在iOS SDK包括了QLPreviewControllerAPI，元件允許使用者瀏覽許多不同的檔案型別，如XLS檔案，Word文件檔案，PDF檔案。約翰已建立了一個示例應用程式演示使用QLPreviewController。在示範中，您可以檢視幾個不同的檔案型別，甚至列印（使用無線印表機。）

隨著一個簡短的教程，我們解釋實施QLPreviewController的基礎步驟，你可以找到約翰的例子：：：：

對於過去的幾個月中，我一直花一些時間檢查出IOS快看檔案預覽 -接下來是一個短的應用程式，我寫著是為了更熟悉QLPreviewControllerAPI。

對於那些不熟悉的讀者可以這麼看，quick look

接下來在演示的程式中，我用了三個不同檔案型別，.xls/image/ms office /pdf

檔案預覽介面

為應用程式的介面檔案如下所示，注意QL資料來源的引用，使用的QLPreviewController時，你必須實現此協議QLPreviewControllerDataSource。這裡的唯一的例項變數是一個數組，包涵每個被預覽檔案的檔案字符串值。UITableViewController類將用於顯示預覽的檔案列表，通過navigation到下一個預覽介面

#import <QuickLook/QuickLook.h>
 
@interface TestViewController : UITableViewController <QLPreviewControllerDataSource>
{
  NSArray *arrayOfDocuments;
}
 
@end

在本節中，我將展示一個選擇適用於設立預覽程式碼。建立表檢視和填充相同的程式碼可以被視為在Xcode專案，你可以從下面的連結下載（如果要學習tableview的使用，可以參考其它的指南）。

初始化程式碼填入檔案名的陣列： 這樣檔名全在陣列了：

-(id)init
{
  if (self = [super init])
  {
    arrayOfDocuments = [[NSArray alloc] initWithObjects: 
        @"iOSDevTips.png
 
", @"Remodel.xls", @"Core J2ME Technology.pdf", nil];
  }
  return self;
}

下面的方法是採用QLPreviewControllerDataSource協議時，必要的兩個之一，此方法通知​​預覽控制器，如何在預覽導航列表中的呈現多少個專案是：

- (NSInteger) numberOfPreviewItemsInPreviewController: (QLPreviewController *) controller 
{
  return [arrayOfDocuments count];
}

這種呢，算是question type的events，就是問 檔案從什麼地方來，NSURL

- (id <QLPreviewItem>)previewController: (QLPreviewController *)controller previewItemAtIndex:(NSInteger)index 
{
  // Break the path into its components (filename and extension)
  NSArray *fileComponents = [[arrayOfDocuments objectAtIndex: index] componentsSeparatedByString:@"."];
 
  // Use the filename (index 0) and the extension (index 1) to get path
  NSString *path = [[NSBundle mainBundle] pathForResource:[fileComponents objectAtIndex:0] ofType:[fileComponents objectAtIndex:1]];
//這個程式碼就體現了靈活性，你也可以寫成 ofType .pdf 
  return [NSURL fileURLWithPath:path];
}

專案中的其餘程式碼是典型的iPhone/的iOS的東西，建立應用程式委託，委託的UIWindow中新增一個子檢視（導航控制器），使視窗可見。我從下面的委託程式碼，在這裡你可以得到更大的圖片檢視我如何設定此應用程式的檢視控制器。

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{   
  // Create and initialize the window
  window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
 
  // Create test view controller
  vc = [[TestViewController alloc] init];
 
  // Create navigation controller 
  nav = [[UINavigationController alloc] initWithRootViewController:vc];
 
  [window addSubview:[nav view]];  
  [window makeKeyAndVisible];
}

在選中特定行的時候，初始化QLPreviewController：

/*---------------------------------------------------------------------------
*  
*--------------------------------------------------------------------------*/
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{  
	// When user taps a row, create the preview controller
	QLPreviewController *previewer = [[[QLPreviewController alloc] init] autorelease];

	// Set data source
	[previewer setDataSource:self];
  
  // Which item to preview
	[previewer setCurrentPreviewItemIndex:indexPath.row];

	// Push new viewcontroller, previewing the document
	[[self navigationController] pushViewController:previewer animated:YES];
}

值得一提的是預覽控制器工作時，你有兩種不同的選擇。首先，你可以推到使用一個UINavigationController物件，你可以看到預覽控制器的物件是我做了什麼。預覽我的應用程式生命在TestViewController這個物件控制器設定為導航控制器的根檢視控制器。

第二種方法來顯示預覽控制器是模態，使用方法presentModalViewController。  //這個和我上篇fastpdfkit的講法是一致的:

#pragma mark -
#pragma mark QLPreviewControllerDataSource

// Returns the number of items that the preview controller should preview
- (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)previewController
{
    return 5; //30//you can increase/decrease the this
}

// returns the item that the preview controller should preview
- (id)previewController:(QLPreviewController *)previewController previewItemAtIndex:(NSInteger)idx
{
    return fileURL;
}


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

 首先雙tap,然後拖動，出現context view，然後選擇功能，copy／define（dictionary）。

====補充：

問題：如何刪除那個print button

I answered an almost identical question the other day here. The question pertained to removing the print button, which isn't too hard. One thing to note about QLPreviewController is that it's not meant to be customized. I have built a subclass ofQLPreviewController that can be customized. I've put it here on Github. It's designed to easily remove the action button, among other features too. It wouldn't take much effort at all to replace the button with a custom one.

The biggest thing to watch out for is that the action button is re-added to the navigation bar anytime a new document is displayed. You should notice this in my code. AnytimeRBFilePreviewer removes the action button, you just need to re-add your custom buttons. To add your custom buttons, you should create aUIBarButtonItem that holds a custom view with four buttons in it. Then set the right bar button item as the customUIBarButtonItem you created.

Update:

I've updated RBFilePreviewer to allow you to set a custom right bar button item right out-of-the-box. Just call-setRightBarButtonItem: on RBFilePreviewer and it just works.

RBFilePreviewer is a subclass of QLPreviewController. It is intended to make it easy to preview anyQLPreviewItem. All you need to do is pass it the desired item(s) to preview to the appropriate initializer. You may use the providedRBFile class or any other class that conforms to QLPreviewItem (includingNSURL).

hint:smples/SmoothDocumentLoaderProject