我只是想在我的 imgView 上设置宽度和高度约束。我有以下代码:
UIImageView *imgView = [[UIImageView alloc] init];
imgView.center = self.view.center;
imgView.image = [UIImage imageNamed:@"favorites5-highlighted.png"];
imgView.contentMode = UIViewContentModeCenter;
[self.view addSubview:imgView];
// width constraint
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[imgView(==100)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]];
// height constraint
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[imgView(==100)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(imgView)]];
我最终收到此错误:无法同时满足约束。 我查了一下并尝试添加:
imgView.translatesAutoresizingMaskIntoConstraints = NO;
和
self.view.translatesAutoresizingMaskIntoConstraints = NO;
编辑:
我只是想将 imageView 的宽度和高度设置为所需的属性。我首先尝试使用
CGRect rect = CGRectMake(0, 0, 10, 10);
imgView.frame = rect;
但没有任何改变
最佳答案
两个问题:
你确实想要:
imgView.translatesAutoresizingMaskIntoConstraints = NO;
你不想要:
self.view.translatesAutoresizingMaskIntoConstraints = NO;
您设置
center
的尝试是徒劳的,因为当应用约束时,它将会丢失。不幸的是,您没有定义约束来定义 ImageView 的位置。您可以使用下面 block 的最后两行来执行此操作:UIImageView *imgView = [[UIImageView alloc] init]; //imgView.center = self.view.center; // this does nothing in auto layout imgView.image = [UIImage imageNamed:@"favorites5-highlighted.png"]; imgView.contentMode = UIViewContentModeCenter; imgView.translatesAutoresizingMaskIntoConstraints = NO; // add this line [self.view addSubview:imgView]; NSDictionary *views = NSDictionaryOfVariableBindings(imgView); // width constraint [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[imgView(100)]" options:0 metrics:nil views:views]]; // height constraint [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[imgView(100)]" options:0 metrics:nil views:views]]; // center align [self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.view attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:imgView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0]]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.view attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:imgView attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0]];
关于ios - 为什么我的约束不起作用? iOS系统,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27755862/