我有一个 UITableView，它由从 XML 提要解析的数据数组填充。我正在努力寻找导致此错误的原因，并想知道是否有人可以帮助我。该错误不会经常发生。它仅在数组计数很大时发生，例如 10-15 个对象，然后一旦刷新，它们的数组就会是一个较小的数字，例如 3-4 个对象。通常在这一行抛出错误： FCCall *currentCall = [[dataController callsArray] objectAtIndex:((indexPath.row - 1 ) / 2)]; 我添加了一个异常断点来中断 On Throw for All Exception，下面是它返回的内容。我明白错误在说什么，但找不到来源，而且很难重现。
CoreFoundation`-[__NSArrayM objectAtIndex:]:
0x329cce54: push {r4, r5, r7, lr}
0x329cce56: add r7, sp, #8
0x329cce58: sub sp, #8
0x329cce5a: movw r1, #62216
0x329cce5e: mov r4, r2
0x329cce60: movt r1, #2113
0x329cce64: add r1, pc
0x329cce66: ldr r1, [r1]
0x329cce68: ldr r1, [r0, r1]
0x329cce6a: cmp r1, r4
0x329cce6c: bhi 0x329ccef8 ; -[__NSArrayM objectAtIndex:] + 164
0x329cce6e: movw r0, #49640
0x329cce72: cmp r1, #0
0x329cce74: movt r0, #2111
0x329cce78: add r0, pc
0x329cce7a: ldr r0, [r0]
0x329cce7c: ldr r0, [r0]
0x329cce7e: beq 0x329cce9c ; -[__NSArrayM objectAtIndex:] + 72
0x329cce80: movw r2, #17054
0x329cce84: subs r5, r1, #1
0x329cce86: movt r2, #2113
0x329cce8a: movw r3, #61062
0x329cce8e: movt r3, #16
0x329cce92: add r2, pc
0x329cce94: add r3, pc
0x329cce96: strd r4, r5, [sp]
0x329cce9a: b 0x329cceb2 ; -[__NSArrayM objectAtIndex:] + 94
0x329cce9c: movw r2, #17044
0x329ccea0: movt r2, #2113
0x329ccea4: movw r3, #61034
0x329ccea8: movt r3, #16
0x329cceac: add r2, pc
0x329cceae: str r4, [sp]
0x329cceb0: add r3, pc
0x329cceb2: movs r1, #0
0x329cceb4: bl 0x329dce60 ; CFStringCreateWithFormat
0x329cceb8: bl 0x329c897c ; CFMakeCollectable
0x329ccebc: mov r1, r0
0x329ccebe: movs r0, #0
0x329ccec0: bl 0x329ffa8c ; _CFAutoreleasePoolAddObject
0x329ccec4: movw r2, #50122
0x329ccec8: mov r3, r0
0x329cceca: movt r2, #2111
0x329ccece: movw r1, #25010
0x329cced2: add r2, pc
0x329cced4: movt r1, #2112
0x329cced8: movw r0, #26280
0x329ccedc: ldr r2, [r2]
0x329ccede: add r1, pc
0x329ccee0: movt r0, #2112
0x329ccee4: ldr r1, [r1]
0x329ccee6: movs r4, #0
0x329ccee8: add r0, pc
0x329cceea: str r4, [sp]
0x329cceec: ldr r0, [r0]
0x329cceee: ldr r2, [r2]
0x329ccef0: blx 0x32abfeec ; symbol stub for: -[NSMutableOrderedSet removeObjectsInRange:inOrderedSet:]
0x329ccef4: blx 0x32abfe8c ; symbol stub for: -[NSMutableOrderedSet removeObjectsAtIndexes:]
0x329ccef8: movw r1, #62064
0x329ccefc: movt r1, #2113
0x329ccf00: movw r3, #62048
0x329ccf04: add r1, pc
0x329ccf06: movt r3, #2113
0x329ccf0a: movw r2, #62048
0x329ccf0e: ldr r1, [r1]
0x329ccf10: add r3, pc
0x329ccf12: movt r2, #2113
0x329ccf16: ldr r3, [r3]
0x329ccf18: add r2, pc
0x329ccf1a: ldr r2, [r2]
0x329ccf1c: ldr r1, [r0, r1]
0x329ccf1e: ldr r3, [r0, r3]
0x329ccf20: ldr r0, [r0, r2]
0x329ccf22: add.w r2, r4, r1, lsr #2
0x329ccf26: sub.w r1, r2, r3, lsr #2
0x329ccf2a: lsrs r3, r3, #2
0x329ccf2c: cmp r3, r2
0x329ccf2e: it hi
0x329ccf30: movhi r1, r2
0x329ccf32: ldr.w r0, [r0, r1, lsl #2]
0x329ccf36: add sp, #8
0x329ccf38: pop {r4, r5, r7, pc}
0x329ccf3a: nop
0x329ccf3c: nop
0x329ccf3e: nop
代码：
- (UITableViewCell *)tableView:(UITableView *)theTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Returns the cell for the given indexPath
static NSString *cellidentifier1 = @"cell1";
static NSString *cellidentifier2 = @"cell2";
self.tableView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"dark-background.jpg"]];
self.tableView.separatorColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"dark-background.jpg"]];
// Invisible Cell
if (indexPath.row % 2 == 0) {
UITableViewCell * cell2 = [theTableView dequeueReusableCellWithIdentifier:cellidentifier2];
if (cell2 == nil) {
cell2 = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellidentifier2];
[cell2.contentView setAlpha:0];
[cell2 setUserInteractionEnabled:NO];
[cell2 setBackgroundColor:[UIColor clearColor]];
}
return cell2;
}
// Standard Cell
SideSwipeTableViewCell *cell = (SideSwipeTableViewCell *)[theTableView dequeueReusableCellWithIdentifier:cellidentifier1];
if (cell == nil) {
cell = [[SideSwipeTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellidentifier1];
}
if ([dataController numberOfCalls] >= 1) {
FCCall *currentCall = [[dataController callsArray] objectAtIndex:((indexPath.row - 1 ) / 2)];
cell.callLabel.text = currentCall.call;
cell.locationLabel.text = currentCall.location;
cell.wcccaNumberLabel.text = currentCall.wcccaNumber;
cell.callNumberLabel.text = currentCall.callnumber;
// Remove leading white space from units string
NSString *units = [currentCall.units stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
cell.unitsLabel.text = units;
cell.stationLabel.text = currentCall.station;
}
return cell;
}
刷新数组的方法：
- (void)refreshData:(id)object success:(void (^)(NSURLRequest *request, NSURL *url, NSArray *calls))success failure:(void (^)(NSURLRequest *request, NSURL *url, NSError *error))failure
{
NSLog(@"Refresh Started");
// Start the network activity indicator
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
// Check to make sure we can even make an HTTP request
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.wccca.com/PITS"]];
AFHTTPRequestOperation *requestOperation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[requestOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(@"Reachable");
// Get the URL we are going to use to parse with
[FCDataController parserURL:[NSURL URLWithString:@"http://www.wccca.com/PITS"] completion:^(NSURL *url) {
NSURLRequest *parserRequest = [NSURLRequest requestWithURL:url];
AFXMLRequestOperation *operation = [AFXMLRequestOperation XMLParserRequestOperationWithRequest:parserRequest success:^(NSURLRequest *request, NSHTTPURLResponse *response, NSXMLParser *XMLParser) {
// Remove all data from our previous calls aray
[self performSelectorOnMainThread:@selector(removeCallsFromArray) withObject:nil waitUntilDone:YES];
// Set the delegate for the XMLParser and start the parse operation
XMLParser.delegate = self;
BOOL successful = [XMLParser parse];
// Determine if the parse operation was a success or not
if (!successful) {
// Return the failure block because the parser failed
failure(request, url, [FCErrors parserError]);
// Stop the network activity indicator
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
else {
// Return the success block
success(request, url, calls);
// Stop the network activity indicator
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}
NSLog(@"Refresh Finished");
} failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, NSXMLParser *XMLParser) {
NSLog(@"AFXMLOperation Error: %@", error.localizedDescription);
// Remove all data from our previous calls aray
[self performSelectorOnMainThread:@selector(removeCallsFromArray) withObject:nil waitUntilDone:YES];
failure(parserRequest, url, [FCErrors badURLError]);
// Stop the network activity indicator
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
NSLog(@"Refresh Finished");
}];
[operation start];
}];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(@"Unreachable. AFHTTPRequestOperation Error: %@", error.localizedDescription);
// Remove all data from our previous calls aray
[self performSelectorOnMainThread:@selector(removeCallsFromArray) withObject:nil waitUntilDone:YES];
failure(request, nil, [FCErrors networkError]);
// Stop the network activity indicator
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
NSLog(@"Refresh Finished");
}];
[requestOperation start];
}