下面具体介绍下实现过程。
先看效果图。
图1. 未实现功能前, iTunes截图
http://img.blog.csdn.net/20140608195557265?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaGl0d2h5bHo=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center

图2. 实现功能后, iTunes截图
http://img.blog.csdn.net/20140608195628703?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaGl0d2h5bHo=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center

图3. 实现功能后, 运行截图。
http://img.blog.csdn.net/20140608195653515

好了, 通过图片, 我们可以看到实现的效果。
功能包括: 允许通过iTunes导入文件。 可以查看沙盒下所有文件。

实现过程:
1。在应用程序的Info.plist文件中添加UIFileSharingEnabled键，并将键值设置为YES。
http://img.blog.csdn.net/20140608200008812?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaGl0d2h5bHo=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center

2。具体代码:
ViewController.h

import <UIKit/UIKit.h>

//step1. 导入QuickLook库和头文件

import <QuickLook/QuickLook.h>

//step2. 继承协议
@interface ViewController : UIViewController<UITableViewDataSource,UITableViewDelegate,QLPreviewControllerDataSource,QLPreviewControllerDelegate,UIDocumentInteractionControllerDelegate>
{
//step3. 声明显示列表
IBOutlet UITableView *readTable;
}

//setp4. 声明变量
//UIDocumentInteractionController : 一个文件交互控制器,提供应用程序管理与本地系统中的文件的用户交互的支持
//dirArray : 存储沙盒子里面的所有文件
@property(nonatomic,retain) NSMutableArray *dirArray;
@property (nonatomic, strong) UIDocumentInteractionController *docInteractionController;
@end

ViewController.m

• (void)viewDidLoad
  {
  [super viewDidLoad];

//step5. 保存一张图片到设备document文件夹中(为了测试方便)  
UIImage *image = [UIImage imageNamed:@"testPic.jpg"];  
NSData *jpgData = UIImageJPEGRepresentation(image, 0.8);  
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory  
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"testPic.jpg"]; //Add the file name  
[jpgData writeToFile:filePath atomically:YES]; //Write the file  
  
  
//step5. 保存一份txt文件到设备document文件夹中(为了测试方便)  
char *saves = "Colin_csdn";  
NSData *data = [[NSData alloc] initWithBytes:saves length:10];  
filePath = [documentsPath stringByAppendingPathComponent:@"colin.txt"];  
[data writeToFile:filePath atomically:YES];  
  
  
//step6. 获取沙盒里所有文件  
NSFileManager *fileManager = [NSFileManager defaultManager];  
//在这里获取应用程序Documents文件夹里的文件及文件夹列表  
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
NSString *documentDir = [documentPaths objectAtIndex:0];  
NSError *error = nil;  
NSArray *fileList = [[NSArray alloc] init];  
//fileList便是包含有该文件夹下所有文件的文件名及文件夹名的数组  
fileList = [fileManager contentsOfDirectoryAtPath:documentDir error:&error];  
  
self.dirArray = [[NSMutableArray alloc] init];  
for (NSString *file in fileList)  
{  
    [self.dirArray addObject:file];  
}  

//step6. 刷新列表, 显示数据
[readTable reloadData];
}

//step7. 利用url路径打开UIDocumentInteractionController

• (void)setupDocumentControllerWithURL:(NSURL *)url
  {
  if (self.docInteractionController == nil)
  {
  self.docInteractionController = [UIDocumentInteractionController interactionControllerWithURL:url];
  self.docInteractionController.delegate = self;
  }
  else
  {
  self.docInteractionController.URL = url;
  }
  }

pragma mark- 列表操作

• (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
  {
  return 1;
  }

• (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
  static NSString *CellName = @"CellName";
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellName];
  if (cell == nil)
  {
  cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellName];
  cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
  }

  NSURL *fileURL= nil;
  NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString *documentDir = [documentPaths objectAtIndex:0];
  NSString *path = [documentDir stringByAppendingPathComponent:[self.dirArray objectAtIndex:indexPath.row]];
  fileURL = [NSURL fileURLWithPath:path];
  [self setupDocumentControllerWithURL:fileURL];
  cell.textLabel.text = [self.dirArray objectAtIndex:indexPath.row];
  NSInteger iconCount = [self.docInteractionController.icons count];
  if (iconCount > 0)
  {
  cell.imageView.image = [self.docInteractionController.icons objectAtIndex:iconCount - 1];
  }

  return cell;
  }

• (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
  {
  return [self.dirArray count];
  }

• (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
  {
  QLPreviewController *previewController = [[QLPreviewController alloc] init];
  previewController.dataSource = self;
  previewController.delegate = self;

  // start previewing the document at the current section index
  previewController.currentPreviewItemIndex = indexPath.row;
  [[self navigationController] pushViewController:previewController animated:YES];
  // [self presentViewController:previewController animated:YES completion:nil];
  }

pragma mark - UIDocumentInteractionControllerDelegate

• (NSString *)applicationDocumentsDirectory
  {
  return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
  }

• (UIViewController *)documentInteractionControllerViewControllerForPreview:(UIDocumentInteractionController *)interactionController
  {
  return self;
  }

pragma mark - QLPreviewControllerDataSource

// Returns the number of items that the preview controller should preview

• (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)previewController
  {
  return 1;
  }

• (void)previewControllerDidDismiss:(QLPreviewController *)controller
  {
  // if the preview dismissed (done button touched), use this method to post-process previews
  }

// returns the item that the preview controller should preview

• (id)previewController:(QLPreviewController *)previewController previewItemAtIndex:(NSInteger)idx
  {
  NSURL *fileURL = nil;
  NSIndexPath *selectedIndexPath = [readTable indexPathForSelectedRow];
  NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString *documentDir = [documentPaths objectAtIndex:0];
  NSString *path = [documentDir stringByAppendingPathComponent:[self.dirArray objectAtIndex:selectedIndexPath.row]];
  fileURL = [NSURL fileURLWithPath:path];
  return fileURL;
  }

• (void)didReceiveMemoryWarning
  {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

@end