GameActivity interacts with Unity via a bridge that you can modify to make changes and implement additional features. The code that makes up the bridge is written in C++ and during the build process, GameActivity builds it into a shared library called libgame.so
.
You can’t modify bridge code within Unity itself; you must first export your project. After you export your project, you can find the files that comprise the bridge code in <exported_project_directory>/unityLibrary/src/main/cpp/GameActivity/
. Most of the code files in this directory contain utility code. The following table shows you the purpose of the most important bridge code files.
File | 目的 |
---|---|
UGAInput.cpp |
Input events: Here you can adjust or transform input data before GameActivity passes it to Unity. |
UGAApplication.cpp |
Lifecycle events: Here you can change how to handle events such as pausing, resuming, focusing, and unfocusing. This is the core of the code bridge. |
UGASoftKeyboard.cpp |
Touchscreen keyboard: Here you can change the implementation of the on-screen keyboard. The default implementation uses GameTextInput. |
During the project export process, Unity’s incremental build pipeline might overwrite any changes you make in the exported project. If you want your changes to persist:
<exported_project_directory>/unityLibrary/src/main/cpp/GameActivity/
directory into your modified bridge code directory.<exported_project_directory>/unityLibrary/src/main/cpp/GameActivity/
directory. When Unity builds your application, this code will overwrite the default bridge code files with your modified versions.You can add extra source files to the existing GameActivity bridge files which are then compiled together.
例:
Create a C# script in Unity and name it SendMessageReceiver.cs
.
using UnityEngine;
public class SendMessageReceiver : MonoBehaviour
{
public void SendMessageFromCpp(string message)
{
Debug.LogFormat(LogType.Log, LogOption.NoStacktrace, null, message);
}
}
Create a new GameObject and name it SendMessageReceiver
.
Attach the SendMessageReceiver script to the SendMessageReceiver GameObject.
Create MyFile.cpp
in \<unityproject\>/ExtraSourceFiles
directory.
Note: Don’t place .cpp
files in the Assets
directory, because they will link into IL2CPP’s libil2cpp.so
shared library and won’t compile.
The following code calls a C# method SendMessageFromCpp
on a GameObject called SendMessageReceiver
and passes HelloFromBridge
as an extra parameter whenever you touch the phone screen.
#include "UGAApplication.h"
#include "game-activity/native_app_glue/android_native_app_glue.h"
void UnityGameActivityPluginLoad(Unity::UnityApplication& application)
{
application.GetEvents().Register<Unity::UnityEventProcessInput>([](const Unity::UnityEventProcessInput& e)
{
auto inputBuffer = e.GetInputBuffer();
if (inputBuffer->motionEventsCount != 0) {
for (uint64_t i = 0; i < inputBuffer->motionEventsCount; ++i) {
GameActivityMotionEvent* motionEvent = &inputBuffer->motionEvents[i];
if (motionEvent->action == AKEY_EVENT_ACTION_DOWN)
e.GetApplication().SendMessage("SendMessageReceiver", "SendMessageFromCpp", "HelloFromBridge");
}
}
});
}
Place the following editor script PostProcessor.cs
in Assets/Editor:
(It ensures that ExtraSourceFiles/MyFile.cpp
is copied to unityLibrary/src/main/cpp/GameActivity/CustomFolder/MyFile.cpp
in an incremental build friendly way.)
using System;
using UnityEditor.Android;
using UnityEditor;
using UnityEngine;
public class PostProcessor : AndroidProjectFilesModifier
{
const string CustomSourceFileSrc = "ExtraSourceFiles/MyFile.cpp";
const string CustomSourceFileDst = "unityLibrary/src/main/cpp/GameActivity/CustomFolder/MyFile.cpp";
public override AndroidProjectFilesModifierContext Setup()
{
var ctx = new AndroidProjectFilesModifierContext();
ctx.Dependencies.DependencyFiles = new[]
{
CustomSourceFileSrc
};
ctx.AddFileToCopy(CustomSourceFileSrc, CustomSourceFileDst);
return ctx;
}
public override void OnModifyAndroidProjectFiles(AndroidProjectFiles projectFiles)
{
}
}
Select GameActivity Application Entry Point in Android Player settings (menu: Edit > Project Settings > Player > Other Settings > Configuration).
Click Build & Run.
Touch the phone screen and check the Logcat.
You should now see HelloFromBridge
log, sent from MyFile.cpp and printed by SendMessageReceiver.cs
script.
ノート:
UnityGameActivityPluginLoad
in MyFile.cpp is weakly linked and is called when GameActivity bridge initializes. There’s also ShutdownUserCode
if you need it.UnityEventProcessInput
event. You can find more events in UGAEvents.h
file.