实现思路
目前ios原生接入web页有两种方式:UIWebView和WKWebView。所以本文两种方式都会介绍方式，思路大同小异，实现方式略微有点区别。周知h5与oc可以双向沟通，所以我们可以注入js脚本，获取js事件回调即可得到需要的信息。
获取图片的js脚本
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;\
};";
设置点击图片事件的js脚本
static NSString * const jsClickImage =
@"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}\
}\
}";
UIWebView
#import "ViewController.h"
//获取web页所有图片的js
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;\
};";
//设置web页点击图片的js
static NSString * const jsClickImage =
@"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}\
}\
}";
@interface ViewController ()<UIWebViewDelegate>
@property (strong, nonatomic) NSMutableArray *mUrlArray;//图片URL数组
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
[self loadWebView];
}
//加载WebView
- (void)loadWebView
{
NSString *htmURL = @"http://finance.ifeng.com/a/20170703/15505126_0.shtml";//注意到plist中允许加载http请求
UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
webView.delegate = self;
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:htmURL]]];
[self.view addSubview:webView];
}
//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* clickedImgURL = [request.URL.absoluteString substringFromIndex:[@"image-preview:" length]];
clickedImgURL = [clickedImgURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//path 就是被点击图片的url
NSInteger count = 0;//计数变量
for (NSString *imgURL in _mUrlArray) {
//比对数组中的图片URL与选定图片的URL
if ([imgURL isEqualToString:clickedImgURL]) {
//第三方图片浏览器
// NSString *userid =@"";//用户id
// [self showPhotoBrower:_mUrlArray andIndex:count dataArray:@[] isSelf:NO authId:userid];
return NO;
}
count ++;
}
return NO;
}
return YES;
}
//webView结束加载
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
[self getImagesFromJSAndClickImgEvent:webView];
}
//收集JS页面传来的图片及添加图片点击事件
- (void)getImagesFromJSAndClickImgEvent:(UIWebView *)webView
{
//注入获取图片的js方法
[webView stringByEvaluatingJavaScriptFromString:jsGetImages];
//urlResurlt - 调用js并获取到H5页面上所有图片的url的拼接
NSString *urlResurlt = [webView stringByEvaluatingJavaScriptFromString:@"getImages()"];
//mUrlArray就是所有图片URL的数组
_mUrlArray = [NSMutableArray arrayWithArray:[urlResurlt componentsSeparatedByString:@"+"]];
//注入图片可点击JS
[webView stringByEvaluatingJavaScriptFromString:jsClickImage];
[webView stringByEvaluatingJavaScriptFromString:@"registerImageClickAction();"];
}
@end
WKWebView
// 页面加载完成之后调用 此方法会调用多次
#pragma mark - 收集JS页面传来的图片及添加图片点击事件
- (void)getImagesFromJSAndClickImgEvent:(WKWebView *)webView
{
[webView evaluateJavaScript:jsGetImages completionHandler:nil];
@weakify(self);
[webView evaluateJavaScript:@"getImages()" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
@strongify(self);
self.mUrlArray = [NSMutableArray arrayWithArray:[result componentsSeparatedByString:@"+"]];
NSLog(@"获取图片数组成功");
}];//注入JS方法
//添加图片可点击JS
[webView evaluateJavaScript:jsClickImage completionHandler:nil];
[webView evaluateJavaScript:@"registerImageClickAction()" completionHandler:nil];
}
- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation
{
//加载完成注入js
[self getImagesFromJSAndClickImgEvent:webView];
}
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
{
//捕获图片链接
NSURL *URL = navigationAction.request.URL;
NSString *str = [NSString stringWithFormat:@"%@",URL];
if ([str containsString:@"image-preview:"]) {
NSString *clickedImgStr = [URL.absoluteString substringFromIndex:[@"image-preview:" length]];
//第三方图片浏览器
// NSString *userid =@"";//用户id
// [self showPhotoBrower:_mUrlArray andIndex:count dataArray:@[] isSelf:NO authId:userid];
decisionHandler(WKNavigationActionPolicyCancel); // 必须实现 不加载
}else {
decisionHandler(WKNavigationActionPolicyAllow); // 必须实现 加载
}
}
