I want to ovserve a UITextField value change. In Swift 4 it's prefer to use block based KVO API. So I got this code:
self.kvo = self.textField.observe(\.text, options: [.new, .old], changeHandler: { (textField, change) in
print(change.newValue)
print(change.oldValue)
})
The block was called when editing ended, not text value changed. How could I do to observe the UITextField value changed?
I know that addTarget could detect editing changed. But I want to know both old value and new value when editing changed. And I don't want to use an additional variable to record the old value. KVO could do this but It seems not be called when editing changed.
Related
I am Creating a tableview using custom cell with textfield. When i enter text in tableviewcell textfield and when i scroll the tableview the data is changing . Means re painting cells . How can i stop reloading cell on drag or scroll in IOS 8 swift
Thanks
If your want your cell not re-used, try to make it a subclass of UITableViewCell with a unique identifier, and do not use the identifier with other cells. I haven't test it yet, just hope it will solve your problem.
Ps. If the textfield's text is still overwritten, make a check at the cell's class file (like making an if-else statement checking if the textfield's text is empty).
Detailed workflow:
In cellForRowAtIndexPath(), after you dequeue the cell, normally you will set some property of your custom cell to refresh the data it holds. To implement this, you need to add a didSet observer on the property at the cell's class file. To achieve the goal you want, you can also add the checking code in the didSet observer.
In Your case. You need to customize your keyboard.
Add [Prev][Next] buttons on top of the keyboard and avoid scrolling.
Basically this idea is useful in form based app. May be your doing that kind.
And yes, Stop relaoding of cells is not good to app. If you will implement this. Apple will not approve your app. So avoid this kind of stuffs.
This is how cells work in a UITableView. The standard implementation of the cellForRowAtIndexPath: method dequeues cells and reuses them.
And ideally your app should save the text from the text fields and change the correct text in the cells depending on their indexPath in the same method's implementation.
If you do not want to do that, a dirty workaround would be to create a new cell every time in the cellForRowAtIndexPath: method instead of dequeuing rows.*
*Do not do this unless absolutely necessary. This is very bad coding practice
How to configure a view-based NSTableView to behave like so:
Rows are selectable
The user are unable to trigger edit mode by clicking a cell
Edit mode can be triggered by calling NSTableView-editColumn:row:withEvent:select: programmatically
The table view is dragged from the object library of Xcode interface builder, i.e., it uses an NSTableCellView (with an NSImageView and an NSTextField as its subviews) as the table view's cell view.
For view-based table views, -editColumn:row:withEvent:select: is relatively ineffective. It attempts to make the cell view the first responder for the window, but only certain views will accept first responder status. NSTableCellView does not, because it is not itself editable.
If you want to programmatically initiate editing in the text field within an NSTableCellView, you can do something like:
NSTableCellView* cellView = (NSTableCellView*)[tableView viewAtColumn:col row:row makeIfNecessary:YES];
if ([cellView.textField acceptsFirstResponder])
[cellView.window makeFirstResponder:cellView.textField];
To disable the user from starting editing through the UI, I think you will need to set the text field to not be editable. You would make it editable just before you initiate editing programmatically. For example, add a line cellView.textField.editable = YES; between the above two lines.
Then, you'll want to set it back to non-editable after editing ends. To do this, you can set the delegate of the text field to your controller object and implement -controlTextDidEndEditing:. Or, similarly, you can add an observer of the NSControlTextDidEndEditingNotification notification from the text field. Either way, when your code is called, you set the text field's editable property back to false. (If you don't otherwise have a reference to the text field in question, you can obtain it from the NSNotification's object property.)
I'm trying to remove focus from a UITextField and even though I resign it from being first responder, I'm still not able to have the cursor not focus on the text field.
I don't have any other input on the view to move the focus to and I don't want to create a dummy one either. What is a good workaround for this?
As per the documentation.
To dismiss the keyboard, send the resignFirstResponder message to the text field that is currently the first responder. Doing so causes the text field object to end the current editing session (with the delegate object’s consent) and hide the keyboard.
If you call resignFirstResponder on your textfield then it will end the editing session and the cursor wont be focussing on that textfield.
So please verify one more time whether resignFirstResponder is getting called on that textfield which you want to remove the focus.
Please try to set your current class as delegate of your UITextField. I think you forget to set the delegate that's why it's not working as you are expecting.
This question already has answers here:
Respond to mouse events in text field in view-based table view
(6 answers)
Closed 9 years ago.
I have a view based NSTableView in which the cells contain a number of controls including text fields and edit fields. When a user tries to click on a control within a cell in order to, for example, start editing a text field, the click's main objective is ignored and the cell gets selected. Another click is then needed to perform the action originally intended, and even this click is subject to a delay before it's taken into account.
How can I avoid this problem and have the row selected and the mouse event forwarded to the control in one go?
I solved this issue by subclassing NSTableView:
#implementation QuickResponseTableView
- (BOOL)validateProposedFirstResponder:(NSResponder *)responder forEvent:(NSEvent *)event
{
// This allows the user to click on controls within a cell withough first having to select the cell row
return YES;
}
#end
Had the same problem. After much struggle, it magically worked when I selected None as against the default Regular (other option is Source List) for the Highlight option in IB! The accepted answer appears to be more specific but a little hacky compared to this.
I have a custom NSCell (actually subclassing NSTextFieldCell), which is used both in a standalone editor, and in an NSTableColumn (bound to Core Data through NSArrayController). When the user changes the value, I call -[NSCell setObjectValue:] to update the value (it's an NSNumber). This works in the standalone editor, since when it's done I manually update the binding on it.
[self setObjectValue:[NSNumber numberWithInt:newValue]];
That step (updating the bound field) is missing when the cell is in an NSTableView - the updated value shows up while the user's editing (with mouse tracking), but as soon as that's over, the value snaps back to the persisted value.
The NSTableColumn is bound to a key of -[NSArrayController arrangedObjects]. Is there some sort of call to "commitEditing" or "updateBinding" that I'm missing? I couldn't find any useful functions in the docs for NSCell or NSTableView.
To solve this, I implemented -tableView:setObjectValue:forTableColumn:row: in my NSArrayController subclass. I get the instance of my NSManagedObject subclass from the Row argument, and then manually assign the new model from the ObjectValue argument. I still don't know why this is necessary, when the text cells do this automatically, but it works.