网络02
- 网络请求的两种形式
第一种不能设置网络请求的信息（缓存策略，超时时间，可以放在请求头里面）
常见的缓存策略
默认
NSURLRequestUseProtocolCachePolicy = 0,
忽略本地的缓存
NSURLRequestReloadIgnoringLocalCacheData = 1,
NSURLRequestReloadIgnoringCacheData = NSURLRequestReloadIgnoringLocalCacheData,
返回数据如果没有缓存就去加载
NSURLRequestReturnCacheDataElseLoad = 2,
返回数据如果没有缓存就不去加载
NSURLRequestReturnCacheDataDontLoad = 3,
NSData 简单同步的方式获取数据,但是不能自定义请求等信息// NSURL *url = [NSURL URLWithString:@"http://127.0.0.1/demo.json"];
NSData *data = [NSData dataWithContentsOfURL:url];
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"%@",string);
第二种请求方式
SURL *url = [NSURL URLWithString:@"http://127.0.0.12/demo.json"]
//设置请求头信息，请求必须使用可变的
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:3];
//User-Agent: iPhone
[request setValue:@"iPhone" forHTTPHeaderField:@"User-Agent"];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
if(connectionError){
NSLog(@"conn error");
return;
}
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"%@",string);
}];
2.常见的json解析
NSURL *url = [NSURL URLWithString:@"http://127.0.0.1/demo.json"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
//网线连接错误
if(connectionError){
NSLog(@"conn error");
return;
}
//服务器的错误
//判断服务器是否有错,状态码
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if(httpResponse.statusCode == 200 || httpResponse.statusCode == 304){
//成功
// NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
// NSLog(@"%@",string);
//网络上传世的都是二进制,反序列化就是从二进制转变成对象
id obj = [NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];
NSLog(@"%@",obj);
}else{
NSLog(@"服务器内部错误");
}
}];
3．将乱码转化为中文
（导入一个类扩展文件）#import "NSArray+Log.h"
文件的具体内容
@implementation NSArray (Log)
- (NSString *)descriptionWithLocale:(id)locale
{
NSMutableString *strM = [NSMutableString stringWithString:@"( "];
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
[strM appendFormat:@" %@, ", obj];
}];
[strM appendString:@")"];
return strM;
}
@end
@implementation NSDictionary (Log)
- (NSString *)descriptionWithLocale:(id)locale
{
NSMutableString *strM = [NSMutableString stringWithString:@"{ "];
[self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
[strM appendFormat:@" %@ = %@; ", key, obj];
}];
[strM appendString:@"} "];
return strM;
}
@end
4.josnkit的使用
第一导入头文件#import "JSONKit.h"
第二：添加键值对
第三：id object = [[JSONDecoder decoder] objectWithData:data];
5.重新写模型的desc方法
//<CZMessage: 0x7fc7c1522cc0>
-(NSString *)description{
return [NSString stringWithFormat:@"%@ {message=%@,messageId=%d}",[super description],self.message,self.messageId.intValue];
}
6.plist的解析
//<CZMessage: 0x7fc7c1522cc0>
-(NSString *)description{
return [NSString stringWithFormat:@"%@ {message=%@,messageId=%d}",[super description],self.message,self.messageId.intValue];
}
7. id object = [NSPropertyListSerialization propertyListWithData:data options:0 format:0 error:NULL];
8. -(void)setValue:(id)value forUndefinedKey:(NSString *)key{}
9.一般reload数据可以放在数值的set方法里面
10.遍历数组，采用block进行遍历
//遍历,字典转模型
[array enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
CZNews *news = [CZNews newsWithDictionary:obj];
[mArray addObject:news];
}];
11.是能够添加refresh Control的方法未找到
设置的信息refresh Control
//设置刷新的颜色
[self.refreshControl setTintColor:[UIColor redColor]];
//设置文字的颜色
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:@"loading" attributes:@{NSForegroundColorAttributeName:[UIColor blueColor]}];
[self.refreshControl setAttributedTitle:attrString];
在加载完数据的时候讲refresh Control去掉
[self.refreshControl endRefreshing];
12，使用SD的步骤
#import "UIImageView+WebCache.h"
[self.iv_img sd_setImageWithURL:[NSURL URLWithString:model.img]];
13. //Xcode7之后可能不会刷新,需要手动刷新
[self.lb_title layoutIfNeeded];
14. //判断title是否一行显示,如果超出一行,summary不显示
CGFloat stringWidth = [self.model.title sizeWithAttributes:@{NSFontAttributeName:self.lb_title.font}].width;
CGFloat labelWidth = self.lb_title.frame.size.width;
if(stringWidth > labelWidth){
self.lb_summary.hidden = YES;
}else{
self.lb_summary.hidden = NO;
}
15.关键掌握通过字符串获取长度
CGFloat stringWidth = [self.model.title sizeWithAttributes:@{NSFontAttributeName:self.lb_title.font}].width;
16.关于注册的问题
collectionView一般都是要注册的，除非使用原型的cell
nib以及使用class的注册，不用判断缓存池里面是否有cell
tableVIEW注册也不用判断cell缓存池
原型用长的方法
自定义class使用短的方法