I'v run into such problem. I need to update the values in my NSArray. And don't know a way to do it. Here's my array
NSArray *arrayWithInfo = [[NSArray alloc] initWithObjects:AMLocalizedString(#"Status", nil),AMLocalizedString(#"Call", nil),AMLocalizedString(#"Location", nil),AMLocalizedString(#"Control", nil),AMLocalizedString(#"Sim", nil),AMLocalizedString(#"Object", nil),AMLocalizedString(#"Info", nil),nil];
self.dataArray = arrayWithInfo;
[arrayWithInfo release];
To be more specific I have tableview initialized with this array. There is a possibility for user to use different localized strings, so I have to update it. By using [tableview reloadData]; i'v got the table to update, but the values in NSArray stay the same as they were initialized in first place.
So how to make array look up at the strings once again and get their new values?
Use NSMutableArray instead of NSArray
NSMutableArray (and all other classes with Mutable in the name) can be modified.
You should be using an NSMutableArray. Doing so will allow you to change its values after instantiation.
Your array doesn't need to be mutable here as the array seems to be all or nothing. You dont mention the requirement to delete some objects and not others. NSMutableArray isn't needed. You want to write a lazy loading getter method for the array which reinstantiates it if the array doesnt exist.
-(NSArray *)dataArray{
if (_dataArray){
return _dataArray;
}
_dataArray = NSArray *arrayWithInfo = [[NSArray alloc] initWithObjects:AMLocalizedString(#"Status", nil),AMLocalizedString(#"Call", nil),AMLocalizedString(#"Location", nil),AMLocalizedString(#"Control", nil),AMLocalizedString(#"Sim", nil),AMLocalizedString(#"Object", nil),AMLocalizedString(#"Info", nil),nil];
return _dataArray;
}
Then when you want to reload the tableView
self.dataArray = nil;
[tableView reloadData];
this destroys the old array, forcing it to be remade but with the new localisation.
EDIT:
The issue is the array isn't storing the statement AMLocalizedString(#"Status", nil) its storing the result of that statement, which is the localised string itself. There is no way to make the array re-evaluate that statement without either re-creating the whole array again or using an NSMutableArray and changing all the objects. The lazy loading getter method is more in the objective-c style.
You need to use the NSMutableArray. The NSArray is immutable.
Related
I am having hard time with a simple array that i want to pass .
I have a class with some NSMutableArray that i pass to another class(the array is global from singleton)
[mgzm saveWithArray:[Globals sharedGlobals].allImages];
To this function :
-(void)saveWithArray:(NSMutableArray*)currentArray
{
dataToSave=[[NSMutableArray alloc] init]; //local
dataToSave=[currentArray mutableCopy]; //copy
Than i saw that is is changing the original array which i don't want .
So i did this :
dataToSave=[[NSMutableArray alloc] initWithArray:currentArray copyItems:YES];
Which result in a situation that i can't change the dataToSave array get get a crash when trying to.(it needs to be changed).
Than i did this :
for(NSMutableDictionary *dic in currentArray)
[dataToSave addObject:dic];
Which again if i change dataToSave it change also the original array (?! )
Is there a way in this language to COPY array without changing the original one ????
When you make a copy of a mutable array, changing the array copy does not change the original array, not the objects inside the array. Here is what happens when you call [currentArray mutableCopy]:
The two arrays are pointing to the same objects. If you remove an object from the copy, the original array would still have it. However, if you modify the object itself (say, change the name of A to X) the change will reflect on the object in the original array, because it is the same object.
Here is what you want to happen:
Now the two arrays are completely independent of each other. This is the effect that you achieve when you call
dataToSave=[[NSMutableArray alloc] initWithArray:currentArray copyItems:YES];
However, there is a catch: in order for this to work, the objects inside the array must conform to NSCopying protocol, otherwise the code is going to crash.
To fix this, make sure that the objects inside NSMutableArray implement NSCopying. Here is an answer that explains how it is done.
The problem is although you are creating a new array the NSDictionary objects within the new array are still the same ones. So you need to make copies of the NSDictionary objects, you we're close but you need to do something like this...
-(void)saveWithArray:(NSMutableArray*)currentArray
{
dataToSave=[[NSMutableArray alloc] init]; //local
for(NSMutableDictionary *dic in currentArray)
[dataToSave addObject:[NSDictionary dictionaryWithDictionary:dic];
}
I want to maintain a list of records, for each one I maintain the same type of data. I want to use this data in 2 different places:
UITableView that takes from each record the "Name" value
UIViewController that takes all the data to use in different fields.
I assume I should be using a plist to store the data; I also assume that the object that should be receiving the data for the UITableView is NSArray so I can use the cellForRowAtIndexPath method to create the table automatically.
So i created the plist "PLForArr.plist":
It seems that i can only get a NSDictionary when calling the plist using
NSString *path = [[NSBundle mainBundle] pathForResource:#"PLForArr" ofType:#"plist"];
NSArray * myArr = [[NSArray alloc] initWithContentsOfFile:path]; //doesn't work...
NSDictionary * myDict = [[NSDictionary alloc] initWithContentsOfFile:path]; //does work, but who to I make a NSArray out of it / or get the data from here to the UITableView?
I understand that i don't understand something basic here... Can someone take me step by step on:
How to keep the data - should I use plist or something else? Should I have a main record of type array (as I did on the example plist here) or can I just keep it as these Dictionaries without the unnecessary MyArr that I used considering the UITableView end target?
How to call the data - Is there a way to get it into a NSArray or must it get into a NSDictionary?
How to call it into the the UITableView - Can I fill in the lines using a NSDictionary?
Storing the data is an Array or a Dictionary is up to you. But if you want to make changes to it over time you can't store it in the main bundle.
Your pList file is a dictionary that contains an array. See code example below.
You will have to store the dictionary in an array for the data source for your table. See code example below.
Assuming that your UITableView's data source is called tableArray. You can use tableArray to fill in the information in the table and your view. Oh yeah,
NSString *path = [[NSBundle mainBundle] pathForResource:#"PLForArr" ofType:#"plist"];
NSDictionary *myDict = [[NSDictionary alloc] initWithContentsOfFile:path];
NSArray *myArray = [myDict objectForKey:#"MyArray"];
self.tableArray = [myArray copy];
[myArray release];
[myDict release];
This goes in tableView: cellForRowAtIndexPath:
cell.text = [[tableArray objectAtIndex:row]objectForKey:#"Obj Name"];
Storing your data either in a dictionary, or in an array is up to you. Depending on the kind of data you have, you will consider storing unordered collection of objects (dictionary), accessing the entries with keys; or rather in ordered collection (array), using numeric indexes.
It's fine to get arrays from property list files, but the root (top level) object is a dictionary (in the screenshot, "MyArr" isn't the top-level object, it is the key for accessing your array in the top-level dictionary). To get your array from it, simply alloc/init the plist dictionary the way you did, and access the array entry using its key ([myDict objectForKey:#"MyArr"]). Otherwise make sure you set the root object of the property list to be an array, and retry NSArray's initWithContentsOfFile:
The real question seems to be How can I fill the cells with my data ? The table views ask its delegate and dataSource about how many sections, rows in a section, to display. Based on these numbers, it will ask the dataSource for cells. Once again depending on the storage type you've chosen, you will implements these methods a little bit differently, but the concepts remain.
You will probably want to read documentation about :
Property List
Table views
Helo! How can i convert a NSMutableArray object to a NSString ? i try to do something like
cell.textLabel.text = [cars objectAtIndex:indexPath.row];
But it doesn't work, my app crashes. If i do something like
cell.textLabel.text =#"yes";
The app loads very nicely(but instead of the elements from the "cars" NSMutableArray i have a view table filled with "yes") . Any idea what the problem is ?
Is the NSMutableArray alloc'd and init'd properly? If you don't call cars = [[NSMutableArray alloc] init] before you use it, the array will not respond to adding objects to it. Make sure that's not the case. Also make sure that the elements in the cars array are NSStrings.
Make sure your cards contains enough cars, if the indexPath.row is large than the cards's count-1, it will crash.
Hey! I've been trying to add an array to an NSMutableArray using the addObject syntax. The app crashes without any explicit mention of an error. Could you please tell me how this is done?
I have a class Stack that creates an array. So I call that class using an instance called tem that I have created. Hence, [self tem] is my call to the array. Through the program I merely add UILabels to the array(I know you'd suggest adding a string and then changing to UILabels, but I need to do it this way) and towards the end, I'd like to add this array to my 'list' array.
-(Stack *)tem {
if(!tem)
tem=[[Stack alloc]init];
return tem;
}
-(void)viewDidLoad{
//code
list=[NSMutableArray arrayWithArray:[self list].array];
}
-(IBAction)opPr:(UIButton *)sender
{
if([[[sender titleLabel]text] compare: #"="]==0) {
//code
UILabel *t=[[UILabel alloc]init];
//complete creating label
[[self tem]push:t];
//add above label to tem array
[list addObject:[self tem].array];
[table reloadData];
}
}
OK, this answer got all cluttered with edits. I've edited it to be more clear, at the possible expense of understanding the thread of how we arrived at the final answer.
The final answer
The answer was to change:
list=[NSMutableArray arrayWithArray:[self list].array];
To:
list = [[NSMutableArray alloc] init];
(...Which isn't really the best way to create an NSMutableArray, but it may work anyway.)
This was based on an erroneous version of the asker's code
Based on your comment that it crashes after [list addObject:[self tem].array];, I must conclude that your instance variable list is of type Stack*, and that Stack is not a subclass of NSMutableArray. If so, that's your issue.
In that case, changing that line to [[list array] addObject:[self tem].array]; should fix it.
This is just good advice
As an aside, NSMutable array is perfectly capable of acting as a stack without modification. Example:
NSMutableArray* ar = [NSMutableArray arrayWithCapacity:someCapacity];
// Push
[ar addObject:narf]; // narf being some object reference
// Pop
id popped = [ar lastObject];
[ar removeLastObject];
If you want to encapsulate stack behavior in a semantically consistent way, you can add push and pop methods to NSMutableArray using a category. This would make your code simpler and less prone to error.
This was my first stab at answering the question, before any code had been posted
This is a stab in the dark since you've not posted any code. BUT. One way to accomplish that with arrays is by creating arrays using [NSArray arrayWithObjects:obj obj ... nil] and omitting the nil terminator on the list of objects. Are you by any chance doing that?
So I have an NSDictionary where one of the keys is an array of dictionaries. The class I'm mapping to has matching key names and setters. Can setValuesForKeysWithDictionary fill the sub-dictionaries for me? When I tried it, it seemed like it filled the objects with pointer junk or something, but I'm a newbe, so maybe I'm doing something wrong. Does that function work like that?
I realized that there was no way for setValuesForKeysWithDictionary to know what kind of object to fill the NSMutableArray with. I ended up making a custom setter for the array property that manually loops the elements of the array (of NSDictionaries) you pass in and calls setValuesForKeysWithDictionary for each one.
Here's the code:
There is a property called itemList of type NSMutableArray that I want filled it objects of type Item. The setItemList setter loops through the array of mystery objects, converting each NSDictionary to my Item type and adds them to a new array. Any comments on how to simplify the code would be welcome.
I also want to add some logic here to handle a situation where the array already contains Item objects instead of dictionaries. In actionscript you can check for null after you try to cast something to see if it worked, not sure what the equivalent process would be here. [item isMemberOfClass [Item class]] always evaluates to YES, even if item is an NSDictionary. I can't understand why...
- (void) setItemList:(NSMutableArray*)input{
[itemList autorelease];
itemList = [[NSMutableArray alloc] initWithCapacity:input.count];
//loop through the array, creating an Item for for each object in the array
for(int i=0;i<input.count;i++){
Item* item = [Item new];
[item setValuesForKeysWithDictionary:(NSDictionary*)[input objectAtIndex:i]];
[itemList insertObject:item atIndex:i];
}
}
- (NSMutableArray*) itemList{
return itemList;
}