Use local service

I. define java interface

public interface CalculateI {
  int addab(int a, int b);
}

Create a Binder subclass, inherit Binder and implement interface methods

public class CalculateBinder extends Binder implements CalculateI{
  @Override
  public int addab(int a, int b) {
    return a+b;
  }
}

III. Onbind in the Service returns the new Binder subclass

  @Override
  public IBinder onBind(Intent intent) {
    return new CalculateBinder();
  }

IV. binding Service in Activity

  Intent serviceintent = new Intent(SERVISE_INTENT);
  serviceintent.setPackage(getPackageName());
  bindService(serviceintent, serviceConnection, BIND_AUTO_CREATE);

1. Where Intent requires setPackage
2. ServiceConnection needs to directly convert the service object to the IBinder subclass when connecting

	 private ServiceConnection serviceConnection = new ServiceConnection() {
			@Override
			public void onServiceConnected(ComponentName name, IBinder service) {
 				calculateBinder = (CalculateBinder) service;
	}

V. using IBinder object to realize functions

calculateBinder.addab(8, 4);

Vi. Android manifest.xml configuration

    <service
        android:name=".CalculateServie"
        android:enabled="true"
        android:exported="true">
       <intent-filter>
           <action android:name="xxxxx.action.open.calculateservice" />
       </intent-filter>
  	</service>

Use of remote services

I. define the Aidl interface. The suffix of the file name is Aidl

interface ICalculateInter {
    int addab(int a, int b);
}

2. Create a subclass of IBindler, which inherits from ICalculateInter.Stub

public class CalculateBinder extends ICalculateInter.Stub{
  @Override
  public int addab(int a, int b) {
    return a+b;
  }
}

III. Onbind in the Service still returns the new Binder subclass

  @Override
  public IBinder onBind(Intent intent) {
    return new CalculateBinder();
  }

IV. binding Service in Activity

	//At this time, onServiceConnected will be different

	 private ServiceConnection serviceConnection = new ServiceConnection() {
			@Override
			public void onServiceConnected(ComponentName name, IBinder service) {
 				iCalculateInter = ICalculateInter.Stub.asInterface(service);
	}

V. to use IBinder object to implement functions, you need to catch RemoteException

 try {
   iCalculateInter.addab(8, 4);
 } catch (RemoteException e) {
   e.printStackTrace();
 }

Vi. Android manifest.xml configuration. Note that the Service is running in a separate process

   <service
       android:process="com.example.xxxxxxx"
       android:name=".CalculateServie"
       android:enabled="true"
       android:exported="true">
       <intent-filter>
           <action android:name="xxxxx.action.open.calculateservice" />
       </intent-filter>
   </service>

What is ICalculateInter.Stub?

After creating the aidl interface file, the compiler will automatically generate a class, which is ICalculateInter.java

public interface ICalculateInter extends android.os.IInterface
{
public static abstract class Stub extends android.os.Binder implements com.example.xxxx.ICalculateInter{
	//Ellipsis content
	public static ICalculateInter asInterface(android.os.IBinder obj)
	{
		if ((obj==null)) {
		return null;
	}
}
public int addab(int a, int b) throws android.os.RemoteException;
}

ICalculateInter has an internal abstract class Stub, which inherits Binder and implements the interface in ICalculateInter.aidl,
This is the same way we used to bind local services.