NSString *norPicPath = [self dataPath:[NSString stringWithFormat:@"%@.png",@"你的文件名字(例如：my.png)"]];
        NSLog(@"filepath: %@",norPicPath);
        
        BOOL norResult = [picData writeToFile:norPicPath atomically:YES];
        if (norResult) {
            [theDelegate refreshPageWithAction:@""];
        }else {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"" message:@"图片保存不成功" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
            [alert show];
        }
?


<pre name="code" class="objc">- (NSString *)dataPath:(NSString *)file
{
    
    NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"你想要自定的文件名字"];
    
    BOOL bo = [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];
    NSString *result = [path stringByAppendingPathComponent:file];
    
    return result;
    
}