如何使用AutoLayouts以编程方式调整UITextView的大小？

Question

我使用自动布局以编程方式添加了UITextView。我想根据文字大小调整UITextView的大小。我尝试了一些代码，但它没有工作，如果有人帮忙我会很感激。

我的代码如下： -

背景类： -

#import "AutoGrowingTextView.h"

@implementation AutoGrowingTextView

- (void) layoutSubviews
{
    [super layoutSubviews];

    if (!CGSizeEqualToSize(self.bounds.size, [self intrinsicContentSize])) {
        [self invalidateIntrinsicContentSize];
    }
}

- (CGSize)intrinsicContentSize
{
    CGSize intrinsicContentSize = self.contentSize;

    // iOS 7.0+
    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0f) {
        intrinsicContentSize.width += (self.textContainerInset.left + self.textContainerInset.right ) / 2.0f;
        intrinsicContentSize.height += (self.textContainerInset.top + self.textContainerInset.bottom) / 2.0f;
    }

    return intrinsicContentSize;
}

@end

我的主要班级

#import "ViewController.h"
#import "AutoGrowingTextView.h"

@interface ViewController ()

{
    AutoGrowingTextView * TextView;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    TextView = [AutoTextView new];
    TextView.translatesAutoresizingMaskIntoConstraints = NO;
    TextView.backgroundColor = [UIColor colorWithRed:0.95 green:0.47 blue:0.48 alpha:1.0];
    TextView.scrollEnabled = NO;

    [TextView layoutSubviews];

    [self.view addSubview:TextView];

    NSLayoutConstraint * constraint2 = [NSLayoutConstraint constraintWithItem:TextView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem: self.view attribute:NSLayoutAttributeTop multiplier:1.0f constant:20.0f];
    [self.view addConstraint:constraint2];

     constraint2 = [NSLayoutConstraint constraintWithItem:TextView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.0f constant:5.0f];
    [self.view addConstraint:constraint2];

    constraint2 = [NSLayoutConstraint constraintWithItem:TextView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1.0f constant:-5.0f];
    [self.view addConstraint:constraint2];

    constraint2 = [NSLayoutConstraint constraintWithItem:TextView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:50.0f];
    [self.view addConstraint:constraint2];

}

@end

Answer 1

这听起来有点疯狂，但我相当确定如果你删除了高度约束，那么布局引擎会调整UITextView的大小以适应字体大小。我上周遇到了同样的问题，这就解决了这个问题。

删除此约束，看看它是否有效：

constraint2 = [NSLayoutConstraint constraintWithItem:TextView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:50.0f];

让我补充一点，你应该为textView定义一个字体，这可能是你在调整大小时获胜的门票