NSScanner可在WiFi上运行，但不能在3G上运行 [英] NSScanner working on WiFi but not 3G
问题描述
我已经设置了NSScanner，可以使用以下代码在UIButton的轻按上工作:
I have set up an NSScanner to work on the tap of a UIButton with the following code:
-(IBAction)doLoadTTData
{
NSString *Period1String = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource: @"Period1String" ofType: @"txt"] usedEncoding:nil error:nil];
NSString *Period2String = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource: @"Period2String" ofType: @"txt"] usedEncoding:nil error:nil];
NSString *Period3String = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource: @"Period3String" ofType: @"txt"] usedEncoding:nil error:nil];
NSString *Period4String = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource: @"Period4String" ofType: @"txt"] usedEncoding:nil error:nil];
NSString *Period5String = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource: @"Period5String" ofType: @"txt"] usedEncoding:nil error:nil];
NSURL *currentURL = [NSURL URLWithString:webView.request.URL.absoluteString];
NSLog(@"Loaded Timetable");
NSError *loaderror;
NSString *page = [NSString stringWithContentsOfURL:currentURL
encoding:NSASCIIStringEncoding
error:&loaderror];
[webView loadHTMLString:page baseURL:currentURL];
NSString *Period1Data = nil;
NSScanner *htmlScanner = [NSScanner scannerWithString:page];
[htmlScanner scanUpToString:Period1String intoString:NULL];
[htmlScanner scanString:Period1String intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&Period1Data];
NSLog(@"Collected Period 1 Data: %@", Period1Data);
if(Period1Data == NULL)
{
Period1Data = @"Not Available";
[period1label setText:@"Not Available"];
}
else if(Period1Data == @"(null)")
{
Period1Data = @"Not Available";
[period1label setText:@"Not Available"];
}
else
{
[period1label setText:Period1Data];
}
NSString *Period2Data = nil;
[htmlScanner scanUpToString:Period2String intoString:NULL];
[htmlScanner scanString:Period2String intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&Period2Data];
if(Period2Data == NULL)
{
Period2Data = @"Not Available";
[period2label setText:@"Not Available"];
}
else if(Period2Data == @"(null)")
{
Period2Data = @"Not Available";
[period2label setText:@"Not Available"];
}
else
{
[period2label setText:Period2Data];
[period2label setText:@"Not Available"];
}
NSLog(@"Collected Period 2 Data: %@", Period2Data);
NSString *Period3Data = nil;
[htmlScanner scanUpToString:Period3String intoString:NULL];
[htmlScanner scanString:Period3String intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&Period3Data];
if(Period3Data == NULL)
{
Period3Data = @"Not Available";
[period3label setText:@"Not Available"];
}
else if(Period3Data == @"(null)")
{
Period3Data = @"Not Available";
[period3label setText:@"Not Available"];
}
else
{
[period3label setText:Period3Data];
}
NSLog(@"Collected Period 3 Data: %@", Period3Data);
NSString *Period4Data = nil;
[htmlScanner scanUpToString:Period4String intoString:NULL];
[htmlScanner scanString:Period4String intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&Period4Data];
if(Period4Data == NULL)
{
Period4Data = @"Not Available";
[period4label setText:@"Not Available"];
}
else if(Period4Data == @"(null)")
{
Period4Data = @"Not Available";
[period4label setText:@"Not Available"];
}
else
{
[period4label setText:Period4Data];
}
NSLog(@"Collected Period 4 Data: %@", Period4Data);
NSString *Period5Data = nil;
[htmlScanner scanUpToString:Period5String intoString:NULL];
[htmlScanner scanString:Period5String intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&Period5Data];
if(Period5Data == NULL)
{
Period5Data = @"Not Available";
[period5label setText:@"Not Available"];
}
else if(Period5Data == @"(null)")
{
Period5Data = @"Not Available";
[period5label setText:@"Not Available"];
}
else
{
[period5label setText:Period5Data];
}
NSLog(@"Collected Period 5 Data: %@", Period5Data);
NSString* TimetableDate = nil;
NSString *DateString = [NSString stringWithFormat:@"<FONT size=2> <STRONG><FONT size=3>"];
[htmlScanner scanUpToString:DateString intoString:NULL];
[htmlScanner scanString:DateString intoString:NULL];
[htmlScanner scanUpToString:@"</FONT>" intoString:&TimetableDate];
NSString *timetablefulldate = [NSString stringWithFormat:@"Timetable for %@", TimetableDate];
[timetabledate setText:timetablefulldate];
[TimetableLoading setHidden:YES];
[TimetableLoadingBG setHidden:YES];
if(Period1Data == NULL && Period2Data == NULL && Period3Data == NULL && Period4Data == NULL && Period5Data == NULL)
{
if(ttbacking.tag == 10)
{
NSLog(@"Already showing message");
}
else
{
UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"Timetable"
message:@"Looks like you don't have any lessons today! Maybe you'd like to get some homework out of the way?"
delegate:nil
cancelButtonTitle:@"I'll have a think"
otherButtonTitles:nil];
[message show];
[ttbacking setTag:10];
}
[period1label setText:@"Free Time"];
[period2label setText:@"Free Time"];
[period3label setText:@"Free Time"];
[period4label setText:@"Free Time"];
[period5label setText:@"Free Time"];
period1backing.image = [UIImage imageNamed:@"redperiodbacking.png"];
period2backing.image = [UIImage imageNamed:@"redperiodbacking.png"];
period3backing.image = [UIImage imageNamed:@"redperiodbacking.png"];
period4backing.image = [UIImage imageNamed:@"redperiodbacking.png"];
period5backing.image = [UIImage imageNamed:@"redperiodbacking.png"];
}
if(TimetableDate == NULL)
{
[timetabledate setText:@"No timetable today"];
}
[prevDay setHidden:NO];
[nextDay setHidden:NO];
NSLog(@"Student Timetable collected and published");
}
不幸的是，这仅适用于WiFi，不适用于3G.
Unfortunately, this only works with WiFi and not 3G.
如果我按3G连接上的按钮，则所有标签都显示不可用"，因为结果为"NULL".这很奇怪，因为我一次将UIWebView放在所有内容的最前面，以测试该页面是否实际加载和加载，就像它在WiFi上一样.由于某些原因，NSScanner无法在3G上运行.
If I press the button on a 3G connection, all the labels show "Not Available" because the results are "NULL". This is weird because I put the UIWebView in front of everything one time to test if the page actually loaded and it did, just as if it were on WiFi. For some reason the NSScanner isn't working on 3G.
为什么会这样?只要告诉我是否还有其他代码需要查看...
Why could this be? Just tell me if there is any other code you need to see...
推荐答案
我有两件事要说.首先，您使用扫描仪之类的东西确实很棘手.如果您尝试解析HTML，则应该以正确的方式进行操作.使用类似 libxml2 (iPhone内置)之类的东西，实际上解析 html并从中获取内容.老实说，您的系统可能会因进行少量更新而中断，或者页面出现故障.
I have a couple things to say. First of all, what you're doing with scanners and stuff is really quite hacky. If you're trying to parse HTML, you should be doing it the right way. Use something like libxml2 (which comes built into the iPhone), to actually parse the html and get stuff from it. Quite honestly your system could break with a small update or malfunction with the page.
已经足够了，但是如果您决定保留当前系统，则可以尝试从当前加载的页面中检索实际的html.
Enough with the ranting, but if you decide to leave your current system in place, you could try retrieving the actual html from the currently-loaded page.
例如(正如我已经在您的其他问题中所述的那样):
For example (as I already posted in your other question):
NSString *path = @"document.body.innerHTML";
NSString *html = [webView stringByEvaluatingJavaScriptFromString:path];
由于可以加载Web视图，因此您应该能够像这样从加载的Web视图中获取内容.
Since your web view can load, then you should be able to grab the contents from the loaded webview like so.
如果我可以补充，这将无法工作:否则if(Period1Data == @(null)").调试器打印(null)，但是如果字符串为null，则永远不会显示为(null).而且，如果您正在比较字符串，那么您会做 isEqualToString:，但是我自己就快要逃跑了.;)
And if I may add, this is not going to work: else if(Period1Data == @"(null)"). The debugger prints (null), but if a string is null it's never going to appear as (null). And if you were comparing strings, you would be doing isEqualToString:, but I'm running away with myself. ;)
这篇关于NSScanner可在WiFi上运行，但不能在3G上运行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
