来自initWithString的NSURL对象给出-[NSURL长度]错误 [英] NSURL object from initWithString gives -[NSURL length] error

问题描述

我正在尝试查找具有路径的文件，然后使用NSFileManager类将其删除。 [info objectForKey：UIImagePickerControllerMediaURL] 确实返回了一个字符串，所以我不明白为什么它在有效参数上失败。

I'm trying to find a file with a path, then delete it using the NSFileManager class. the [info objectForKey:UIImagePickerControllerMediaURL] does return a string, so I dont' understand why its failing on a valid parameter.

NSError *error;

NSFileManager *manager = [NSFileManager defaultManager];

NSURL *url = [[NSURL alloc] initWithString:[info
              objectForKey:UIImagePickerControllerMediaURL]];


if ([manager isDeletableFileAtPath: [info 
                  objectForKey:UIImagePickerControllerMediaURL]]) {
    BOOL success = [manager removeItemAtURL:url error:&error];
    if (!success) {
        NSLog(@"Error removing file at path: %@", error.localizedDescription);
    }
}

我收到此错误：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException'
   , reason: '-[NSURL length]: unrecognized selector sent to instance 0x175ede10'

推荐答案

文档说明 UIImagePickerControllerMediaURL ：

指定电影的文件系统URL。此键的值为
一个NSURL对象。

Specifies the filesystem URL for the movie. The value for this key is an NSURL object.

您的错误消息也是如此：

And your error message says the same:

因此

NSError *error;
NSFileManager *manager = [NSFileManager defaultManager];
NSURL *url = [info objectForKey:UIImagePickerControllerMediaURL];

if ([manager isDeletableFileAtPath:url]) {
    BOOL success = [manager removeItemAtURL:url error:&error];
    if (!success) {
        NSLog(@"Error removing file at path:%@", error.localizedDescription);
    }
}

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