iOS：自定义表格视图单元中的约束

我有一个带有自定义单元格的tableview，在其中有一个textview。对于此单元格，我用文本大小确定其高度，这没关系。

我在自动布局中工作，因此对于我的单元格，我使用两个约束以这种方式扩展所有空间单元格的textview

我可以说它可以正常工作，并且我的textview可以针对所有单元格空间进行扩展。

在视图控制器中，我有一个控件来检查文本（字符串）何时为空。当它为空时，我为单元格hight返回0。

但是在这种情况下，当我返回0且text_view为空时，我崩溃了，但是我不知道如何解决。

这是消息

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.