iOS - Add view without knowing its size - ios

Question

I am trying, programmatically, to add subviews to my view. The process goes as follows:
1) Fetch an array of medias from the web
2) If it is a picture, build a UIImageView and add it to the bottom of the view. If it is text, build a UITextView and add it to the bottom of the view
3) Repeat step 2 until the end of the array
The problems:
How do I create the views if I don't know what will be the height of them? It seems that to add a view I need to specify its frame.
How do I add each view to the bottom of the already existing views?
Thanks in advance,
Tiago

Answer 1

If you don't know the size of the view, call the sizeToFit and layoutIfNeeded method after adding the view. Here's the code:
Objective-C :
[superView addSubview: view];
[view sizeToFit];
[view layoutIfNeeded];
Swift :
superView.addSubview(view)
view.sizeToFit()
view.layoutIfNeeded()

Answer 2

You can always create the view with a zero-sized frame (CGRectZero) and set its frame later once you know it.

Answer 3

I think you can use a UITableView to implement this feature. The tableView is normally used for displaying 'N' number of items. You can create two custom cells,
1 for displaying an Image
2nd for displaying a textview.
And then based on the item type of the Array you can reuse these custom cells.

Answer 4

I'm assuming you are looking to initialize and then add the view as a subview. If so, you can do the following:
UIView *yourView = [[UIView alloc] initWithFrame: CGRectZero];
//Note - CGRectZero is equivalent to CGRectMake(0,0,0,0)
[superView addSubview: yourView];
Now when you are ready to resize the view, you can do so as follows:
[yourView setFrame: CGRectMake(newXOrigin, newYOrigin, newWidth, newHeight)];
or alternatively
[yourView sizeToFit];

Answer 5

So I've figured an answer to both my questions:
How do I create the views if I don't know what will be the height of them?
After getting the content from web, call .layoutIfNeeded() to lay out the view. You are now able to use the contentSize of the view to draw it. See example below.
How do I add each view to the bottom of the already existing views?
2 ways:
1) Use a UITableView, easier and more reliable
2) Have a variable to hold the bottom of the stack of views, and update it every time you add a new view. Use this variable to decide where to add a new view.
Here's the code with 2):
var yAxis: CGFloat = 0
var textContent: String = "" {
didSet{
var textView = UITextView()
textView.text = textContent
textView.layoutIfNeeded()
textView.frame.size = CGSizeMake(UIScreen.mainScreen().bounds.width, textView.contentSize.height)
textView.frame.origin.y = yAxis
yAxis += textView.contentSize.height
view.addSubview(textView)
}
}
Thanks to #Dhruv Ramani for the hint.