通过调用系统摄像头拍照,拍视频,然后写入文件的代码范例.

//这一段是,点击一个takePicture按钮的操作.
- (IBAction)takePicture:(id)sender {
    
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        NSArray *temp_MediaTypes = [UIImagePickerController availableMediaTypesForSourceType:picker.sourceType];
        picker.mediaTypes = temp_MediaTypes;
        picker.delegate = self;
        picker.allowsImageEditing = YES;    
    }
    
    [self presentModalViewController:picker animated:YES];
    [picker release];
    
}


//下面两个函数是遵守UIImagePickerControllerDelegate这个协议所实现的类.这样就能够完整的实现,获取照片或者视频,然后写入文件的过程.
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    
    if ([mediaType isEqualToString:@"public.image"]){
        
        UIImage *image = [info objectForKey:@"UIImagePickerControllerEditedImage"];
        NSLog(@"found an image");
        
        NSString *imageFile = [documentsDirectory stringByAppendingPathComponent:@"temp.jpg"];
        NSLog(@"%@", imageFile);
        
        success = [fileManager fileExistsAtPath:imageFile];
        if(success) {
            success = [fileManager removeItemAtPath:imageFile error:&error];
        }
        
        imageView.image = image;
        [UIImageJPEGRepresentation(image, 1.0f) writeToFile:imageFile atomically:YES];
        
        //SETIMAGE(image);
        //CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);
    }
    else if([mediaType isEqualToString:@"public.movie"]){
        NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
        NSLog(@"%@", videoURL);
        NSLog(@"found a video");
        NSData *videoData = [NSData dataWithContentsOfURL:videoURL];
        
        /****************************************/

        NSString *videoFile = [documentsDirectory stringByAppendingPathComponent:@"temp.mov"];
        NSLog(@"%@", videoFile);
        
        success = [fileManager fileExistsAtPath:videoFile];
        if(success) {
            success = [fileManager removeItemAtPath:videoFile error:&error];
        }
        [videoData writeToFile:videoFile atomically:YES];
        //CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);
        //NSLog(videoURL);
    }
    [picker dismissModalViewControllerAnimated:YES];
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    
    [picker dismissModalViewControllerAnimated:YES];
    
}

参考了,以下文章:
http://hi.baidu.com/hh20040410/blog/item/3b9950f2a049da19b17ec559.html/cmtid/ef4e0fc210c98e160ff477db