UIWebView中点击放大图片

下午，遇到一个要在UIWebView里面点击图片放大的问题，由于LZ也是刚出道不久，便在网上搜集了这个比较实用的方法。原文地址：http://my.oschina.net/linxiaoxi1993/blog/465905?p={{page}}

亲测，可行。简单修改一下代码，可以直接运行。

在UIWebView的代理方法：

- (void)webViewDidFinishLoad:(UIWebView *)webView{

//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);
}

处理webView事件的代理方法

- (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, KScreenWidth-40, 220);
[_imgView sd_setImageWithURL:[NSURL URLWithString:imageUrl]];
//[_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;
}

#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, KScreenWidth, KScreenHeight)];
[_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, KScreenWidth-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 sd_setImageWithURL:[NSURL URLWithString:imageUrl]];
//[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:)]];

}

//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;
}