I have a bunch of text fields in a registration form that are organized in two vertical stack views in a XIB file. I noticed that when running the app in the simulator I can press the Tab key and iOS will automatically move on to the next text field.
But this doesn't work sometimes, and I was wondering why. Sometimes the system focuses a text field from another stack view instead of the field below it.
I have already set up a chain of Next text fields (when pressing Next on the software keyboard) like this:
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
NSUInteger index = [self.textFields indexOfObject:textField];
if (index != NSNotFound) {
if (index == self.textFields.count - 1) {
[textField resignFirstResponder];
[self createAccount];
} else {
UITextField *nextTextField = self.textFields[index + 1];
[nextTextField becomeFirstResponder];
}
return NO;
}
return YES;
}
textFields is an array of all text fields that this screen has from top to bottom.
I just want to be able to fill the form fast by typing a few characters and pressing Tab without additional mouse clicks. Is it possible?
It seems that -textFieldShouldReturn is not called during this "tab switch" so I can't control which text field becomes the next first responder. What is the trick for getting them to focus in the right order?
Check the index that returns by indexOfObject:. If you have some equal objects in the array, this method returns the index of the first of them.
If the index is wrong, use the tag property of UITextField like this:
UITextField * nextResponder = [self.textFields objectAtIndex:textField.tag + 1];
or if all of your text fields are in the same superview:
UITextField * nextResponder = (UITextField*)[textField.superview viewWithTag:textField.tag + 1];
Apple documentation:
Starting at index 0, each element of the array is passed as an argument to an isEqual: message sent to anObject until a match is found or the end of the array is reached. Objects are considered equal if isEqual: (declared in the NSObject protocol) returns YES.
https://developer.apple.com/documentation/foundation/nsarray/1417076-indexofobject?language=objc
This method defines what it means for instances to be equal. For example, a container object might define two containers as equal if their corresponding objects all respond YES to an isEqual: request. See the NSData, NSDictionary, NSArray, and NSString class specifications for examples of the use of this method.
If two objects are equal, they must have the same hash value. This last point is particularly important if you define isEqual: in a subclass and intend to put instances of that subclass into a collection. Make sure you also define hash in your subclass.
https://developer.apple.com/documentation/objectivec/1418956-nsobject/1418795-isequal?language=objc
Related
I have a relatively large iPhone application with many views.
I would like implement a next/previous option on my keyboard.
I have managed to implement it UI-wise, with some code examples i saw online, but all of them are assuming we need to add code to each view controller to implement the actual transition between the text fields.
My question is: is there a general way to know, given some text field, who is the next field in order? (i.e without refactoring each of my view controllers)
I ask this question because when i use the iPhone simulator and press the computer's Tab key - the switch between the fields happen, so i wonder if there is a built-in or generic way to implement it on iOS.
clarification:
is there a way of doing it without adding a specific code for each type of view controller? (adding a generic code is acceptable)
I want to write how i solved this problem, with the help of many good answers given to me here :)
First, i could not create fully generic code that creates tab regardless of the view it is in.
Instead i created this thing, which i think is the most generic solution with the firstResponder method not working:
i created custom toolbar with my next/previous/done buttons and appropriate actions delegate.
than i extended UIViewController by adding category "Tab". this category declares a fieldsArray and implements the delegate method.
Now what every specific view controller needs to do (beside importing the category) is to provide this fieldsArray according to its properties and calling the init method which adds the buttons toolbar to this fields
I hope you could benefit from this, and again thanks for all the good answers
you could have a method in a utility class that takes as arguments a textfield and a viewcontroller. then you could use the "tag"-attribute of the textfields to find the next textfield in that viewcotroller, assuming that you assigned the tags accordingly. numbers would be great, i think. a simple callback method in the vc could handle the focus-change. thats about as generic as i can see right now.
This is some generic code that I came up with:
// add a property for the fieldsArray
//add this in viewDidLoad
_fieldsArray = [[NSMutableArray alloc] init];
NSArray *viewsArray = [self.view subviews];
for (id view in viewsArray) {
if ([view isKindOfClass:NSClassFromString(#"UITextField")]) {
[_fieldsArray addObject:view];
}
}
//add this in your action that switches the fields
for (UITextField *field in _fieldsArray) {
if ([field isFirstResponder]) {
if ([fieldsArray lastObject] == field) {
[_fieldsArray[0] becomeFirstResponder];
}else {
NSUInteger nextIndex = [_fieldsArray indexOfObject:field] + 1;
[_fieldsArray[nextIndex] becomeFirstResponder];
}
break;
}
}
Before using it it should be improved.
1) find all subviews of self.view recursively
2) do some checks if the arrays are empty or nil or have just one object in them.
Good luck!
I have implemented the standard 'next' feature on UITextFields in my app (pressing next will move you to the next appropriate text field). Most of the time this works well and will move to the appropriate textfield no problem. However on a few occasions for some reason the textField will return NO when i ask it to become the first responder and I am not sure why.
Some information about the textfields/view:
The view has multiple UITableViews, some of the UITableViewCells in these have the UITextfields i want to become first responder in them, others do not.
When the tables are created i loop through the main views subviews to find all the first responders and add them to an array of first responders (_firstResponders - variable name).
Each cell calls back via a delegate to the main view when the next responder is wanted.
Below is the code i use to get the next responder:
//get the current first responders index
NSInteger currentIndex = [_firstResponders indexOfObject:currentResponder];
// if the current index plus 1 is less than the overall count of first responders on this view then continue, else resign the responder as no more are avilable
if((currentIndex+1) < [_firstResponders count])
{
// get the potential next responder
UIResponder *nextResponder = [_firstResponders objectAtIndex:currentIndex+1];
// if it can become the first responder assign it,
// else callback into this function with the unavilable first responder
if([nextResponder canBecomeFirstResponder])
{
[currentResponder resignFirstResponder];
BOOL becomeFirstResponder = [nextResponder becomeFirstResponder];
if(becomeFirstResponder == NO)
{
DLog(#"TextField at index: %d has returned no to becoming first responder", (currentIndex+1));
}
}
else
[self getNextResponder:nextResponder];
}
else
[currentResponder resignFirstResponder];
}
As you can see i check that it is available to become the first responder in code and i have also checked that the textfield is enabled manually (I also check this at the time of adding the responder to the array of responders). It is also worth mentioning i have checked the array size and the responder to be set when this occurs and they are correct/valid.
The strangest part for me about this is that I had only previously seen this if I did not call resignFirstResponder on the current responder before setting the new responder.
Does anyone know the reason for it returning NO/how i can fix this?
Thanks in advance!
The apple docs offer:
Asks the delegate if the text field should process the pressing of the
return button.
- (BOOL)textFieldShouldReturn:(UITextField *)textField
Parameters textField The text field whose return button was pressed.
Return Value YES if the text field should implement its default
behavior for the return button; otherwise, NO.
Discussion The text field callsthis method whenever the user tapsthe
return button. You can use this method to implement any custom
behavior when the button is tapped.
My question is what does the return value do? I have been implementing the behavior in this method so it makes no difference what is returned. Is this not the correct method to perform the action?
For instance, if I implement a search function, should I trigger the search action in this method or somewhere else.
This is the correct method to trigger an action when the user taps the Return keyboard key (whatever it happens to be labeled).
The return value from the textFieldShouldReturn: delegate method almost never matters. If you are dealing with a single text field then it definitely doesn't matter.
I ran into one issue a while back that made me realize that just under the right situation, the return value does matter. I had a screen with several text fields and then a text view. I was using this text field delegate method to change the first responder from text field to text field to text view. I found that if I returned YES in this delegate method and then made the text view the first responder, the newline was being sent to the text view.
As a result of this, I now always return NO from this delegate method to be safe.
When you press the return button on the keyboard the textFieldShouldReturn is called.
I never experienced any difference between the return value.
Customization example:
If you have two textFields when the user presses return button from first textField, you can give focus to second field in the following way:
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
NSLog(#"textFieldShouldReturn:");
if (textField.tag == 1)
{
UITextField *passwordTextField = (UITextField *)[self.view viewWithTag:2];
[passwordTextField becomeFirstResponder];
}
else
{
[textField resignFirstResponder];
}
return YES;
}
So you can use this delegate method for triggering search functionality.
In my project I must control action of 40 buttons, but I don't want to create 40 IBAction, can I use only a IBAction, how?
If you're using interface builder to create the buttons, simply point them at the same IBAction in the relevant class.
You can then differentiate between the buttons within the IBAction method either by reading the text from the button...
- (IBAction)buttonClicked:(id)sender {
NSLog(#"Button pressed: %#", [sender currentTitle]);
}
...or by setting the tag property in Xcode and reading it back via [sender tag]. (If you use this approach, start the tags at 1, as 0 is the default and hence of little use.)
-(IBAction)myButtonAction:(id)sender {
if ([sender tag] == 0) {
// do something here
}
if ([sender tag] == 1) {
// Do something here
}
}
// in Other words
-(IBAction)myButtonAction:(id)sender {
switch ([sender tag]) {
case 0:
// Do something here
break;
case 1:
// Do something here
break;
default:
NSLog(#"Default Message here");
break;
}
Set all the buttons to use that one action. Actions generally have a sender parameter, which you can use to figure out which button is calling the action. One popular way to tell the difference between buttons is to assign a different value to each button's tag property. So you might have 40 buttons with tags ranging from 1 to 40. (0 probably isn't a great choice for a tag since that's what the default value is, and any button for which you forget to set the tag will have 0 as the tag value.)
This technique is most useful when all the buttons do approximately the same thing, like the buttons on a calculator or keyboard. If each of the buttons does something completely different, then you still end up with the equivalent of 40 methods, but you substitute your own switch statement for Objective-C's messaging system. In that case, it's often better just to spend the time to create as many actions as you need an assign them appropriately.
Sure. Just connect all buttons to the same action method in Interface Builder. Use the method's sender argument (possibly in conjunction with the buttons' tag property) to identify which button is sending the event.
Just use one IBAction and assign it to all your buttons.
Just used the above method myself , had a selection of buttons but converted them all and used switch case instead
-(IBAction)buttons:(id)sender
{
switch ([sender tag])
{
case 0 :
}
}
Seems like you are getting all the answers you need, but I wanted to add to everyone else's answers.
Whether you want to use one IBAction or 40 actions is up to what you want the buttons to do. If all the buttons do completely different things, you need all separate IBActions, but if you want all of them to do the same thing, you can use just one. I need more details of those buttons and action, but you probably have title for each button, so you can use that to differentiate each button and create a message or something that's being customized by the particular button pressed. Here is the example. Each time a button is pressed, a label displays a message that say "i.e.title of the button" pressed.
By doing it this way, you don't need to do switch case with all 40 patterns. You can still display or do something that's individualized by the button pressed with just 2-3 lines of code.
- (IBAction)button_Clicked:(UIButton *)sender {
//Get the buttons' titles.
NSString *title =[sender titleForState:UIControlStateNormal];
//Construct a message that includes the *title.
NSString *plainText=[NSString stringWithFormat:#"%# button pressed.", title];
//Assigns the *plainText to the label.
self.Label.text=plainText;
}
#end
Is there a way (either in IB or code) to set the tab order between text fields in a view?
Note that I'm not talking about the next form field after the return (or "Next") button is pressed -- many bluetooth keyboards have a tab key, which seems to cycle through the fields in completely different order. In my particular case, this order doesn't correspond to the fields' position in the view or even the order in which the fields were added. Modifying the xib file by hand to change the NSNextKeyView doesn't seem to make a difference either.
Does anyone know how to change this order?
#sprocket's answer was only somewhat helpful. Just because something works out of the box doesn't mean you should stop thinking about a better way -- or even the right way -- of doing something. As he noticed the behavior is undocumented but fits our needs most of the time.
This wasn't enough for me though. Think of a RTL language and tabs would still tab left-to-right, not to mention the behavior is entirely different from simulator to device (device doesn't focus the first input upon tab). Most importantly though, Apple's undocumented implementation seems to only consider views currently installed in the view hierarchy.
Think of a form in form of (no pun intended) a table view. Each cell holds a single control, hence not all form elements may be visible at the same time. Apple would just cycle back up once you reached the bottommost (on screen!) control, instead of scrolling further down. This behavior is most definitely not what we desire.
So here's what I've come up with. Your form should be managed by a view controller, and view controllers are part of the responder chain. So you're perfectly free to implement the following methods:
#pragma mark - Key Commands
- (NSArray *)keyCommands
{
static NSArray *commands;
static dispatch_once_t once;
dispatch_once(&once, ^{
UIKeyCommand *const forward = [UIKeyCommand keyCommandWithInput:#"\t" modifierFlags:0 action:#selector(tabForward:)];
UIKeyCommand *const backward = [UIKeyCommand keyCommandWithInput:#"\t" modifierFlags:UIKeyModifierShift action:#selector(tabBackward:)];
commands = #[forward, backward];
});
return commands;
}
- (void)tabForward:(UIKeyCommand *)command
{
NSArray *const controls = self.controls;
UIResponder *firstResponder = nil;
for (UIResponder *const responder in controls) {
if (firstResponder != nil && responder.canBecomeFirstResponder) {
[responder becomeFirstResponder]; return;
}
else if (responder.isFirstResponder) {
firstResponder = responder;
}
}
[controls.firstObject becomeFirstResponder];
}
- (void)tabBackward:(UIKeyCommand *)command
{
NSArray *const controls = self.controls;
UIResponder *firstResponder = nil;
for (UIResponder *const responder in controls.reverseObjectEnumerator) {
if (firstResponder != nil && responder.canBecomeFirstResponder) {
[responder becomeFirstResponder]; return;
}
else if (responder.isFirstResponder) {
firstResponder = responder;
}
}
[controls.lastObject becomeFirstResponder];
}
Additional logic for scrolling offscreen responders visible beforehand may apply.
Another advantage of this approach is that you don't need to subclass all kinds of controls you may want to display (like UITextFields) but can instead manage the logic at controller level, where, let's be honest, is the right place to do so.
I'm interested in solving the same problem, although so far the default order, which appears to be left to right, then top to bottom, is the one I want.
I tested the hypothesis that the cursor moves in depth-first order through the tree of subviews and superview, but that is not true. Changing the order of subviews without changing their location didn't change the order of fields traversed by tab presses.
One possibly useful feature is that the text field delegate's textFieldShouldBeginEditing method appears to be called for every text field in the application's window. If that returns NO, then the text field won't be chosen, so if you can define your desired order and make only the right one return YES, that might solve your problem.
This is how you set the tab order on iOS:
http://weaklyreferenced.wordpress.com/2012/11/13/responding-to-the-tab-and-shift-tab-keys-on-ios-5-ios-6-with-an-external-keyboard/
The Tab key behaviour in ios will be as follows:-
when u press tab on external keyboard- the control traverses across all the textfields in that screen by calling only shouldBeginEditing method where its return value is also determined by Apple which cant be override.
After scanning all the fields it calculates nearest x positioned Textfield relative to view offset from the current Textfield and then nearest Y Positioned Field.
Also can't be done anything until control comes to textFieldDidBeginEditing method.
Reason for apple's restriction might be to let devs to follow the guidelines of UI where next responder of field should be it's closest positioned Field rather than any other field .
Register a UIKeyCommand to detect the tab key pressed. I did this in my current view controller.
self.addKeyCommand(UIKeyCommand(input: "\t", modifierFlags: [], action: #selector(tabKeyPressed)))
Inside the key tabKeyPressed handler find your current active field then set your next responder. orderedTextFields is an array of UITextField in the tab order I want.
func tabKeyPressed(){
let activeField = getActiveField()
if(activeField == nil){
return
}
let nextResponder = getNextTextField(activeField!)
nextResponder?.becomeFirstResponder()
}
func getActiveField() -> UITextField? {
for textField in orderedTextFields {
if(textField.isFirstResponder()){
return textField
}
}
return nil
}
func getNextTextField(current: UITextField) -> UITextField? {
let index = orderedTextField.indexOf(current)
if(orderedTextField.count-1 <= index!){
return nil
}
return orderedTextField[index! + 1]
}
You can do this by setting the tag for each textfield and handling this in the textfieldShouldReturn method.
See this blogpost about it:
http://iphoneincubator.com/blog/windows-views/how-to-create-a-data-entry-screen
The only way I've found to uniquely detect a Tab keystroke from a physical keyboard, is implementing the UIKeyInput protocol's insertText: method on a custom object that canBecomeFirstResponder.
- (void)insertText:(NSString *)text {
NSLog(#"text is equal to tab character: %i", [text isEqualToString:#"\t"]);
}
I didn't get this to work while subclassing UITextField, unfortunately, as UITextField won't allow the insertText: protocol method to get called.
Might help you on the way, though..
I solved this by subclassing UITextField as NextableTextField. That subclass has a property of class UITextField with IBOutlet a hookup.
Build the interface in IB. Set the class of your text field to NextableTextField. Use the connections Inspector to drag a connection to the 'next' field you want to tab to.
In your text field delegate class, add this delegate method...
- (BOOL)textFieldShouldReturn:(UITextField *) textField
{
BOOL didResign = [textField resignFirstResponder];
if (!didResign) return NO;
if ([textField isKindOfClass:[NextableTextField class]])
dispatch_async(dispatch_get_current_queue(), ^{ [[(NextableTextField *)textField nextField] becomeFirstResponder]; });
return YES;
}
BTW - I didn't come up with this; just remember seeing someone else's idea.