针对Xcode的警告忽略消除处理

一、问题描述

html代码如下

 1 <html>
 2     <head>
 3         <meta charset="utf-8"/>
 4         <title>我的网页</title>
 5         <script type="text/javascript">
 6             function JS2OC()
 7             {
 8                 window.location.href="fzw://send";
 9             }
10         </script>
11     </head>
12     <body>
13         <input value="js调用oc" type="button" onclick='JS2OC();'></input>
14     </body>
15 </html>

显示效果如下

 oc代码如下

 1 /**
 2  *  跳转判断
 3  */
 4 - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
 5 {
 6     NSString *urlString = request.URL.absoluteString;
 7     NSLog(@"urlString:%@",urlString);
 8     NSString *preString = @"fzw://";
 9     if([urlString hasPrefix:preString])
10     {
11         NSString *methodString = [urlString substringFromIndex:preString.length];
12         NSLog(@"methodString:%@",methodString);
13         [self performSelector:NSSelectorFromString(methodString)];
14         return NO;
15     }
16     return YES;
17 }
18 
19 -(void)send
20 {
21     NSLog(@"%s",__func__);
22 }

 

点击demo.html的按钮“js调用oc”，网页跳转到fzw://send。UIWebView的代理方法- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType拦截页面并获取网页链接fzw://send，经过处理，最后调用oc指定方法-(void)send，并返回NO取消跳转，从而达到js调用oc方法。

但xcode提示警告： PerformSelector may cause a leak because its selector is unknown

二、问题分析

编译器的警告对开发者来说是很有用的信息，但有时由于编译器的智商实在太低，会提示一些无谓的警告。当有些警告不想看到时，可以用如下代码消除警告。

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-W警告名称"
        需要关闭警告的代码
#pragma clang diagnostic pop

三、问题解决

该警告的名称为-Warc-performSelector-leaks

 1 /**
 2  *  跳转判断
 3  */
 4 - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
 5 {
 6     NSString *urlString = request.URL.absoluteString;
 7     NSLog(@"urlString:%@",urlString);
 8     NSString *preString = @"fzw://";
 9     if([urlString hasPrefix:preString])
10     {
11         NSString *methodString = [urlString substringFromIndex:preString.length];
12         NSLog(@"methodString:%@",methodString);
13 #pragma clang diagnostic push
14 #pragma clang diagnostic ignored "-Warc-performSelector-leaks"
15         [self performSelector:NSSelectorFromString(methodString)];
16 #pragma clang diagnostic pop
17         return NO;
18     }
19     return YES;
20 }
21 
22 -(void)send
23 {
24     NSLog(@"%s",__func__);
25 }

 

posted @ 2016-06-22 17:45  阿水zev  阅读(1812)  评论(1)  编辑  收藏  举报