Android 上的 Qt - C++ 代码是否在 Dalvik 虚拟机中运行

Question

I have heard it said that the C++ code runs "natively" on all platforms. By this I guess that what is being suggested is that the cross-platform ability of Qt is not using something like HTML 5.

But does this mean that on Android Qt code runs in the Dalvik virtual machine?

Answer 1

Please check https://www.qt.io/blog/2013/07/23/anatomy-of-a-qt-5-for-android-application

At the very top of levels, a Qt for Android application consists of two parts:

The Qt application: This is the cross-platform code and resources that you, as the app developer, manage yourself, and which are summarized by your qmake .pro file.

An Android application launcher: This is generated for you by Qt Creator the first time you connect your project to a Qt for Android Kit.

So, Android application launcher should run in Dalvik VM. I can't sure if this works well with ART runtime of Android 5.0

Answer 2

Android understands either Dalvik or the newer ART. Dalvik and ART both have the ability to link to C/C++ code through the Android NDK which is Android's take on JNI. QT for Android while being C++ based still requires a minimal amount of Java based initialization. What this means is that even if the C++ code runs natively (architecture dependent) to the underlying OS, it is still required to be presented through code that runs on the VM (Android specific) as the VM does not directly understand C++ but can link to it through it's own Java based framework which is the Android NDK.