I'm trying to extend UIView with shortcuts to setting size and origin, as done in Obj-C here.
Getters work great, but setters don't. Any ideas why? What am I doing wrong?
Here is my code rewritten from Obj-C to Swift:
extension UIView {
...
var height : CGFloat {
get {
return self.frame.size.height
}
set {
var r = self.frame;
r.size.height = height;
self.frame = r;
}
}
And here is another one, since CGRect properties are "val"
var width : CGFloat {
set {
self.frame.size.width = width
}
get {
return self.frame.size.width
}
}
But none of this setters works
This works great, but it's too long :)
self.frame.size.width = 100
Thank you for you help!
The setter name and enclosing parentheses is optional. If you provide
a setter name, it is used as the name of the parameter to the setter.
If you do not provide a setter name, the default parameter name to the
setter is newValue.
Change your set method to:
set {
self.frame.size.width = newValue
}
Related
Suppose I want to change size of an uiView: UIView to w,h. I can do it like that:
uiView.frame.size.width = w
uiView.frame.size.height = h
In another system I can avoid replication of dereferencing (which means waste of both size and performance) by keeping a reference in a variable (using Swift syntax):
let ref = uiView.frame.size
ref.width = v
ref.height = h
This however doesn't work in iOS, where CGSize is a structure and therefore is copied when assigned to another value.
Is there a way to avoid redundant dereferencing (something like with(uiView.frame.size){...} available in some languages)
I don't think there is a way to do it exactly because the frame is a value-copied structure. You could set the frame directly as Reiner Melian suggests, but to me that seems even longer and uses dereferencing at least the same amount of time as your approach.
There is a way how to make it simpler this using extensions, but behind the scenes it will again be using dereferencing:
extension UIView {
var width: CGFloat {
get {
return self.frame.size.width
}
set {
self.frame.size.width = newValue
}
}
var height: CGFloat {
get {
return self.frame.size.height
}
set {
self.frame.size.height = newValue
}
}
}
And then you could use:
uiView.width = w
uiView.height = h
on any UIView instance.
This is even simpler:
uiView.frame.size = CGSize(width: w, height: h)
As I understand it, RHS is a temporary value released as soon as the content has been copied to frame structure.
i am trying to set imageview as subview for scrollview.for that i am setting different frame depends upon the screensize.
This is my code
let screensize:CGRect=UIScreen.mainScreen().bounds
let screenwidth=screensize.width
var frames:CGRect
for var index=0 ;index < arrBirds.count ;index++
{
if(screenwidth==320)
{
frames.origin.x = CGFloat(index) * (self.view.frame.size.width);
frames.origin.y = 0;
frames.size=scrollview.frame.size;
}
else if(screenwidth==375)
{
frames.origin.x = CGFloat(index) * (self.view.frame.size.width);
frames.origin.y=0;
frames.size=scrollview.frame.size;
}
else
{
frames.origin.x = CGFloat(index) * (self.view.frame.size.width);
frames.origin.y=0;
frames.size=scrollview.frame.size;
}
imageView=UIImageView(frame:frames)
imageView.image=UIImage(named: arrBirds[index] as! String)
scrollview .addSubview(imageView)
But i am getting error this line
frames.origin.x = CGFloat(index) * (self.view.frame.size.width);//struct frame must be completely initialised before a member is stored to.
You have not yet created an instance of the struct CGRect yet. Before accessing / setting any members on it you you need to create a instance first and only after that set the different members of it:
Change the line var frames:CGRect to:
var frames = CGRectZero
According to Apple Docs :
Classes and structures must set all of their stored properties to an
appropriate initial value by the time an instance of that class or
structure is created.
Your frames object isn't initialized, instead you should write :
var frames = CGRectZero
I'm trying to make a draggable image (monkey) takes the place of another draggable image (banana) when I'm pushing a button.
So far, I've been able to get the coordinates of the banana, and store them as the new x,y coordinates of the monkey. But, the view is not updating and the monkey does not moves to it's new place.
I'm sure that I need to update the view, but can't figure it out.
I've tried to add a new subview (self.view.addSubview(monkey)) but when I do that, it's the entire view that is reset and both monkey and banana are going back to their original coordinates.
Here's the code of the action button :
#IBAction func getCoordinates (sender : AnyObject) {
var bananax = banana.frame.origin.x
var bananay = banana.frame.origin.y
var monkeyx = monkey.frame.origin.x
var monkeyy = monkey.frame.origin.y
println("Banana : \(bananax) et \(bananay)")
println("Monkey's default coordinates : \(monkeyx) et \(monkeyy)")
monkeyx = bananax
monkeyy = bananay
println("Monkey's new coordinates : \(monkeyx) et \(monkeyy)")
}
Any idea on how to update only the monkey and not reseting the entire view ?
Thanks :)
These values are just thrown away when you set monkeyx and monkeyy below.
var monkeyx = monkey.frame.origin.x
var monkeyy = monkey.frame.origin.y
Assigning the values below just assigns the values from one local variable to another. It does not actually change the coordinates for monkey.
monkeyx = bananax
monkeyy = bananay
You must set the new coordinates on monkey by constructing a new CGRect and assigning monkey's frame:
monkey.frame = CGRect(x: bananax, y: bananay, width: monkey.frame.size.width, height: monkey.frame.size.height)
As you are just setting monkey's origin to banana's origin, you can remove all the var declarations and reduce this to one line by constructing monkey's new frame with monkey's size and banana's origin:
monkey.frame = CGRect(origin: banana.frame.origin, size: monkey.frame.size)
Hi create this extends if you want. For Swift
Create File Extends.Swift and add this code
/**
Extension UIView
by DaRk-_-D0G
*/
extension UIView {
/**
Set x Position
:param: x CGFloat
by DaRk-_-D0G
*/
func setX(#x:CGFloat) {
var frame:CGRect = self.frame
frame.origin.x = x
self.frame = frame
}
/**
Set y Position
:param: y CGFloat
by DaRk-_-D0G
*/
func setY(#y:CGFloat) {
var frame:CGRect = self.frame
frame.origin.y = y
self.frame = frame
}
/**
Set Width
:param: width CGFloat
by DaRk-_-D0G
*/
func setWidth(#width:CGFloat) {
var frame:CGRect = self.frame
frame.size.width = width
self.frame = frame
}
/**
Set Height
:param: height CGFloat
by DaRk-_-D0G
*/
func setHeight(#height:CGFloat) {
var frame:CGRect = self.frame
frame.size.height = height
self.frame = frame
}
}
For Use (inherits Of UIView)
inheritsOfUIView.setX(x: 100)
button.setX(x: 100)
view.setY(y: 100)
Now you can do
monkey.frame.origin = banana.frame.origin
If you are using a UIImageView for monkey and banana, you can simplify this by doing the following
monkey.center = banana.center
Understand that there is a difference between origin and center. See more here:
UIView's frame, bounds, center, origin, when to use what?
but based on question, I think center should work fine and it is simpler.
I am trying to experiment with UIViews on screen and using pan gestures. So I got some open source code from another project that I am looking at - and trying to learn a few things from it.
-(BOOL)isPointContainedWithinBezelRect:(CGPoint)point {
CGRect leftBezelRect;
CGRect tempRect;
CGFloat bezelWidth = 20;
CGRectDivide(self.view.bounds, &leftBezelRect, &tempRect, bezelWidth, CGRectMinXEdge);
return CGRectContainsPoint(leftBezelRect, point);
}
I understand that CGRectDivide function "Slices up a rect", but thats as far as I can make out.
I hope to get more clarification regarding the function. Also, how does the function return value vide a false / true value?
void CGRectDivide(
CGRect rect,
CGRect *slice,
CGRect *remainder,
CGFloat amount,
CGRectEdge edge
)
The CGRectDivide method splits a CGRect into two CGRects based on the CGRectEdge and distance from the rectangle side amount provided to the method.
Source
You should check
https://developer.apple.com/library/ios/documentation/graphicsimaging/reference/CGGeometry/Reference/reference.html#//apple_ref/c/func/CGRectDivide
and
http://nshipster.com/cggeometry/
But it seems that this method could be simplified to
-(BOOL)isPointContainedWithinBezelRect:(CGPoint)point {
CGRect leftBezelRect = self.view.bounds;
leftBezelRect.size.width = 20;
return CGRectContainsPoint(leftBezelRect, point);
}
or even to
-(BOOL)isPointContainedWithinBezelRect:(CGPoint)point {
return CGRectContainsPoint(self.view.bounds, point) && (point.x <= 20);
}
In my app, I use a UIPopoverController and I use the presentPopoverFromRect API. What I am doing now is just setting it to the frame of my whole UISegmentedControl. However I want to be more precise than this. Is there any way to get the frame of a specific index in the UISegmentedControl?
Thanks!
For our project we needed the actual frames of each segment, frame division wasn't enough. Here's a function I wrote that calculates the exact frame for every segment. Be aware that it accesses the segmented control actual subviews, so it might break in any iOS update.
- (CGRect)segmentFrameForIndex:(NSInteger)index inSegmentedControl:(UISegmentedControl *)control
{
// WARNING: This function gets frame from UISegment objects, undocumented subviews of UISegmentedControl.
// May break in iOS updates.
NSMutableArray *segments = [NSMutableArray arrayWithCapacity:self.numberOfSegments];
for (UIView *view in control.subviews) {
if ([NSStringFromClass([view class]) isEqualToString:#"UISegment"]) {
[segments addObject:view];
}
}
NSArray *sorted = [segments sortedArrayUsingComparator:^NSComparisonResult(UIView *a, UIView *b) {
if (a.frame.origin.x < b.frame.origin.x) {
return NSOrderedAscending;
} else if (a.frame.origin.x > b.frame.origin.x) {
return NSOrderedDescending;
}
return NSOrderedSame;
}];
return [[sorted objectAtIndex:index] frame];
}
If the segments are equal, why not just divide the width of the control by the number of the selected segment (+1 because numbering starts at 0)?
EDIT: Like this
-(void)showPopover:(id)sender {
if ((UISegmentedControl*)sender.selectedSegmentIndex == 0)
[self.popover presentPopoverFromRect:CGRectMake(self.segmentedControl.frame.size.width/6, self.segmentedControl.frame.origin.y, aWidth, aHeight)]
}
It's over 6 (I'm assuming a 3 segment implementation), because you have to get the center of the segment, and 3 would put it on the lines. And if you do some simple math here (let's assume the whole control is 60 px wide), then 60/3 yeilds 20. Because each segment is 20 px wide, the width of 60 over six yields the correct answer 10.
This can be done much easier without matching class names, providing that you use no custom segmented control (Swift version)
extension NSSegmentedControl {
func frameForSegment(segment: Int) -> NSRect {
var left : CGFloat = 0
for i in 0..<segmentCount {
let w = widthForSegment(i)
if i == segment {
let off = CGFloat(i) + 2 // Account for separators and border.
return NSRect(x: left + off, y: bounds.minY, width: w, height: bounds.height)
}
left += w
}
return NSZeroRect
}
}
If somebody is searching for a solution for NSSegmentedControl, I've slightly modified #erik-aigner's answer. For UISegmentedControl it should work similarly.
This version improves the geometry computation for spacing and the code in general. Disclaimer: It was tested only for a segmented control placed in a toolbar.
import AppKit
public extension NSSegmentedControl {
/// The width of a single horizontal border.
public static let horizontalBorderWidth: CGFloat = 3
/// The height of a single vertical border.
public static let verticalBorderWidth: CGFloat = 2
/// The horizontal spacing between segments.
public static let horizontalSegmentSpacing: CGFloat = 1
/// Returns the frame of the specified segment.
///
/// - Parameter segment: The index of the segment whose frame should be computed.
/// - Returns: The frame of the segment or `.zero` if an invalid segment index is passed in.
public func frame(forSegment segment: Int) -> NSRect {
let y = bounds.minY - NSSegmentedControl.verticalBorderWidth
let height = bounds.height
var left = NSSegmentedControl.horizontalBorderWidth
for index in 0..<segmentCount {
let width = self.width(forSegment: index)
if index == segment {
return NSRect(x: left, y: y, width: width, height: height)
}
left += NSSegmentedControl.horizontalSegmentSpacing
left += width
}
return .zero
}
}
Swift 5.3 version of #CodaFi's answer:
func showPopover(_ sender: Any?) {
if sender?.selectedSegmentIndex as? UISegmentedControl == 0 {
popover.presentPopover(fromRect: CGRect(x: segmentedControl.frame.size.width / 6, y: segmentedControl.frame.origin.y, width: aWidth, height: aHeight))
}
}
For me widthForSegment returns 0, so the other answers always fail to produce frame. I think a better solution is to just get the frame of a subview:
public extension UISegmentedControl {
func frame(forSegment segment: Int) -> CGRect {
subviews[segment].frame
}
}