Hi friends i'm beginner
and sorry for simple Questions.
how can i add new lines in ""plist"" for saving data
and access keys in it.
NSArray *values = [[NSArray alloc] initWithObjects:#"Hello",nil];
[values writeToFile:[self PathArray] atomically:YES];
because , this method Only overwrite Values in ([self PathArray]) "path";
Thanks
Plist files are not designed for incremental updates, instead you should load plist contents in memory, add an item to it and save back:
NSMutableArray *oldValues = [NSMutableArray arrayWithContentsOfFile:[self PathArray]];
NSArray *values = [[NSArray alloc] initWithObjects:#"Hello",nil];
[oldValues addObjectsFromArray:values];
[oldValues writeToFile:[self PathArray] atomically:YES];
[values release]; // Do not forget this line to avoid memory leak
In my item, the dictionary data includes null, for example :
{
"category_id" = 29;
"category_name" = "\U5f69\U6f2b";
coverurl = "<null>";
position = 29;
}
so writetofile, return value always FALSE.
Related
Im creating a application that writes strings to a plist file, but the problem im having is every time its writing to the plist file, it deletes the previous one, im trying to figure out either how to write to the existing one without deleting its original contents, or replace the plist file and keep the original contents and then re write them on to it..
Heres what my code looks like to save the file
- (NSString *) saveFilePath
{
NSArray *pathArray =
NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
return [[pathArray objectAtIndex:0] stringByAppendingPathComponent:#"scores.plist"];
}
-(void)alertView:(UIAlertView *)alert_view didDismissWithButtonIndex:
(NSInteger)button_index{
if(button_index == 0){
NSLog(#"1");
score = 0;
}
if(button_index == 1){
NSLog(#"2");
NSString *scoreString = [NSString stringWithFormat:#"%i by %#", score, name.text];
NSLog(#"%#", scoreString);
NSArray *values = [[NSArray alloc] initWithObjects:scoreString, nil];
[values writeToFile:[self saveFilePath] atomically:YES];
[values release];
score = 0;
}
}
Any ideas? Thanks!
You can read the plist and write it to the NSMutableArray. Then append it with your data and write it back to the file overwriting the existing one.
The same thing with NSMutableDictionary.
The basic structure of my program has the user select an item from a UITableView, which corresponds to a stored text file. The file is then read into an array and a dictionary, where the array has the keys (I know I can just get the keys from the dictionary itself, this isn't my question).
The view is then changed to a UISplitView where the master view has the keys, and the detail view has the items in the dictionary attributed to that key. In this case, it's a series of "Yes/No" questions that the user selects the answer to.
My problem is this: When I click on a cell in the UITableView (first screen), it works fine, the data is read in perfectly, and so on. When I go back to the UITableView and click on the same cell again, the program crashes. Here is the read-in-from-file method:
-(NSArray *)readFromFile:(NSString *)filePath{
// NSLog(#"Path was: %#", filePath);
NSString *file = [[NSString alloc] initWithContentsOfFile:filePath];
// NSLog(#"File was: %#", file);
NSScanner *fileScanner = [[NSScanner alloc] initWithString:file];
NSString *held;
NSString *key;
NSMutableArray *detailStrings;
NSMutableArray *keys = [[NSMutableArray alloc] init];
NSMutableDictionary *details = [[NSMutableDictionary alloc] init];
/**
This is where the fun stuff happens!
**/
while(![fileScanner isAtEnd]){
//Scan the string into held
[fileScanner scanUpToString:#"\r" intoString:&held];
NSLog(#"Inside the while loop");
// If it is a character, it's one of the Key points, so we do the management necessary
if ([[NSCharacterSet lowercaseLetterCharacterSet] characterIsMember:[[held lowercaseString] characterAtIndex: 0]]){
NSArray *checkers = [[NSArray alloc] initWithArray:[held componentsSeparatedByString:#"\t"]];
NSLog(#"Word at index 2: %#", [checkers objectAtIndex:2]);
if(detailStrings != nil){
[details setObject:detailStrings forKey:key];
[detailStrings release];
}
NSLog(#"After if statement");
key = [checkers objectAtIndex:2];
[keys addObject:(NSString *) key];
detailStrings = [[NSMutableArray alloc] init];
}
else if ([[NSCharacterSet decimalDigitCharacterSet] characterIsMember:[[held lowercaseString] characterAtIndex: 0]]){
NSArray *checkers = [[NSArray alloc] initWithArray:[held componentsSeparatedByString:#"\t"]];
NSLog(#"Word at index 1: %#", [checkers objectAtIndex:1]);
[detailStrings addObject:[checkers objectAtIndex:1]];
}
}
NSLog(#"File has been read in");
[details setObject:detailStrings forKey:key];
NSArray *contents = [[NSArray alloc] initWithObjects:(NSMutableArray *) keys, (NSMutableDictionary *) details, nil];
[detailStrings release];
return contents;
}
I've determined that the program crashes inside the
if(detailStrings != nil)
statement. I figure this is because I'm missing some memory management that I am supposed to be doing, but don't have the knowledge of where it's going wrong. Any ideas as to the problem, or why it is crashing without giving me a log?
detailStrings is not initialized when you enter the while loop. When you declare NSMutableArray *detailStrings; inside a method, detailStrings is not automatically set to nil. So when you do
if ( detailStrings != nil ) { .. }
it enters the if statement and since it is not initialized, it will crash when you access detailStrings.
Another thing is that detailStrings won't be initialized if it enters the else part of the loop first. That will cause a crash too. So based on your requirement, either do
NSMutableArray *detailStrings = nil;
or initialize it before you enter the while loop.
Deepak said truth. You should initialize detailStrings with nil first.
But there is second possible issue:
I recommend also to set nil after release, because in the next loop you may test nonexistent part of memory with nil.
if(detailStrings != nil){
[details setObject:detailStrings forKey:key];
[detailStrings release];
detailStrings = nil;
}
And the third possible issue: depending from incoming data you may go to the second part of IF statement first time and try to addObject into non-initialized array.
The fourth (hope last): you have memory leak with "checkers" arrays
Here's what I'm seeing:
//read in the file
NSString *file = [[NSString alloc] initWithContentsOfFile:filePath];
//create the scanner
NSScanner *fileScanner = [[NSScanner alloc] initWithString:file];
//declare some uninitialized stuff
NSString *held;
NSString *key;
NSMutableArray *detailStrings;
//initialize some stuff
NSMutableArray *keys = [[NSMutableArray alloc] init];
NSMutableDictionary *details = [[NSMutableDictionary alloc] init];
//begin loop
while(![fileScanner isAtEnd]){
//scan up to a newline
[fileScanner scanUpToString:#"\r" intoString:&held];
//see if you scanned a lowercase string
if ([[NSCharacterSet lowercaseLetterCharacterSet] characterIsMember:[[held lowercaseString] characterAtIndex: 0]]){
//make an array
NSArray *checkers = [[NSArray alloc] initWithArray:[held componentsSeparatedByString:#"\t"]];
//do a check... against an uninitialized value
if(detailStrings != nil){
//set a potentially uninitialized value into an array with an uninitialized key
[details setObject:detailStrings forKey:key];
At this point, you're pretty much hosed.
The fix:
properly initialize your variables
run the static analyzer
read the memory management programming guide
I've done the following to put a fetched request into an array of arrays but now i don't know which methods i need to call from chcsvparser to write this into a csv file
NSArray *objectsForExport = [fetchedResultsController fetchedObjects];
NSArray *exportKeys = [NSArray arrayWithObjects:#"best_checkout", #"darts_thrown", #"high_score", #"score_100", #"score_140", #"score_180",#"three_dart_average",nil];
NSMutableArray *csvObjects = [NSMutableArray arrayWithCapacity:[objectsForExport count]];
for (NSManagedObject *object in objectsForExport) {
NSMutableArray *anObjectArray = [NSMutableArray arrayWithCapacity:[exportKeys count]];
for (NSString *key in exportKeys) {
id value = [object valueForKey:key];
if (!value) {
value = #"";
}
[anObjectArray addObject:[value description]];
}
[csvObjects addObject:anObjectArray];
}
As Johann suggests, you should use the writeToCSVFile:atomically: convenience method. However, be aware that using it as you describe in your comment is not correct.
The NSString you pass in should be the filepath you want the data writing to.
This webpage should give you the necessary information and methods when writing CSV files:
https://github.com/davedelong/CHCSVParser#readme
Hope this helps!
I am not a Cocoa developer, but I have been dabbling in it to build some plugins for PhoneGap. This particular plugin method is either 1) crashing the app without saying why or 2) complaining about how I release/don't release an object. I have tried a ton of things on my end, including using an Enumerator instead of the for loop. If anyone can point me in the right direction, that would be awesome. I don't mind legwork:
- (void)getPreferences:(NSMutableArray*)arguments withDict:(NSMutableDictionary*)options {
NSUInteger argc = [arguments count];
NSString* jsCallback = nil;
if (argc > 0) {
jsCallback = [arguments objectAtIndex:0];
} else {
NSLog(#"Preferences.getPreferences: Missing 1st parameter.");
return;
}
NSDictionary *defaults = [[NSUserDefaults standardUserDefaults] dictionaryRepresentation];
NSMutableArray *keys = (NSMutableArray *) [options objectForKey:#"keys"];
NSMutableDictionary *values = [[NSMutableDictionary alloc] init];
NSUInteger ky = [keys count];
for (int i = 0; i < ky; i ++) {
#try {
[values setObject:[defaults objectForKey:[keys objectAtIndex:i]] forKey:[keys objectAtIndex:i]];
}
#catch (NSException * err) {
NSLog(#"Error %#", err);
}
}
[keys release];
NSString* jsString = [[NSString alloc] initWithFormat:#"%#(%#);", jsCallback, [values JSONRepresentation]];
[defaults release];
[values release];
[webView stringByEvaluatingJavaScriptFromString:jsString];
[jsString release];
}
Human version:
options contains a dictionary with a single key of "keys"
that key contains an array of strings (that are going to be used as keys for lookup)
I want to loop through that array and
For every value that exists in defaults for that key, copy it to values using the same key
Finally, I want to send that values back as JSON (This part was working when I just passed the entire defaults object in, so I think the JSON method is working)
From your code, it follows that you 'own' objects values and jsString (the ones you created with alloc), so you should release them and not any other.
You can read more on memory management here.
Is this the whole code? Also, what exactly error do you get?
Nikita is right, it looks as though you're overreleasing defaults, which would cause a crash later when the autorelease pool gets released. Also, if I understand what you're trying to do correctly, you could create the values dictionary with a single line of code:
NSDictionary *values = [defaultsDict dictionaryWithValuesForKeys:keys];
I have an app that needs to connect and receive data, different each time that you click in one tab.
Then to show the data to the user, i use a "element.plist" where i have one array of dictionaries( each dictionary has the info in different strings: name, category, ...). I load the info from this plist.
I would like then, to continue using the same structure. Each time i receive the connection data:
delete the content in the plist
save the new content (I can do this in the parser method, each time that i have one object with all the information)
Read the info like i'm doing now.
The step that i can't do is the second.
thanks
I'm not sure I completely understand your question,
but I'll try to help.
below is some apple sample code that saves a plist when an application is exiting.
the second line sets the name of the plist file:
NSString *bundlePath = the application directory + "Data"
the third line defines a dictionary with all the data to be saves:
NSDictionary *plistDict
the fourth line formats this dictionary as property list data:
NSData *plistData
which then gets saved as Data.plist
- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)sender
{
NSString *errorDesc;
NSString *bundlePath = [[NSBundle mainBundle] pathForResource:#"Data" ofType:#"plist"];
NSDictionary *plistDict = [NSDictionary dictionaryWithObjects:
[NSArray arrayWithObjects: personName, phoneNumbers, nil]
forKeys:[NSArray arrayWithObjects: #"Name", #"Phones", nil]];
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict
format:NSPropertyListXMLFormat_v1_0
errorDescription:&errorDesc];
if (plistData)
{
[plistData writeToFile:bundlePath atomically:YES];
}
else {
NSLog(errorDesc);
[errorDesc release];
}
return NSTerminateNow;
}
You can find this information in the Property list programming guide
Mey,
I'm not sure that I understand your statement about having an empty plist. I assume that you mean that if you read back the plist file that you created, it is null when you print it out. Suggesting that you are writing out an empty file or not reading correct or ...
I further assume that your intent is to replace the existing plist contents by a new plist while keeping the same name.
And caveat emptor - I'm new to Objective C etc. Here is a way to do that which I think you are trying to do.
// Implement viewDidLoad to do additional setup after loading the view,
// typically from a nib.
- (void)viewDidLoad {
NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle pathForResource:#"TmpPList" ofType:#"plist"]; //Not NARC
//NSLog(#"plistPath : %#", plistPath);
//My plist is a simple array, but it could be an array of dictionary objects etc
NSMutableArray *arrayFromPList = [[NSMutableArray alloc] initWithContentsOfFile:plistPath]; //NARC
//NSLog(#"arrayFromPList : %#", arrayFromPList);
//Delete the arrays contents and put new contents
[arrayFromPList removeAllObjects];
//NSLog(#"arrayFromPList : %#", arrayFromPList);
//[arrayFromPList addObjectsFromArray:[NSArray arrayWithObjects:#"A", #"B", "#C", nil]];
//NSLog(#"arrayFromPList : %#", arrayFromPList);
[arrayFromPList setArray:[NSMutableArray arrayWithObjects:#"A", #"B", #"C", #"D", #"E", #"F", nil]];
//NSLog(#"arrayFromPList : %#", arrayFromPList);
/* */
//Write it out to the original file name
[arrayFromPList writeToFile:plistPath atomically:YES];
NSMutableArray *newArray = [[NSMutableArray alloc] initWithContentsOfFile:plistPath]; //NARC
NSLog(#"newArray : %#", newArray);
[arrayFromPList release];
[newArray release];
}