iphone - 一些来自 NSSearchPathDirectory 枚举的目的

Question

我如何使用枚举 NSMoviesDirectory 或 NSMusicDirectory。文档说我们可以从 ios 4 开始使用他们的，但在我的应用程序中我找不到任何方法如何在那里复制文件？如果我们不能使用它们，为什么苹果会添加这些枚举？

Answer 1

默认情况下，“电影”、“音乐”和“图片”不会在目录中。您必须创建路径并放置数据文件。

例如：NSMoviesDirectory

NSArray * paths = NSSearchPathForDirectoriesInDomains (NSMoviesDirectory,NSUserDomainMask, YES);
NSString * documentsDirectory = [paths objectAtIndex:0];
NSError * error;
if (![[NSFileManager defaultManager] fileExistsAtPath: documentsDirectory])
{
   [[NSFileManager defaultManager] createDirectoryAtPath:documentsDirectory withIntermediateDirectories:NO attributes:nil error:&error];
   NSString * resourceDBFolderPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"sleep.mp4"];
   [[NSFileManager defaultManager] copyItemAtPath:resourceDBFolderPath toPath:[documentsDirectory stringByAppendingPathComponent:@"sleep.mp4"] error:&error];

}
else
{
   NSString * resourceDBFolderPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"sleep.mp4"];
  [[NSFileManager defaultManager] copyItemAtPath:resourceDBFolderPath toPath:[documentsDirectory stringByAppendingPathComponent:@"sleep.mp4"] error:&error];

}

Answer 2

只需编写一个示例，默认情况下不存在音乐目录（或其他内容），您应该以编码方式创建它。样本：

- (void)testDir
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSMusicDirectory, NSUserDomainMask, YES);
    NSString *musicDirectory = [paths objectAtIndex:0];
    NSFileManager *defaultFileManager = [NSFileManager defaultManager];
    if (![defaultFileManager fileExistsAtPath:musicDirectory]) {
        [defaultFileManager createDirectoryAtPath:musicDirectory withIntermediateDirectories:NO attributes:nil error:NULL];
    }
    NSString *testDataFilePath = [musicDirectory stringByAppendingPathComponent:@"test.mp3"];
    unsigned int bufferLength = 1024;
    void *buffer = malloc(1024 * sizeof(char));
    NSData *testData = [[NSData alloc] initWithBytes:buffer length:bufferLength];
    free(buffer); buffer = NULL;
    if (![testData writeToFile:testDataFilePath atomically:NO]) {
        NSLog(@"fail to save data");
    }
    [testData release]; testData = nil;
}