UWP app with multiple views with different sizes - windows

Question

I have a UWP app. I want to be ale to create new windows from the app, but any subsequent window needs to be a specific smaller size compared to the main window. I don't do anything with regards to sizing the main window and let the OS take care of sizing it for me.
I bring up a new window like this:
auto window = CoreApplication::CreateNewView();
window->show();
void NewWindow::show() {
auto currView = ApplicationView::GetForCurrentView();
currView->PreferredLaunchViewSize =
Windows::Foundation::Size(float(options.width), float(options.height));
currView->PreferredLaunchWindowingMode = ApplicationViewWindowingMode::PreferredLaunchViewSize;
currView->SetPreferredMinSize(Size(20,20));
Xaml::Window::Current->Activate();
ApplicationViewSwitcher::TryShowAsStandaloneAsync(
window_->id(),
ViewSizePreference::Default,
window_->parentId(),
ViewSizePreference::Default);
}
When the main window comes up, it comes up just fine. When I click on a button which gets to this function, the new window comes up in the same size as the main window. I reopen the app, but now the main window shows up in the size I wanted the new window to show up in. Then clicking the button to bring up the new window brings up the new window in the size I wanted it in. So I am a bit confused. Am I setting the sizes the right way? Is there anything else glaringly wrong here?

Answer 1

As # Raymond Chen said, PreferredLaunchViewSize set the size when the app launches, it will change the size of your main window. And you can use ApplicationView.TryResizeView method to set the size of new window.
For example:
auto parentView = ApplicationView::GetForCurrentView();
auto newView = CoreApplication::CreateNewView();
newView->Dispatcher->RunAsync(Windows::UI::Core::CoreDispatcherPriority::Normal,
ref new Windows::UI::Core::DispatchedHandler([this,parentView]()
{
int newViewId = 0;
Windows::UI::Xaml::Controls::Frame^ rootFrame = ref new Windows::UI::Xaml::Controls::Frame();
rootFrame->Navigate(Windows::UI::Xaml::Interop::TypeName(MainPage::typeid), nullptr);
Window::Current->Content = rootFrame;
// You have to activate the window in order to show it later.
Window::Current->Activate();
newViewId = ApplicationView::GetForCurrentView()->Id;
IAsyncOperation<bool>^ mytask = ApplicationViewSwitcher::TryShowAsStandaloneAsync(newViewId);
auto deviceEnumTask = concurrency::create_task(mytask);
deviceEnumTask.then([this](bool res)
{
// set the size of new window
ApplicationView::GetForCurrentView()->TryResizeView(Size(600, 320));
});
}));