iOS开发 之 WebView点击图片看大图效果

gf67的头像 gf67 12 2015-06-12 16:48 0

 基本信息

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项目里面需要实现,点击webView里面的图片,看大图并且能够放大缩小效果,在此记录下实现过程。
  • 在webViewDelegate里面添加如下代码:

  • - (void)webViewDidFinishLoad:(UIWebView *)aWebView {
    
        //调整字号
        NSString *str = @"document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust= '95%'";
        [webView stringByEvaluatingJavaScriptFromString:str];
        
        //js方法遍历图片添加点击事件 返回图片个数
        static  NSString * const jsGetImages =
        @"function getImages(){\
        var objs = document.getElementsByTagName(\"img\");\
                                                 for(var i=0;i<objs.length;i++){\
                                                     objs[i].onclick=function(){\
                                                         document.location=\"myweb:imageClick:\"+this.src;\
                                                     };\
                                                 };\
                                                 return objs.length;\
                                                 };";
        
        [webView stringByEvaluatingJavaScriptFromString:jsGetImages];//注入js方法
        
        //注入自定义的js方法后别忘了调用 否则不会生效(不调用也一样生效了,,,不明白)
        NSString *resurlt = [webView stringByEvaluatingJavaScriptFromString:@"getImages()"];
        //调用js方法
    //    NSLog(@"---调用js方法--%@  %s  jsMehtods_result = %@",self.class,__func__,resurlt);
    }
  • - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
        //将url转换为string
        NSString *requestString = [[request URL] absoluteString];
    //    NSLog(@"requestString is %@",requestString);
        
        //hasPrefix 判断创建的字符串内容是否以pic:字符开始
        if ([requestString hasPrefix:@"myweb:imageClick:"]) {
            NSString *imageUrl = [requestString substringFromIndex:@"myweb:imageClick:".length];
    //        NSLog(@"image url------%@", imageUrl);
            
            if (bgView) {
                //设置不隐藏,还原放大缩小,显示图片
                bgView.hidden = NO;
                imgView.frame = CGRectMake(10, 10, SCREEN_WIDTH-40, 220);
                [imgView setImageWithURL:[NSURL URLWithString:imageUrl] placeholderImage:LOAD_IMAGE(@"house_moren")];
            }
            else
                [self showBigImage:imageUrl];//创建视图并显示图片
            
            return NO;
        }
        return YES;
    }
  • 创建放大图片的视图

  • #pragma mark 显示大图片
    -(void)showBigImage:(NSString *)imageUrl{
        //创建灰色透明背景,使其背后内容不可操作
        bgView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];
        [bgView setBackgroundColor:[UIColor colorWithRed:0.3
                                                   green:0.3
                                                    blue:0.3
                                                   alpha:0.7]];
        [self.view addSubview:bgView];
        
        //创建边框视图
        UIView *borderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH-20, 240)];
        //将图层的边框设置为圆脚
        borderView.layer.cornerRadius = 8;
        borderView.layer.masksToBounds = YES;
        //给图层添加一个有色边框
        borderView.layer.borderWidth = 8;
        borderView.layer.borderColor = [[UIColor colorWithRed:0.9
                                                        green:0.9
                                                         blue:0.9
                                                        alpha:0.7] CGColor];
        [borderView setCenter:bgView.center];
        [bgView addSubview:borderView];
        
        //创建关闭按钮
        UIButton *closeBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    //    [closeBtn setImage:[UIImage imageNamed:@"close.png"] forState:UIControlStateNormal];
        closeBtn.backgroundColor = [UIColor redColor];
        [closeBtn addTarget:self action:@selector(removeBigImage) forControlEvents:UIControlEventTouchUpInside];
        [closeBtn setFrame:CGRectMake(borderView.frame.origin.x+borderView.frame.size.width-20, borderView.frame.origin.y-6, 26, 27)];
        [bgView addSubview:closeBtn];
        
        //创建显示图像视图
        imgView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, CGRectGetWidth(borderView.frame)-20, CGRectGetHeight(borderView.frame)-20)];
        imgView.userInteractionEnabled = YES;
        [imgView setImageWithURL:[NSURL URLWithString:imageUrl] placeholderImage:LOAD_IMAGE(@"house_moren")];
        [borderView addSubview:imgView];
        
        //添加捏合手势
        [imgView addGestureRecognizer:[[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(handlePinch:)]];
        
    }
  • 实现关闭和捏合手势的方法

  • //关闭按钮
    -(void)removeBigImage
    {
        bgView.hidden = YES;
    }
    
    - (void) handlePinch:(UIPinchGestureRecognizer*) recognizer
    {
        //缩放:设置缩放比例
        recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
        recognizer.scale = 1;
    }

效果图如下

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