iOS：限制在自定义表格视图单元格中

Question

I have a tableview with a custom cell, where inside it I have a textview. For this cell I determinate its hight with the size of text and it's ok.

I work in autolayout, so for my cell I use two constraints to expand the textview for all space cell in this way

I can say that it work fine and my textview expand itself for all cell space.

In the view controller I have a control to check when the text (the string) is empty. When it is empty I return 0 for the cell hight.

But in this case when I return 0 and text_view is empty I have a crash but I don't know how to solve.

this is the message

Unable to simultaneously satisfy constraints.

Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSLayoutConstraint:0x1704864a0 V:|-(25)-[UITextView:0x15454d960]   (Names: '|':UITableViewCellContentView:0x178179680 )>",
    "<NSLayoutConstraint:0x1704864f0 V:[UITextView:0x15454d960]-(23)-|   (Names: '|':UITableViewCellContentView:0x178179680 )>",
    "<NSAutoresizingMaskLayoutConstraint:0x17889a220 h=--& v=--& V:[UITableViewCellContentView:0x178179680(0)]>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x1704864f0 V:[UITextView:0x15454d960]-(23)-|   (Names: '|':UITableViewCellContentView:0x178179680 )>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

Answer 1

将单元格contentView的TranslatesAutoresizingMaskIntoConstraints设置为NO ，

[self.contentView setTranslatesAutoresizingMaskIntoConstraints:NO];