Ios 以编程方式向UITextField添加约束

我正在学习不使用故事板的自动布局。我已经给出了四个约束条件：尾随、前导、顶部和底部

代码：

UITextField *searchBarTF=[[UITextField alloc]init];  
[searchBarTF setText:@"is it coming?"];
[views addSubview:searchBarTF];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeLeading multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeTrailing   relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeTrailing multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeTop    relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeTop multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeBottom multiplier:1.0 constant:230]];

Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want.

文本字段未出现在屏幕上

错误：

UITextField *searchBarTF=[[UITextField alloc]init];  
[searchBarTF setText:@"is it coming?"];
[views addSubview:searchBarTF];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeLeading multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeTrailing   relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeTrailing multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeTop    relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeTop multiplier:1.0 constant:30]];

[views addConstraint:[NSLayoutConstraint constraintWithItem:searchBarTF attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:views attribute:NSLayoutAttributeBottom multiplier:1.0 constant:230]];

Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want.

---

您只是忘记了这段代码：

[searchBarTF setTranslatesAutoresizingMaskIntoConstraints:NO];

默认情况下，这是

True

。因此，您的约束与自动调整大小约束冲突

---

上面的行将禁用文本字段的自动调整大小，并应用定义的约束

您只是忘记了这段代码：

[searchBarTF setTranslatesAutoresizingMaskIntoConstraints:NO];

默认情况下，这是

True

。因此，您的约束与自动调整大小约束冲突

---

上面的行将禁用文本字段的自动调整大小，并应用定义的约束

您只是忘记了这段代码：

[searchBarTF setTranslatesAutoresizingMaskIntoConstraints:NO];

默认情况下，这是

True

。因此，您的约束与自动调整大小约束冲突

---

上面的行将禁用文本字段的自动调整大小，并应用定义的约束

您只是忘记了这段代码：

[searchBarTF setTranslatesAutoresizingMaskIntoConstraints:NO];

默认情况下，这是

True

。因此，您的约束与自动调整大小约束冲突

---

上面的行将禁用文本字段的自动调整大小，并应用定义的约束

你能分享一下你出错的名单吗。同时，只需设置TranslateAutoreSizingMaskinToConstraints:NO for Search Bartf，您是否可以分享错误列表。同时，只需设置TranslateAutoreSizingMaskinToConstraints:NO for Search Bartf，您是否可以分享错误列表。同时，只需设置TranslateAutoreSizingMaskinToConstraints:NO for Search Bartf，您是否可以分享错误列表。同时，只需设置TranslateAutoreSizingMaskinToConstraints:NO for searchBarTF