WKWebview & UIImageView 在 UIScrollView 内以编程方式自动布局 Objective-C
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【中文标题】WKWebview & UIImageView 在 UIScrollView 内以编程方式自动布局 Objective-C【英文标题】：WKWebview & UIImageView Inside UIScrollView programmatically autolayout Objective-C 【发布时间】：2018-01-17 08:40:32 【问题描述】：我想以编程方式在 UIScrollView 中实现 WKWebView 和 UIImageView，但它不能满足我的要求。我首先将 UIImageView 和 WKWebView 添加到 scrollView，然后将 scrollView 添加到 ViewController 子视图。我为它编写了如下的Objective-C代码。
#import "StoryDetailViewController.h"
#import <WebKit/WebKit.h>
@interface StoryDetailViewController ()
//@property(strong,nonatomic) WKWebView *webView;
@end
@implementation StoryDetailViewController
UIScrollView* scrollView;
WKWebView* webView;
UILabel* title;
UIImageView* imageView;
- (void)viewDidLoad
[super viewDidLoad];
[self setUpSubview];
// Do any additional setup after loading the view.
-(void)setUpSubview
scrollView = [[UIScrollView alloc]init];
scrollView.backgroundColor=[UIColor redColor];
scrollView.translatesAutoresizingMaskIntoConstraints=NO;
imageView=[[UIImageView alloc]init];
imageView.backgroundColor=[UIColor yellowColor];
imageView.translatesAutoresizingMaskIntoConstraints=NO;
webView = [[WKWebView alloc]init];
webView.backgroundColor=[UIColor purpleColor];
webView.translatesAutoresizingMaskIntoConstraints=NO;
[scrollView addSubview:imageView];
[scrollView addSubview:webView];
[self.view addSubview:scrollView];
[self addConstraints];
-(void)addConstraints
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeHeight
multiplier:0.35
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:webView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:webView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:0.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:webView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:imageView
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:10.0]];
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:webView
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:0.0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrollView
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1.0
constant:0.0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrollView
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:0.0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrollView
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeBottom
multiplier:1.0
constant:0.0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrollView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:0.0]];
@end
**我正在使用 WKwebview，因为 UIWebView 在 Xcode 9 中已弃用，而情节提要中的 WKwebview 仅支持 ios 11 ** 所以如果代码错误，请帮忙。
【问题讨论】：
【参考方案1】：首先你要把这段代码放在 viewDidLayoutSubviews
-(void)viewDidLayoutSubviews
[self setUpSubview];
其次，您应该在滚动视图中创建一个内容视图并向其中添加元素，但作为一种解决方法，添加这两个约束
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeRight
multiplier:1.0
constant:0.0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0]];
并删除它，因为滚动视图期望它的大小来自子元素，反之亦然
[scrollView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:scrollView
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0]];
第三个给imageView的高度不等于滚动视图删除它并给一个静态高度或与self.view成比例的高度
[imageView addConstraint:[NSLayoutConstraint constraintWithItem:imageView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNone
multiplier:1.0
constant:200.0]];
最后用 webview 做 setp 2,3
【讨论】：
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