automatic sizing by screen calculations - ios

I have a picture in the center of my cell, I added a leading and a trailing to center this, it works in a lot of devices but when I try to display this on the iPhone 4 the screen is too small so the length of the leading and trailing are too longs so the picture is compressed and we could not see the image.
So I want to do calculations like leading = screen_width/3 and trailing = screen_width/3
It is possible and it is a good solution ? How to do this or here is an better way ?

When there is such requirement that you want to show View A in centre of View B, I recommend the following constraints:
- View A : Equal Width to superview (i.e. View B), with multiplier. (In your case 1/3 = 0.33).
- View B : Equal Height to superview (i.e. View A), with multiplier. (In your case 1/3 = 0.33).
- View A Center Vertically to superview (i.e. View B).
- View A Center Horizontally to superview (i.e. View B).

If the leading will be w / 3 and trailing is the same. So the image width itself is w / 3 as well. So set Width constraint to be width = superview.width / 3. Then add another constraint to center it horizontally

If you want to centralize your image, you can do it through auto layout and that should work for all the devices. This is the approach I would take-
First take an image view inside your table view cell and with cursor centralize it.
Now-
Step 1: control drag from the image view to you table view's content view.
and select "Center horizontally" and "Center vertically option".
At this point, you may see some red or yellow line but avoid that. We are going to deal with that now.
Step 2:
Pin the top and botton to the content view. Here I assumed your image height is same as your cell height but that can change according to your requirement.
So, pin to the content view like -
Now you are just left with your image's width. In my case I assumed it is going to be same as the height , so I just had to control drag to itself and select "Aspect Ration" like-
This is you final constrains
That should work fine. If your image view's width is not same as your its height then you can you "Equal Width" property with respect to the cell's content view and tell it how you like your width to be.
You DO NOT use trailing or leading space constraints when you are centralize an object inside another.

Related

Constraints not resizing properly for all screen devices

I am trying to do the constraints for these horizontals button. I want the ratio of size of buttons to be the same, and the icons to be of equal widths and heights of each others.
Any idea of how i can do that so these buttons resize properly according to the screen size? Thanks!
Make groups of UIView containing the icon and text. Lets call this container view
Place all the n container views inside your storyboard as you would like them to appear. Now:
To the left most container view add a leading and bottom constraint to the super view.
Now to the second container view add a leading space of 0 (or anything you want). Control + drag your second button to the first button. Hold down shift and select equal width, equal height and align bottom.
Now apply the same constraints as your second container view to all your n - 1 container view. n being the number of container view you want to add. Now to your last (nth) container view add, one extra constraint, which would be a trailing space to the superView. Now all your container view ought to have an equal width that will be determined depending on the width of the screen!
If you want to have a specific height or aspect ratio to all your container view. Just add the height or aspect ratio constraint to your first container view and all your subsequent views will get updated accordingly.
OR
If you wish for the height to be dependent on the screen size and not maintain a specific aspect ratio, then you will have to give the first container view a equal height to the whole view with a specific multiplier like 0.15.
You will also have to add appropriate constraints to the icon and label present inside each UIView
Edit: A much easier thing for you to do would be add the icon as an image to the UIButton and add the text as you would normally to the UIButton. The UIButton will appear quite similar to the screenshot you posted. And then just apply the constraints I mentioned above.
Set the width and height as ratio of the SuperView. Set if for one button and for the remaining buttons make the height and width equal to the first button for which you defined the height and width in terms of superview height and size. Use this SO Post to see how to set height and width as ratio of the superview.
Hope this helps.
It's Simple because your All buttons are in single Direction so you can use StackView.
Just simple first apply the equal hight and equal width to all your buttons
now select all the buttons and add them in the stackview
it will be in the right side bottom. (with the constraint icon)
now simple Apply add missing constraint. it will done the work by own and gives better result. (but take care here apply it from the all views in View Controller Section)
And now Bingo try this every Size will show same.
This will work same in simulator also.
The solution is very simple.
See the image below (5 buttons)
The first (blue) button is pinned to the left and bottom of the superview
Each of the other 4 buttons (red, black, green, pink) are top aligned to the first (blue) button
Each button is using a horizontal spacing to the previous button (with a constant of 0). So red button has 0 horizontal spacing to blue, black has 0 horizontal spacing to red, etc
The Last (pink) button is also pinned to the right of the superview
Finally all 4 other buttons are set to have same width to the first (blue) button
That's it!
As for you icons, all you need is to set them to have same width & height to the first icon you have

Need help to set autolayout

Am new to iOS & am facing it very difficult to set autolayout. Watched many videos to learn, but all of them giving solution to a specific problem. No video covers all base rules to set an UI object into it's place & with proper flow.
I came from Corona Background & used to set UI programatically very well. Am thinking here same way, but I think apple made it so difficult or people are not able to explain me properly.
Please see 2 images attached in this question & tell me rules to apply to achieve this UI. I request you people to please explain in the general manner so that my other screen can be completed using same rules.
Image 1: http://i.stack.imgur.com/MPE47.png
Image 2: http://i.stack.imgur.com/qEiCm.jpg
A really helpful guideline is
Every element should be able to figure out its position (x and y) and size (width and height).
Ensure that every element only has one way to figure out its position and size.
Remember that the autolayout of all the elements can influence each other.
The most used layout constraints are:
Top The space between the top of the view to another view.
Trailing The space between the right edge of the view to another view.
Leading The space between the left edge of the view to another
Bottom The space between the bottom edge of the view and another view
Width Assign a fix width to a view (Note that it can also be a percentage - aspect ratio)
Height Assign a fix width to a view (Can also be a percentage)
Center Horizontally Always align the view relative to the horizontal center of another view
Center Vertically Always align the view relative the the vertical center of another view
For example in your second image, say the yellow bar is a UIView called titleView.
Set the position of titleView by setting the top layout constraint to the container view. y position is set.
Set the leading constraint to the container view. x position is set.
Set the trailing constraint to the container view. The view's width will now stretch with the screen size. Thus width can now be determined.
Set height to 50. Height is set.
Now... If you also set the width of this view, it will cause the layoutConstraints to break, because you have redefined the width constraint. Some of the constraints will then be ignored.
Another example of how layoutConstraints might influence each other. Lets look at determining the y positions of the second image.
Say titleView has a top constraint to the container + height of 50.
currentCampaignView has a top constraint to the bottom of titleView. (Use vertical spacing) + equal height to titleView. (y + height can be calculated)
the 5 buttons have equal heights. Top buttons have Top space to Bottom of currentCampaignView. Centre buttons have Top space to bottom of top buttons. Bottom button have Top space to bottom of centre buttons.
startCampaignView has equal height to currentCampaignView. Top constraint to bottom of bottom button and Bottom constraint to container view.
Note that because views and buttons have equal heights, all are considered when determining the height. Thus it is very important that they are all interlinked and that the entire height that can be used is specified. In this case it is specified by the first element titleView that has a Top Constraint to the Container view (of which the height should be known) and the last element, startCampaignView, that has a Bottom constraint to the Container view. Because all the views in between are linked on y position and height, the view can work out what each view's height and y position should be.
One more example. (Your first image)
topLeftButton Set the top constraint to Superview. (y), Set the leading constraint to Superview (x), Set height = 100 (height), Set equal width to topRightButton (Note that we do not quite have the width yet, because the width of topRightButton can not be determined)
topRightButton Set the top constraint to Superview. (y), leading constraint to topLeftButton (will be used for x), Set trailing constraint to superview. Now the width of both buttons can be determined, because we have an external startX + endX and we know the two buttons touches each other and are equal widths. Thus the available space will be split to get the width of the two buttons.

Q: Auto Layout 4 squares Issue/General Auto Layout Issue

So I'm just trying to wrap my head around Auto Layout; I understand how to use constraints, just not how to apply them appropriately. In the picture below I had set no constraints and simply want this simple design to resize correctly on all size classes (Horizontally and Vertically).
http://tinypic.com/r/2ymxbop/9
What constraints would I need to put in to have these squares resize appropriately on all screens (horizontal/vertical) and can you do this in the ( W:Any H:Any ) size class or do you have to set constraints for each individual size class?
Thanks!
One size class is all you need in this case.
Set a constraint for each of the 4 gaps between the rects (i.e. the space between the top 2, between the top-left and bottom-left, ...).
Set a constraint for each rect to its 2 closest outer edges.
Now you've set four constraints for each rect - and that's all you need!
For that case: follow the steps
1.Add four uiview to screen, two top and two bottom.
2.In your case the view not touching to bottom layout guide,so you have to give fixed height.
Start the add constraints to views.
All views are correct width and height.
3.So take first view from left top,give leading space ,top space and adjecent spacing to right top view. And select the pin button from the canvas below right side option availabe, select height ,give how much height you need.
4.Now select right top view ,give constraint to top layout guide and trailing space.and also same height what you selected before for view one.
5.Now view three ,left bottom view , give leading ,spacing to top view and right spacing to fourth view and select same height .
6.Now fourth view, give spacing to top view ,trailing to container and select height.
Almost completed.
7.Select all views at once ,give equal withs(option available in pin).
lastly some warning will shows ,do update frames.

iOS Auto layout in percentage

I wanna create a simple iOS application using autolayout that displays three UIViews. One on the top, one on the left and
the other on the right. The top view should be 50 pixels high and fills the horizontal space completely. The left column should fill 40% of the horizontal space and should fill 100% of the
vertical space. The right column should be 60% of the horizontal space and 100% of the vertical space. Finally in the left UIView wanna add a single button.
Yes, You can.
Add first view at the top, add four constraint, top 0 left 0 right 0 and height 50.
Add second view at bottom of first view, make it top 0 left 0 heigth 100.
Here is the trick, choose first and secound view, then make them equal width.
Choose secound view's width constraint, and change the multiplier to 0.4.
The two existing answers didn't work for me. My answer was built using Xcode version 10.1 (10B61).
The core question is "How Can I Set a View’s Width to be a Percentage in a Storyboard". Answer: the view's width needs to be associated with the superview.
Explanation:
In the Main.storyboard (already containing a View Controller and a View), add a View. I’m going to call it YellowView). And change its containing view name to SuperView.
In the YellowView's Attributes Inspector change the Background to Yellow.
Click on New Constraints and Top = 0, Leading (left) = 0, height = 50
Control Drag from the YellowView to the Superview and let go, in the resulting dialog select "Equal Widths"
Note: YellowView's width becomes the width of the SuperView.
In the Storyboard, Double-click the width constraint we just added and change the Multiplier to 0.25 (Note: Typing .25 will not work - the leading zero is necessary)
Your constraints should be like,
first view - top,leading(left),trailing(right) and fix height
left view - top, left(leading), bottom and equal width with superview with multiplier 0.4 (or width constraint with 0.4 multiplier)
right view - top,right(trailing),bottom and equal width with superview with multiplier 0.6 (or width constraint with 0.6 multiplier)
hope this will help :)

Dividing screen in to 1/3 and 2/3 views using autolayout

Is there a way to divide the screen by percentage (not equal percentage)
I need to split the screen to two parts 1/3 and 2/3.
I know how to split to equal parts but cant figure out how to split to non equal.
Thanks
Make an "Equal widths" constraints between your view and the super view with multiplier 2:3 for one view and 1:3 for the other. See picture. "Equal height" if you want to split in the other direction.
Steps :
Drag a Two UIView objects on viewcontroller.
Pin left-view to left, top and bottom of superview
And Right-view to right, top and bottom of superview.
Pin the horizontal spacing between two views(left and right). Make sure constant is zero since/if you want no spacing.
Select left-view and superview and set width equally (hold your patience). Now go to size inspector and edit width equally constraint having left view selected. Now set the multiplier to 0.33 (now % width is set).
See the result :
Using storyboard & autolayout it's very easy: I suppose you need to split the screen vertically (but horizontally it's the same trick).
So using a single view controller, drag&drop two views and set them attached to top and bottom. For the the view 1:
view 2:
Now you need to set the constraint equal height for the view 1 among the main view and the same for the view 2. After that you can edit these constraints settings a value (between 0 and 1) as multiplier. Double click on the constraint:
and set the value that you want for proportion (the trick it's maintain the sum of these constraints as 1 or just put in "2:3" here and "1:3" in the other view):
So this is the result:
I hope this is what you need, tell me if you need more details!
You can use the Equal Widths constraint as in the accepted answer, however, if what you're trying to constrain is not two sizes but rather one point to another, such as constraining one view's horizontal center to the 1/3 or 2/3's point on the screen, then it won't work because you can't constrain a point in space to a size.
But if you know say, view1, in your xib is going to be the full width of the screen, then, for example with the horizontal center point, you can constrain it to that view's trailing edge, and if you want the view to be centered at 1/3 or 2/3's the screen's width then set the multiplier to 1:3 or 2:3, respectively.

Resources