NSArray *listItems = [temp componentsSeparatedByString:#","];
Can anyone please tell me why?
temp is an NSString
Here's the entire code
- (NSString *)getStreetAddress
{
NSString* temp = [addressArray objectAtIndex:0];
if (temp != nil) {
NSArray *listItems = [temp componentsSeparatedByString:#","];
temp = [listItems objectAtIndex:0];
}
return temp;
}
EXC_BAD_ACCESS is the error
If execution gets to the line you say, en the most likely problem is that the first item in addressArray has been improperly deallocated while still part of the array. Since the array doesn't check to make sure the object it contains is valid, it will return a pointer to free memory. When you try to access this memory, it crashes. You can try running with NSZombiesEnabled=YES in the environment. If I am correct, you will get a error message logged to the console.
Related
My app crashed when run to NSLog(#"...") statement, and the log on console showed an object was double freed. I used zombie instrument to check it, and got that one of strings in myAreas was over released. But I cannot understand why it happened? Any help? Thank you.
NSString *myArea = #"Europe";
NSArray *myTimeZones = [NSTimeZone knownTimeZoneNames];
NSMutableArray *myAreas = [NSMutableArray arrayWithCapacity:1];
[myTimeZones enumerateObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSString *name = (NSString *)obj;
if ([name hasPrefix:myArea]) {
NSString *tmpArea = [name substringFromIndex:myArea.length+1];
[myAreas addObject:tmpArea];
}
}];
NSLog(#"My Cities in %# time zone: %#", myArea, myAreas);
NSMutableArray is not thread safe, thus it can lead to subtle bugs when used in different threads, drop NSEnumerationConcurrent and it should work fine.
I have this plist that I have created
I have written most of my controller class which gets this plist and loads it into the documents directory so its possible to read/write to is.
Currently I have the reading working fine, and I used to have the writing working also, however I have just recently changed one of the objects (cache value) to a Dictionary with values related to that. Now when I try to write to this plist my app is crashing.
This is the error I am getting.
2012-04-05 09:26:18.600 mycodeTest[874:f803] * Terminating app due to
uncaught exception 'NSInvalidArgumentException', reason: '*
-[NSDictionary initWithObjects:forKeys:]: count of objects (4) differs from count of keys (5)'
*** First throw call stack: (0x12cc022 0x1884cd6 0x1248417 0x12685e2 0x19844 0x17e86 0x17669 0x13b67 0xe53a49 0xe51e84 0xe52ea7 0xe51e3f
0xe51fc5 0xd96f5a 0x1d2aa39 0x1df7596 0x1d21120 0x1df7117 0x1d20fbf
0x12a094f 0x1203b43 0x1203424 0x1202d84 0x1202c9b 0x21aa7d8 0x21aa88a
0x450626 0x77ed 0x1e35 0x1) terminate called throwing an
exceptionCurrent language: auto; currently objective-c
with all of this in mind I will now show you my method, which is called from another class when it has the values ready to be saved.
//This method gets called from another class when it has new values that need to be saved
- (void) saveData:(NSString *)methodName protocolSignature:(NSString *)pSignature protocolVersion:(NSNumber *)pVersion requestNumber:(NSNumber *)rNumber dataVersionReturned:(NSNumber *)dvReturned cacheValue:(NSMutableDictionary *)cValue
{
// get paths from root direcory
NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
// get documents path
NSString *documentsPath = [paths objectAtIndex:0];
// get the path to our Data/plist file
NSString *plistPath = [documentsPath stringByAppendingPathComponent:#"EngineProperties.plist"];
// set the variables to the values in the text fields that will be passed into the plist dictionary
self.protocol = pSignature;
self.Version = pVersion;
self.request = rNumber;
self.dataVersion = dvReturned;
//if statment for the different types of cacheValues
if (methodName == #"GetMan")
{
//cache value only returns the one cachevalue depending on which method name was used
[self.cacheValue setValue:cValue forKey:#"Man"]; //do I need to have the other values of cacheValue dictionary in here? if so how do I do that.
c
}
else if (methodName == #"GetMod")
{
[self.cacheValue setValue:cValue forKey:#"Mod"];
}
else if (methodName == #"GetSubs")
{
[self.cacheValue setValue:cValue forKey:#"Subs"];
}
// This is where my app is falling over and giving the error message
// create dictionary with values in UITextFields
NSDictionary *plistDict = [NSDictionary dictionaryWithObjects: [NSArray arrayWithObjects: protocol, pVersion, rNumber, dvReturned, cacheValue, nil] forKeys:[NSArray arrayWithObjects: #"Signature", #"Version", #"Request", #"Data Version", #"Cache Value", nil]];
NSString *error = nil;
// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
// check is plistData exists
if(plistData)
{
// write plistData to our Data.plist file
[plistData writeToFile:plistPath atomically:YES];
NSString *myString = [[NSString alloc] initWithData:plistData encoding:NSUTF8StringEncoding];
NSLog(#"%#", myString);
}
else
{
NSLog(#"Error in saveData: %#", error);
// [error release];
}
}
I am abit lost when the error is saying that 4 keys differ from 5 when as far as i can tell i am applying 5 values to the dictionary any help would be appreciated.
Edit** another thing I noticed when debugging my issues was the fact it looks like I am not getting my cacheValue dictionary set up properly as its showing 0 key valuepairs??? is this right or wrong?
this is what happens when I log my plist in xcode as suggested below when I use [NSDictionary dictionaryWithObjectsAndKeys:..etc
Check setup is everything there?
Temp Dic output = {
Root = {
"Cache Value" = {
Manu = 0;
Mod = 0;
Sub = 0;
};
"Data Version returned" = 0;
"Signature" = null;
"Version" = 0;
"Request Number" = 0;
};
Run Man cache check results
Temp Dic output = {
"Version returned" = 5;
"Signature" = Happy;
"Version" = 1;
"Request Number" = 4;
as you can see Cache Value is completely missing after I have run the request.
I'm going to guess that cacheValue is nil when the crash occurs, resulting in only 4 objects in your values array, but 5 in keys.
Try using [NSDictionary dictionaryWithObjectsAndKeys:] instead.
In a situation like this, break up your code. Do each piece on a separate line, with temporary variables.
Put your keys and your values into temporary arrays.
Lot the values of everything, or set breakpoints in the debugger and examine all your values. Eli is almost certainly right that cacheValue is nil. The arrayWithObjects method stops on the first nil.
This code:
NSString *string1 = #"string 1";
NSString *string2 = #"string 2";
NSString *string3 = #"string 3";
NSString *string4 = nil;
NSString *string5 = #"string 5";
NSArray *anArray = [NSArray arrayWithObjects:
string1,
string2,
string3,
string4,
string5,
nil];
NSLog(#"anArray has %d elements", [anArray count]);
Will only show 3 elements in the array, even though the arrayWithObjects line appears to add 5 elements
I get a Sigabrt at the NSlog and i have no idea why - any suggestions?
NSString* contentList = [NSString stringWithContentsOfFile:currentFilePath encoding:NSUTF8StringEncoding error:nil];
NSArray* contentArray = [contentList componentsSeparatedByString:#"$$"];
NSLog(#"%#%#",contentList,[contentArray count]);
kunden = [contentArray objectAtIndex:0];
kundenView.text = kunden;
Following Joes suggestions, I now got:
NSString* contentList = [NSString stringWithContentsOfFile:currentFilePath encoding:NSUTF8StringEncoding error:nil];
NSArray* contentArray = [[contentList componentsSeparatedByString:#"$$"] retain];
if ([contentArray count] > 0) {
NSLog(#"%#%#",contentList,[contentArray count]);
kunden = [contentArray objectAtIndex:0];
kundenView.text = kunden;
}
Which gives me an EXC_BAD_ACCESS at the NSLog thing.
I get a Sigabrt at the NSlog
Your NSLog statement is trying to print an integer as if it was an object:
NSLog(#"%#%#",contentList,[contentArray count]);
^
Here!
Replace %# with %d.
You can read more on format specifiers in the String Programming Guide.
You are not checking to make sure you have at least 1 element in your array. Accessing [contentArray objectAtIndex:0] will be an issue if the contentArray is empty.
I am attempting to cache a web request. Basically I have an app that uses a facebook user's friend list but I don't want to grab it every single time they log in. Maybe refresh once per month. Caching the friend list in a plist in the documents directory seems to make sense for this functionality. I do this as follows:
- (void)writeToDisk {
NSLog(#"writing cache to disk, where cache = %#", cache);
BOOL res = [cache writeToFile:[FriendCache persistentPath] atomically:YES];
NSLog(#"reading cache from disk immediately after writing, res = %d", res);
NSMutableArray *temp = [[NSMutableArray alloc] initWithContentsOfFile:[FriendCache persistentPath]];
NSLog(#"cache read in = %#", temp);
}
+ (NSString *)persistentPath {
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:#"FriendCache.plist"];
}
These are members of a FriendCache singleton I am using which basically wraps an NSMutableArray. I have verified that the peristentPath method is returning a valid path. As you you can see in the writeToDisk method, I verify there is data in the cache and then I print the result of the write and check if any data could be read back in. There is never data read back in, because the result of the file write is 0.
The output of the cache print is very long, but here is the abbreviated version:
2010-12-28 13:35:23.006 AppName[51607:207] writing cache to disk, where cache = (
{
birthday = "<null>";
name = "Some Name1";
pic = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs1324.snc4/7846385648654.jpg";
"pic_big" = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs442.snc4/784365789465746.jpg";
"pic_square" = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs1324.snc4/7846357896547.jpg";
sex = female;
status = "<null>";
uid = 892374897165;
},
{
birthday = "<null>";
name = "Some Name2";
pic = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs625.ash1/54636536547_s.jpg";
"pic_big" = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs170.ash2/65465656365666_n.jpg";
"pic_square" = "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs625.ash1/654635656547_q.jpg";
sex = female;
status = "<null>";
uid = 7658436;
},
...
One thing I checked out is when using writeToFile, I must make sure the object I am writing has valid plist objects. I did check this and here is how I construct the cache object:
- (void)request:(FBRequest*)request didLoad:(id)result{
NSMutableArray *friendsInfo = [[[NSMutableArray alloc] init] autorelease];
for (NSDictionary *info in result) {
NSString *friend_id = [NSString stringWithString:[[info objectForKey:#"uid"] stringValue]];
NSString *friend_name = nil;
NSString *friend_sex = nil;
NSString *friend_relationship_status = nil;
NSString *friend_current_location = nil;
if ([info objectForKey:#"name"] != [NSNull null]) {
friend_name = [NSString stringWithString:[info objectForKey:#"name"]];
}
if ([info objectForKey:#"relationship_status"] != [NSNull null]) {
friend_relationship_status = [NSString stringWithString:[info objectForKey:#"relationship_status"]];
}
if ([info objectForKey:#"sex"] != [NSNull null]) {
friend_sex = [NSString stringWithString:[info objectForKey:#"sex"]];
}
if ([info objectForKey:#"current_location"] != [NSNull null]) {
friend_current_location = [[info objectForKey:#"current_location"] objectForKey:#"name"];
}
NSString *friend_pic_square = [info objectForKey:#"pic_square"];
NSString *friend_status = [info objectForKey:#"status"];
NSString *friend_pic = [info objectForKey:#"pic"];
NSString *friend_pic_big = [info objectForKey:#"pic_big"];
NSString *friend_birthday = [info objectForKey:#"birthday"];
NSDictionary *friend_info = [NSDictionary dictionaryWithObjectsAndKeys:
friend_id,#"uid",
friend_name, #"name",
friend_pic_square, #"pic_square",
friend_status, #"status",
friend_sex, #"sex",
friend_pic, #"pic",
friend_pic_big, #"pic_big",
friend_birthday, #"birthday",
friend_relationship_status, #"relationship_status",
friend_current_location, #"current_location",
nil];
// If the friend qualifies as a single of your gender, add to the friend cache
if ( [AppHelpers friendQualifies:friend_info] == YES) {
[[FriendCache sharedInstance] push:friend_info];
}
}
[[FriendCache sharedInstance] writeToDisk];
}
My push method just wraps the NSMutableArray push:
- (void)push:(id)o {
[cache addObject:o];
}
Can you think of any reason why the write would fail?
Thanks!
So as we already pointed out, it's because of the usage of the NSNull objects.
The best way to avoid this is to create an object Friend, with all of the needed properties. Then you can easily set nil values, something not possible with NSDictionary objects (well, you'd have to remove the key, which is not very good practice).
Then, by implementing the NSCoding protocol, you can easily archive (serialize) your custom object.
This is a much better way of handling your data, and it will become MUCH easier in the future. You'll be able to call messages on the Friend objects, something not possible with NSDictionary.
Use NSError-aware API for NSPropertyListSerialization to get the data and the NSData NSError aware write API so you get a meaningful error helping you understand what your problem might be.
Im just wrapping up my app, so im onto the stage of running instruments to identify leaks in the app. Ive come across a leak that I cannot work out why it is being registered as a leak.
I have the following lines for example:
NSString *imageType = [[[NSString alloc] initWithString:[loopString substringToIndex:[loopString rangeOfString:#"</IMAGE>"].location]] autorelease];
imageType = [imageType substringFromIndex:[imageType rangeOfString:#"<IMAGE>"].location + :#"<IMAGE>".length];
So basically all im doing is pulling out a section of the "loopstring" and putting that into the imagetype string than just cutting off the trailing fluff of the string using the SubstringFromIndex method.
When I run instruments it says "NSCFString substringwithRange" leak. It highlights the second line:
imageType = [imageType substringFromIndex:[imageType rangeOfString:#"<IMAGE>"].location + :#"<IMAGE>".length];
I would think the substringFromIndex method should return a string that is automatically added to the autorelease pool.
Any ideas on where im going wrong?
Thanks
Following is the refactored code:
- (void)SetupTop10:(NSString *)Top10Data
{
while (Top10Data != #"") {
NSLog(Top10Data);
if ([Top10Data rangeOfString:#"</TOP10ENTRY>"].location == NSNotFound){
Top10Data = #"";
}
else
{
NSString *loopString = [Top10Data substringToIndex:[Top10Data rangeOfString:#"</TOP10ENTRY>"].location + 13];
Top10Data = [Top10Data stringByReplacingOccurrencesOfString:loopString withString:#""];
//NOW CREATE A RECORD FOR THIS ITEM
NSString *imageType = [loopString substringToIndex:[loopString rangeOfString:#"</IMAGE>"].location];
imageType = [imageType substringFromIndex:[imageType rangeOfString:#"<IMAGE>"].location + 7];
NSString *displayText = [loopString substringToIndex:[loopString rangeOfString:#"</DISPLAYTEXT>"].location];
displayText = [displayText substringFromIndex:[displayText rangeOfString:#"<DISPLAYTEXT>"].location + 13];
NSString *link = [loopString substringToIndex:[loopString rangeOfString:#"</INTERESTID>"].location];
link = [link substringFromIndex:[link rangeOfString:#"<INTERESTID>"].location + 12];
[Top10Images addObject:imageType];
[Top10Links addObject:link];
[Top10s addObject:displayText];
Top10RowCount = Top10RowCount + 1;
}
}
[self.Top10Table reloadData];
Top10Table.hidden = NO;
loadingLabel.hidden = YES;
loadingIndicator.hidden = YES;
}
//******************
It doesn't look leaky. But why
NSString *imageType = [[[NSString alloc] initWithString:
[loopString substringToIndex:[loopString
rangeOfString:#"</IMAGE>"].location]
] autorelease];
if you effectively get the same with
NSString *imageType = [loopString substringToIndex:[loopString
rangeOfString:#"</IMAGE>"].location];
with half the memory usage?
Leaks will tell you where the leaked memory was allocated. If you click around (there's a right-arrow icon by the memory address, I think) then you can look at all the allocations/retains/releases for that addresses.
In this example, Leaks will point you to the first line, when it's the fifth one that "leaks" (actually it's a missing release in dealloc/on assignment that leaks):
NSString * s = [someString substringFromIndex:1];
[myArray addObject:s];
// ...
NSString * s2 = [myArray lastObject];
instanceVariable = [s2 retain];
// ... and forget to release in dealloc
What does tableView:cellForRowAtIndexPath: do?
I can't see any problem in the above code. Did you release Top10Images in your dealloc method?