There are 24 buttons that their labels change from a function driven by a UISegmentedControl that has 7 segments. There is also a UIPickerView with 9 different objects. These two dynamically change the labels of the buttons. Then, when a button is pressed i have to know the UIPickerView object that is selected, the UISegmentedControl selection and which button is this.
My function that receives and executes is this:
- (int)ButtonPlayController:(int)buttonPressed {
NSString *button = [NSString stringWithFormat:#"%#%i", #"button", buttonPressed];
if (button.titleLabel.text == #"1C") {
[self Play1C];
}
else if .....
}
The function receives a number (the button number) and combines the string name to create the UIButton name, e.g. if the function receives number 8 then the UIButton name is button8 (i already have on my .h file: IBOutlet UIButton *button8;)
I remember these work on PHP but what about Object C? What do i have to change for this to work?
Looks like there some pointers for you in the comments, but I'm wondering why you are implementing your target-action this way? Maybe there is a part of your program I don't understand but why not just pass the button as the argument to the receiver of the action:
- (IBAction)doStuffWithButton:(id)sender
{
if ( sender.tag == 1 )
{
[self actOnOne];
}
else if ( sender.tag == 2 )
{
....
}
}
Like I say, this doesn't answer your original question, but maybe a different design pattern would make things easier?
Related
I am dumping multiple inputs into a view. They consist of UITextFields UIPickerViews and UIDatePickers.
Each of them have an ID and a Key that need to be saved when the input value is saved. So when the 'Save' button is clicked, I need to loop through and store something like:
{
ID: 'inputid',
Key: 'yearly',
Value: (UITextField value)
}
In HTML, I would just add these values to the input (<input type="text" id="inputid" name="yearly" />) and then loop through each one using $(input).attr('id') etc.
In Objective-C, the only way I can think to do this is to keep a hashtable of this information when I draw the inputs, and then store some kind of identifier against the 'tag' field of the UITextField, then read that by getting all of the inputs from a view and comparing them to the hashtable.
Is this the right way to go about it?? Am I missing something simple here? How would you go about it?
EDIT
To better frame the situation, the number of UITextFields on the page is being pulled from an XML file, therefore I don't know how many UITextFields there will be (so can't assign them to the controller necessarily)
I need something along the lines of:
foreach(var question in ArrayOfQuestions) {
UITextField *textField = [[UITextField alloc] initWithFrame:];
textField.attributes["id"] = question.Id;
textField.attributes["key"] = question.Key;
}
and in the save method
foreach(var textField in UIView) {
textField = (UITextField)textField;
NSString *id = textField.attributes["id"];
NSString *key = textField.attributes["key"];
}
This maybe something I could find in google but can't think of the right search terms and keep coming up empty handed. On the same level, if you can better describe my request please update the title of my question
I think you are actually at the best solution, in regards to the hash table (NSDictionary) of attribute data. It is really a bad design decision to have too much semantic data in the view object itself, as it has nothing to do with the view.
What you need to do concretely in code is the following:
To set up your views & attribute data:
UIView *containerView; // The view that contains your UITextViews.
NSMutableDictionary *attributes; // A dictionary mapping tags to questions.
NSMutableArray *arrayOfQuestions; // The questions that you've parsed from a file or whatever.
// ...
// Each "question" would be of the form #{ #"id" : ____, #"key" : ____ }
for (NSDictionary *question in arrayOfQuestions) {
UITextField *textField = [[[UITextField alloc] initWithFrame:aFrame] autorelease];
[containerView addSubview:textField];
textField.tag = getATag(); // However you want to tag them.
// Fancy new objective-C container/object-literal syntax :)
attributes[#(textField.tag)] = question;
}
Then for your "save" method:
for (UIView *childView in containerView.subviews) {
if ([childView isKindOfClass:[UITextView class]]) {
// We know the class and can thus safely typecast the UIView.
UITextField *textField = (UITextField *)childView;
NSDictionary *aQuestion = attributes[#(textView.tag)];
// Now you can access the id and key properties of the question.
// ... Whatever else you want to do.
}
}
The enumerated loop over the subviews is I think the big thing you were looking for here. It is very similar to the way that you would do it in jQuery with selectors.
If you make each of the elements a property of the view controller, you can access them directly from anywhere and get the current value.
So in the method attached to the save button, you can get the current string value of a UITextField like this, for example:
NSString *currentTextFieldString = self.someTextField.text;
I have an array full of buttons and when a use clicks one I would like to search the array for it.
Yes, I have given the buttons tags, but they are used for another purpose. So I am hoping that there is another way to check for equality.
I was hoping that I would be able to do something like button1.frame.origin == button2.frame.origin, but the compiler doesnt like that.
You can use the method bool CGRectEqualToRect(CGRect rect1, CGRect rect2). Just pass in both of the button's frames as parameters into this method and it'll return a bool stating whether they are equal.
UIButton (and UIView) inherits from NSObject so you should just be able to do isEqual.
if([button1 isEqual:button2])
{
// do whatever
}
you can compare memory addressed of those objects, same as isEqual method is using
NSArray *buttons=#[button1,button2,button3,button4];//your array of buttons
UIButton *b = (UIButton *)sender;//button to search
[buttons enumerateObjectsUsingBlock:^(UIButton * button, NSUInteger idx, BOOL *stop) {
if (button==b) {
//do your thing here...
*stop=TRUE;
}
}];
So I am trying pass in parameters to my "buttonClicked" function so that I can dynamically control what happens when you click the button. Every way that I try to do it on my own just breaks my code. I have searched many different sites and answers on stackOverflow, but I can't seem to find an answer. I am fairly new to objective C, especially with functions, So I could really use some help figuring out how to do this. Thanks in advance
Here is my code thus far and what I am trying to do:
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
NSLog(#"Hi 1!");
[button addTarget:self action:#selector(buttonClicked:buttonType:buttonID:) forControlEvents:UIControlEventTouchUpInside];
button.frame = CGRectMake(buttonViewXvalue, buttonViewYvalue, buttonViewWidth, buttonViewLength);
[self.view addSubview:button];
Then the Declaration in the Header File:
- (IBAction)buttonClicked:(id)sender theButtonType: (int)buttonType: theButtonID: (int) buttonID;
and the implementation:
- (IBAction)buttonClicked:(id)sender theButtonType: (int)buttonType: theButtonID: (int) buttonID
{
//Here I would use the buttonType and buttonID to create a new view.
NSLog(#"Hi!");
}
You can't use multi-parameter methods with addTarget:action:forControlEvents:. Instead you might set the button's tag, then look up information later based on the tag.
The action you add to UIButton (or any UIControl for that matter) must have a signature like (void)actionName or (void)actionName:(id)sender; as defined by target-action design pattern.
That gives you two simple solutions. One is that each of your buttons calls different (void)actionName-like method, which then calls a more complex method on self and passes the required parameters. Other way is to give each of your buttons a tag property and have them call (void)actionName:(id)sender-like method (they can all call the same one) and then you call the right method with right parameters depending on this tag:
- (void)actionName:(UIButton)sender;
{
if (sender.tag == 1) {
[self firstMethodWithString:someString andNumber:someNumber];
} else if (sender.tag == 2) {
[self secondMethodWithArray:someArray dictionary:someDictionary andColor:someColor];
} // and so on
}
Notice how I changed sender from id to UIButton here. This enables you to call tag without casting and not get a compiler warning, because compiler know you only expect UIButton instances to call this method.
If you really wanted to you could create a separate callback for each button, like:
// In your Whatever.h file
- (IBOutlet)actionButton1:(UIButton *)sender;
- (IBOutlet)actionButton2:(UIButton *)sender;
// In your Whatever.m file
- (IBOutlet)actionButton1:(UIButton *)sender
{
// do button 1 specific stuff
}
- (IBOutlet)actionButton2:(UIButton *)sender
{
// do button 2 specific stuff
}
// etc you get the idea
Then from Interface Builder look at your Whatever.xib file. You can link the "Sent Event" (drag from right side column) of "Touch Up Inside" to any of those actions above which will pop up in "File's Owner" (left column, when you release drag). You can do a different one for each button.
I should mention that generally if these are variants of the same functionality it makes more sense to use the tag property of UIButton.
I have solved this problem with an array of objects: all the parameters are stored in one object, then the object is inserted in the array, finally, the index of the object in the array is passed in the TAG property of the button. This technique works for one or many buttons. I did it for an app that had a list of contacts, where you were able to accept or reject them with buttons, and this buttons were calling the same action method, thanks to the TAG it was possible to know what parameters send to database. Steps:
1- Create a new class : New File, Objective-C class, name it, subclass of NSOBJECT, save it.
2- In the header of this new class declare one property for each parameter.
3- Now go to the IMPLEMENTATION file of the class of the viewcontroller where your button belongs to.
4- Import your new class :
#import "new_class.h"
5- Declare the array in the INTERFACE section :
#interface my_viewcontroller ()
{ NSMutableArray * my_array; }
6- In the VIEWDIDLOAD method create the array as empty :
my_array = [ [ NSMutableArray alloc ] initWithObjects : nil ];
7- In the method where you get the data for the parameters, declare an object of the new class, instantiate it and fill the properties :
new_class * nc;
nc = [ [ new_class alloc ] init ];
nc.param1 = #"abc";
nc.param2 = 123;
nc.param3 = true;
8- Now insert it in the array :
[ my_array addObject : nc ];
9- Store the value 0 in the TAG of the button. You will use this value as index to access the parameters in the my_array[ 0 ] position.
If there are more buttons, for example, from a web service that returns JSON data, just loop through the data creating more instances of the new class and inserting them in the array. Later, for example, in a tableview with dynamic cells and a template cell with buttons, in the method CELLFORROWATINDEXPATH, you will be able to store the INDEXPATH value in the TAG of every button, so these buttons will access their own parameters.
I have a UILabel that adds one to its value -- basically it counts up -- when a button is pressed. Could someone please help me with a minus button? That way if the user accidentally presses the add button more than they needed, they can subtract their mistake. I've tried this, but the label's text is set to -1 now. and I want it to just subtract one each time its pressed:
- (IBAction)subtractButton:(id)sender {
static int integerSaved;
integerSaved = integer;
integerSaved -= 1;
[label2 setText:[NSString stringWithFormat:#"%i", integerSaved]];
}
Try this:
- (IBAction)subtractButton:(id)sender {
[label2 setText:[NSString stringWithFormat:#"%d",[label2.text intValue] - 1]];
}
-(void)subtract
{
label2.text = [NSString stringWithFormat:#"%d", [label2.text intValue]-1];
}
This code assumes that you are not using Interface Builder, and that you are manually linking "subtract" to the UIButton. If you are using Interface Builder, try this code.
-(IBAction)subtract:(id)sender
{
label2.text = [NSString stringWithFormat:#"%d", [label2.text intValue]-1];
}
I have not tested this but I think it should work. Good luck!
Using the value of the UIView instance to do arithmetic is not the MVC-way. You should really be separating your data model from your view.
Expose an int, NSInteger or NSNumber property in a class somewhere, where that class is dedicated to holding data values for your app.
When a touch event comes in for a given button, increment the data property and fire a notification that updates the view based on what's in the property. Or add an observer to the property. The observer then updates the view when the property value changes.
Following the MVC pattern would be a more "Apple"-ish or "iOS"-ish way of doing things, than getting the UIView's value, converting it to an integer, and then converting it back to a string.
I'm new to Obj-C and I have run in to a very, very basic mental block that's making me feel a little stupid. I want to pass a variable from one method to another in an purely objective-C way. So far I'm stuck and have resorted to writing it in C. In C it goes as follows;
//detect the change in the segmented switch so we can; change text
- (IBAction)switchChanged:(id)sender
{
NSLog(#"Switch change detected");
//grab the info from the sender
UISegmentedControl *selector = sender;
//grab the selected segment info from selector. This returns a 0 or a 1.
int selectorIndex = [selector selectedSegmentIndex];
changeText (selectorIndex);
}
int changeText (int selectorPosition)
{
NSLog(#"changeText received a value. Selector position is %d", selectorPosition);
//Idea is to receive a value from the segmented controler and change the screen text accordingly
return 0;
}
This works perfectly well, but I want to learn how to do this with objects and messages. How would I rewrite these two methods to do this?
Cheers
Rich
Actually, you will only need to rewrite one of them since - (IBAction)switchChanged:(id)sender is an objective c method.
once you have your class definition, you can rewrite the changeTextFunction as:
//detect the change in the segmented switch so we can; change text
- (IBAction)switchChanged:(id)sender
{
NSLog(#"Switch change detected");
//grab the info from the sender
UISegmentedControl *selector = sender;
//grab the selected segment info from selector. This returns a 0 or a 1.
int selectorIndex = [selector selectedSegmentIndex];
[self changeText:selectorIndex];
}
-(int) changeText:(int) selectorPosition
{
NSLog(#"changeText received a value. Selector position is %d", selectorPosition);
//Idea is to receive a value from the segmented controler and change the screen text
return 0;
}
Also note that you will should add to your header file:
-(int) changeText:(int) selectorPosition;
Also note that this is for adding the changeText method to the class that has the switchChanged method. Tip: use command+option+up to jump to the header file directly.