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@property (nonatomic, strong) UIWebView *webView;

- (UIWebView *)webView
{
    if(!_webView)
    {
        _webView = [[UIWebView alloc] initWithFrame:CGRectZero];
    }
    return _webView;
}

 NSString *str =@"weixin://qr/JnXv90fE6hqVrQOU9yA0";
 [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:str]]];