iOS 关于webView的一些小技巧记录

1.webView图片自适应
-(void)webViewDidFinishLoad:(UIWebView *)webView
{
NSString *script = [NSString stringWithFormat:
@"var script = document.createElement('script');"
"script.type = 'text/javascript';"
"script.text = "function ResizeImages() { "
"var img;"
"var maxwidth=%f;"
"for(i=0;i <document.images.length;i++){"
"img = document.images[i];"
"if(img.width > maxwidth){"
"img.width = maxwidth;"
"}"
"}"
"}";"
"document.getElementsByTagName('head')[0].appendChild(script);", SCREEN_WIDTH - 20];
[webView stringByEvaluatingJavaScriptFromString: script];
[webView stringByEvaluatingJavaScriptFromString:@"ResizeImages();"];
}

2.webView根据内容自适应高度
-(void)webViewDidFinishLoad:(UIWebView *)webView{
//获取到webview的高度
CGFloat height = [[self.webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];
self.webView.frame = CGRectMake(self.webView.frame.origin.x,self.webView.frame.origin.y, kScreenWidth-20, height+40);
}

3.webView网络图片添加点击事件
-(void)webViewDidFinishLoad:(UIWebView *)webView
{
//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()"];

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

[_webView stringByEvaluatingJavaScriptFromString:@"registerImageClickAction();"];
[[NSUserDefaults standardUserDefaults] setInteger:0 forKey:@"WebKitCacheModelPreferenceKey"];
[[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"WebKitDiskImageCacheEnabled"];
[[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"WebKitOfflineWebApplicationCacheEnabled"];
[[NSUserDefaults standardUserDefaults] synchronize];

//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];
  if (_webImgArr.count != 0) {

      // 这里添加需要操作的事件  
    }
  
    return NO;
  

  }
  return YES;
  }