IOS 预览功能（轻松实现对各种文本、图片等查看）

首先需要#import<QuickLook/QuickLook.h>

然后实现<QLPreviewControllerDataSource>协议
别的不多说上代码

-(NSURL *)urlForFile:(NSString *)file

{

NSArray *segments=[file componentsSeparatedByString:@"."];

NSString *path=[[NSBundle mainBundle] pathForResource:[segments objectAtIndex:0] ofType:[segments objectAtIndex:1]];

return [NSURL fileURLWithPath:path];

}

-(void)viewDidLoad

{

[super viewDidLoad];

files=[NSArray alloc]initWithObjects:@"grocery.pdf",@"index.html",@"newsletter.pages",@"plain.txt",@"smile.jpg",nil];

}

#pragma mark Quick Look Data Source 

- (NSInteger) numberOfPreviewItemsInPreviewController: (QLPreviewController *) controller {

return [files count];

}

- (id <QLPreviewItem>) previewController: (QLPreviewController *) controller previewItemAtIndex: (NSInteger) index {

return [self urlForFile:[files objectAtIndex: index]];

}

 (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 

{

QLPreviewController * ql = [[[QLPreviewController alloc] init] autorelease];

ql.dataSource = self;

ql.currentPreviewItemIndex = indexPath.row;

[self.navigationController pushViewController:ql animated:YES];

}