使用 C++ 检测 iPhone 的方向

Question

Embarcadero C++Builder 10.3.2 Enterprise

Searching the internet, I could not find any FMX code for this. Based on Delphi code, this should have worked but the compiler does not like it

if (Application->FormFactor->Orientations == Fmx::Types::TScreenOrientations::Landscape) {
    //Landscape
}

Also, the value of Application->FormFactor->Orientations is the same whatever the orientation of the iphone. {System::SetBase = {Data = {[0] = 11 '\v'}}} How does one determine the orientation?

Answer 1

The Orientations property is a TFormOrientations , which is a System::Set of TFormOrientation values. You can't use Set::operator== to compare it to a single value, which is why you are getting a compiler error. However, you can use theSet::Contains() method to check if it has a given value, eg:

if (Application->FormFactor->Orientations.Contains(Fmx::Forms::TFormOrientation::Landscape)) {
    //...
}

In any case, the Orientations property specifies which orientation(s) the application's Forms are allowed to take (a value of 11 has its 1st, 2nd, and 4th bits set to 1, which correspond to the Portrait , Landscape , and InvertedLandscape orientations being enabled). It does not report what the device's current orientation is. For that, use the IFMXScreenService::GetScreenOrientation() method instead, eg:

_di_IFMXScreenService ScreenService;
if (TPlatformServices::Current->SupportsPlatformService(__uuidof(IFMXScreenService), &ScreenService)) {
    if (ScreenService->GetScreenOrientation() == Fmx::Types::TScreenOrientation::Landscape) {
        //...
    }
}

Answer 2

If (Screen->Width > Screen->Height) {
  //code here
} else {
  //code here
}