import <QuickLook/QuickLook.h>

QLPreviewControllerDelegate,QLPreviewControllerDataSource

• (void)addQLPreviewVC {
  QLPreviewController *QLPreviewVC = [[QLPreviewController alloc] init];
  QLPreviewVC.view.frame = self.view.bounds;
  QLPreviewVC.dataSource = self;
  QLPreviewVC.delegate = self;
  if([[UIDevice currentDevice].systemVersion floatValue] >= 10.0) {
  [self addChildViewController:QLPreviewVC];

    QLPreviewVC.currentPreviewItemIndex = 0;
  

  }
  [self.view addSubview:QLPreviewVC.view];
  }

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

• (id<QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index {
  //根据文件名判断文件类型
  NSRange pointRange = [self.fileName rangeOfString:@"."];
  NSString *subName;
  if (pointRange.location>0 && pointRange.location < self.fileName.length-2) {
  subName = [self.fileName substringFromIndex:pointRange.location+1];
  }
  if (subName.length > 3 && [subName containsString:@"#"]) {
  subName = [subName substringToIndex:3];
  }
  if ([subName isEqualToString:@"txt"]&&[[UIDevice currentDevice].systemVersion floatValue] < 9.0) {

    //使用QLPreviewController展示TXT等文档时，Windows下生成的UTF-8格式的文件会出现中文（以及其他特殊字符）乱码的问题。QLPreviewController只有在UTF16的编码下才能正确显示中文，需要在展示文件之前将文件的编码改为UTF16
    //需针对ANSI编码和Unicode编码分别进行解码
    
    //处理txt格式内容显示有乱码的情况
    NSData *fileData = [NSData dataWithContentsOfFile:self.filePath];
    
    //判断编码如果已经是NSUTF16StringEncoding编码，则isUNICODE与isANSI为空。
    //判断是UNICODE编码
    NSString *isUNICODE = [[NSString alloc] initWithData:fileData encoding:NSUTF8StringEncoding];
    //还是ANSI编码（-2147483623，-2147482591，-2147482062，-2147481296）encoding 任选一个就可以了。
    NSString *isANSI = [[NSString alloc] initWithData:fileData encoding:-2147483623];
    if (isUNICODE) {
        NSString *retStr = [[NSString alloc]initWithCString:[isUNICODE UTF8String] encoding:NSUTF8StringEncoding];
        NSData *data = [retStr dataUsingEncoding:NSUTF16StringEncoding];
        [data writeToFile:self.filePath atomically:YES];
    }
    else if(isANSI){
        NSData *data = [isANSI dataUsingEncoding:NSUTF16StringEncoding];
        [data writeToFile:self.filePath atomically:YES];
    }
  

  }

  return [NSURL fileURLWithPath:self.filePath];
  }

/*

• 这个方法可不实现
  */

• (void)previewControllerWillDismiss:(QLPreviewController *)controller {
  }