I am looking for a non private way to find the position of the Cursor or Caret (blinking bar) in a UITextView preferably as a CGPoint.
There may be a question like this already but it does not provide a definitive way for doing it.
And,
I do not mean the NSRange of the selected area.
Just got it in another thread:
Requires iOS 3.2 or later.
CGPoint cursorPosition = [textview caretRectForPosition:textview.selectedTextRange.start].origin;
Remember to check that selectedTextRange is not nil before calling this method. You should also use selectedTextRange.empty to check that it is the cursor position and not the beginning of a text range. So:
if (textview.selectedTextRange.empty) {
// get cursor position and do stuff ...
}
Pixel-Position of Cursor in UITextView
SWIFT 2.1 version:
let cursorPosition = infoTextView.caretRectForPosition( (infoTextView.selectedTextRange?.start)! ).origin
print("cursorPosition:\(cursorPosition)")
There is no such way. Full stop.
The only thing you could do to come close is to in parallel lay out the text using CoreText, there calcualte the text position from a point and apply that on the UITextView. This, however, works with non-0 selections only. In addition CoreText has a different text layout engine, that e.g. supports kerning, which UITextView doesn't. This may result in deviations of the rendered and laid out text and thus give sub-optimal results.
There is absolutely no way to position the caret. This task is even very though if you do use private API. It's just one of the many "just don't" in iOS.
Swift 4 version:
// lets be safe, thus if-let
if let selectedTextRange = textView.selectedTextRange {
let caretPositionRect = textView.caretRect(for: selectedTextRange.start)
let caretOrigin = caretPositionRect.origin
print(">>>>> position rect: \(caretPositionRect), origin: \(caretOrigin)")
}
We simply use textView.selectedTextRange to get selected text range and than textView.caretRect(for:) to get CGRect defining position of the caret.
Related
Say you have a UICollectionView with a normal custom UICollectionViewLayout.
So that is >>> NOT <<< a flow layout - it's a normal custom layout.
Custom layouts are trivial, in the prepare call you simply walk down the data and lay out each rectangle. So say it's a vertical scrolling collection...
override func prepare() {
cache = []
var y: CGFloat = 0
let k = collectionView?.numberOfItems(inSection: 0) ?? 0
// or indeed, just get that direct from your data
for i in 0 ..< k {
// say you have three cell types ...
let h = ... depending on the cell type, say 100, 200 or 300
let f = CGRect(
origin: CGPoint(x: 0, y: y ),
size: CGSize(width: screen width, height: h)
)
y += thatHeight
y += your gap between cells
cache.append( .. that one)
}
}
In the example the cell height is just fixed for each of the say three cell types - all no problem.
Handling dynamic cell heights if you are using a flow layout is well-explored and indeed relatively simple. (Example, also see many explanations on the www.)
However, what if you want dynamic cell heights with a (NON-flow) completely normal everyday UICollectionViewLayout?
Where's the estimatedItemSize ?
As far as I can tell, there is NO estimatedItemSize concept in UICollectionViewLayout?
So what the heck do you do?
You could naively just - in the code above - simply calculate the final heights of each cell one way or the other (so for example calculating the height of any text blocks, etc). But that seems perfectly inefficient: nothing at all of the collection view, can be drawn, until the entire 100s of cell sizes are calculated. You would not at all be using any of iOS's dynamic heights power and nothing would be just-in-time.
I guess, you could program an entire just-in-time system from scratch. (So, something like .. make the table size actually only 1, calculate manually that height, send it along to the collection view; calculate item 2 height, send that along, and so on.) But that's pretty lame.
Is there any way to achieve dynamic height cells with a custom UICollectionViewLayout - NOT a flow layout?
(Again, of course obviously you could just do it manually, so in the code above calculate all at once all 1000 heights, and you're done, but that would be pretty lame.)
Like I say above the first puzzle is, where the hell is the "estimated size" concept in (normal, non-flow) UICollectionViewLayout?
Just a warning: custom layouts are FAR from trivial, they may deserve a research paper on their own ;)
You can implement size estimation and dynamic sizing in your own layouts. Actually, estimated sizes are nothing special; rather, dynamic sizes are. Because custom layouts give you a total control of everything, however, this involves many steps. You will need to implement three methods in your layout subclass and one method in your cells.
First, you need to implement preferredLayoutAttributesFitting(_:) in your cells (or, more generally, reusable views subclass). Here you can use whatever calculations you want. Chances are that you will use auto layout with your cells: if so, you will need to add all cell's subviews to its contentView, constrain them to the edges and then call systemLayoutSizeFitting(_:withHorizontalFittingPriority:verticalFittingPriority:) within this "preferred attributes" method. For example, if you want your cell to resize vertically, while being constrained horizontally, you would write:
override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
// Ensures that cell expands horizontally while adjusting itself vertically.
let preferredSize = systemLayoutSizeFitting(layoutAttributes.size, withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel)
layoutAttributes.size = preferredSize
return layoutAttributes
}
After the cell is asked for its preferred attributes, the shouldInvalidateLayout(forPreferredLayoutAttributes:withOriginalAttributes:) on the layout object will be called. What's important, you can't just simply type return true, since the system will reask the cell indefinitely. This is actually very clever, since many cells may react to each other's changes, so it's the layout who ultimately decides if it's done satisfying the cells' wishes. Usually, for resizing, you would write something like this:
override func shouldInvalidateLayout(forPreferredLayoutAttributes preferredAttributes: UICollectionViewLayoutAttributes, withOriginalAttributes originalAttributes: UICollectionViewLayoutAttributes) -> Bool {
if preferredAttributes.size.height.rounded() != originalAttributes.size.height.rounded() {
return true
}
return false
}
Just after that, invalidationContext(forPreferredLayoutAttributes:withOriginalAttributes:) will be called. You usually would want to customize the context class to store the information specific to your layout. One important, rather unintuitive, caveat though is that you should not call context.invalidateItems(at:) because this will cause the layout to invalidate only those items among the provided index paths that are actually visible. Just skip this method, so the layout will requery the visible rectangle.
However! You need to thoroughly think if you need to set contentOffsetAdjustment and contentSizeAdjustment: if something resizes, your collection view as a whole probably will shrink or expand. If you do not account for those, you will have jump-reloads when scrolling.
Lastly, invalidateLayout(with:) will be called. This is the step that's intended for you to actually adjust your sections/rows heights, move something that's been affected by the resizing cell etc. If you override, you will need to call super.
PS: This is really a hard topic, I just scratched the surface. You can look here how complicated it gets (but this repo is also a very rich learning tool).
How can I detect if a button is in a desired area
I have used if( button.frame.orgin.x == area.framee.orgin.x){
if (button.frame.orgin.y == area.frame.orgin.y )};
The Problem with this code is that it is very exact so it is hard to match up the button with the label. So I would like to know how to detect if a button is inside a desired area. And how to make the area bigger than the button. Thanks In advance
Your best option is probably CGRectContainsRect() which would work something like:
if(CGRectContainsRect(someRect, button.frame))
{
//Button is in area.
}
To expand the rect you can use CGRectInset(), passing negative values to increase the frame size by that amount. This function will maintain the center of the original rect.
CGRect newRect = CGRectInset (smallRect, -10.0f, -10.0f);
You can read more about CGGeometry functions in the docs.
Use GCRectContainsRect(frame1, frame2); to see if an object is contained within another object. Or use CGRectIntersectsRect(frame1, frame2); to see if the rects overlap at all.
Note: for this I am using a program called spritebuilder, which allows me to create a game with less code than would normally be needed. If you know a solution that's just all code, then by all means feel free to share it :)
Also, for this question, I followed a tutorial at this link: Build Your Own Flappy Bird Clone. Just scroll down to the part that says: "Loop the Ground"
So here's my problem. Im currently working on a game, and I created a camera which scrolls vertically long with the character sprite i created, however i need a certain image to loop. When the image leaves the bottom part of the screen I would like it to loop around to the top of the screen, infinitely. For this i created two identical images (in this case its the bark of a tree). One will be on screen, while the other will be offscreen, so as the first image leaves the screen, the second will replace it (seamlessly). I created two objects for the images, and assigned them the name _ground1, and _ground2, and I also created an NSArray in which to store them in. (Please refer to the link above if it is somewhat confusing)
Here is the code that I have:
CCNode *_ground1;
CCNode *_ground2;
NSArray *_grounds;
for (CCNode *ground in _grounds) {
// get the world position of the ground
CGPoint groundWorldPosition = [_physicsNode convertToWorldSpace:ground.position];
// get the screen position of the ground
CGPoint groundScreenPosition = [self convertToNodeSpace:groundWorldPosition];
// if the left corner is one complete width off the screen, move it to the right
if (groundScreenPosition.y <(-1 * ground.contentSize.height)) {
ground.position = ccp(ground.position.x , ground.position.y + 2 * ground.contentSize.height);
}
For some reason when I try this, it doesnt seem to work. what happens is that, the camera will travel vertically as it is meant to do, but the images do not loop. Once the two images leave the bottom of the screen, no new images replace them.
i also done this project as above tutorials. it work fine but you have some mistake to set variable in spritebuilder. in your above code replce code as and try it. you only put less than may be it issue.
if (groundScreenPosition.y <=(-1 * ground.contentSize.height)) {
ground.position = ccp(ground.position.x , ground.position.y + 2 * ground.contentSize.height);
}
You are using CCNode objects as _ground1and _ground2.
CCNode objects usually do not have a contentSize, they will return 0 unless you explicitly set them inSpriteBuilder`.
Make sure that you are using CCSprite objects in SpriteBuilder and in your code.
Also, as a friendly hint you should also consider refactoring (renaming) your sprites with more meaningful names for your use case like _treeBark1 and treeBark2 for example.
I’m trying to put together what seems to be a simple case of two NSTextFields with dynamic width and fixed spacing in between. I cannot figure out an effective way to do so though.
I’m looking to get something like this:
The blue boxes are the NSTextFields. When more text is entered into one, it should grow and thus make the other one shrink, maintaining the lead space, trailing space and the spacing in between the fields. The first one should take the priority if both of the fields have too much text. Each field will also clearly have a maximum and a minimum possible width it can reach.
How would I go around handling this, preferably utilising IB autolayout as much as possible?
It seems to me that all of constraints you mentioned directly translate into interface builder --
First view has width >= something.
First view has width <= something
Same for Second view.
Space between views is fixed.
Second view wants to be as small as possible (have its width at 0) but this has lower lower priority than the previous constraints and lower priority than inner content size constraints.
The code I had to add to my view controller, after applying the constraints as per the ilya’s answer:
In controlTextDidChange (_controlWidthConstraint refers to the fixed width constraint of the input; it’s probably 0 by default for the second input):
// Get the new width that fits
float oldWidth = textControl.frame.size.width;
[input sizeToFit];
float controlWidth = textControl.frame.size.width;
// Don’t let the sizeToFit method modify the frame though
NSRect controlRect = textControl.frame;
controlRect.size.width = oldWidth;
textControl.frame = controlRect;
_controlWidthConstraint.constant = controlWidth;
The key lies in invalidating the intrinsicContentSize for the text field when text is input.
You can check a sample project here, to get you on the right track.
I have an NSSplitView (NO UISplitView(Controller)!!) with three subviews. Now, for the last divider (index 1), I want the divider to not show the dragging cursor (two arrows pointing out of eachother). I have this to stop the dragging, but the cursor is still showing up:
- (CGFloat)splitView:(NSSplitView *)splitView constrainSplitPosition:(CGFloat)proposedPosition ofSubviewAt:(NSInteger)dividerIndex {
if (dividerIndex == 1) {
return [splitView frame].size.width - 161;
}
}
Note that I only want to hide the cursor for the divider at index 1. Can anyone help me? Thanks. :)
No, I don't want to use BWToolkit.
I know this has been answered for a while, but the supplied answer did not suit my needs.
The delegate method splitView:effectiveRect:forDrawnRect:ofDividerAtIndex: allows you to set the effective rectangle for dragging the divider. If you return NSZeroRect no drag cursor will ever appear, regardless of your setup in splitView:constrainMaxCoordinate:ofSubviewAt: and splitView:constrainMinCoordinate:ofSubviewAt:.
Try using splitView:constrainMaxCoordinate:ofSubviewAt: and splitView:constrainMinCoordinate:ofSubviewAt: instead of splitView:constrainSplitPosition:ofSubviewAt:.
The former two methods are called once as the user drags the mouse and they give enough information for NSSplitView to know how to change the cursor during the drag.
The latter is called repeatedly as the user drags the splitter, so NSSplitView doesn't have enough information to know that you're returning a constant value each time and therefore can't change the cursor.