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  • 与webView进行交互,webView小记

     

    本文转载至 http://www.verydemo.com/demo_c101_i46895.html

    一、与webView进行交互，调用web页面中的需要传参的函数时，参数需要带单引号，或者双引号（双引号需要进行转义在转义字符前加）,在传递json字符串时不需要加单引号或双引号。

    1 -(void)webViewDidFinishLoad:(UIWebView *)webView
    2 {
    3     NSString *sendJsStr=[NSString stringWithFormat:@"openFile("%@")",jsDocPathStr];
    4   [webView stringByEvaluatingJavaScriptFromString:sendJsStr];
    5 }

    2、在该代理方法中判断与webView的交互，可通过html里定义的协议实现

    1 - (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType
    3、只有在webView加载完毕之后在能够调用对应页面中的js方法。（对应方法如第一条）

     4、为webView添加背景图片

    1 approvalWebView.backgroundColor=[UIColor clearColor];
    2 approvalWebView.opaque=NO;//这句话很重要，webView是否是不透明的，no为透明
    3 //在webView下添加个imageView展示图片就可以了

     5、获取webView页面内容信息

    1 NSString *docStr=[webView stringByEvaluatingJavaScriptFromString:@"document.documentElement.textContent"];//获取web页面内容信息，此处获取的是个json字符串
    2  
    3 SBJsonParser *parserJson=[[[SBJsonParser alloc]init]autorelease];
    4  
    5 NSDictionary *contentDic=[parserJson objectWithString:docStr];//将json字符串转化为字典

     6、加载本地文件的方法

    1 第一种方法：
    2 NSString* path = [[NSBundle mainBundle] pathForResource:name ofType:@"html"inDirectory:@"mobile"];//mobile是根目录，name是文件名称，html是文件类型
    3 [webView loadRequest:[NSURLRequest requestWithURL:[NSURL fileURLWithPath:path]]]; //加载本地文件
    4 第二种方法：
    5 NSString *resourcePath = [[NSBundle mainBundle] resourcePath]; 
    6 NSString *filePath = [resourcePath stringByAppendingPathComponent:@"mobile.html"]; 
    7 NSString *htmlstring=[[NSString alloc] initWithContentsOfFile:filePath  encoding:NSUTF8StringEncoding error:nil]; 
    8 [uiwebview loadHTMLString:htmlstring baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]]];

     7、将文件下载到本地址然后再用webView打开

    01 NSString *resourceDocPath = [[NSString alloc] initWithString:[[[[NSBundle mainBundle]  resourcePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"Documents"]];
    02  self.filePath = [resourceDocPath stringByAppendingPathComponent:[NSString stringWithFormat:@"maydoc%@",docType]];
    03 NSData *attachmentData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:theUrl]];
    04 [attachmentData writeToFile:filePath atomically:YES];
    05  NSURL *url = [NSURL fileURLWithPath:filePath];
    06  NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
    07  [attachmentWebView loadRequest:requestObj];
    08 //删除指定目录下的文件
    09  
    10 NSFileManager *magngerDoc=[NSFileManager defaultManager];
    11 [magngerDoc removeItemAtPath:filePath error:nil];
    8、处理webView展示txt文档乱码问题
    01 if ([theType isEqualToString:@".txt"])
    02  {
    03 //txt分带编码和不带编码两种，带编码的如UTF-8格式txt，不带编码的如ANSI格式txt
    04 //不带的，可以依次尝试GBK和GB18030编码
    05 NSString* aStr = [[NSString alloc] initWithData:attachmentData encoding:NSUTF8StringEncoding];
    06 if (!aStr)
    07 {
    08 //用GBK<strong>进行</strong>编码
    09 aStr=[[NSString alloc] initWithData:attachmentData encoding:0x80000632];
    10 }
    11 if (!aStr)
    12 {
    13 //用GBK编码不行,再用GB18030编码
    14  aStr=[[NSString alloc] initWithData:attachmentData encoding:0x80000631];
    15 }
    16 //通过html语言<strong>进行</strong>排版
    17  NSString* responseStr = [NSString stringWithFormat:
    18                                  @"<HTML>"
    19                                  "<head>"
    20                                  "<title>Text View</title>"
    21                                  "</head>"
    22                                  "<BODY>"
    23                                  "<pre>"
    24                                  "%@"
    25                                  "/pre>"
    26                                  "</BODY>"
    27                                  "</HTML>",
    28                                  aStr];
    29  [attachmentWebView loadHTMLString:responseStr baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]]];
    30         return;
    31  }

     9 、使用webView加载本地或网络文件整个流程

    01 1、 Loading a local PDF file into the web view
    02  
    03 - (void)viewDidLoad {
    04     [super viewDidLoad];
    05  //从本地加载
    06     NSString *thePath = [[NSBundle mainBundle] pathForResource:@"iPhone_User_Guide" ofType:@"pdf"];
    07     if (thePath) {
    08         NSData *pdfData = [NSData dataWithContentsOfFile:thePath];
    09         [(UIWebView *)self.view loadData:pdfData MIMEType:@"application/pdf"
    10             textEncodingName:@"utf-8" baseURL:nil];
    11     }
    12 //从网络加载
    13 [self.myWebView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.apple.com/"]]];
    14 }
    15 2、The web-view delegate managing network loading
    16  
    17 - (void)webViewDidStartLoad:(UIWebView *)webView
    18 {
    19     // starting the load, show the activity indicator in the status bar
    20     [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    21 }
    22   
    23 - (void)webViewDidFinishLoad:(UIWebView *)webView
    24 {
    25     // finished loading, hide the activity indicator in the status bar
    26     [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    27 }
    28   
    29 - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
    30 {
    31     // load error, hide the activity indicator in the status bar
    32     [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    33   
    34     // report the error inside the webview
    35     NSString* errorString = [NSString stringWithFormat:
    36                              @"<html><center><font size=+5 color='red'>An error occurred:<br>%@</font></center></html>",
    37                              error.localizedDescription];
    38     [self.myWebView loadHTMLString:errorString baseURL:nil];
    39 }
    40 3、Stopping a load request when the web view is to disappear
    41  
    42 - (void)viewWillDisappear:(BOOL)animated
    43 {
    44     if ( [self.myWebView loading] ) {
    45         [self.myWebView stopLoading];
    46     }
    47     self.myWebView.delegate = nil;    // disconnect the delegate as the webview is hidden
    48     [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    49 }
    50 /************/
    51 引用自苹果官方文档（displaying web content）

    10、查找webView中的scrollview

    01 - (void) addScrollViewListener
    02 {
    03     UIScrollView* currentScrollView;
    04     for (UIView* subView in self.webView.subviews) {
    05         if ([subView isKindOfClass:[UIScrollView class]]) {
    06             currentScrollView = (UIScrollView*)subView;
    07             currentScrollView.delegate = self;
    08         }
    09     }
    10 }

    11、去掉webView的阴影，做成类似scrollView

    01 - (void)clearBackgroundWithColor:(UIColor*)color
    02 {
    03   // 去掉webview的阴影
    04   self.backgroundColor = color;
    05   for (UIView* subView in [self subviews])
    06   {
    07     if ([subView isKindOfClass:[UIScrollView class]]) {
    08       for (UIView* shadowView in [subView subviews])
    09       {
    10         if ([shadowView isKindOfClass:[UIImageView class]]) {
    11           [shadowView setHidden:YES];
    12         }
    13       }
    14     }
    15   }
    16  
    17 }

     12、取消长按webView上的链接弹出actionSheet的问题

    1 -(void)webViewDidFinishLoad:(UIWebView *)webView
    2 {
    3  [webView stringByEvaluatingJavaScriptFromString:@"document.documentElement.style.webkitTouchCallout = 'none';"];
    4 }
    13、取消webView上的超级链接加载问题
    1 -(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
    2 {
    3     if (navigationType==UIWebViewNavigationTypeLinkClicked) {
    4         return NO;
    5     }
    6     else {
    7         return YES;
    8     }
    9 }

    14、一、webView在ios5.1之前的bug：在之前的工程中使用webView加载附件，webView支持doc，excel，ppt，pdf等格式，但这些附件必须先下载到本地然后在加载到webView上才可以显示， 当附件下载到本地之后刚刚开始加载到webView上时，此时退出附件页面会导致程序崩溃。会崩溃是由于webView控件内部没有把相关代理取消掉，所以导致退出之后程序崩溃。

    二、webView在5.1上的bug：之前项目需求要webView可以左右活动，但在往webView上加载页面时导致页面加载不全，这个bug是由于webView本身的缓存所致。（还有待研究）

    15、在使用webView进行新浪微博分享时，webView会自动保存登陆的cookie导致项目中的分享模块有些问题，删除 webView的cookie的方法

    01 -(void)deleteCookieForDominPathStr:(NSString *)thePath
    02 {
    03     //删除本地cookie，thePath为cookie路径通过打印cookie可知道其路径   
    04     for(NSHTTPCookie *cookie in [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookies]) {
    05          
    06         if([[cookie domain] isEqualToString:thePath]) {
    07              
    08             [[NSHTTPCookieStorage sharedHTTPCookieStorage] deleteCookie:cookie];
    09         }
    10     }
    11 }

     16、在UIWebView中使用flashScrollIndicators

    使用UIScrollView时，我们可以使用flashScrollIndicators方法显示滚动标识然后消失，告知用户此页面可以滚动，后面还有更多内容。UIWebView内部依赖于UIScrollView,但是其没有flashScrollIndicators方法，但可以通过其他途径使用此方法，如下所示。

    1 for (id subView in [webView subviews])
    2 {   if ([subView respondsToSelector:@selector(flashScrollIndicators)])     
    3      {
    4        [subView flashScrollIndicators];
    5      }
    6 }
    上述代码片段可以到webViewDidFinishLoad回调中使用，加载完网页内容后flash显示滚动标识。

    17、根据内容获取UIWebView的高度

    有时候需要根据不同的内容调整UIWebView的高度，以使UIWebView刚好装下所有内容，不用拖动，后面也不会留白。有两种方式可根据加载内容获取UIWebView的合适高度，但都需要在网页内容加载完成后才可以，即需要在webViewDidFinishLoad回调中使用。

    ①.使用sizeThatFits方法。

    1 - (void)webViewDidFinishLoad:(UIWebView *)webView
    2 {    
    3     CGRect frame = webView.frame;   
    4     frame.size.height = 1;    
    5     webView.frame = frame;    
    6     CGSize fittingSize = [webView sizeThatFits:CGSizeZero];    
    7     frame.size = fittingSize;   
    8     webView.frame = frame;
    9 }
    sizeThatFits方法有个问题，如果当前UIView的大小比刚好合适的大小还大，则返回当前的大小，不会返回最合适的大小值，所以使用sizeThatFits前，先将UIWebView的高度设为最小，即1，然后再使用sizeThatFits就会返回刚好合适的大小。 

    ②、使用JavaScript

    1 - (void)webViewDidFinishLoad:(UIWebView *)webView
    2 {     CGRect frame = webView.frame;  
    3       NSString *fitHeight = [webview stringByEvaluatingJavaScriptFromString:@"document.body.scrollHeight;"];    
    4      frame.size.height = [fitHeight floatValue];   
    5      webView.frame = frame;
    6 }

    参考：
    Three useful UIWebView tweaks
    How to determine UIWebView height based on content, within a variable height UITableView?
    How to determine the content size of a UIWebView?
    clientHeight,offsetHeight和scrollHeight区别
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  • 原文地址：https://www.cnblogs.com/Camier-myNiuer/p/3765347.html
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