Objective-C:从 NSString 生成 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(如 NSStrings)，我循环遍历它们，然后像​​这样分解每个路径:

//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:@"/"];

有一半时间我的程序在这里崩溃。我收到以下错误消息:

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

imageList 是拖放到 View 上的文件数组。因为这个问题开始出现，所以我一次只删除一个文件。例如:

此文件不起作用:

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

这做到了

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

所以，如果我正确理解错误消息，我会尝试将 ComponentsSeparatedByString 选择器应用到 NSArray，但它不支持该选择器。但在我的循环中，我正在调用 NSString，如果该对象是一个数组，我不应该在那里崩溃吗？ (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获取文件名，有没有比我正在采取的方法更好的方法？

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

但是如果我点击继续，它就会崩溃。

按照建议，我更改了代码来记录数据:

//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，因为一切都是 NSString 类。但是，有些文件可以工作，有些则不能...

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%确定你真的在这里得到一个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