如何在iOS中水平居中查看UITextView内容,但不使用对齐中心?
我想实现一些非常具体的目标。很难用语言来描述,所以这里有一些模型 当前阶段:我有一个UITextView,它的自动布局约束设置为与父容器一样宽。 我想要实现的是:我希望将UITextView中的内容水平居中,以便它们显示在中间,但仍保持左对齐 大多数解决方案依靠TextAlignCenter选项将文本水平居中,但这不是我想要的,因为它将显示为: 有什么办法可以做到这一点 我尝试了以下方法:如何在iOS中水平居中查看UITextView内容,但不使用对齐中心?,ios,objective-c,xcode,ipad,uitextview,Ios,Objective C,Xcode,Ipad,Uitextview,我想实现一些非常具体的目标。很难用语言来描述,所以这里有一些模型 当前阶段:我有一个UITextView,它的自动布局约束设置为与父容器一样宽。 我想要实现的是:我希望将UITextView中的内容水平居中,以便它们显示在中间,但仍保持左对齐 大多数解决方案依靠TextAlignCenter选项将文本水平居中,但这不是我想要的,因为它将显示为: 有什么办法可以做到这一点 我尝试了以下方法: textview.sizeToFit()似乎可以调整高度,但不能调整宽度 textview.cont
我之所以想这样做,是因为虽然在iPhone上看不到,但在iPad上,如果文本很短,它们会一直显示在左侧,这与我的应用程序中的其他可交互按钮相去甚远。看起来你可能正在使用Swift,但这很好,这是Objective-C的代码,请转换它
UITextView * _descriptionText = [UITextView new];
[_descriptionText setDelegate:self];
[_descriptionText setBackgroundColor:[UIColor whiteColor];
[_descriptionText setTranslatesAutoresizingMaskIntoConstraints:false];
[_descriptionText setTextColor:[UIColor lightGrayColor]];
[_descriptionText setTextAlignment:NSTextAlignmentLeft];
然后,将此textview添加到UIView
[sss addSubview:_descriptionText];
以下是UIView的代码:
UIView * sss = [UIView new];
[sss setTranslatesAutoresizingMaskIntoConstraints:FALSE];
[self addSubview:sss];
向UIView添加约束以使UITextView居中,并在左右两侧将其边界约束一定的宽度:
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeHeight multiplier:1.0f constant:SOME_HEIGHT_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeHeight multiplier:1.0f constant:SOME_RIGHT_MARGIN_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeLeft multiplier:1.0f constant:SOME_LEFT_MARGIN_NUMBER_YOU_CHOOSE]];
或者选择UITextView的宽度,如下所示,带有CenterX约束:
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:SOME_WIDTH_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterX multiplier:1.0f constant:0]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterY multiplier:1.0f constant:0]];
最后,添加中心约束:
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:SOME_WIDTH_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterX multiplier:1.0f constant:0]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:descriptionText attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterY multiplier:1.0f constant:0]];
最后,将UIView“sss”约束到它的超级视图“self”或它的超级视图是什么:
NSDictionary * views = NSDictionaryOfVariableBindings(sss);
NSDictionary * metrics = @{@"bh" : @30, @"bsh" : @40, ... etc, etc,};
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[sss]|" options:0 metrics:metrics views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-bh-[sss]" options:0 metrics:metrics views:views]];
然后,利润
带有子类UIView的格式化代码
ExampleView.m
@implementation ExampleView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
UIView * sss = [UIView new];
[sss setTranslatesAutoresizingMaskIntoConstraints:false];
[self addSubview:sss];
UITextView * _descriptionText = [UITextView new];
[_descriptionText setBackgroundColor:[UIColor whiteColor]];
[_descriptionText setTranslatesAutoresizingMaskIntoConstraints:false];
[_descriptionText setTextColor:[UIColor lightGrayColor]];
[_descriptionText setTextAlignment:NSTextAlignmentLeft];
[sss addSubview:_descriptionText];
//do these three constraints
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeHeight multiplier:1.0f constant:SOME_HEIGHT_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeRight multiplier:1.0f constant:SOME_RIGHT_MARGIN_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeLeft multiplier:1.0f constant:SOME_LEFT_MARGIN_NUMBER_YOU_CHOOSE]];
//or do these three constraints, but don't do all 6 constraints between these three and the three above
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:SOME_WIDTH_NUMBER_YOU_CHOOSE]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterX multiplier:1.0f constant:0]];
[sss addConstraint:[NSLayoutConstraint constraintWithItem:_descriptionText attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:sss attribute:NSLayoutAttributeCenterY multiplier:1.0f constant:0]];
NSDictionary * views = NSDictionaryOfVariableBindings(sss);
NSDictionary * metrics = @{@"bh" : @30, @"bsh" : @40};
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[sss]|" options:0 metrics:metrics views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-bh-[sss]" options:0 metrics:metrics views:views]];
// this: V:|-bh-[sss] SHOULD WORK, BUT IT MIGHT REQUIRE YOU TO DO THIS: V:|-bh-[sss(HEIGHT_OF_THE_TEXT_VIEW_THAT_YOU_CHOOSE)]
}
return self;
}
@end
示例视图.h
#import <UIKit/UIKit.h>
@interface NSHMessagesView : UIView
@end
#导入
@界面消息视图:UIView
@结束
我认为您可以将UITextView子类化或设置contentInset。因为它是scrollView的子类,所以我想set-contentInset可以实现这个目标。谢谢,但是UITextView似乎需要在运行前知道它的宽度?对于我使用的示例,我在运行前不知道最长行的宽度,因为它取决于用户输入。是的,您应该将其设置为某个值,这是肯定的,但是你可以在我写这类东西的约束中设置它:一些左边距,数字,你只需改变你看到的一切,然后选择前三个约束或那些约束下面的三个,wincontentInset使它可以水平滚动,这是我想要避免的。