in my project i use HttpWebRequest to download Feed. But when i download , memory increase and not decrease when they return to the previous form :
#region RequestDataFromServer
private void RequestDataFromServer(object o)
{
if (!string.IsNullOrEmpty(ServerUri))
{
if (DownloadStatus == DownloadState.Downloading)
return;
DownloadStatus = DownloadState.Downloading;
HttpWebRequest serverRequest = (HttpWebRequest)WebRequest.Create(ServerUri);
serverState = new ServerRequestUpdateState();
serverState.AsyncRequest = serverRequest;
IAsyncResult result =
(IAsyncResult)serverRequest.BeginGetResponse(new AsyncCallback(RequestResponse), serverState);
}
}
#endregion
#region RequestResponse
void RequestResponse(IAsyncResult asyncResult)
{
var offlineStream = IsolatedStorageSettings.ApplicationSettings;
serverState = (ServerRequestUpdateState)asyncResult.AsyncState;
HttpWebRequest serverRequest = (HttpWebRequest)serverState.AsyncRequest;
try
{
serverState.AsyncResponse = (HttpWebResponse)serverRequest.EndGetResponse(asyncResult);
if (serverState != null)
{
Stream stream = serverState.AsyncResponse.GetResponseStream();
if (stream != null && serverState.AsyncResponse.StatusCode == HttpStatusCode.OK)
{
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
DownloadStatus = DownloadState.FileReady;
if (serverState != null)
{
try
{
if (offlineStream.Contains("streamOffline"))
{
offlineStream["streamOffline"] = null;
offlineStream.Remove("streamOffline");
}
offlineStream.Add("streamOffline", stream);
if (onComplete != null)
onComplete.Invoke(this, DownloadStatus, IndexImg);
stream.Close();
stream.Dispose();
stream = null;
}
catch (Exception)
{ }
}
});
}
}
}
catch (WebException ex)
{
DownloadStatus = DownloadState.Error;
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
//if (onComplete != null)
// onComplete.Invoke(this, DownloadStatus, null, IndexImg);
});
}
catch (Exception)
{ }
finally
{
serverRequest = null;
}
}
#endregion
I thought I had destroyed all the things that can increase the memory, but the memory is still very high up, I saved Isostorage Stream I get into, but it still does not reduce
In .NET memory doesn't decrease at the moment you dispose an object. It would go down when the GC fires up next time.
Read more on... http://msdn.microsoft.com/en-us/magazine/bb985010.aspx
How are you determining that memory is high?
Related
Apologies for my English :) Following is my Web API .NET Framework 4.8 Compression Handler which i copied from an old blog to compress the response manually for Android Client
public class CompressionHandler : HttpContent
{
private HttpContent originalContent;
private string encodingType;
public CompressionHandler(HttpContent content, string encodingType)
{
if (content == null)
{
throw new ArgumentNullException("content");
}
if (encodingType == null)
{
throw new ArgumentNullException("encodingType");
}
originalContent = content;
this.encodingType = encodingType.ToLowerInvariant();
if (this.encodingType != "gzip" && this.encodingType != "deflate")
{
throw new InvalidOperationException(string.Format("Encoding '{0}' is not supported. Only supports gzip or deflate encoding.", this.encodingType));
}
// copy the headers from the original content
foreach (KeyValuePair<string, IEnumerable<string>> header in originalContent.Headers)
{
this.Headers.TryAddWithoutValidation(header.Key, header.Value);
}
this.Headers.ContentEncoding.Add(encodingType);
}
protected override bool TryComputeLength(out long length)
{
length = originalContent.Headers.ContentLength.GetValueOrDefault();
return false;
}
protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
Stream compressedStream = null;
if (encodingType == "gzip")
{
compressedStream = new GZipStream(stream, CompressionMode.Compress, leaveOpen: false);
}
else if (encodingType == "deflate")
{
compressedStream = new DeflateStream(stream, CompressionMode.Compress, leaveOpen: true);
}
return originalContent.CopyToAsync(compressedStream).ContinueWith(tsk =>
{
if (compressedStream != null)
{
compressedStream.Dispose();
}
});
}
}
Following is the code in delegate handler to compress the response contents.
return await base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>((responseToCompleteTask) =>
{
HttpResponseMessage response = responseToCompleteTask.Result;
if (response.RequestMessage?.Headers?.AcceptEncoding != null)
{
string encodingType = response.RequestMessage.Headers.AcceptEncoding.First().Value;
IEnumerable<string> headerValues2 = null;
request.Headers.TryGetValues("pHubDeCompression", out headerValues2);
var id = headerValues2?.FirstOrDefault();
if (id == "1")
response.Content = new CompressionHandler(response.Content, encodingType);
}
return response;
},
TaskContinuationOptions.OnlyOnRanToCompletion);
Problem is when I hit the api from post man It keep loading the response which ends in connection reset but I get HTTP 200 already. Please see the following image (Same Request Images at different time).
we have implement file chooser for web view. it works successfully when attachment is selected, but fails when cancelled without file specification. The file chooser just stops to react on click
any help is appreciated. Thanks
we use chrome client. it works fine if in all cases, file selection is listed. but even from the first file selection is cancelled, no longer file chooser will work. It is Xamarin.Android app based fully on webview
Our code is:
protected override void OnActivityResult(int requestCode, Result resultCode, Intent intent)
{
if (requestCode == FILECHOOSER_RESULTCODE)
{
if (null == _mUploadMessage)
return;
// Check that the response is a good one
if (resultCode == Result.Ok)
{
Android.Net.Uri[] results = null;
if (intent == null)
{
// If there is not data, then we may have taken a photo
if (mCameraPhotoPath != null)
{
results = new Android.Net.Uri[] { Android.Net.Uri.Parse(mCameraPhotoPath) };
}
}
else
{
if (intent.DataString != null)
{
results = new Android.Net.Uri[] { Android.Net.Uri.Parse(intent.DataString) };
}
}
_mUploadMessage.OnReceiveValue(results);
_mUploadMessage = null;
}
}
}
Chrome client:
var chrome = new FileChooserWebChromeClient((uploadMsg) =>
{
_mUploadMessage = uploadMsg;
mCameraPhotoPath = null;
Intent takePictureIntent = new Intent(Android.Provider.MediaStore.ActionImageCapture);
//Create the File where the photo should go
File photoFile = null;
try
{
string folder = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
photoFile = new File(folder, "image" + DateTime.Now.Millisecond + ".png");
takePictureIntent.PutExtra("PhotoPath", mCameraPhotoPath);
}
catch (IOException ex)
{
// Error occurred while creating the File
System.Console.WriteLine("" + ex.ToString());
}
// Continue only if the File was successfully created
if (photoFile != null)
{
mCameraPhotoPath = "file:" + photoFile.AbsolutePath;
takePictureIntent.PutExtra(Android.Provider.MediaStore.ExtraOutput,
Android.Net.Uri.FromFile(photoFile));
}
else
{
takePictureIntent = null;
}
Intent contentSelectionIntent = new Intent(Intent.ActionGetContent);
contentSelectionIntent.AddCategory(Intent.CategoryOpenable);
contentSelectionIntent.SetType("image/*");
Intent[] intentArray;
if (takePictureIntent != null)
{
intentArray = new Intent[] { takePictureIntent };
}
else
{
intentArray = new Intent[0];
}
Intent chooserIntent = new Intent(Intent.ActionChooser);
chooserIntent.PutExtra(Intent.ExtraIntent, contentSelectionIntent);
chooserIntent.PutExtra(Intent.ExtraTitle, this.GetStringFromResource(Resource.String.chose_photo));
chooserIntent.PutExtra(Intent.ExtraInitialIntents, intentArray);
base.StartActivityForResult(chooserIntent, HarmonyAndroid.AndroidMainActivity.FILECHOOSER_RESULTCODE);
});
return chrome;
Part 2
class FileChooserWebChromeClient : WebChromeClient
{
Action<IValueCallback> callback;
public FileChooserWebChromeClient(Action<IValueCallback> callback)
{
this.callback = callback;
}
public override bool OnShowFileChooser(WebView webView, IValueCallback filePathCallback, FileChooserParams fileChooserParams)
{
callback(filePathCallback);
return true;
}
public override void OnCloseWindow(WebView window)
{
base.OnCloseWindow(window);
}
}
Part 3
webView.ImprovePerformance();
webView.SetWebViewClient(new HomeWebViewClient(customWebViewClientListener, clientId));
webView.SetWebChromeClient(chrome);
webView.Settings.JavaScriptEnabled = true;
webView.Settings.DomStorageEnabled = true;
webView.SetDownloadListener(new CustomDownloadListener(activity, customDownloadListener));
webView.AddJavascriptInterface(new JavaScriptToCSharpCommunication(activity, javaScriptToCSharpCommunicationListener), Constants.JS_CSHARP_COMMUNICATOR_NAME);
Try to give a null object to the uri callback, when the resultCode is not RESULT_OK.
add in your OnActivityResult method:
if (resultCode != Result.Ok)
{
_mUploadMessage.OnReceiveValue(null);
_mUploadMessage = null;
return;
}
I have an forms app where i need to pick "1 to many" images from the phone storage.
For this i use the dependency injection system.
My problem is the somewhere i get an Android.netUri that resolves to a file that do not exist... and to a file name that i have never seen before.
The kicker is that if i pick pictures that was takes within the last couple of hours this code works...
Im am at the end of my hoap, i really hope someone can point me to something that i'm doing wrong.
i start the Picker activity with:
[assembly: Dependency(typeof(ImagePickerService))]
namespace MyApp.Droid
{
public class ImagePickerService : Java.Lang.Object, IImagePickerService
{
public async Task OpenGallery()
{
try
{
var status = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Storage);
if (status != PermissionStatus.Granted)
{
if (await CrossPermissions.Current.ShouldShowRequestPermissionRationaleAsync(Permission.Storage))
{
Toast.MakeText(CrossCurrentActivity.Current.Activity, "Need Storage permission to access to your photos.", ToastLength.Long).Show();
}
var results = await CrossPermissions.Current.RequestPermissionsAsync(new[] { Permission.Storage });
status = results[Permission.Storage];
}
if (status == PermissionStatus.Granted)
{
Toast.MakeText(CrossCurrentActivity.Current.Activity, "Pick max 20 images", ToastLength.Long).Show();
var imageIntent = new Intent(Intent.ActionPick);
imageIntent.SetType("image/*");
imageIntent.PutExtra(Intent.ExtraAllowMultiple, true);
imageIntent.SetAction(Intent.ActionPick);
CrossCurrentActivity.Current.Activity.StartActivityForResult(Intent.CreateChooser(imageIntent, "Pick pictures"), 100);
}
else if (status != PermissionStatus.Unknown)
{
Toast.MakeText(CrossCurrentActivity.Current.Activity, "Permission Denied. Can not continue, try again.", ToastLength.Long).Show();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
Toast.MakeText(CrossCurrentActivity.Current.Activity, "Error. Can not continue, try again.", ToastLength.Long).Show();
}
}
}
then in my MainActivity.cs i have the OnActivityResult
I have tried to use the ContentResolver.OpenInputStream to get the image bytes with no luck, so this is commented out atm.
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
if (requestCode == OPENGALLERYCODE && resultCode == Result.Ok)
{
List<string> images = new List<string>();
if (data != null)
{
ClipData clipData = data.ClipData;
if (clipData != null)
{
for (int i = 0; i < clipData.ItemCount; i++)
{
ClipData.Item item = clipData.GetItemAt(i);
/*
var stream = ContentResolver.OpenInputStream(item.Uri); //This throws "FileNotFound"
byte[] byteArray;
using (var memoryStream = new MemoryStream())
{
stream.CopyTo(memoryStream);
byteArray = memoryStream.ToArray();
stream.Close();
stream = null;
}
stream = ContentResolver.OpenInputStream(item.Uri);
var exif = new ExifInterface(stream);
stream.Close();
*/
Android.Net.Uri uri = item.Uri;
var path = GetActualPathFromFile(uri);
if (path != null)
{
var tmpImgPath = RotateToOriginalDimention(path);
images.Add(tmpImgPath);
}
}
}
else
{
Android.Net.Uri uri = data.Data;
var path = GetActualPathFromFile(uri);
if (path != null)
{
var tmpImgPath = RotateToOriginalDimention(path);
images.Add(tmpImgPath);
}
}
MessagingCenter.Send<App, List<string>>((App)Xamarin.Forms.Application.Current, "ImagesSelected", images);
}
}
}
And the GetActualPathFromFile (also in my MainActivity.cs)
The hole func is below but i hit this part of the code and get at "FileNotFound"
(...)
else if ("content".Equals(uri.Scheme, StringComparison.OrdinalIgnoreCase))
{
var retval2 = getDataColumn(this, uri, null, null);
if (File.Exists(retval2)) //<----------------------- This returns "false"
{
return retval2;
}
else
{
throw new Exception("file not found " + retval2);
}
}
(...)
The Hole GetActualPathFromFile
private string GetActualPathFromFile(Android.Net.Uri uri)
{
bool isKitKat = Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Kitkat;
if (isKitKat && DocumentsContract.IsDocumentUri(this, uri))
{
// ExternalStorageProvider
if (isExternalStorageDocument(uri))
{
string docId = DocumentsContract.GetDocumentId(uri);
char[] chars = { ':' };
string[] split = docId.Split(chars);
string type = split[0];
if ("primary".Equals(type, StringComparison.OrdinalIgnoreCase))
{
var retval = Android.OS.Environment.ExternalStorageDirectory + "/" + split[1];
if (File.Exists(retval))
{
return retval;
}
else
{
throw new Exception("file not found " + retval);
}
}
}
// DownloadsProvider
else if (isDownloadsDocument(uri))
{
string id = DocumentsContract.GetDocumentId(uri);
Android.Net.Uri contentUri = ContentUris.WithAppendedId(
Android.Net.Uri.Parse("content://downloads/public_downloads"), long.Parse(id));
//System.Diagnostics.Debug.WriteLine(contentUri.ToString());
var retval = getDataColumn(this, contentUri, null, null);
if (File.Exists(retval))
{
return retval;
}
else
{
throw new Exception("file not found " + retval);
}
}
// MediaProvider
else if (isMediaDocument(uri))
{
String docId = DocumentsContract.GetDocumentId(uri);
char[] chars = { ':' };
String[] split = docId.Split(chars);
String type = split[0];
Android.Net.Uri contentUri = null;
if ("image".Equals(type))
{
contentUri = MediaStore.Images.Media.ExternalContentUri;
}
else if ("video".Equals(type))
{
contentUri = MediaStore.Video.Media.ExternalContentUri;
}
else if ("audio".Equals(type))
{
contentUri = MediaStore.Audio.Media.ExternalContentUri;
}
String selection = "_id=?";
String[] selectionArgs = new String[]
{
split[1]
};
var retval = getDataColumn(this, contentUri, selection, selectionArgs);
if (File.Exists(retval))
{
return retval;
}
else
{
throw new Exception("file not found " + retval);
}
}
}
// MediaStore (and general)
else if ("content".Equals(uri.Scheme, StringComparison.OrdinalIgnoreCase))
{
// Return the remote address
if (isGooglePhotosUri(uri))
{
var retval = uri.LastPathSegment;
if (File.Exists(retval))
{
return retval;
}
else
{
throw new Exception("file not found " + retval);
}
}
var retval2 = getDataColumn(this, uri, null, null);
if (File.Exists(retval2))
{
return retval2;
}
else
{
throw new Exception("file not found " + retval2);
}
}
// File
else if ("file".Equals(uri.Scheme, StringComparison.OrdinalIgnoreCase))
{
var retval = uri.Path;
if (File.Exists(retval))
{
return retval;
}
else
{
throw new Exception("file not found " + retval);
}
}
throw new Exception("file not found ");
}
public static String getDataColumn(Context context, Android.Net.Uri uri, String selection, String[] selectionArgs)
{
ICursor cursor = null;
String column = "_data";
String[] projection =
{
column
};
try
{
cursor = context.ContentResolver.Query(uri, projection, selection, selectionArgs, null);
if (cursor != null && cursor.MoveToFirst())
{
int index = cursor.GetColumnIndexOrThrow(column);
return cursor.GetString(index);
}
}
finally
{
if (cursor != null)
cursor.Close();
}
return null;
}
//Whether the Uri authority is ExternalStorageProvider.
public static bool isExternalStorageDocument(Android.Net.Uri uri)
{
return "com.android.externalstorage.documents".Equals(uri.Authority);
}
//Whether the Uri authority is DownloadsProvider.
public static bool isDownloadsDocument(Android.Net.Uri uri)
{
return "com.android.providers.downloads.documents".Equals(uri.Authority);
}
//Whether the Uri authority is MediaProvider.
public static bool isMediaDocument(Android.Net.Uri uri)
{
return "com.android.providers.media.documents".Equals(uri.Authority);
}
//Whether the Uri authority is Google Photos.
public static bool isGooglePhotosUri(Android.Net.Uri uri)
{
return "com.google.android.apps.photos.content".Equals(uri.Authority);
}
Found out that the real problem was that Google Photos App was not updating and was still showing images that were deleted.
After 2x reboot of the phone, Google Photos app finally updated.
So this looks more like a cache problem with Google Foto than a xamarin problem.
I am facing a problem in value 'return' in Asynctask class in doInBackground method. I am getting an error, about 'missing return statement in below code.
`public class ForecastNetwork extends AsyncTask {
public final String TAG = ForecastNetwork.class.getSimpleName();
#Override
protected Void doInBackground(Void... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String forecastJsonStr = null;
try {
// Construct the URL for the OpenWeatherMap query
// Possible parameters are avaiable at OWM's forecast API page, at
// http://openweathermap.org/API#forecast
URL url = new URL("http://api.openweathermap.org/data/2.5/forecast/daily?q=94043&mode=json&units=metric&cnt=7");
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
forecastJsonStr = buffer.toString();
} catch (IOException e) {
Log.e(TAG, "Error ", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(TAG, "Error closing stream", e);
}
}
}
}`
What Should I return at the end?
I assume that you forgot to return the processing result
forecastJsonStr = buffer.toString();
return forecastJsonStr;
Does anyone know great idea How to return result to UI thread ?
I wrote this code, but It will be compile error because it can't return "img" in async.
public byte[] DownloadAsync2(Uri address)
{
byte[] img;
byte[] buffer = new byte[4096];
var wc = new WebClient();
wc.OpenReadCompleted += ((sender, e) =>
{
using (MemoryStream memoryStream = new MemoryStream())
{
int count = 0;
do
{
count = e.Result.Read(buffer, 0, buffer.Length);
memoryStream.Write(buffer, 0, count);
} while (count != 0);
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
if (e.Error == null) img = memoryStream.ToArray();
});
}
}
);
wc.OpenReadAsync(address);
return img; //error : Use of unassigned local variable 'img'
}
Change your method to:
public void DownloadAsync2(Uri address, Action<byte[]> callback, Action<Exception> exception)
{
var wc = new WebClient();
wc.OpenReadCompleted += ((sender, e) =>
{
using (MemoryStream memoryStream = new MemoryStream())
{
int count = 0;
do
{
count = e.Result.Read(buffer, 0, buffer.Length);
memoryStream.Write(buffer, 0, count);
} while (count != 0);
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
if (e.Error == null) callback(memoryStream.ToArray());
else exception(e.Error);
});
}
}
);
wc.OpenReadAsync(address);
}
Usage:
DownloadAsync2(SomeUri, (img) =>
{
// this line will be executed when image is downloaded,
// img - returned byte array
},
(exception) =>
{
// handle exception here
});
Or (old-style code without lambda expressions):
DownloadAsync2(SomeUri, LoadCompleted, LoadFailed);
// And define two methods for handling completed and failed events
private void LoadCompleted(byte[] img)
{
// this line will be executed when image is downloaded,
// img - returned byte array
}
private void LoadFailed(Exception exception)
{
// handle exception here
}