调整uiwebview中html文件中的img大小

来源：互联网发布：免费配音软件编辑：程序博客网时间：2024/05/04 13:26

refs:

http://www.cocoachina.com/bbs/read.php?tid-251513-keyword-uiwebview.html

http://www.cocoachina.com/bbs/read.php?tid=254790&page=e&#a

1）通过动态添加js到html文件中，并在适当的时候调用。

//拦截网页图片并修改图片大小

[webView stringByEvaluatingJavaScriptFromString:   @"var script = document.createElement('script');"    "script.type = 'text/javascript';"    "script.text = "function ResizeImages() { "        "var myimg,oldwidth;"       "var maxwidth=380;" //缩放系数        "for(i=0;i <document.images.length;i++){"            "myimg = document.images;"           "if(myimg.width > maxwidth){"                "oldwidth = myimg.width;"                "myimg.width = maxwidth;"                "myimg.height = myimg.height * (maxwidth/oldwidth);"            "}"        "}"    "}";"    "document.getElementsByTagName('head')[0].appendChild(script);"];

[webView stringByEvaluatingJavaScriptFromString:@"ResizeImages();"];

隐藏图片，只显示文字

[webViewstringByEvaluatingJavaScriptFromString:@"var script = document.createElement('script');""script.type = 'text/javascript';""script.text = "function ResizeImages() { ""var myimg,oldwidth;""var maxwidth=380;"//缩放系数"for(i=0;i <document.images.length;i++){""myimg = document.images;""myimg.style.display = 'none’;”//隐藏图片"}""}";""document.getElementsByTagName('head')[0].appendChild(script);"];[webView stringByEvaluatingJavaScriptFromString:@"ResizeImages();"];

2）之前遇到过类似问题，通过解析html文件中的img tag来修改的，相比这个方法是比较笨了。

我的原有方法，引用了第三方库 TFHpple(https://github.com/topfunky/hpple)。

+ (NSString *) strImgStrip:(NSString *)strHtml Width:(NSString *)width  Height:(NSString *)height{    @try{        NSRange rang1=[strHtml rangeOfString:@"<img"];        if(rang1.length==0){            return strHtml;        }                NSString *prefixStr=[[NSString alloc]initWithString:[strHtml substringToIndex:rang1.location]];                NSMutableString *imageStr1=[[NSMutableString alloc]initWithString:[strHtml substringFromIndex:rang1.location]];                NSRange rang2=[imageStr1 rangeOfString:@"/>"];        //some elformter html        NSString *imageStr=[[NSMutableString alloc]initWithString:[imageStr1 substringToIndex:rang2.location]];                NSString *suffixStr=[[NSString alloc]initWithString:[imageStr1 substringFromIndex:rang2.location+rang2.length]];                        NSRange rang3=[suffixStr rangeOfString:@"<img"];        if(rang3.length){            suffixStr=[self strImgStrip:suffixStr Width:width  Height:height];        }                NSData *dataTitle=[imageStr dataUsingEncoding:NSUTF8StringEncoding];                TFHpple *xpathParser=[[TFHpple alloc]initWithHTMLData:dataTitle];                NSArray *elements=[xpathParser searchWithXPathQuery:@"//img"];                        NSMutableString *xmlString=[[NSMutableString alloc] initWithString:@""];        for (TFHppleElement *element in elements) {            NSMutableDictionary *elementContent =[[NSMutableDictionary alloc] initWithCapacity:4];            [elementContent addEntriesFromDictionary:[element attributes]];            if([elementContent objectForKey:@"width"]){                [elementContent removeObjectForKey:@"width"];            }                        [elementContent setObject:width forKey:@"width"];                        if([elementContent objectForKey:@"height"]){                [elementContent removeObjectForKey:@"height"];            }                        [elementContent setObject:height forKey:@"height"];                        NSString * str=[self dictionaryToXmlstring:elementContent];                        NSLog(@"result: %@", str);                        [xmlString appendFormat:@"<img %@ >",str];        }                return [NSString stringWithFormat:@"%@%@%@",prefixStr,xmlString,suffixStr];    }@catch (NSException *exception ) {        NSLog(@"exception.name = %@" , exception.name);        NSLog(@"exception.reason = %@" , exception.reason);        //如果出错，原路返回        return strHtml;    }    }

3）web页面切换时禁止当前页面media播放

-(BOOL)hasMedia:(MediaType)mediaType{    NSString *str_mediaType = [self getMediaTypeString:mediaType];        __block BOOL hasMediaTag = NO;    if (![[NSThread currentThread] isMainThread])    {        dispatch_semaphore_t sema = dispatch_semaphore_create(0);        dispatch_async(dispatch_get_main_queue(), ^{            NSString *hasMediaTestString = [NSString stringWithFormat:@"document.documentElement.getElementsByTagName(\"%@\").length",str_mediaType];            NSString * result = [self stringByEvaluatingJavaScriptFromString:hasMediaTestString];            hasMediaTag = [result integerValue] >= 1? YES : NO;            dispatch_semaphore_signal(sema);        });        dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);    }    else    {        NSString *hasMediaTestString = [NSString stringWithFormat:@"document.documentElement.getElementsByTagName(\"%@\").length",str_mediaType];        NSString * result = [self stringByEvaluatingJavaScriptFromString:hasMediaTestString];        hasMediaTag = [result integerValue] >= 1? YES : NO;    }        return hasMediaTag;}

- (void)stopMedia:(MediaType)mediaType{    NSString *str_mediaType = [self getMediaTypeString:mediaType];    if (![[NSThread currentThread] isMainThread])    {        dispatch_semaphore_t sema = dispatch_semaphore_create(0);        dispatch_async(dispatch_get_main_queue(), ^{            NSString * requestDurationString = [NSString stringWithFormat:@"document.documentElement.getElementsByTagName(\"%@\")[0].pause()",str_mediaType];            [self stringByEvaluatingJavaScriptFromString:requestDurationString];            dispatch_semaphore_signal(sema);        });        dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);    }    else    {        NSString * requestDurationString = [NSString stringWithFormat:@"document.documentElement.getElementsByTagName(\"%@\")[0].pause()",str_mediaType];        [self stringByEvaluatingJavaScriptFromString:requestDurationString];    }}

0 0