在你的 ViewController.m 文件中设置 WKWebView：
#import <WebKit/WebKit.h>
@interface ViewController () <WKScriptMessageHandler>
@property (nonatomic, strong) WKWebView *webView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
WKUserContentController *userContentController = [[WKUserContentController alloc] init];
[userContentController addScriptMessageHandler:self name:@"imageHandler"];
WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];
configuration.userContentController = userContentController;
self.webView = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:configuration];
[self.view addSubview:self.webView];
NSURL *url = [NSURL URLWithString:@"https://example.com"];
[self.webView loadRequest:[NSURLRequest requestWithURL:url]];
}
// 处理从JavaScript发送的消息
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
if ([message.name isEqualToString:@"imageHandler"]) {
if ([message.body isKindOfClass:[NSString class]]) {
NSString *base64String = (NSString *)message.body;
NSData *imageData = [[NSData alloc] initWithBase64EncodedString:base64String options:NSDataBase64DecodingIgnoreUnknownCharacters];
UIImage *image = [UIImage imageWithData:imageData];
// 在这里可以处理或显示提取到的图片了
}
}
}
@end
在你的网页中，插入 JavaScript 代码，提取图片并将其转换为 Base64 编码，然后通过 JavaScript 接口发送消息给 WKWebView：
<html>
<body>
<script>
// 提取图片并将其转换为 Base64 编码
function extractImage() {
var imgElement = document.getElementsByTagName('img')[0];
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');
context.drawImage(imgElement, 0, 0);
var base64String = canvas.toDataURL();
// 发送消息给原生代码
window.webkit.messageHandlers.imageHandler.postMessage(base64String);
}
// 在适当的时候调用提取图片的方法
extractImage();
</script>
<img src="example.jpg" alt="Example Image">
</body>
</html>
