I'm using this well documented solution to add a back button to our app. I'm setting things up like this when the App is initialized:
Windows.UI.Core.SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible;
Windows.UI.Core.SystemNavigationManager.GetForCurrentView().BackRequested += CreateNewKeyView_BackRequested;
private void CreateNewKeyView_BackRequested(object sender, BackRequestedEventArgs e)
{
NavigationService.Instance.GoBack();
}
The back button is shown on the desktop app and works as expected, navigating our Frame back to previous pages.
However, on Windows Phone, the hardware button just exits the app. The various places that I found code like this all state that this should work for the mobile hardware button, but it simply isn't working for us.
You should set e.Handled = true in your CreateNewKeyView_BackRequested method.
Don't know how you code for your NavigationService, I just tested the following code, it works by my side:
private void CreateNewKeyView_BackRequested(object sender, BackRequestedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame != null)
{
if (rootFrame.CanGoBack)
{
e.Handled = true;
rootFrame.GoBack();
}
}
}
Or, for a phone, we use also special API for Hardware Buttons.
You can judge if the current using a phone Api is or not in the OnLaunched method:
if (Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons"))
{
Windows.Phone.UI.Input.HardwareButtons.BackPressed += OnBackPressed;
}
then complete the OnBackPressed method:
public void OnBackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame != null)
{
if (rootFrame.CanGoBack)
{
e.Handled = true;
rootFrame.GoBack();
}
}
}
To do this, you need at first add the Windows Mobile Extensions for the UWP references in your project.
Here is
private void CreateNewKeyView_BackRequested(object sender, BackRequestedEventArgs e) //event handle nya untuk backbutton
{
var frame = ((Frame)Window.Current.Content);
if (frame.CanGoBack)
{
frame.GoBack();
e.Handled = true;
}
}
Related
I have to show a web browser inside a scroll viewer in windows phone application, with these requirements :
Web browser height should be adjusted based on its content.
Web browser scrolling should be disabled, ( when user scrolls within web browser, scrolling of scroll viewer should take place )
Web browser can do pinch-zoom and navigate to links inside its content.
How can I implement that? Any links or samples is greatly appreciated.
I'm using code like this. Attach events to the Border element in the Browser control tree (I'm using Linq to Visual Tree - http://www.scottlogic.co.uk/blog/colin/2010/03/linq-to-visual-tree/).
Browser.Loaded +=
(s,e)=>
{
var border = Browser.Descendants<Border>().Last() as Border;
if (border != null)
{
border.ManipulationDelta += BorderManipulationDelta;
border.ManipulationCompleted += BorderManipulationCompleted;
border.DoubleTap += BorderDoubleTap;
}
};
Further more the implementation I'm using is to prevent pinch and zoom, something you want to have working. Though this should help you in the right direction.
private void BorderDoubleTap(object sender, GestureEventArgs e)
{
e.Handled = true;
}
private void BorderManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{
// suppress zoom
if (Math.Abs(e.DeltaManipulation.Scale.X) > 0.0||
Math.Abs(e.DeltaManipulation.Scale.Y) > 0.0)
e.Handled = true;
}
private void BorderManipulationCompleted(object sender, ManipulationCompletedEventArgs e)
{
// suppress zoom
if (Math.Abs(e.FinalVelocities.ExpansionVelocity.X) > 0.0 ||
Math.Abs(e.FinalVelocities.ExpansionVelocity.Y) > 0.0)
e.Handled = true;
}
On Mark's direction, I used
private void Border_ManipulationDelta(object sender,
System.Windows.Input.ManipulationDeltaEventArgs e)
{
e.Complete();
_browser.IsHitTestVisible = false;
}
My scenario is , When I navigate to a new page It takes some time to load the content. And for that duration of time, If I press back key it throws exception for some reason. So I want to stop the back key behaviour for that much duration and when content is fully loaded, user can press the back key and then navigate to previous page. I just want to be clear, Is it permitted in application certification requirement from microsoft so that my app could not get rejected. so please give answer.
You could do something like this:
bool flag = false;
// Assuming this is where you can handle executions during loading
loading()
{
flag = true;
}
// After loading is completed
loadComplete()
{
flag = false;
}
// Handle back button
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
if (flag)
{
e.Cancel = true;
}
}
As long as you don't lock the user to never allow him to go back, it should pass the certification.
In xaml
<phone:PhoneApplicationPage
.....
BackKeyPress="PhoneApplicationPage_BackKeyPress">
In code
private void PhoneApplicationPage_BackKeyPress(object sender, System.ComponentModel.CancelEventArgs e)
{
e.Cancel = CouldStepBack();
}
private bool CouldStepBack()
{
// todo return true, when load comleted
// else return false
}
And if you need you also can clean stack of pages (optional)
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (NavigationService.CanGoBack)
{
while (NavigationService.RemoveBackEntry() != null)
{
NavigationService.RemoveBackEntry();
}
}
base.OnNavigatedTo(e);
}
Hope its help
I am making an Flashlight app, in which I need to use the camera's LED constantly on pressing ON button and OFF it on pressing the same button. I followed this article Turning on the LED with the video camera using Reflection. The ON/OFF operation works fine only once. The Code is as:
private VideoCamera _videoCamera;
private VideoCameraVisualizer _videoCameraVisualizer;
bool _isFlashOff = true;
private void FlashButton_Click(object sender, RoutedEventArgs e)
{
try
{
if (_isFlashOff)
{
_isFlashOff = false;
// Check to see if the camera is available on the device.
if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary))
{
// Use standard camera on back of device.
_videoCamera = new VideoCamera();
// Event is fired when the video camera object has been initialized.
_videoCamera.Initialized += VideoCamera_Initialized;
// Add the photo camera to the video source
_videoCameraVisualizer = new VideoCameraVisualizer();
_videoCameraVisualizer.SetSource(_videoCamera);
}
}
else
{
_isFlashOff = true;
_videoCamera.StopRecording();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void VideoCamera_Initialized(object sender, EventArgs e)
{
_videoCamera.LampEnabled = true;
_videoCamera.StartRecording();
}
Since there was no implementation of StopRecording Method in VideoCamera class as specified in the article: Turning on the LED with the video camera using Reflection . I made the function as:
public void StopRecording()
{
// Invoke the stop recording method on the video camera object.
_videoCameraStopRecordingMethod.Invoke(_videoCamera, null);
}
The problem is when I again press ON button "Exception' is thrown as "TargetInvocationException". I am unable to figure out the problem that causes exception. Is StopRecording() function right..??
That's because you should initialize the camera only once. Do it during the OnNavigatedTo event, then re-use the same instances:
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
// Use standard camera on back of device.
_videoCamera = new VideoCamera();
// Event is fired when the video camera object has been initialized.
_videoCamera.Initialized += VideoCamera_Initialized;
// Add the photo camera to the video source
_videoCameraVisualizer = new VideoCameraVisualizer();
_videoCameraVisualizer.SetSource(_videoCamera);
}
private void VideoCamera_Initialized(object sender, EventArgs e)
{
isInitialized = true;
}
bool isInitialized;
bool isFlashEnabled;
private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
{
if (!isInitialized)
{
MessageBox.Show("Please wait during camera initialization");
return;
}
if (!isFlashEnabled)
{
isFlashEnabled = true;
// Check to see if the camera is available on the device.
if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary))
{
_videoCamera.LampEnabled = true;
_videoCamera.StartRecording();
}
}
else
{
isFlashEnabled = false;
_videoCamera.StopRecording();
}
}
Try this:
http://msdn.microsoft.com/en-us/library/hh202949.aspx
I have had a problem where on some instances in the emulator, when I click the back hardware button the back page loads with the constructor being called and some other time the constructor is not called.Why is this? Is this because its the emulator?
How are you performing navigation? Are you canceling the initial OnNavigatingFrom in order to perform an animation, then listening initiating navigation again after the animation completes?
protected override void OnNavigatingFrom(System.Windows.Navigation.NavigatingCancelEventArgs e)
{
if (_pendingNavigation == null)
{
VisualStateManager.GoToState(this, "LeavingPage", true);
_pendingNavigation = e.Uri;
e.Cancel = true;
}
base.OnNavigatingFrom(e);
}
void LeavingPage_Completed(object sender, EventArgs e)
{
var uri = _pendingNavigation;
NavigationService.Navigate(uri);
_pendingNavigation = null;
}
The bug occurs when you call NavigationService.Navigate(), which then adds a new page instance to the navigation stack. To fix this bug, you need to check and make sure the initial page navigation is a "New" navigation. Something like so:
if (e.NavigationMode == NavigationMode.New && _pendingNavigation == null)
{
VisualStateManager.GoToState(this, "LeavingPage", true);
_pendingNavigation = e.Uri;
e.Cancel = true;
}
i am trying to create a simple demo application that does the following: i have a button at MainPage.xaml (with Name="btnCamera") and an image control (with Name="photo") and when i press the button i want to start the camera task, capture a photo and display it on the image control. The problem is that my code works on the emulator but not on a real device. The device i have is updated to the latest update(7740). Do you have an explanation for that or any change to my code to make it work? That is my code:
public partial class MainPage : PhoneApplicationPage
{
CameraCaptureTask _cameraCapture;
public MainPage()
{
InitializeComponent()
_cameraCapture = new CameraCaptureTask();
_cameraCapture.Completed += new EventHandler(_cameraCapture_Completed);
}
private void btnCamera_Click(object sender, RoutedEventArgs e)
{
try
{
_cameraCapture.Show();
}
catch (Exception)
{
MessageBox.Show("Error occured");
}
}
void _cameraCapture_Completed(object sender, PhotoResult e)
{
if (e.TaskResult == TaskResult.OK)
{
BitmapImage image = new BitmapImage();
image.SetSource(e.ChosenPhoto);
photo.Source = image;
}
}
}
You need to make sure Zune is not running. The code looks fine and should work if you unplug the phone from the PC. If you want to debug whilst plugged into the PC, use WPConnect instead of Zune.