iOS【webView 加载微信文章注入JS实现交互 浏览图片及保存】

最近项目某个模块中要求可以实现对网页中图片的查看，并要求在多张图片的情况下可以实现滑动浏览。

所以，问题的集中点就是如何获取所有的图片地址及添加图片的点击事件。不多说，直接上码！

在网页加载完成时，通过js获取图片和添加点击的识别方式

- (void)webViewDidFinishLoad:(UIWebView *)webView {
[IDProgressHUD IDPlaceViewHideDirect:self.view];

//这里是js，主要目的实现对url的获取
static  NSString * const jsGetImages =
@"function getImages(){\
var objs = document.getElementsByTagName(\"img\");\
var imgScr = '';\
for(var i=0;i<objs.length;i++){\
imgScr = imgScr + objs[i].src + '+';\
};\
return imgScr;\
};";

[webView stringByEvaluatingJavaScriptFromString:jsGetImages];//注入js方法
NSString *urlResurlt = [webView stringByEvaluatingJavaScriptFromString:@"getImages()"];
mUrlArray = [NSMutableArray arrayWithArray:[urlResurlt componentsSeparatedByString:@"+"]];
if (mUrlArray.count >= 2) {
[mUrlArray removeLastObject];
}
//urlResurlt 就是获取到得所有图片的url的拼接；mUrlArray就是所有Url的数组

//添加图片可点击js
[mWebView stringByEvaluatingJavaScriptFromString:@"function registerImageClickAction(){\
var imgs=document.getElementsByTagName('img');\
var length=imgs.length;\
for(var i=0;i<length;i++){\
img=imgs[i];\
img.onclick=function(){\
window.location.href='image-preview:'+this.src}\
}\
}"];
[mWebView stringByEvaluatingJavaScriptFromString:@"registerImageClickAction();"];
}

//在这个方法中捕获到图片的点击事件和被点击图片的url

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {

//预览图片
if ([request.URL.scheme isEqualToString:@"image-preview"]) {
NSString* path = [request.URL.absoluteString substringFromIndex:[@"image-preview:" length]];
path = [path stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
//path 就是被点击图片的url
return NO;
}
return YES;
}

以下是保存所在作用域的图片

//添加长按事件
UILongPressGestureRecognizer *longPressed = [[UILongPressGestureRecognizer alloc]
initWithTarget:self action:@selector(longPressed:)];
longPressed.minimumPressDuration = 0.3;
longPressed.delegate = self;
[webView addGestureRecognizer:longPressed];

/**
获取长按事件所在的位置图片
*/
- (void)longPressed:(UILongPressGestureRecognizer*)recognizer
{
if (recognizer.state != UIGestureRecognizerStateBegan) {
return;
}
CGPoint touchPoint = [recognizer locationInView:_webView];
NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src",
touchPoint.x, touchPoint.y];
NSString *webImage = [_webView stringByEvaluatingJavaScriptFromString:imgURL];

if([webImage rangeOfString:@"player"].location !=NSNotFound || webImage.length == 0){
return;
}
[self showImageOptionsWithUrl:webImage];
}

- (void)showImageOptionsWithUrl:(NSString *)imageUrl
{
_webImageURL = imageUrl;
IBActionSheet *standardIBAS = [[IBActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"保存图片" otherButtonTitles:nil];
[standardIBAS setFont:FontWithSize(SIZE_FONT_CONTENT)];
[standardIBAS setTitleFont:FontWithSize(SIZE_FONT_SUBCONTENT)];
[standardIBAS setButtonTextColor:[UIColor blackColor]];
[standardIBAS showInView:self.navigationController.view];
}

#pragma mark - IBActionSheetDelegate

-(void)actionSheet:(IBActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{

if (buttonIndex == 0) {

NSURL *url = [NSURL URLWithString:_webImageURL];
NSURLSessionConfiguration * configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:[NSOperationQueue new]];
NSURLRequest *imgRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:30.0];

NSURLSessionDownloadTask  *task = [session downloadTaskWithRequest:imgRequest completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {
if (error) {
return ;
}
NSData * imageData = [NSData dataWithContentsOfURL:location];
dispatch_async(dispatch_get_main_queue(), ^{
UIImage * image = [UIImage imageWithData:imageData];
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
});
}];
[task resume];
}
}

后记：js挺好玩，我相信以后还会去多接触它。