iOS开发之WebView点击图片看大图效果

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

104018_hGrM_2320599.png