xcode 检查 .nib 或 .xib 文件是否存在
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原文地址: http://stackoverflow.com/questions/923706/
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Checking if a .nib or .xib file exists
提问by Richard Stelling
What's the best way to check if a Nib or Xib file exists before trying to load it using initWithNibName:bundle:or similar?
在尝试使用initWithNibName:bundle:或类似方法加载之前检查 Nib 或 Xib 文件是否存在的最佳方法是什么？
回答by Richard Stelling
Macro
宏
#define AssertFileExists(path) NSAssert([[NSFileManager defaultManager] fileExistsAtPath:path], @"Cannot find the file: %@", path)
#define AssertNibExists(file_name_string) AssertFileExists([[NSBundle mainBundle] pathForResource:file_name_string ofType:@"nib"])
Here are a set of macros that you can call before you try an load a .xibor .nib, they will help identify missing files and spit out useful message about what exactly is missing.
这里有一组宏，您可以在尝试加载 a.xib或之前调用.nib它们，它们将帮助识别丢失的文件并输出有关究竟丢失了什么的有用信息。
Solutions
解决方案
Objective-C:
目标-C：
if([[NSBundle mainBundle] pathForResource:fileName ofType:@"nib"] != nil)
{
//file found
...
}
Please note, the documentation states that ofType:should be the extension of the file. However even if you are using .xib you need to pass `@"nib" or you will get a false-negative.
请注意，文档说明这ofType:应该是文件的扩展名。但是，即使您使用 .xib，您也需要传递 `@"nib" 否则您将得到假阴性。
Swift:
斯威夫特：
guard Bundle.main.path(forResource: "FileName", ofType: "nib") != nil else {
...
}
(See: touti's original answer: https://stackoverflow.com/a/55919888/89035)
回答by touti
Solution For swift :
快速解决方案：
guard Bundle.main.path(forResource: "FileName", ofType: "nib") != nil else {
...
}
回答by Dietrich Epp
There are two solutions I see here.
我在这里看到了两种解决方案。
You could just call initWithNibName:bundle: and catch an exception if it fails (I like this idea, it feels robust). You will probably want to verify that the exception is in fact a "file not found" exception rather than, say, an "out of memory" exception.
你可以只调用 initWithNibName:bundle: 并在它失败时捕获异常（我喜欢这个想法，感觉很强大）。您可能想要验证异常实际上是“未找到文件”异常，而不是“内存不足”异常。
Alternatively, you could check the existence of the nib first, using NSBundle's pathForResource:ofType:, which returns nil for files that don't exist.
或者，您可以首先检查笔尖是否存在，使用 NSBundle 的 pathForResource:ofType:，它为不存在的文件返回 nil。
