检查文档目录中是否存在文件名

Question

在我的应用程序中,我使用以下代码将图像/文件保存到应用程序的文档目录中:

-(void)saveImageDetailsToAppBundle{
    NSData *imageData = UIImagePNGRepresentation(userSavedImage); //convert image into .png format.
    NSFileManager *fileManager = [NSFileManager defaultManager];//create instance of NSFileManager
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); //create an array and store result of our search for the documents directory in it
    NSString *documentsDirectory = [paths objectAtIndex:0]; //create NSString object, that holds our exact path to the documents directory
    NSString *fullPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",txtImageName.text]]; //add our image to the path

    NSLog(fullPath);

    [fileManager createFileAtPath:fullPath contents:imageData attributes:nil]; //finally save the image

    NSLog(@"image saved"); 
}

但是,图像名称存在问题.如果文档目录中存在文件,则具有相同名称的新文件将覆盖旧文件.如何检查文件目录中是否存在文件名？

Answer 1

使用NSFileManager的fileExistsAtPath:方法来检查它是否存在与否.

用法

if ( ![fileManager fileExistsAtPath:filePath] ) {
    /* File doesn't exist. Save the image at the path */
    [fileManager createFileAtPath:fullPath contents:imageData attributes:nil]; 
} else {
    /* File exists at path. Resolve and save */
}

Answer 2

if ([[NSFileManager defaultManager] fileExistsAtPath:myFilePath])

Answer 3

NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writablePath = [documentsDirectory stringByAppendingPathComponent:@"file name"];

if([fileManager fileExistsAtPath:writablePath]){ 
// file exist
}
else{ 
    // file doesn't exist
}