Question

NSURL *url = [NSURL URLWithString:@"PDFLINK"];
// Get the PDF Data from the url in a NSData Object
NSData *pdfData = [[NSData alloc] initWithContentsOfURL:url];
NSString * name = @"First";
// Store the Data locally as PDF File
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];



NSString *newFilePath = [documentsDirectory stringByAppendingPathComponent:@"my.pdf"];
NSError *error;
if ([fileManager createFileAtPath:newFilePath contents:pdfData attributes:nil])
{
    NSLog(@"Create Sucess");
    [self loadPDF];
}
else
{
    NSLog(@"Create error: %@", error);
}

}


-(void)loadPDF
{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    NSArray *resultArray = [fileManager subpathsOfDirectoryAtPath:documentsDirectory error:nil];
    if (![resultArray containsObject:arrObj])
    {
        // do something
    }
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:[resultArray objectAtIndex:0]];

   // Now create Request for the file that was saved in your documents folder
   //NSLog(@"The filePath %@",filePath);
   NSURL *url = [NSURL fileURLWithPath:filePath];
   NSLog(@"The url %@",url);
   NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
   [_webView setUserInteractionEnabled:YES];
   [_webView setDelegate:self];
   [_webView loadRequest:requestObj];
}

这是我的代码。我有更多的10 pdf，并希望将它们本地存储在设备上并在下次显示而无需下载。

它再次保存pdf，我无法检查是否已下载？

请帮帮我

Answer 1

我不确定你的意思但是，要下载文件，你需要使用NSData：

   NSString *stringURL = @"your file URL";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *urlData = [NSData dataWithContentsOfURL:url];
if ( urlData )
{
  NSArray       *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString  *documentsDirectory = [paths objectAtIndex:0];  

  NSString  *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory,@"filename.extension"];
  [urlData writeToFile:filePath atomically:YES];
}

现在下载的文件存在于filePath中，您可以使用以下命令获取它：

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"filename with extension"];
NSString *content = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];

您可以尝试检查文件路径中是否存在文件：

 NSString* documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

   NSString* file = [documentsPath stringByAppendingPathComponent:@"filename"];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:file];

 if(fileExists){
         //dont download, just grab it and display it
   }
     else{
      //download and display it
    }

在设备上本地保存许多pdf并在点击时检索它

1 个答案: