I am new in android studio and I am using Parse to store images. I am creating an image gallery and I am able to display downloaded images from parse to gridview. The problem is everytime I restart the app, my SDcard will download the exact same files from Parse. Is there a way to delete these unnecessary files? Or how can I put these Downloaded image files into a temporary storage where they will be deleted once the user is finished with the app?
This is my code for downloading the images and store them in gridview:
for (ParseObject imageOb : objects) {
final ParseFile file = (ParseFile) imageOb.get("image");
file.getDataInBackground(new GetDataCallback() {
#Override
public void done(byte[] data, ParseException e) {
if (e == null) {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
Uri uri = getImageUri(getApplicationContext(), bitmap);
File imageFiles = new File(getRealPathFromURI(uri));
imageAdapter.add(imageFiles.toString());
}
imageAdapter.notifyDataSetChanged();
}
});
}
There are some answers already on Stack overflow about temporary files, for example What is the best way to create temporary files
You could also manually delete the downloaded files when the application doesn't need them anymore. If you download them in onCreate you should delete them in onDestroy. Otherwise, check out this Article about the Android lifecycle
Related
I was wondering if it is possible with xamarin.forms to download any type of file to the device.. de files are stored on Azure, i get a Memorystream of the file, its very important for my app. my question excists of 2 parts actually,
how to download de file to the device of the user?,
and how to show the file of Any type in a default application of the type ( like pdf reader)
this is what i tried
MemoryStream memoryStream = AzureDownloader.DownloadFromAzureBlobStorage(null, doc.azure_container, doc.file_path, ref filen, true);
string documentsPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string localFilename = doc.filename;
string localPath = Path.Combine(documentsPath, localFilename);
File.WriteAllBytes(localPath, memoryStream.ToArray()); // this is a try to save to local storage
any help appreciated
how to download the file to the device of the user?
Use PCLStorage as its cross-platform and would work for iOS and Android:
public async Task CreateRealFileAsync()
{
// get hold of the file system
IFolder rootFolder = FileSystem.Current.LocalStorage;
// create a folder, if one does not exist already
IFolder folder = await rootFolder.CreateFolderAsync("MySubFolder", CreationCollisionOption.OpenIfExists);
// create a file, overwriting any existing file
IFile file = await folder.CreateFileAsync("MyFile.txt", CreationCollisionOption.ReplaceExisting);
// populate the file with some text
await file.WriteAllTextAsync("Sample Text...");
}
how to show the file of Any type in a default application of the type
( like pdf reader)
this is too broad and could have several solutions depending on what exactly you want to achieve.
Hope this helps
I am running win8.1 , and VS2013 SP3, trying to create a windows phone app which should retrieve all the document names and paths (for later reference) from the 'Assets' folder.
I added a bunch of word documents in the Assets folder and set the build to content, and copy to always.
Is it possible to get a list of all files (or file names) in the assets folder?
I can't seem to find the way to do it.
What I can do is reference a specific file, but what I would like to do, is list out all the file names/paths within the Assets folder and show the details of these files in a specific view...
I tried the following:
var package = Windows.ApplicationModel.Package.Current.InstalledLocation;
var assetsFolder = await package.GetFolderAsync("Assets");
foreach (var file in await assetsFolder.GetFilesAsync())
{
_documents.Add(new Document() { Category = section, Title = file.Name, Uri = file.Path });
}
This code freezes on the foreach line...?
I would very much appreciate some guidance or references in this matter.
Maybe it's the way you're calling it.
Here's mine with screenshots.
I only call it once the whole page has loaded.
private void Page_Loaded(object sender, RoutedEventArgs e)
{
ReadAssetFolder();
}
public async void ReadAssetFolder()
{
var package = Windows.ApplicationModel.Package.Current.InstalledLocation;
var assetsFolder = await package.GetFolderAsync("Assets");
foreach (var file in await assetsFolder.GetFilesAsync())
{
int debug_var = 1;
}
}
Screenshot of when the debugger hits my breakpoint:
Screenshot of my Asset folder
Finally all my files have these Properties
Hope that helps you.
I have a Windows Forms project. I have a Resources folder and I wan to use the files there using relative path. Here is a printscreen of my project tree
As you may see I have folder UserControls where I have FileExplorer.cs it contains aa openFileDialog + pictureBox. I use this control in some of my forms which are in Forms folder. The case is that in Resources folder I have this T380.jpg image that I want to load by default but for now I can do it only by inserting the full path to it. Here is my code where I try to load the image:
private void FileExplorer_Load(object sender, EventArgs e)
{
pictureBox1.ImageLocation = #"ShoesUnlimitedAdmin\Resources\T380.jpg";
pictureBox1.Load();
}
I use the Load event of the user control to load my image but it only works when I set the full path to the image like C:\\... and so. How can I point to the Resources folder of the project using relative path?
If these images are small then favor adding them as resources in the executable file so you can use Properties.Resources in your code and don't have to deploy the files on the user's machine. Use Project + Properties, Resources. Click the arrow on the "Add Resource" button and select Add Existing File.
If they are big (more than a couple of megabytes) then you'll indeed want to deploy them as separate files. You can find them back by using the location of the EXE program, here's a helper method, spelled out for clarity:
public static string GetResourcePath(string filename) {
string exepath = System.Reflection.Assembly.GetEntryAssembly().Location;
string exedir = System.IO.Path.GetDirectoryName(exepath);
string resdir = System.IO.Path.Combine(exedir, "Resources");
return System.IO.Path.Combine(resdir, filename);
}
Hi I have a wpf application that plays sounds on events such as button click. And the current code I have now plays the sound file, but Ive realized that it has to be in another folder which for example if the user deletes, makes the application pretty much not useable.
I was wondering, How could I get a .wav file without creating a whole new folder in the application Release directory.
Any ideas?
Thanks.
If the .wav files is added to your project at the root then marked as content (Right Click on the .wav file and click properties. Then change the build action to content) then it will be copied directly to the root output folder
You can the reference the wav file in code or XAML as a relative path (simple "Myfile.wav")
I believe this is what you are asking for?
How about putting the .wav-file as en embedded resource in the dll?
Just add the file to the project, right-click on the file and set Build Action to Embedded Resource.
Then you can load the .wav file as a stream and save it to disc like this:
private void WriteEmbeddedResourceToFile(string writePath, string assemblyName)
{
Assembly asm = Assembly.GetExecutingAssembly();
Stream s = asm.GetManifestResourceStream(assemblyName);
if (s != null)
{
var file = new byte[s.Length];
s.Read(file, 0, (int)s.Length);
File.WriteAllBytes(writePath, file);
s.Close();
}
}
The string assemblyName must be set like this: namespace.(if you put the file in a folder, insert folder subpath here).filename.wav
Alternatively, you can drop saving it to disc, and just use the stream directly:
private byte[] GetEmbeddedResource(string assemblyName)
{
Assembly asm = Assembly.GetExecutingAssembly();
Stream s = asm.GetManifestResourceStream(assemblyName);
if (s != null)
{
var file = new byte[s.Length];
s.Read(file, 0, (int)s.Length);
s.Close();
return file;
}
}
Then, when you want to load the file, GetEmbeddedResource will return the byte array.
I have the following requirement for a business application:
(All of this could be on local or server)
Allow user to select folder location
Show contents of folder
Print selected items from folder (*.pdf)
Display which files have been printed
Potentially move printed files to new location (sub-folder of printed)
How can I make this happen in Silverlight?
Kind regards,
ribald
First of all, all but the last item can be done (the way you expect). Due to security protocols, silverlight cannot access the user's drive and manipulate it. The closest you can get is accessing silverlight's application storage which will be of no help to you whatsoever in this case. I will highlight how to do the first 4 items.
Allow user to select folder location & Show contents of folder
public void OnSelectPDF(object sender)
{
//create the open file dialog
OpenFileDialog ofg = new OpenFileDialog();
//filter to show only pdf files
ofg.Filter = "PDF Files|*.pdf";
ofg.ShowDialog();
byte[] _import_file = new byte[0];
//once a file is selected proceed
if (!object.ReferenceEquals(ofg.File, null))
{
try
{
fs = ofg.File.OpenRead();
_import_file = new byte[fs.Length];
fs.Read(_import_file, 0, (int)fs.Length);
}
catch (Exception ex)
{
}
finally
{
if (!object.ReferenceEquals(fs, null))
fs.Close();
}
//do stuff with file - such as upload the file to the server
};
}
If you noticed, in my example, once the file is retrieved, i suggest uploading it to a webserver or somewhere with temporary public access. I would recommend doing this via a web service. E.g
//configure the system file (customn class)
TSystemFile objFile = new TNetworkFile().Initialize();
//get the file description from the Open File Dialog (ofg)
objFile.Description = ofg.File.Extension.Contains(".") ? ofg.File.Extension : "." + ofg.File.Extension;
objFile.FileData = _import_file;
objFile.FileName = ofg.File.Name;
//upload the file
MasterService.ToolingInterface.UploadTemporaryFileAsync(objFile);
Once this file is uploaded, on the async result, most likely returning the temporary file name and upload location, I would foward the call to some javascript method in the browser for it to use the generic "download.aspx?fileName=givenFileName" technique to force a download on the users system which would take care of both saving to a new location and printing. Which is what your are seeking.
Example of the javascript technique (remember to include System.Windows.Browser):
public void OnInvokeDownload(string _destination)
{
//call the browser method/jquery method
//(I use constants to centralize the names of the respective browser methods)
try
{
HtmlWindow window = HtmlPage.Window;
//where BM_INVOKE_DOWNLOAD is something like "invokeDownload"
window.Invoke(Constants.TBrowserMethods.BM_INVOKE_DOWNLOAD, new object[] { _destination});
}
catch (Exception ex) { System.Diagnostics.Debug.WriteLine(ex.ToString()); }
}
Ensure you have the javascript method existing either in an included javaScript file or in the same hosting page as your silverlight app. E.g:
function invokeDownload(_destination) {
//some fancy jquery or just the traditional document.location change here
//open a popup window to http://www.myurl.com/downloads/download.aspx? fileName=_destination
}
The code for download.aspx is outside the scope of my answer, as it varies per need and would just lengthen this post (A LOT MORE). But from what I've given, it will "work" for what you're looking for, but maybe not in exactly the way you expected. However, remember that this is primarily due to silverlight restrictions. What this approach does is rather than forcing you to need a pluging to view pdf files in your app, it allows the user computer to play it's part by using the existing adobe pdf reader. In silverlight, most printing, at least to my knowledge is done my using what you call and "ImageVisual" which is a UIElement. To print a pdf directly from silverlight, you need to either be viewing that PDF in a silverlight control, or ask a web service to render the PDF as an image and then place that image in a control. Only then could you print directly. I presented this approach as a lot more clean and direct approach.
One note - with the temp directory, i would recommend doing a clean up by some timespan of the files on the server side everytime a file is being added. Saves you the work of running some task periodically to check the folder and remove old files. ;)