Objective-C：从NSString制作NSArray

Question

我正在尝试从文件路径组件创建一个数组。我有一个文件路径数组（作为NSStrings），我循环遍历它们，然后像​​这样分解每个：

//get the array of image paths
imageList = [[notification userInfo] objectForKey:@"images"];

//loop through the array and get the image names
for (NSString* thisImagePath in imageList) {
    NSArray* thisImagePathArray = [thisImagePath componentsSeparatedByString:@"/"];

我的程序在这里崩溃的时间有一半。我收到以下错误消息：

-[NSCFArray componentsSeparatedByString:]: unrecognized selector sent to instance 0x1a7940

imageList是一个放在视图上的文件数组。因为这个问题开始出现，我一次只丢弃一个文件。例如：

此文件不起作用：

/Users/steve/Desktop/thinkstock/PT121211_PI_bariatric.tif

这确实

/Users/steve/Desktop/thinkstock/Studentexhausted82557038.jpg

所以，如果我正确理解错误消息，我试图将componentsSeparatedByString选择器应用于NSArray，它不支持该选择器。但在我的循环中我调用NSString，如果对象是一个数组不应该崩溃吗？ （而且我99％确定imageList索引0处的对象是一个字符串。）

我的目标是从文件路径中获取文件名，有没有比我采用的方法更好的方法呢？

当我单步执行时（在componentsSeparatedByString行放置一个调试点，它似乎按照我的计划工作：

但如果我点击继续它会崩溃。

根据建议我将代码更改为记录数据：

//loop through the array and get the image names
for (NSString* thisImagePath in imageList) {
if (![thisImagePath isKindOfClass:[NSString class]]) { 
    NSLog(@"The class of this object is: %@", [thisImagePath className]);
}
NSLog(@"%@", thisImagePath); 

NSArray* thisImagePathArray = [thisImagePath componentsSeparatedByString:@"/"];
NSString* thisImageName = [thisImagePathArray objectAtIndex:[thisImagePathArray count]-1];

类检查的条件永远不会被触发，因为所有内容都是NSString类。但是，有些文件可以工作，有些文件没有...

2012-01-19 13:59:04.631 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/rbrb_0556.jpg
2012-01-19 13:59:06.799 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/Manracefinish78464007.jpg
2012-01-19 13:59:08.319 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/ManLabtop86510699.jpg
2012-01-19 13:59:08.320 archiveDrop_cocoa[76758:10b] *** -[NSCFArray componentsSeparatedByString:]: unrecognized selector sent to instance 0x1a75c0
2012-01-19 13:59:08.321 archiveDrop_cocoa[76758:10b] *** Canceling drag because exception 'NSInvalidArgumentException' (reason '*** -[NSCFArray componentsSeparatedByString:]: unrecognized selector sent to instance 0x1a75c0') was raised during a dragging session
2012-01-19 13:59:10.726 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/LasVegassign78058995.jpg
2012-01-19 13:59:10.728 archiveDrop_cocoa[76758:10b] *** -[NSCFArray componentsSeparatedByString:]: unrecognized selector sent to instance 0x1a9010
2012-01-19 13:59:10.729 archiveDrop_cocoa[76758:10b] *** Canceling drag because exception 'NSInvalidArgumentException' (reason '*** -[NSCFArray componentsSeparatedByString:]: unrecognized selector sent to instance 0x1a9010') was raised during a dragging session
2012-01-19 13:59:13.342 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/kidscolor57448860.jpg
2012-01-19 13:59:15.014 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/IVDrip76801701.jpg
2012-01-19 13:59:18.263 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/stk26719pin.jpg
2012-01-19 13:59:23.414 archiveDrop_cocoa[76758:10b] /Users/steve/Desktop/thinkstock/WomanLabtop78634274.jpg

Answer 1

当你100％确定你真的在这里获得NSString时，为什么不使用[thisImagePath lastPathComponent]？

http://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html#//apple_ref/occ/instm/NSString/lastPathComponent

Answer 2

图像列表中的一个条目是NSArray。你需要找出原因。

Answer 3

您可能需要查看NSString's -lastPathComponent或-pathComponents，而不是调用-componentsSeparatedByString:，因为它们会可靠地解析路径。

就像Hot Licks建议的那样，您似乎试图在-componentsSeparatedByString上致电NSArray。我会NSLog( @"imageList: %@", imageList )查看一些示例文件，看看你得到了什么，或者可能在for循环中看看

if ( ![thisImagePath isKindOfClass:[NSString class] ) NSLog( @"Not a String: %@", thisImagePath );