获取URL的不同方式
为了获取URL，我通常采用这种方式。
NSString *userText = urlText.text;
NSURL *url = [NSURL URLWithString:userText];
当然，urlText 是与 UITextField 关联的。
然而，最近，我在audioStreaming程序中看到了这段代码。
(这是程序。)
NSString *escapedValue =
[(NSString *)CFURLCreateStringByAddingPercentEscapes(nil, (CFStringRef)downloadSourceField.text, NULL, NULL,
kCFStringEncodingUTF8) autorelease];
NSURL *url = [NSURL URLWithString:escapedValue];
downloadSourceField 与 UITextField 链接。
这两种方法有什么区别？
当我用 (escapedValue = downloadSourceField.text;) 替换第二种方法 (escapedValue = ~~~ ) 时，程序运行良好。 你能让我知道有什么不同吗？ 获取流媒体 URL 的最佳方法是什么？
In order to obtain URL, I usually follow this way.
NSString *userText = urlText.text;
NSURL *url = [NSURL URLWithString:userText];
Of coursely, urlText is linked with UITextField.
However, Recently, I saw this code in audioStreaming program.
(This is the program.)
NSString *escapedValue =
[(NSString *)CFURLCreateStringByAddingPercentEscapes(nil, (CFStringRef)downloadSourceField.text, NULL, NULL,
kCFStringEncodingUTF8) autorelease];
NSURL *url = [NSURL URLWithString:escapedValue];
downloadSourceField is linked with UITextField.
What is diffence between these two methodes?
When I replaced the second method (escapedValue = ~~~ ) with (escapedValue = downloadSourceField.text;), the program worked well.
Could you let me know what is difference?
And What is the best method to obtain URL for streaming?
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第二种方法将对 URL 中通常不允许的某些字符进行百分比转义。例如，空格字符是不允许的，将被编码为 %20。 NSURL 不支持传递包含未转义为 +URLWithString: 的不允许字符的字符串，因此首先通过 CFURLCreateStringByAddingPercentEscapes 传递字符串将使您支持此类 URL。
The second method will percent-escape some characters which are typically not allowed in URLs. As an example, the space character is not allowed and will be encoded as %20. NSURL does not support passing a string containing a non-allowed character which has not been escaped to +URLWithString:, therefore passing the string through CFURLCreateStringByAddingPercentEscapes first will let you support such URLs.
然而，有趣的
是，深入研究 NSString 文档，您会发现这两个函数：
我认为这些是执行此操作的“官方”方式
interesting,
however, digging in the NSString docs you find these two functions:
I think those are the "official" way of doing this