Using scatterview as a region with Prism throws an exception - prism

I'm playing around with Surface and I'm trying to use a scatterview as a module region.
<s:ScatterView cal:RegionManager.RegionName="{x:Static common:RegionNames.MainRegion}"></s:ScatterView>
What happens is that when I run the app, a exception is thrown. With a litle reflection I got to the place where the exception occours:
The DelayedRegionCreationBehavior tries to create the region:
protected virtual IRegion CreateRegion(DependencyObject targetElement, string regionName)
{
try
{
// Build the region
IRegionAdapter regionAdapter = this.regionAdapterMappings.GetMapping(targetElement.GetType());
IRegion region = regionAdapter.Initialize(targetElement, regionName);
return region;
}
catch (Exception ex)
{
throw new RegionCreationException(string.Format(CultureInfo.CurrentCulture, Resources.RegionCreationException, regionName, ex), ex);
}
}
Then the ItemsControlRegionAdapter attemps to the set region target ItemsSource:
protected override void Adapt(IRegion region, ItemsControl regionTarget)
{
bool itemsSourceIsSet = regionTarget.ItemsSource != null;
#if !SILVERLIGHT
itemsSourceIsSet = itemsSourceIsSet || (BindingOperations.GetBinding(regionTarget, ItemsControl.ItemsSourceProperty) != null);
#endif
if (itemsSourceIsSet)
{
throw new InvalidOperationException(Resources.ItemsControlHasItemsSourceException);
}
// If control has child items, move them to the region and then bind control to region. Can't set ItemsSource if child items exist.
if (regionTarget.Items.Count > 0)
{
foreach (object childItem in regionTarget.Items)
{
region.Add(childItem);
}
// Control must be empty before setting ItemsSource
regionTarget.Items.Clear();
}
regionTarget.ItemsSource = region.Views;
}
The scatterview fires a notification of the ItemsSource change and class the ItemsControlHelper is called :
internal static bool IsItemsReadOnly(ItemsControl itemsControl)
{
IList itemsControlItems = GetItemsControlItems(itemsControl);
if (!itemsControlItems.IsReadOnly)
{
return itemsControlItems.IsFixedSize;
}
return true;
}
I think that the GetItemsControlItems returns null, causing the exception.
Any thoughts on how to overcome this situation?

I think this is a known issue with ScatterView. We are aware of the issue, and will fix it for the future. If it is the same issue we have seen, it has to do with the ItemsSource of the ScatterView being an IList<foo> or some other "generic" list. If you could change your ItemSource to be a simple IList (not an IList<foo>), I think that would resolve your issue.
I hope this helps,
-Luis Cabrera
Software Design Engineer, Microsoft Surface

Related

Turning Bluetooth Tethering On in Xamarin.Android

I'm currently trying to add some Bluetooth functionality to my app. I want to be able to change the Bluetooth Tethering on or off, as well as check its status.
I found the Java code on StackOverflow: How to check Bluetooth tethering status programmatically in Android
I have translated it into C#, but I don't seem to be able to get any result.
Regardless of the tethering setting, it always shows the toast with "Tethering:false", and the setBluetoothTethering doesn't change anything.
Any idea what I'm missing?
Here's my code:
[...]
try
{
Class classBluetoothPan = Class.ForName("android.bluetooth.BluetoothPan");
Method mBTPanConnect = classBluetoothPan.GetDeclaredMethod("connect", Class.FromType(typeof(BluetoothDevice)));
Constructor BTPanCtor = classBluetoothPan.GetDeclaredConstructor(Class.FromType(typeof(Context)), Class.FromType(typeof(IBluetoothProfileServiceListener)));
BTPanCtor.Accessible = true;
Java.Lang.Object BTSrvInstance = BTPanCtor.NewInstance(Activity, new BTPanServiceListener(Activity));
Method isTetheringOnMethod = classBluetoothPan.GetDeclaredMethod("isTetheringOn", null);
var isTetheringOn = isTetheringOnMethod.Invoke(BTSrvInstance);
Toast.MakeText(Activity, "Tethering:" + isTetheringOn, ToastLength.Short).Show();
Method setBluetoothTetheringMethod = classBluetoothPan.GetDeclaredMethod("setBluetoothTethering", new Class[1] { Class.FromType(typeof(bool)) });
setBluetoothTetheringMethod.Invoke(BTSrvInstance, true);
// tether = !tether;
}
catch (ClassNotFoundException e)
{
e.PrintStackTrace();
}
catch (Java.Lang.Exception e)
{
e.PrintStackTrace();
}
[...]
public class BTPanServiceListener : Java.Lang.Object, IBluetoothProfileServiceListener
{
private Activity _activity;
public BTPanServiceListener(Activity activity)
{
_activity = activity;
}
public void OnServiceConnected([GeneratedEnum] ProfileType profile, IBluetoothProfile proxy)
{
// throw new NotImplementedException();
}
public void OnServiceDisconnected([GeneratedEnum] ProfileType profile)
{
// throw new NotImplementedException();
}
}
I figured out how to enable Bluetooth tethering via setBluetoothTethering.
I wrote an entire blog about this
You can find the final code here
I assume that isTetheringOn works in the same way

Fatal error when camera is initializing and back button is pressed or page navigating

I'm working on WP7/8 application with barcode scanning. And have a problem with disposing camera. Camera initialize too long, and when camera is still initializing and I press back button, I've got a fatal error:
A first chance exception of type 'System.ObjectDisposedException'
occurred in Microsoft.Devices.Camera.ni.dll WinRT information: Fatal
error. Disposing capture device.
Could anybody helps me how to avoid this error?
my code:
protected override void OnNavigatedTo(NavigationEventArgs e)
{
InitializeAndGo();
base.OnNavigatedTo(e);
}
protected override void OnNavigatingFrom(System.Windows.Navigation.NavigatingCancelEventArgs e)
{
disposeCamera();
}
private void PhotoCameraOnInitialized(object sender, CameraOperationCompletedEventArgs cameraOperationCompletedEventArgs)
{
_width = Convert.ToInt32(_photoCamera.PreviewResolution.Width);
_height = Convert.ToInt32(_photoCamera.PreviewResolution.Height);
_luminance = new PhotoCameraLuminanceSource(_width, _height);
if (_photoCamera.IsFlashModeSupported(FlashMode.Auto))
{
_photoCamera.FlashMode = FlashMode.Off;
}
cameraInitialized = true;
Dispatcher.BeginInvoke(() =>
{
FlashCheckbox.IsEnabled = true;
if (_photoCamera.IsFlashModeSupported(FlashMode.Auto))
{
_photoCamera.FlashMode = FlashMode.Off;
}
});
_photoCamera.Focus();
}
private void InitializeAndGo()
{
stopScan = false;
_photoCamera = new PhotoCamera();
_photoCamera.Initialized += PhotoCameraOnInitialized;
_photoCamera.AutoFocusCompleted += PhotoCameraOnAutoFocusCompleted;
viewfinderBrush.SetSource(_photoCamera);
_previewTransform.Rotation = _photoCamera.Orientation;
_results = new ObservableCollection<Result>();
_barcodeReader = new BarcodeReader();
_barcodeReader.TryHarder = true;
_barcodeReader.AutoRotate = true;
_service = new MyMoviesDataService(ErrorDataService);
}
private void disposeCamera()
{
try
{
cameraInitialized = false;
StopScan();
_photoCamera.Initialized -= PhotoCameraOnInitialized;
_photoCamera.AutoFocusCompleted -= PhotoCameraOnAutoFocusCompleted;
_photoCamera.Dispose();
_photoCamera = null;
}
catch (Exception ex)
{
App.ShowErrorToast(ex.Message);
}
}
Don't use the camera until it's been successfully initialized (You can check this in the camera's Initialized event).
Also, wrap any usages of the camera in a
try
{
// camera code here
}
catch (ObjectDisposedException)
{
// re-initialize the camera?
}
to handle situations like suspension, which will dispose of the camera automatically.
As for the
An exception of type 'System.ObjectDisposedException' occurred in
Microsoft.Devices.Camera.ni.dll and wasn't handled before a
managed/native boundary WinRT information: Fatal error. Disposing
capture device.
This is something Microsoft needs to fix; I mean, how are you supposed to handle a native code exception if it isn't allowed to propagate to managed code?
Where is the exception coming from (which code line / block)?
I would for starter put a try...catch around InitializeAndGo() in the OnNavigatedTo event handler. And on the whole PhotoCameraOnInitialized event handler also.
Cheers,

GLSurfaceView.Renderer crashes when resuming because "bitmap is recycled"

once again I need some help:
yesterday I asked this question that was about the way to use a large jpg image as a Bitmap (http://stackoverflow.com/questions/13511657/problems-with-big-drawable-jpg-image) and I resolved myself (Is my own response on that question) but whenever I resume my activity, as it uses that bitmap as the GLRenderer texture it crashes. I've tried many things, the last try was to make that bitmap static in order to keep it as a member variable into the activity but it crashes because, I supose, it looses it's mBuffer.
More details on the Activity code:
I declared it as SingletonInstance into the manifest:
android:launchMode="singleInstance"
in order to keep the tiles for the renderer.
and here some code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mGLSurfaceView = new GLSurfaceView(this);
mGLSurfaceView.setEGLConfigChooser(true);
mSimpleRenderer = new GLRenderer(this);
getTextures();
if (!mIsTileMapInitialized){
tileMap = new LandSquareGrid(1, 1, mHeightmap, mLightmap, false, true, true, 128, true);
tileMap.setupSkybox(mSkyboxBitmap, true);
mIsTileMapInitialized = true;
}
initializeRenderer();
mGLSurfaceView.setRenderer(mSimpleRenderer);
setContentView( R.layout.game_layout );
setOnTouchListener();
initializeGestureDetector();
myCompassView = (MyCompassView)findViewById(R.id.mycompassview);
// Once set the content view we can set the TextViews:
coordinatesText = (TextView) findViewById(R.id.coordDynamicText);
altitudeText = (TextView) findViewById(R.id.altDynamicText);
directionText = (TextView) findViewById(R.id.dirDynamicText);
//if (!mIsGLInitialized){
mOpenGLLayout = (LinearLayout)findViewById(R.id.openGLLayout);
mOpenGLLayout.addView(mGLSurfaceView);
mVirtual3DMap = new Virtual3DMap(mSimpleRenderer, tileMap);
if (mGameThread == null){
mGameThread = new Thread(mVirtual3DMap);
mGameThread.start();
}
}
On getTextures method I get few small textures and the largest one as in my last question self response:
if (mTerrainBitmap==null){
InputStream is = getResources().openRawResource(R.drawable.terrain);
try {
// Set terrain bitmap options to 16-bit, 565 format.
terrainBitmapOptions.inPreferredConfig = Bitmap.Config.RGB_565;
Bitmap auxBitmap = BitmapFactory.decodeStream(is, null, terrainBitmapOptions);
mTerrainBitmap = Bitmap.createBitmap(auxBitmap);
}
catch (Exception e){
}
finally {
try {
is.close();
}
catch (IOException e) {
// Ignore.
}
}
}
So, again, first time it works great but when I go back I do:
protected void onPause() {
super.onPause();
mGLSurfaceView.onPause();
}
#Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
if (mVirtual3DMap != null) {
try {
mVirtual3DMap.cancel();
mGameThread=null;
mVirtual3DMap = null;
mGLSurfaceView.destroyDrawingCache();
mSimpleRenderer=null;
System.gc();
} catch (Throwable e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
And whan I resume the activity:
#Override
protected void onResume() {
super.onResume();
mGLSurfaceView.onResume();
if (mVirtual3DMap != null) {
try {
mVirtual3DMap.resume();
} catch (Throwable e) {
e.printStackTrace();
}
}
}
And it crashes.
Why?? Ok, here is the exception cause on the GLThread:
java.lang.IllegalArgumentException: bitmap is recycled...
I tried this messy stuff because launching more than two times the original activity the application crashes bacuse of this or because of the amount of memory used and now I don't know if revert all these changes or what todo with this.
Is there a good way to keep in memory and usable, by this or another application activity, this bitmap?
Please, I need your advices.
Thanks in advance.
Do not handle resources manually or your app's surface will broke up. You can't handle your resources manually.
If you worry about reloading resources and you use API level 11+, you can use setPreserveEGLContextOnPause(). It will perserve your textures and FBOs.
If you can't use API 11+, you can port GLSurfaceView() to your app. You can check my own GLSurfaceView that is ported from ICS.
PS: Sorry about my poor english.
No. Let Android handle all the resources. You must handle the appropriate events and reload the bitmap when the activity is resumed. You cannot expect, that any OpenGL handles are still valid after the activity has been resumed.
Think of it as in the example of a laptop coming out from hibernation. Although all memory has been restored, you cannot expect that any open socket has still a real active connection going.
I am an Android noobie, so please correct me if I am wrong.

MVVM - View loading and eventhandling

In my windows phone app, I need to track some events to get a good flow. But I'm not sure how to handle them in good sequence.
What needs to be done at startup of the app:
Main view is loaded and corresponding view model instantiated
In the constructor of the view model I initiate a login sequence that signals when completed with an eventhandler
Now when the login sequence has finished AND the view is completely loaded I need to startup another sequence.
But here is the problem, the order of these 2 events 'completing' is not always the same...
I've use the EventToCommand from MVVMLight to signal the view model that the view has 'loaded'.
Any thoughts on how to synchronize this.
As you should not use wait handles or something similar on the UI thread. You will have to sync the two method using flags in your view model and check them before progressing.
So, implement two boolean properties in your view model. Now when the login dialog is finished set one of the properties (lets call it IsLoggedIn) to true, and when the initialization sequence is finished you set the other property (how about IsInitialized) to true. The trick now lies in the implementation of the setter of these two properties:
#region [IsInitialized]
public const string IsInitializedPropertyName = "IsInitialized";
private bool _isInitialized = false;
public bool IsInitialized {
get {
return _isInitialized;
}
set {
if (_isInitialized == value)
return;
var oldValue = _isInitialized;
_isInitialized = value;
RaisePropertyChanged(IsInitializedPropertyName);
InitializationComplete();
}
}
#endregion
#region [IsLoggedIn]
public const string IsLoggedInPropertyName = "IsLoggedIn";
private bool _isLoggedIn = false;
public bool IsLoggedIn {
get {
return _isLoggedIn;
}
set {
if (_isLoggedIn == value)
return;
var oldValue = _isLoggedIn;
_isLoggedIn = value;
RaisePropertyChanged(IsLoggedInPropertyName);
InitializationComplete();
}
}
#endregion
public void InitializationComplete() {
if (!(this.IsInitialized && this.IsLoggedIn))
return;
// put your code here
}
Alternatively you can remove the InitializationComplete from the setters and change InitializationComplete to:
public void InitializationComplete() {
// put your code here
}
Then subscribe to the 'PropertyChanged' event use the following implementation:
private void Class1_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e) {
if (e.PropertyName == IsInitializedPropertyName || e.PropertyName == IsLoggedInPropertyName) {
if (this.IsInitialized && this.IsLoggedIn)
InitializationComplete();
}
}

Silverlight TabItem template not working correctly

In a SL4 application i need to restyle my TabItems (actually add a button in the header).
So i took the TabItem's control template from here and added the functionality i wanted.
This seems to work fine, (i could dynamically add tabitems) with one exception:
i think this posted control template is behaving somehow "arbitrary": every time the mouse hoovers over a non selected TabItem header, this gets selected WHITHOUT clicking!! (afaik this is not the default behavior: the user user has to click a header to make this tabitem the selected one).
I tried to find why it is behaving like this, with no luck!
Is there someone who can enlighten my darkness???
Thanks in advance!
Well it turns out the error was not in the control template but in the class, the style was applied to.
In detail: the class the style was applied to is the following (in it you will see my comment about the "wrong behavior"):
public class WorkspaceViewModel : TabItem
{
public WorkspaceViewModel()
{
DefaultStyleKey = typeof(WorkspaceViewModel);
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
Button closeButtonSel = base.GetTemplateChild("PART_CloseTopSelected") as Button;
Button closeButtonUnsel = base.GetTemplateChild("PART_CloseTopUnSelected") as Button;
if (closeButtonSel != null)
closeButtonSel.Click += new RoutedEventHandler(closeButtonSel_Click);
if (closeButtonUnsel != null)
closeButtonUnsel.Click += new RoutedEventHandler(closeButtonSel_Click);
//this part is causing the effect i was complaining about!
//and has to be removed
this.MouseEnter += delegate(object sender, MouseEventArgs e)
{
IsSelected = true;
};
}
void closeButtonSel_Click(object sender, RoutedEventArgs e)
{
//this is the close request method used in the CloseTabItemCommand
OnRequestClose();
}
#region CloseTabItemCommand
private RelayCommand closeTabItemCommand;
public ICommand CloseTabItemCommand
{
get
{
if (this.closeTabItemCommand == null)
this.closeTabItemCommand = new RelayCommand(p => this.OnRequestClose(), p => this.CanCloseTabItem());
return this.closeTabItemCommand;
}
}
private bool CanCloseTabItem()
{
return true;
}
public event EventHandler RequestClose;
private void OnRequestClose()
{
if (RequestClose != null)
RequestClose(this, EventArgs.Empty);
}
#endregion
}

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