ios几个技巧

1. 如何除去UITableViewStyleGroup类型的UITableView的边框:

    UITableViewStylePlain类型的UITableView去除边框线有直接的属性方法:

    separatorStyle = UITableViewCellSeparatorStyleNone;

    但在UITableViewStyleGrouped类型的UITableView中,该方法无效

    如何去除边框线呢?答案很简单:

    separatorColor=[UIColor clearColor];

 

2. UITableView划动删除的实现

    需要实现下面两个方法

        - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { 

           return YES;

            }

        - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:                    (NSIndexPath *)indexPath { 

              if (editingStyle == UITableViewCellEditingStyleDelete) { 

                  [dataArray removeObjectAtIndex:indexPath.row]; 

                    // Delete the row from the data source.                         [testTableView deleteRowsAtIndexPaths:    [NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; 

              }else if (editingStyle == UITableViewCellEditingStyleInsert) {                                            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.

              }  

         }

3. NSURLConnection同步,异步与SSL  
    同步请求
NSURL *url=[[NSURL alloc]initWithString:urlString];
NSMutableURLRequest *request=[[NSMutableURLRequest alloc]init];
NSError *err=nil;
NSData *data=[NSURLConnection sendSynchronousRequest:request
returningResponse:nil
error:&err];
if(data==nil)
{
//if([err code])

NSLog(@"Code:%d,domain:%@,localizedDesc:%@",[err code],
[err domain],[err localizedDescription]);
}
else
{
}
    这种情况,通过一个静态方法,请求request,这种情况下,会一直阻塞,等到返回结果,简单易用
        异步请求
NSURL *url=[[NSURL alloc]initWithString:urlString];
NSMutableURLRequest *request=[[NSMutableURLRequest alloc]init];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
[url release];
[request release];
if(connection)
{
receivedData = [[NSMutableData data] retain];
NSLog(@"intial done!");
}
else
{
NSLog(@"sorry");
}
        通过一个delegate来做数据的下载以及Request的接受等等消息,此处delegate:self,所以需要本类实现一些方法,并且定义receivedData做数据的接受
        基本上要实现下面节歌方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(@"get the whole response");
[receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
NSLog(@"get some data");
[receivedData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[connection release];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
[connection release];
NSLog(@"Connection failed! Error - %@ %@",
[error localizedDescription],
[[error userInfo] objectForKey:NSErrorFailingURLStringKey]);
}
    基本上这样就搞定了!!!
    但是异步模式下带来了一个新的问题,很多情况下,网络请求不在主线程,或者界面等待网络结果,不在主线程的时候,调用线程如果生命周期over,下面这些可能都没有调用到,导致得不到想要得效果,所以需要在NSURLConnection请求后面加点东西来阻塞
    while(!finished) {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
}

    好了,现在我们看看SSL的问题,在NSURLConnnection本来有方法可以跳过ssl检查,可惜被apple无情的私有了,所以同步的数据请求肯定不行了,看看文档,只能通过异步delegate的方式了
    - (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
    {
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
    }
    - (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
    {
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust])
if ([trustedHosts containsObject:challenge.protectionSpace.host])
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
    }
    第一个方法会根据你的URL来判断是否需要做认证
    第二个方法是认证的过程,if ([trustedHosts containsObject:challenge.protectionSpace.host]),这行代码注释掉,就可以自动所有SSL通过,否则,你可以加一些Trust的hosts,其他的不通过就行了!!!

 

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