不安全。而POST请求相对安全。
3.虽然GET请求和POST请求都可以用来请求和提交数据，但是一般的GET多用于从后台请求数据，POST多用于向后台提交数据。
同步和异步的区别：
同步链接：主线程去请求数据，当数据请求完毕之前，其他线程一律不响应，会造成程序就假死现象。
异步链接：会单独开一个线程去处理网络请求，主线程依然处于可交互状态,程序运行流畅。
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原文地址：http://www.cnblogs.com/liyanlan/p/4650466.html
