android

一、Binder与传统IPC对比

二、AIDL（安卓接口描述语言）的使用

1、创建接口，使用到自定义类的话，需要导包，加in。

// TestAidl.aidl
package com.example.aidl.service;

// Declare any non-default types here with import statements

import com.example.aidl.service.Person;

interface TestAidl {
    void addPerson(in Person person);

    List<Person> getPersonList();
}

2、自定义数据通信类，需要实现序列化

package com.example.aidl.service;

import android.os.Parcel;
import android.os.Parcelable;

public class Person implements Parcelable {

    private String name;
    private int grade;

    public Person(String name, int grade) {
        this.name = name;
        this.grade = grade;
    }

    protected Person(Parcel in) {
        this.name = in.readString();
        this.grade = in.readInt();
    }

    public static final Creator<Person> CREATOR = new Creator<Person>() {
        @Override
        public Person createFromParcel(Parcel in) {
            return new Person(in);
        }

        @Override
        public Person[] newArray(int size) {
            return new Person[size];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
        dest.writeInt(grade);
    }
}

3、在AIDL中定义自定义数据通信类

// Person.aidl
package com.example.aidl.service;

// Declare any non-default types here with import statements

parcelable Person;

4、拷贝服务端的aidl，包名不变
5、拷贝自定义数据通信类，包名必须一致
6、创建服务端Service，new一个Binder（实现了aidl接口）

package com.example.app.aidl.service;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.annotation.Nullable;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

public class TestAidlService extends Service {
    private ArrayList<Person> persons;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        persons = new ArrayList<>();
        Log.e("TestAidlService", "success onBind");
        return iBinder;
    }

    private IBinder iBinder = new TestAidl.Stub() {
        @Override
        public void addPerson(Person person) throws RemoteException {
            persons.add(person);
        }

        @Override
        public List<Person> getPersonList() throws RemoteException {
            return persons;
        }
    };

    @Override
    public void onCreate() {
        super.onCreate();
        Log.e("TestAidlService", "onCreate：onBind");
    }
}

5、客户端bindService，绑定服务端。new一个serviceConnection，onServiceConnected方法中

package com.example.app.aidl.client;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.example.app.R;
import com.example.app.aidl.service.Person;
import com.example.app.aidl.service.TestAidl;

import java.util.List;

public class AidlClientActivity extends AppCompatActivity {
    private final static String TAG = "TestActivity";

    private TestAidl testAidl;

    private Button btn;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_aidl_client);

        initView();
        bindService();
    }

    private void initView() {
        btn = findViewById(R.id.but_click);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    testAidl.addPerson(new Person("leo", 3));
                    List<Person> persons = testAidl.getPersonList();
                    Log.e(TAG, persons.toString());
                } catch (RemoteException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    private void bindService() {
        Intent intent = new Intent();
        intent.setComponent(new ComponentName("com.example.app", "com.example.app.aidl.service.TestAidlService"));
        bindService(intent, connection, BIND_AUTO_CREATE);
    }

    private ServiceConnection connection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.e(TAG, "onServiceConnected：success");
            testAidl = TestAidl.Stub.asInterface(service);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            Log.e(TAG, "onServiceDisconnected：success");
            testAidl = null;
        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(connection);
    }
}

三、aidl源码分析

1、AIDL目的：如何获取到另一个进程服务的对象？

2、通过这个对象，如何跨进程调用的？

客户端proxy调用调用binder 的transact()方法传输数据，c、c++方法
服务端sub的 onTransact()

1、Android深入源码分析理解Aidl整体调用流程（雷惊风）