我的應用程序使用一個由動態xml提要填充的表。我還使用pull來刷新Grant Paul編寫的代碼以重新加載包含新內容的表格(如果有的話)。第三,我正在使用Apple的Reachability在重新加載表格時確定互聯網連接。我的問題是這樣的;如果我打開應用程序與互聯網連接,然後當應用程序正在運行,關閉我的互聯網連接,然後我拉來刷新應用程序,它崩潰。當應用程序在Reachable和NotReachable之間切換時發生了一些情況。以下是我的代碼。該應用程序失敗,並在此行顯示線程6:SIGABRT信號:TFHppleElement * element = [elements objectAtIndex:0];iOS桌面刷新問題
以下是錯誤代碼:
2012-10-02 14:00:03.715 FireCom[2229:1517] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array'
*** First throw call stack:
(0x2d63012 0x21a0e7e 0x2d050b4 0x603f 0xd810d5 0xd81034 0x96213557 0x961fdcee)
libc++abi.dylib: terminate called throwing an exception
(lldb)
這裏是可達代碼:
- (void)loadCallList
{
Reachability* reach = [Reachability reachabilityWithHostname:@"www.apple.com"];
NetworkStatus netStatus = [reach currentReachabilityStatus];
switch (netStatus)
{
case NotReachable:
{
NSLog(@"Access Not Available");
[pull finishedLoading];
[self displayInternetMessage];
break;
}
case ReachableViaWWAN:
{
NSLog(@"Reachable WWAN");
// Parse HTML for random ID and create XML link
NSURL *theURL = [NSURL URLWithString:@"http://www.wccca.com/PITS/"];
NSData *data = [[NSData alloc] initWithContentsOfURL:theURL];
xpathParser = [[TFHpple alloc] initWithHTMLData:data];
NSArray *elements = [xpathParser searchWithXPathQuery:@"//input[@id='hidXMLID']//@value"];
TFHppleElement *element = [elements objectAtIndex:0];
TFHppleElement *child = [element.children objectAtIndex:0];
NSString *idValue = [child content];
NSString *idwithxml = [idValue stringByAppendingFormat:@".xml"];
NSString *url = @"http://www.wccca.com/PITS/xml/fire_data_";
NSString *finalurl = [url stringByAppendingString:idwithxml];
xmlParser = [[XMLParser alloc] loadXMLByURL:finalurl];
if (xmlParser.calls.count == 0)
{
self.headerHeight = 0.0;
UIAlertView *noCalls = [[UIAlertView alloc] initWithTitle:@"No Current Calls"
message:@"There are no current 9-1-1 calls in Clackamas or Washington County."
delegate:self
cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[noCalls show];
[noCalls release];
}
else
{
self.headerHeight = 45.0;
}
[callsTableView reloadData];
[pull finishedLoading];
break;
}
case ReachableViaWiFi:
{
NSLog(@"Reachable WiFi");
// Parse HTML for random ID and create XML link
NSURL *theURL = [NSURL URLWithString:@"http://www.wccca.com/PITS/"];
NSData *data = [[NSData alloc] initWithContentsOfURL:theURL];
xpathParser = [[TFHpple alloc] initWithHTMLData:data];
NSArray *elements = [xpathParser searchWithXPathQuery:@"//input[@id='hidXMLID']//@value"];
TFHppleElement *element = [elements objectAtIndex:0];
TFHppleElement *child = [element.children objectAtIndex:0];
NSString *idValue = [child content];
NSString *idwithxml = [idValue stringByAppendingFormat:@".xml"];
NSString *url = @"http://www.wccca.com/PITS/xml/fire_data_";
NSString *finalurl = [url stringByAppendingString:idwithxml];
xmlParser = [[XMLParser alloc] loadXMLByURL:finalurl];
if (xmlParser.calls.count == 0)
{
self.headerHeight = 0.0;
UIAlertView *noCalls = [[UIAlertView alloc] initWithTitle:@"No Current Calls"
message:@"There are no current 9-1-1 calls in Clackamas or Washington County."
delegate:self
cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[noCalls show];
[noCalls release];
}
else
{
self.headerHeight = 45.0;
}
[callsTableView reloadData];
[pull finishedLoading];
break;
}
}
}
你的代碼假定你的'elements'數組將有數據。您應該首先檢查是否爲零或計數== 0並添加邏輯以處理「無數據」情形。 – Jeremy
元素數組將始終有數據。它永遠不會是空的。 –
如果'xpathParser'找不到任何id爲'hidXMLID'的元素?我認爲答案在於數據。你沒有回覆你的想法。你的問題相當乾脆。元素中沒有任何東西,因此你得到錯誤。 – Jeremy