Method 2. Unity methods be invoked passively by JAR file using UnitySendMessage

1. Writing JAR file

• 1. import classes.jar to app -> libs, right click it and choose Add As Library

path of classes.jar :

[your unity intall path]\Editor\Data\PlaybackEngines\AndroidPlayer\Variations\mono\Release\Classes

• 2. inherit UnityPlayerActivity class
• 3. call UnityPlayer.UnitySendMessage(String objectName, String methodName, String methodParameter) to invoke Unity methods.

eg: send Bluetooth state change state once u receive the broadcast.

… …
switch (message) {
  case BluetoothAdapter.STATE_OFF:
    UnityPlayer.UnitySendMessage("SetState", "setBluetoothState", "bt_state_off");
  break;
… …

• 4. Comment out the line setContentView(R.layout.activity_main);
• 5. Add the following code in the app-> build.gradle root node (which is the same level as android and dependencies).

task createJarDebug(type: Jar,dependsOn: ['build']) {
  baseName "test"
  from 'build/intermediates/javac/debug/compileDebugJavaWithJavac/classe        s'
  include('**')
  exclude('**/R.class')
  exclude('**/R$*.class')
  exclude('**/BuildConfig.class')
}
//add the following code if you want to obfuscate code
task proguard(type: proguard.gradle.ProGuardTask, dependsOn: buildJar) {
  //  input path
  injars "build/libs/test.jar"
  //  output path
  outjars "lib/testProguard.jar"
  //  add config info
  configuration 'proguard-rules.pro'
}

• 6. In Android Terminal, type gradlew createJarDebug

You need to generate the conflation package by typing gradlew createJarDebug proguard

If prompted build success, the package succeeds

Jar package path: app/build/libs/test.jar

Copy to Unity engineer and tell them package name. Class name, interface name

2. Define the methods to be invoked in Unity project

• 1. Copy the JAR file to Assets/Plugins/Android/ path
• 2. To be invoked by UnitySendMessage(String objectName, String method same, String methodParameter) method in the JAR file, In Unity project please create a GameObject by name of objectName, and add a script that include the method by name of methodName, which has the same type of the input parameter as methodParameter. Please refer to the example codes below:

public class test : MonoBehaviour {
  public Text wifiText;
  public void setWifiState(string s)
  {
    wifiText.text = s;
  }
}