I added a feedback box inside my IOS application, and I want it to take only text to submit the response from the user, but when I tried to enter a white spaces inside the box it took it as a text and accept the submitting! How can I prevent that?
Specify the UIViewController as the delegate to your text view (you can do this either programmatically or specify the delegate in Interface Builder); and
Your UITextViewDelegate method shouldChangeTextInRange needs to check to see if the string to be inserted contains a space:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
if ([text rangeOfCharacterFromSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]].location != NSNotFound) {
return NO;
}
return YES;
}
Related
When using a UITextView to gather user input in Objective-C, how can I limit the user from trying to do more than one line break at a time?
So, this would be fine:
This is my text.
Here is some more text.
But this would not be fine:
This is my text.
Here is some more text way down here.
In your ViewController.h add UITextViewDelegate:
YourViewController : UIViewController <UITextViewDelegate>
and in the ViewController.m implement the method textView:shouldChangeTextInRange:replacementText: this way:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
if ([text isEqualToString:#"\n"]) {
NSMutableString *futureString = [textView.text mutableCopy];
[futureString insertString:text atIndex:range.location];
NSRange rangeOflineBreaks = [futureString rangeOfString:#"\n\n\n"];
if (rangeOflineBreaks.location != NSNotFound) {
return NO;
}
}
return YES;
}
This will be executed every time before the user wants to add some text to the textView and wont let him add another line break if it notices that he wants to add a line break and it finds, after trying adding it (that's why the futureString name) a triple line break mode. In that case he wont let the user add another line break.
Try it out, it should work :)
PS: Don't forget to set your textView delegate the viewController in the viewDidLoad (yourTextView.delegate = self)
Needing to present user a multiline text field for comment entry, I am using a UITextView instead of a UITextField. I would like to use textFieldShouldReturn on my UITextView to send the data to server. How might I do that? Based on my readings so far, the method is only applicable to UITextField. So what is the equivalent for UITextView?
By adding the UITextViewDelegate to your viewControllerHeader
#interface ViewController : UIViewController<UITextViewDelegate>
This'll allow you access to the UITextViewDelegate methods of which there are a couple of which should allow you to know when the user has either pressed return or let you know when they have finished editing, for example
- (void)textViewDidEndEditing:(UITextView *)textView{
//From here you can action your methods to send the data to your server as required etc.
}
There's also this method
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
//Which you can use to listen for the #"\" return action if you prefer.
}
I hope this helps
I am trying to achieve the same effect as Facebook's new status field: place something next to the last character which cannot be modified or selected by the user (for example, a tag: "with Joh Doe").
What's the best way of achieving it?
Thanks
Nick
An easier solution would be to simply make the last n characters in the TextView not editable. Then let the TextView handle moving and wrapping the text as needed. I would guess that is what Facebook is doing, just with some attributed text at the end.
In your ViewControllers.h, make sure the viewController conforms to the UITextViewDelegate as follows.
#interface ViewController : UIViewController <UITextViewDelegate>
Then in the viewDidLoad: method, set the delegate for the UITextView to the ViewController. You can also add your fixed text.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.myTextView.delegate = self;
self.myTextView.text = " posted by Mike";
}
Then, we will use the shouldChangeCharactersInRange: method to prevent the user from editing the text at the end you want to preserve.
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
BOOL deleteKeyPressed = ([text length] == 0 && range.length > 0);
if( range.location > (textView.text.length - #" - posted by Mike".length) || (deleteKeyPressed && range.location > (textView.text.length - #" - posted by Mike".length)) )
{
return NO;
}
return YES;
}
I think this should get you started and make you life easier than finding the end of the last text, then putting another view at the end that may need to wrap if there is not enough room to fit it.
So to prevent the user from selecting the "reserved" text, add the following delegate method to your ViewController's .m:
-(void) textViewDidChangeSelection:(UITextView *)textView
{
if( textView.selectedRange.location > (textView.text.length - #" - posted by Mike".length) )
{
[textView setSelectedRange:NSMakeRange((textView.text.length - #" - posted by Mike".length), 0 )];
}
}
You'll still need to handle if the user selects all the text, and chooses to "cut" or "paste", but that should just be another special case in shouldChangeTextInRange. I'll let you figure that one out - shouldn't be hard. Certainly a lot easier than trying to dynamically place, size, and wrap a TextView within another TextView.
Is there a way to disable the iOS keyboard's feature where when you hold backspace down for long enough it starts to delete many characters at a time?
You can use the UITextViewDelegate (or UITextFieldDelegate method) shouldChangeTextInRange stop the user from deleting words at a time.
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if (text.length == 0) {
//Backspace
return range.length == 1;
}
return YES;
}
I have a UITextView. I have the delegate for myTextView set to self and, when I do normal editing, this method calls just fine:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
NSLog(#"Called");
}
In my app, I call in my code: [myTextView insertText:#"Hello World"];. When I do, I need to call textView:shouldChangeTextInRange:replacementText: after the text is inserted. How do I do this?
Call it explicitly. Call it before editing and only perform the edit if it returns YES. To call it explicitly you need to know the selected range (get the selected range with selectedTextRange), that's it. You already have the text to add and the text view.
Thanks for the answer, #Wain!
Here's what worked:
- (void)insertText
{
NSString *stringToAdd = #"Hello World";
NSString *replacementText = [myTextView.text stringByAppendingString:stringToAdd];
[napkinTextView insertText:stringToAdd];
[self textView:myTextView shouldChangeTextInRange:NSMakeRange(0, stringToAdd.length) replacementText:replacementText];
}