I have an application where I need to show the .pptx and .pdf files. For pdf files I am using react-native-pdf and file is opening fine in my App but when it comes to .pptx files we have 2 libraries:
1. https://www.npmjs.com/package/react-native-doc-viewer
2. https://www.npmjs.com/package/react-native-file-viewer
react-native-doc-viewer is not being actively maintained and a lot of issues :(
But both of them were giving a prompt to select an app like Wps Office or Microsoft apps but they were not opening as Pdf files opened in my app. Whats the reason behind this? We cannot open pptx file in our app?
I read the react-native-doc-viewer android native code. it is actually is to download a doc not to view it. the following is the code:
#ReactMethod
public void openDoc(ReadableArray args, Callback callback) {
final ReadableMap arg_object = args.getMap(0);
try {
if (arg_object.getString("url") != null && arg_object.getString("fileName") != null) {
// parameter parsing
final String url = arg_object.getString("url");
final String fileName =arg_object.getString("fileName");
final String fileType =arg_object.getString("fileType");
final Boolean cache =arg_object.getBoolean("cache");
final byte[] bytesData = new byte[0];
// Begin the Download Task
new FileDownloaderAsyncTask(callback, url, cache, fileName, fileType, bytesData).execute();
}else{
callback.invoke(false);
}
} catch (Exception e) {
callback.invoke(e.getMessage());
}
}
it uses FileDownloaderAsyncTask to download files. if you are familiar with it.
if you want to show excels, Docx, you can use the google doc line convert it to Html, then in the webView to show it. the format like it: https://docs.google.com/gview?embedded=true&url=[doc address], the same effect as ios.
Related
I can't get Process.Start to simply launch a PDF with default PDF viewer.
I tried so many combinations of shell execute, working folder etc etc. Keeps giving me either 'The system cannot find the file specified' or 'the directory name is invalid'
private void button1_Click(object sender, EventArgs e)
{
string filename = #"Milking and cooling software set 2018-39.pdf";
MessageBox.Show(currentpath + #"\Astronaut A5 v1.5(b7)\documentation\" + filename);
fullpath = currentpath + #"\Astronaut A5 v1.5(b7)\documentation";
fullfile = fullpath + filename;
ProcessStartInfo process = new ProcessStartInfo();
process.WorkingDirectory = fullpath;
process.UseShellExecute = false;
process.FileName = fullfile;
process.RedirectStandardOutput = true;
process.Verb = "run as";
Process.Start(process);
}
Why is this so hard, I have tried for hours to simply lauch Acrobat Reader to open a PDF file. I can double click it no problem in it's location but C# can't open it, either I get .NET errors or Adobe opens and says it can't find the file. Tried so many combinations of "\"", full path, hard coded path etc etc...unbelievable that this is so hard to code in this day and age.
You’ve told the system to not use ShellExecute. This means the path you’re giving should be an actual executable program. PDFs are not so if you want to open it with the default reader use ShellExecute.
process.UseShellExecute = true;
Also using “run as” as the verb doesn’t make any sense here, unless there is such a verb defined for PDFs which I’m pretty sure there isn’t. That should be removed.
I need to navigate to a web site that ultimately contains a .pdf file and I want to save that file locally. I am using CEFSharp to do this. The nature of this site is such that once the .pdf appears in the browser, it cannot be accessed again. For this reason, I was wondering if once you have a .pdf displayed in the browser, is there a way to access the source for that file in the cache?
I have tried implementing IDownloadHandler and that works, but you have to click the save button on the embedded .pdf. I am trying to get around that.
OK, here is how I got it to work. There is a function in CEFSharp that allows you to filter an incoming web response. Consequently, this gives you complete access to the incoming stream. My solution is a little on the dirty side and not particularly efficient, but it works for my situation. If anyone sees a better way, I am open for suggestions. There are two things I have to assume in order for my code to work.
GetResourceResponseFilter is called every time a new page is downloaded.
The PDF is that last thing to be downloaded during the navigation process.
Start with the CEF Minimal Example found here : https://github.com/cefsharp/CefSharp.MinimalExample
I used the WinForms version. Implement the IRequestHandler and IResponseFilter in the form definition as follows:
public partial class BrowserForm : Form, IRequestHandler, IResponseFilter
{
public readonly ChromiumWebBrowser browser;
public BrowserForm(string url)
{
InitializeComponent();
browser = new ChromiumWebBrowser(url)
{
Dock = DockStyle.Fill,
};
toolStripContainer.ContentPanel.Controls.Add(browser);
browser.BrowserSettings.FileAccessFromFileUrls = CefState.Enabled;
browser.BrowserSettings.UniversalAccessFromFileUrls = CefState.Enabled;
browser.BrowserSettings.WebSecurity = CefState.Disabled;
browser.BrowserSettings.Javascript = CefState.Enabled;
browser.LoadingStateChanged += OnLoadingStateChanged;
browser.ConsoleMessage += OnBrowserConsoleMessage;
browser.StatusMessage += OnBrowserStatusMessage;
browser.TitleChanged += OnBrowserTitleChanged;
browser.AddressChanged += OnBrowserAddressChanged;
browser.FrameLoadEnd += browser_FrameLoadEnd;
browser.LifeSpanHandler = this;
browser.RequestHandler = this;
The declaration and the last two lines are the most important for this explanation. I implemented the IRequestHandler using the template found here:
https://github.com/cefsharp/CefSharp/blob/master/CefSharp.Example/RequestHandler.cs
I changed everything to what it recommends as default except for GetResourceResponseFilter which I implemented as follows:
IResponseFilter IRequestHandler.GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response)
{
if (request.Url.EndsWith(".pdf"))
return this;
return null;
}
I then implemented IResponseFilter as follows:
FilterStatus IResponseFilter.Filter(Stream dataIn, out long dataInRead, Stream dataOut, out long dataOutWritten)
{
BinaryWriter sw;
if (dataIn == null)
{
dataInRead = 0;
dataOutWritten = 0;
return FilterStatus.Done;
}
dataInRead = dataIn.Length;
dataOutWritten = Math.Min(dataInRead, dataOut.Length);
byte[] buffer = new byte[dataOutWritten];
int bytesRead = dataIn.Read(buffer, 0, (int)dataOutWritten);
string s = System.Text.Encoding.UTF8.GetString(buffer);
if (s.StartsWith("%PDF"))
File.Delete(pdfFileName);
sw = new BinaryWriter(File.Open(pdfFileName, FileMode.Append));
sw.Write(buffer);
sw.Close();
dataOut.Write(buffer, 0, bytesRead);
return FilterStatus.Done;
}
bool IResponseFilter.InitFilter()
{
return true;
}
What I found is that the PDF is actually downloaded twice when it is loaded. In any case, there might be header information and what not at the beginning of the page. When I get a stream segment that begins with %PDF, I know it is the beginning of a PDF so I delete the file to discard any previous contents that might be there. Otherwise, I just keep appending each segment to the end of the file. Theoretically, the PDF file will be safe until you navigate to another PDF, but my recommendation is to do something with the file as soon as the page is loaded just to be safe.
I want to open and view a password protected PDF file in VB6/VB.NET program. I have tried using the Acrobat PDF Library but could not do it.
The reason I want to create a password protected PDF file is because I dont want the PDF file to be opened without the password externally i.e outside the program.
To open a password protected PDF you will need to develop at least a PDF parser, decryptor and generator. I wouldn't recommend to do that, though. It's nowhere near an easy task to accomplish.
With help of a PDF library everything is much simpler. You might want to try Docotic.Pdf library for the task.
Here is a sample for you task:
public static void unprotectPdf(string input, string output)
{
bool passwordProtected = PdfDocument.IsPasswordProtected(input);
if (passwordProtected)
{
string password = null; // retrieve the password somehow
using (PdfDocument doc = new PdfDocument(input, password))
{
// clear both passwords in order
// to produce unprotected document
doc.OwnerPassword = "";
doc.UserPassword = "";
doc.Save(output);
}
}
else
{
// no decryption is required
File.Copy(input, output, true);
}
}
Docotic.Pdf can also extract text (formatted or not) from PDFs. It might be useful for indexing (I guess it's what you are up to because you mentioned Adobe IFilter)
you can convert code to vb over the internet
Where can i find folder with installed modern ui apps? Im developing some app which uses .txt files to store information (win8 doesnot support datebase on arm - facepalm) but they seem to not work properly - thats why i want to access them.
Thanks!
That is not the correct way of doing things in Metro. I assume you mean db files, or txt files. Simply access the local text file from the project folder.
Here is a great tutorial on how you would go about doing so: http://www.codeproject.com/Articles/432876/Windows-8-The-Right-Way-to-Read-Write-Files-in-Win
An example:
private async void ProjectFile()
{
// settings
var _Path = #"Metro.Helpers.Tests\MyFolder\MyFolder.txt";
var _Folder = Windows.ApplicationModel.Package.Current.InstalledLocation;
// acquire file
var _File = await _Folder.GetFileAsync(_Path);
Assert.IsNotNull(_File, "Acquire file");
// read content
var _ReadThis = await Windows.Storage.FileIO.ReadTextAsync(_File);
Assert.AreEqual("Hello world!", _ReadThis, "Contents correct");
}
I've been trying to read a pre-built file with Car Maintenance tips, there's one in each line of my "Tips.txt" file. I've tried to follow around 4 or 5 different approaches but It's not working, it compiles but I get an exception. Here's what I've got:
using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication())
{
using (StreamReader sr = new StreamReader(store.OpenFile("Tips.txt", FileMode.Open, FileAccess.Read)))
{
string line;
while ((line = sr.ReadLine()) != null)
{
(App.Current as App).MyTips.Insert(new DoubleNode(line));
}
}
}
I'm getting this "Operation not permitted on IsolatedStorageFileStream", from the info inside the 2nd using statement. I tried with the build action of my "Tips.txt" set to resource, and content, yet I get the same result.
Thanks in advance.
Since you've added it to your project directory, you can't read it using Isolated Storage methods. There are various ways you can load the file. One way would be to set the text file's build type to Resource, then read it in as a stream:
//Replace 'MyProject' with the name of your XAP/Project
Stream txtStream = Application.GetResourceStream(new Uri("/MyProject;component/myTextFile.txt",
UriKind.Relative)).Stream;
using(StreamReader sr = new StreamReader(txtStream))
{
//your code
}