I have several UIViews in my Storyboard and, of course, I can switch between them using a segue. Initially this works just fine:
notenKurse is a NSMutableArray, and kurse1Outlets is an outlet collection with my UITextFields.
int counter = 0;
for (UITextField *tf in kurse1Outlets) {
NSMutableString *t = [NSMutableString stringWithFormat:#"%#", [notenKurse objectAtIndex:counter]];
NSLog(#"Object at index %i is %#", counter, [notenKurse objectAtIndex:counter]);
if ([t isEqualToString:#"42"]) {
[t setString:#""];
}
[tf setText:t];
NSLog(#"UITextField in slot %i should now display %#", counter, t);
counter++;
}
All of my UITextFields are displaying the value stored in the array. But if I go to another view (let's assume I have a Button for it ;) ) Change something, and then go back to the original UIView the above code still gets executed, and there are different values in the array (this is supposed to be). I can see that in the log. But the stupid UITextField just doesn't display anything. Neither what was in there before, nor the new text. But why? The log clearly shows that t is what it's supposed to be, so the error must be in writing it into the textfield, and therefore I guess it's an outlet issue...
There is no guarantee of the order of your outlet collection. It's treated very much like an NSDictionary as opposed to an NSArray - where order is guaranteed. Iterating over this sort of collection will yield different results for different devices/people/phase of the moon.
When I use a collection like this I tend to set the 'tag' and then reorder the outlet collection when viewDidLoad by sorting off of the tag.
self.calendarDayImageViews = [_calendarDayImageViews sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
if ([(UIView *)obj1 tag] < [(UIView *)obj2 tag]) {
return NSOrderedAscending;
}
else if([(UIView *)obj1 tag] > [(UIView *)obj2 tag]){
return NSOrderedDescending;
}
else{
return NSOrderedSame;
}
}];
You can just output the tf,by
NSLog(#"%#",tf);
To check if the tf is null
Ok, i found it. I forgot to release some stuff, and so my UITextFields did get set before the array was sorted. My mistake!
Related
I am having an issue with NSMutableArray wiping its contents.
Consider my code: (int i; is in my file's .h as is NSMutableArray* newFileControllerArray)
-(void)awakeFromNib{
i = 0;
newFileWindowControllerArray = [[NSMutableArray alloc]init];
}
-(IBAction)newFileMenubar:(id)sender{
[newFileWindowControllerArray addObject:[[NewFileWindowController alloc]initWithWindowNibName:#"NewFileWindowController"]];
NSUInteger elementsInArray = [newFileWindowControllerArray count];
NSLog(#"%lu",(unsigned long)elementsInArray);
[[newFileWindowControllerArray objectAtIndex:i] showWindow:nil];
}
-(IBAction)OKButtonClicked:(id)sender{
NSUInteger elementsInArray = [newFileWindowControllerArray count];
NSLog(#"THERE ARE %lu ELEMENTS IN THE ARRAY",(unsigned long)elementsInArray);
}
The first method called (other than awakeFromNib:) is newFileMenubar: This will add one element to the array. I can confirm that this works because 1 is printed in the console. However, once OKbutton is called and I print out the number of elements in my array it says that no elements are in the array. Why is that?
Am I missing something very obvious here? Why does my array reset itself?
EDIT:
The comments have gotten long and unwieldy so here is the code w/NSLogs and outputs:
-(void)awakeFromNib{
i = 0;
newFileWindowControllerArray = [NSMutableArray array];
NSLog(#"self=%p, array=%p", self, newFileWindowControllerArray);
}
-(IBAction)newFileMenubar:(id)sender{
[newFileWindowControllerArray addObject:[[NewFileWindowController alloc]initWithWindowNibName:#"NewFileWindowController"]];
[[newFileWindowControllerArray objectAtIndex:i] showWindow:nil];
i++;
NSLog(#"self=%p, array=%p", self, newFileWindowControllerArray);
}
-(IBAction)OKButtonClicked:(id)sender{
NSUInteger elementsInArray = [newFileWindowControllerArray count];
NSLog(#"self=%p, array=%p", self, newFileWindowControllerArray);
[documentController newDocument:sender];
[[newFileWindowControllerArray objectAtIndex:i]close];
}
When the program launches, this is the output: self=0x100141480, array=0x100140f30
This should be coming from awakeFromNib:
The next method called is newFileMenubar:
The output from this is
self=0x1001ac990, array=0x1005228a0 and immediately after self=0x100141480, array=0x100140f30
The last method called is OKButtonClicked:
The output from the last method (OKButtonClicked:) is self=0x1001ac990, array=0x1005228a0
As you can see from the code, the name of the array doesn't change, but my outputs beg to differ? What could cause this?
There are good clues in your log output. There are multiple instances of the view controller (see the different values for 'self'?). They each have their own array. See this code...
-(IBAction)newFileMenubar:(id)sender{
[newFileWindowControllerArray addObject:[[NewFileWindowController alloc]initWithWindowNibName:#"NewFileWindowController"]];
When you press the button associated with that action, your app builds another view controller and places it in the array. That view controller gets the awake from nib message and allocates another array, and so on.
To confirm this, change the code as follows:
-(IBAction)newFileMenubar:(id)sender{
[newFileWindowControllerArray addObject:#"Hello world"];
// and comment this out, for now:
// [[newFileWindowControllerArray objectAtIndex:i] showWindow:nil];
In the other methods, comment out your expectations that the array has anything other than strings in it, and see what you get. e.g. ...
- (IBAction)OKButtonClicked:(id)sender {
NSUInteger elementsInArray = [newFileWindowControllerArray count];
NSLog(#"self=%p, array=%p", self, newFileWindowControllerArray);
[documentController newDocument:sender];
// and comment this out, for now:
// [[newFileWindowControllerArray objectAtIndex:i]close];
// instead...
NSLog(#"danh thinks my array will be ok: %#", newFileWindowControllerArray);
}
You probably do not mean to create another view controller on every button press, but I'm not sure what function you do want. Maybe you want an array of views? (To create many view controllers under the control of another, you'll want to read up on container view controllers, here).
I don't know if what I see with a popup button populated by bindings with a value transformer is the way it's supposed to be or not -- the unusual thing I'm seeing (at least with respect to what I've seen with value transformers and table views) is that the "value" parameter in the transformedValue: method is the whole array bound to the array controller, not the individual strings in the array. When I've done this with table views, the transformer is called once for each displayed row in the table, and the "value" parameter is whatever object is bound to that row and column, not the whole array that serves as the content array for the array controller.
I have a very simple app to test this. In the app delegate there is this:
+(void)initialize {
RDTransformer *transformer = [[RDTransformer alloc] init];
[NSValueTransformer setValueTransformer:transformer forName:#"testTransformer"];
}
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
self.theData = #[#{#"name":#"William", #"age":#"24"},#{#"name":#"Thomas", #"age":#"23"},#{#"name":#"Alexander", #"age":#"64"},#{#"name":#"James", #"age":#"47"}];
}
In the RDTransformer class is this:
+ (Class)transformedValueClass {
return [NSString class];
}
+(BOOL)allowsReverseTransformation {
return NO;
}
-(id)transformedValue:(id)value {
NSLog(#"%#",value);
return value;
}
In IB, I added an NSPopupButton to the window and an array controller to the objects list. The content array of the controller is bound to App Delegate.theData, and the Content Values of the popup button is bound to Array Controller.arrangedObjects.name with the value transformer, testTransformer.
When I run the program, the log from the transformedValue: method is this:
2012-09-19 20:31:39.975 PopupBindingWithTransformer[793:303] (
)
2012-09-19 20:31:40.019 PopupBindingWithTransformer[793:303] (
William,
Thomas,
Alexander,
James
)
This doesn't seem to be other people's experience from what I can see on SO. Is there something I'm doing wrong with either the bindings or the value transformer?
Unfortunately, this is how NSPopUpButton works. The problem is not limited to that control. If you try binding an NSArrayController.contentArray to another NSArrayControllers.arrangedObject.someProperty you will get the same problem. Here is a simple workaround that I use in all my value transformers, which makes them work with both tables and popups:
You can modify your value transformer in the following way:
-(id)transformedArrayValue:(NSArray*)array
{
NSMutableArray *result = [NSMutableArray array];
for (id value in array)
[result addObject:[self transformedValue:value]];
return result;
}
-(id)transformedValue:(id)value
{
if ([value isKindOfClass:[NSArray class]])
return [self transformedArrayValue:value];
// Do your normal-case transform...
return [value lowercaseString];
}
It's not perfect but it's easy to replicate. I actually put the transformedArrayValue: in a class category so that I don't need to copy it everywhere.
First of all, I'm new to this so excuse my any simplest question.
I'm trying to view data and filter it which is very common.
So I use different tutorials. First, I loaded data from my SQLite database, then I used custom cell tutorials and customized my cells. But I got stuck in UISearchBar.
The tutorial I followed uses an NSArray to fill the table which is declared in code-behind. Since my SQLite methods gets the data from database to an Array, I thought if I copy this array to the array in filtering methods, that would work.But it didn't.
Here is some code with explanations:
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
if ([searchText length] == 0) {
[displayItems removeAllObjects];
[displayItems addObjectsFromArray:allItems];
} else {
[displayItems removeAllObjects];
for (NSString *string in allItems) {
NSRange r = [string rangeOfString:searchText options:NSCaseInsensitiveSearch];
if (r.location != NSNotFound) {
[displayItems addObject:string];
}
}
}
[tableViewScreen reloadData];
}
Code above is for filtering and I tried to copy the array that I used to fill the table to allItems array like this:
MyProjectAppDelegate *appDelegate = (MyProjectAppDelegate *)[[UIApplication sharedApplication] delegate];
allItems = appDelegate.mySqliteArray;
Or like this:
allItems = [[NSArray alloc] initWithArray:appDelegate.mySqliteArray];
But none of them did work.
I'd like to point my problem again,I have a method that gets the data into an array in AppDelegate class, and in my TableView class, I want to copy that array to another.P.S. mySqliteArray is mutable array and allItems array is not.And also, my cells are created by custom cell class, and there are 2 labels in each row.
Since I was defining an array that has objects created by my defined class, I later realized that I was mistaken to carry objects but not strings.So I updated my code like this and succeeded to create the needed array:
for (MyClass *object in appDelegate.mySqliteArray) {
[allItems addObject:[NSString stringWithFormat:#"%#", object.objectName]];
}
In the main window of my application, I have a collection view such that each collection view item contains an NSTableView. The window controller for this window has an NSString * property projecttitle. This property is bound to an NSTextField in the window for which I have overridden the default return key behavior so that the user can hit Return and write a carriage return into the text field. Now, after changing the string in the text field and THEN dragging an item between the table views for two different collection view items, the projecttitle property becomes nil. I sort of feel like maybe I just have way too much going on here and that this bug will be impossible to track down, but maybe someone has seen something even remotely similar to this behavior elsewhere?
EDIT: Putting a breakpoint on the projecttitle property doesn't seem to yield anything useful. The program execution does not break at all upon dragging and dropping, but the property will indeed be nil after this.
EDIT 2: After more digging around, it appears the behavior is related to the NSFormatter object. It happens not only when dragging and dropping, but apparently any time the nstextfield attempts to resign as responder. This behavior stops when I disconnect the formatter object in IB. Here's the string validation code for the formatter which forces the string to be less than or equal to 4 lines long and with each line being no longer than 32 characters. This seems to work fine when actually typing the in the text field, but apparently, not after.
-(BOOL)isPartialStringValid:(NSString **)partialStringPtr
proposedSelectedRange:(NSRangePointer)proposedSelRangePtr
originalString:(NSString *)origString
originalSelectedRange:(NSRange)origSelRange
errorDescription:(NSString **)error {
NSArray * lines = [*partialStringPtr componentsSeparatedByString:#"\n"];
if ( [lines count] > 4 ) {
return NO;
}
for (NSString * line in lines) {
if ( [line length] > self.maxlength ) {
return NO;
}
}
return YES;
}
Okay, solved. Turned out it was the -getObjectValue:forString:errorDescription: method. I had it implemented as
-(BOOL)getObjectValue:(id *)obj forString:(NSString *)string errorDescription:(NSString **)error {
*obj = string;
return YES;
}
Changing *obj = string to *obj = [NSString stringWithString:string] fixed everything right up.
In my application I add objects directly to an ArrayController. When I want to clean all items I do:
[[downloadItemsController content] removeAllObjects];
This command however does not refresh the TableView the arraycontroller is bound to. If I remove all items and add another new items I only see that item. That is fine but if I don't add anything I still have all my items in the table.
If I do
[downloadItemsController prepareContent];
all old items are removed from the tableview but than I will get an new and empty item I can edit. I don't want that and because one of my columns has a checkboxcell I always get an row with a checkbox.
I just need an empty table with no items after I remove all existing items.
To quickly remove all the objects from an NSArrayController object:
NSRange range = NSMakeRange(0, [[anArrayController arrangedObjects] count]);
[anArrayController removeObjectsAtArrangedObjectIndexes:[NSIndexSet indexSetWithIndexesInRange:range]];
The bindings should update automatically. See original SO answer.
This is because you're modifying the controller's content "behind its back." Try using the array controller's -removeObjects: method.
This worked for me
[anArrayController setContent:nil]
You can start populating its contents right away like this
[anArrayController addObject: #{ .... }]
[anArrayController addObject: #{ .... }.mutablecopy]
[anArrayController addObject: aDictionary]
Calling removeObject.. group of methods is particularly inconvenient for a collection of Core Data objects. It seems that remove... is meant for those cases when we really need to get rid of the data (like when user press 'Remove' button at UI), so the NSArrayController will try it's best to remove objects from Core Data DB too.
I have simple manual control of NSArrayController and I found that setContent: method works great for adding, removing and replacing the array of objects inside it. And just to clear the contents setContents:#[] can be used.
Sometimes when you remove is the key; here I defer using a volatile bool (undoInProgress) in a revert action, using solution above to flush a change array which observing method ignores while undo is in progress:
volatile bool undoInProgress = 0;
- (IBAction)revert:(id)sender
{
NSUserDefaults * prefs = [NSUserDefaults standardUserDefaults];
NSArray * undo = [NSArray arrayWithArray:changes];
undoInProgress = YES;
// We have a single key/value pair but do so in reverse order
for (NSInteger i=[undo count]-1; i>=0; --i)
{
NSDictionary * change = [undo objectAtIndex:i];
NSString * key = [change objectForKey:#"keyPath"];
id val = [change objectForKey:NSKeyValueChangeOldKey];
[prefs setValue:val forKey:key];
}
dispatch_async(dispatch_get_main_queue(), ^{
NSRange range = NSMakeRange(0, [[changeController arrangedObjects] count]);
[changeController removeObjectsAtArrangedObjectIndexes:[NSIndexSet indexSetWithIndexesInRange:range]];
undoInProgress = NO;
});
}