CODEWITHSUNDEEP
asynchronouscamerawindows-phone
Rudi
Rudi

Reputation: 936

Windows Phone change CameraType

I'm trying to change the CameraType (FrontFacing/Primary) of my Camera in my app.

<Grid x:Name="LayoutRoot" Background="Transparent">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="Auto" />
    </Grid.ColumnDefinitions>

    <Canvas x:Name="viewfinderCanvas" Width="720" Height="480" 
               HorizontalAlignment="Left" >

        <!--Camera viewfinder -->
        <Canvas.Background>
            <VideoBrush x:Name="viewfinderBrush" />
        </Canvas.Background>

        <!-- Brackets for Touch Focus -->
        <TextBlock 
            x:Name="focusBrackets" 
            Text="[   ]" 
            FontSize="40"
            Visibility="Collapsed"/>

    </Canvas>

    <!--Button StackPanel to the right of viewfinder>-->
    <StackPanel Grid.Column="1" >
        <Button Content="Front" Name="btCameraType" Click="changeFacing_Clicked" FontSize="26" FontWeight="ExtraBold" Height="75"/>
    </StackPanel>

    <!--Used for debugging >-->
    <TextBlock Height="40" HorizontalAlignment="Left" Margin="8,428,0,0" Name="txtDebug" VerticalAlignment="Top" Width="626" FontSize="24" FontWeight="ExtraBold" />
</Grid>

And this is the Code Behind:

private void changeFacing_Clicked(object sender, RoutedEventArgs e)
{
    if (cam.CameraType == CameraType.FrontFacing)
        cam = new Microsoft.Devices.PhotoCamera(CameraType.Primary);
    else
        cam = new Microsoft.Devices.PhotoCamera(CameraType.FrontFacing);
    viewfinderBrush.Dispatcher.BeginInvoke(delegate()
    {
        viewfinderBrush.SetSource(cam);
    });
}

So I'm actually just changing the CameraType when the user clicks on a button. The problem is that when the user clicks several times on the button (so like 5 times in 2 seconds), the program can't handle it and it stops working... Any solution on how to avoid this problem?

I've also tried en-/disabling the button, but I still can click on the button..

Upvotes: 0

Views: 152

Answers (1)

Olivier Payen
Olivier Payen

Reputation: 15268

The problem is that when the user clicks several times on the button (so like 5 times in 2 seconds), the program can't handle it and it stops working

In my experience, I've noticed that the PhotoCamera class has a tendency of throwing a lot of exception, sometimes for obscure reasons.

I might get some downvotes but here is what I would do: put the code in a try...catch block, like so:

try
{
    if (cam.CameraType == CameraType.FrontFacing)
        cam = new Microsoft.Devices.PhotoCamera(CameraType.Primary);
    else
        cam = new Microsoft.Devices.PhotoCamera(CameraType.FrontFacing);
    viewfinderBrush.Dispatcher.BeginInvoke(delegate()
    {
        viewfinderBrush.SetSource(cam);
    });
}
catch (Exception) { }

Of course, before using the FrontFacing camera, you need to check if the device has one:

PhotoCamera.IsCameraTypeSupported(CameraType.FrontFacing)

EDIT :
Based on the comments, the try..catch method is not enough. Here is an even uglier solution that should work:

DateTime lastChange = DateTime.MinValue;
private void changeFacing_Clicked(object sender, RoutedEventArgs e)
{
    TimeSpan elapsedTime = DateTime.Now - lastChange;
    if (elapsedTime.TotalMilliseconds < 2000) // If the last change occured less than 2 seconds ago, ignore it
        return;

    if (cam.CameraType == CameraType.FrontFacing)
        cam = new Microsoft.Devices.PhotoCamera(CameraType.Primary);
    else
        cam = new Microsoft.Devices.PhotoCamera(CameraType.FrontFacing);

    viewfinderBrush.Dispatcher.BeginInvoke(delegate()
    {
        viewfinderBrush.SetSource(cam);
    });

    lastChange = DateTime.Now;
}

Upvotes: 2

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