将Objective-C的变量传递给javascript函数？

问题描述

我有一个简单的JavaScript函数需要两个变量。我需要将我已经在Objective-C（iOS）应用程序中使用的两个变量传递给此javascript函数。我的代码运行的JavaScript是：

  [webView stringByEvaluatingJavaScriptFromString：@onScan（）]; 
  

javascript函数将这两个变量应用于HTML表单并提交。因为变量缺失，我当然会在表单中得到未定义的值。 8-）我一直无法找到关于这个的很多文档，但也许我在错误的地方看？

FWIW，我的Objective-C变量是字符串。我的JavaScript函数是 onscan（a，b）

更新：

我可以通过在每个传递给javascript函数的变量周围放置单引号来得到这个工作。更新的代码是：

  [webView stringByEvaluatingJavaScriptFromString：@onScan（'％@'，'％@'），a ，b]上; 
  

解决方案

stringByEvaluatingJavaScriptFromString：需要一个 NSString ，所以你只需要使用 stringWithFormat：和<$ c
$ b

  NSString * stringOne = @first_parameter; $ c>％@ 对象格式化程序如下所示： 
 NSString * stringTwo = @second_parameter; 
 
 NSString * javascriptString = [NSString stringWithFormat：@onScan（'％@'，'％@'），stringOne，stringTwo]; 
 
 [webView stringByEvaluatingJavaScriptFromString：javascriptString]; 
  

查看Apple的文档 NSString ，它是一个非常有用的对象！

I have a simple javascript function that takes two variables. I need to pass two variables that I already have in my Objective-C (iOS) application to this javascript function. My line of code to run the javascript is:

[webView stringByEvaluatingJavaScriptFromString:@"onScan()"];

The javascript function just applies the two variables to a HTML form and submits it. I'm of course getting undefined in my form since the variables are missing. 8-) I've been unable to find much documentation on this, but maybe I'm looking in the wrong places?

FWIW, my Objective-C variables are strings. My javascript function is onscan(a,b)

UPDATE:

I was able to get this working by placing single quotes around each of the variables being passed to the javascript function. The updated code is:

[webView stringByEvaluatingJavaScriptFromString:@"onScan('%@','%@')",a,b];

解决方案

stringByEvaluatingJavaScriptFromString: takes an NSString so all you have to do is combine strings using stringWithFormat: and the %@ object formatter like below:

NSString *stringOne = @"first_parameter";
NSString *stringTwo = @"second_parameter";

NSString *javascriptString = [NSString stringWithFormat:@"onScan('%@','%@')", stringOne, stringTwo];

[webView stringByEvaluatingJavaScriptFromString:javascriptString];

Check out Apple's documentation for NSString, it's an insanely useful object!

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