iOS 8：UIWebView的简单使用

1  基本用法

1、实例化：UIWebView *webView = [[UIWebView alloc] initWithFrame:self.view.window.bounds];

2、配置参数：delegate、scalesPageToFit等

3、加载请求：[webView loadRequest:NSRequest实例];

4、委托方法：

1）、完成加载

- (void)webViewDidFinishLoad:(UIWebView *)webView

2  操作JavaScript

1、获得网页地址

NSString *currentURL = [webView stringByEvaluatingJavaScriptFromString:@"document.location.href"];

2、获得网页标题

NSString *title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];

3、修改字体大小

NSString *jsString = [[NSString alloc] initWithFormat:@"document.getElementsByTagName(‘body‘)[0].style.webkitTextSizeAdjust= ‘%d%%‘",
50];
[webView stringByEvaluatingJavaScriptFromString:jsString];

4、水平垂直居中

NSString *bodyStyleVertical = @"document.getElementsByTagName(‘body‘)[0].style.verticalAlign = ‘middle‘;";
NSString *bodyStyleHorizontal = @"document.getElementsByTagName(‘body‘)[0].style.textAlign = ‘center‘;";
NSString *mapStyle = @"document.getElementById(‘mapid‘).style.margin = ‘auto‘;";

[webView stringByEvaluatingJavaScriptFromString:bodyStyleVertical];
[webView stringByEvaluatingJavaScriptFromString:bodyStyleHorizontal];
[webView stringByEvaluatingJavaScriptFromString:mapStyle];

5、修改字体颜色

[webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByTagName(‘body‘)[0].style.webkitTextFillColor= ‘red‘"];

6、修改页面背景颜色

[webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByTagName(‘body‘)[0].style.background=‘black‘"];

7、改变图片大小

 1 [webView stringByEvaluatingJavaScriptFromString:
 2 @"var script = document.createElement(‘script‘);"
 3 "script.type = ‘text/javascript‘;"
 4 "script.text = \"function ResizeImages() { "
 5 "var myimg,oldwidth;"
 6 "var maxwidth=320;" //缩放系数
 7 "for(i=0;i <document.images.length;i++){"
 8 "myimg = document.images[i];"
 9 "if(myimg.width > maxwidth){"
10 "oldwidth = myimg.width;"
11 "myimg.width = maxwidth;"
12 "myimg.height = myimg.height * (maxwidth/oldwidth);"
13 "}"
14 "}"
15 "}\";"
16 "document.getElementsByTagName(‘head‘)[0].appendChild(script);"];
17
18 [webView stringByEvaluatingJavaScriptFromString:@"ResizeImages();"];

改变图片大小

8、提交表单

1 NSString * currentURL = [webView stringByEvaluatingJavaScriptFromString:@"document.location.href"];
2 //取得标题
3 NSString * title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];
4 //设置表单
5 NSString * js_result = [webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByName(‘q‘)[0].value=‘username‘;"];
6 //提交表单
7 NSString * js_result2 = [webView stringByEvaluatingJavaScriptFromString:@"document.forms[0].submit();"];
8
9 NSLog(@"pp%@,qq%@,ww%@,ee%@",currentURL,title,js_result,js_result2);

提交表单

9、查看源代码

NSString *jsToGetHTMLSource = @"document.getElementsByTagName(‘html‘)[0].innerHTML";
NSString *HTMLSource = [webView_ stringByEvaluatingJavaScriptFromString:jsToGetHTMLSource];
NSLog(@"%@",HTMLSource);

10、长按菜单

[webView stringByEvaluatingJavaScriptFromString:@"document.documentElement.style.webkitUserSelect=‘none‘;"];

11、滚动到某个位置

[webView stringByEvaluatingJavaScriptFromString:@"window.scrollTo(0,200);"];

12、获取图片手势

UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTap:)];
doubleTap.numberOfTouchesRequired = 2;
[webView addGestureRecognizer:doubleTap];

13、获取图片地址

 1 - (void) doubleTap:(UITapGestureRecognizer*) sender {
 2     //  <Find HTML tag which was clicked by user>
 3     //  <If tag is IMG, then get image URL and start saving>
 4     UIWebView *webView = (UIWebView*)[self.window viewWithTag:1000];
 5     int scrollPositionY = [[webView stringByEvaluatingJavaScriptFromString:@"window.pageYOffset"] intValue];
 6     int scrollPositionX = [[webView stringByEvaluatingJavaScriptFromString:@"window.pageXOffset"] intValue];
 7
 8     int displayWidth = [[webView stringByEvaluatingJavaScriptFromString:@"window.outerWidth"] intValue];
 9     CGFloat scale = webView.frame.size.width / displayWidth;
10
11     CGPoint pt = [sender locationInView:webView];
12     pt.x *= scale;
13     pt.y *= scale;
14     pt.x += scrollPositionX;
15     pt.y += scrollPositionY;
16
17     NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", pt.x, pt.y];
18     NSString * tagName = [webView stringByEvaluatingJavaScriptFromString:js];
19     if ([tagName isEqualToString:@“IMG”]) {// IMG可能会换
20         NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", pt.x, pt.y];
21         NSString *urlToSave = [webView stringByEvaluatingJavaScriptFromString:imgURL];
22         NSLog(@"image url=%@", urlToSave);
23     }
24
25
26 }

获取图片地址

14、获取视频地址

1 NSString *lJs2 = @"(document.getElementsByTagName(\"video\")[0]).getElementsByTagName(\"source\")[0].src";  //qiyi
2 NSString *lJs2 = @"(document.getElementsByTagName(\"video\")[0]).src";  // youku,tudou,ku6 ,souhu
3 NSString *lm3u8 = [webView stringByEvaluatingJavaScriptFromString:lJs2];
4 NSLog(@"video source:%@",lm3u8);