Unable to programmatically resize UITextView frame

Question

I inserted a UITextView into the view using Interface Builder, now I would like to change its frame size to fit the content programmatically. The problem is that the size seems to be locked and unchanged from the code due to limitations. If I disable the use of automatic layout in the file inspector, each object removes the restrictions, but I only want to change the UITextView, but not the other objects.

[textview setFrame:CGRectMake(x,y,w,h)]; // This doesn't do anything to the uitextview 

Answer 1

If you use restrictions, then you should use restrictions to resize the UITextView. Configure the outputs at the tip to access the restrictions you need to change from your code. You can set a constant constraint in real time, and this is usually enough.

Just to find out the reasons for this: you cannot change the view frame if it is placed by restrictions. Well, you can, but it's futile, and it's bad practice. This is because the limitations themselves will be used by the layout system to change the viewing frame for you! Thus, you can change the frame, but the layout system will read and allow restrictions and change the frame back.

Think of restrictions as a “to-do list” for a layout system. Constraints do nothing on their own; this is just a list of rules. It is the layout system that does the work (when layoutSubviews is layoutSubviews ). Each time a layout is needed, the layout system comes in, reads the constraints, works on how to obey them, and does this - by setting the frames of your views. You need to work with this system, not against it.

Answer 2

All UIViews and classes inherit from UIView, have the same property: "Lock" in the XIB file. If you want to change the frame of these views. You must set the Nothing Lock

Answer 3

If you do not want to become an expert on restriction, do it like this (in your controller).

@property UITextView * textView;

// Create a UITextView on the fly in viewWillAppear

 rect = CGRectMake(194., 180., 464., 524.); _textView = [[UITextView alloc] initWithFrame:rect]; [self.view addSubview:_textView]; 

// Now you can resize as you wish

  CGRect oldFrame = _textView.frame; CGRect newFrame = oldFrame; newFrame.size.height += 300; [_textView setFrame:newFrame];