AIDL基本使用

AIDL的概念

AIDL：全称是Android Interface Definition Language(Android接口定义语言)。它主要用在Android进程间通信中，Android中有一种进程间通信方式是Binder，AIDL就是帮我们自动生成了Binder相关代码，不需要我们自己去手动书写复杂的Binder类，我们只需要在AIDL接口文件中书写自己的调用远程服务的业务方法就可以了，大大简化了开发过程。

AIDL支持的数据类型

八种基本数据类型：byte、char、short、int、long、float、double、boolean
String，CharSequence
实现了Parcelable接口的数据类型
List 类型。List承载的数据必须是AIDL支持的类型，或者是其它声明的AIDL对象
Map类型。Map承载的数据必须是AIDL支持的类型，或者是其它声明的AIDL对象

AIDL使用步骤

例子源自《Android开发艺术探索》，点击获取Demo

Server端

1.首先创建一个Book类和两个aidl文件

class Book : Parcelable {
    var bookId: Int
    var bookName: String?

    constructor(bookId: Int, bookName: String?) {
        this.bookId = bookId
        this.bookName = bookName
    }

    override fun describeContents(): Int {
        return 0
    }

    override fun writeToParcel(dest: Parcel, flags: Int) {
        dest.writeInt(bookId)
        dest.writeString(bookName)
    }

    constructor(source: Parcel) {
        bookId = source.readInt()
        bookName = source.readString()
    }

    override fun toString(): String {
        return "Book{" +
                "bookId=" + bookId +
                ", bookName='" + bookName + '\'' +
                '}'
    }


    companion object CREATOR : Parcelable.Creator {
        override fun createFromParcel(parcel: Parcel): Book {
            return Book(parcel)
        }

        override fun newArray(size: Int): Array {
            return arrayOfNulls(size)
        }
    }
}

Book.aidl文件

// Book.aidl
package com.example.helloaidl;

parcelable Book;

IBookManager.aidl文件

// IBookManager.aidl
package com.example.helloaidl;
import com.example.helloaidl.Book;

interface IBookManager {
    // 获取图书列表
    List getBookList();

    //添加图书
    void addBook(in Book book);
}

2.rebuild项目，会自动生成一个 IBookManager的java类，里面书写了Binder相关代码。

public interface IBookManager extends android.os.IInterface
{
  /** Default implementation for IBookManager. */
  public static class Default implements com.example.helloaidl.IBookManager
  {
    // 获取图书列表

    @Override public java.util.List getBookList() throws android.os.RemoteException
    {
      return null;
    }
    //添加图书

    @Override public void addBook(com.example.helloaidl.Book book) throws android.os.RemoteException
    {
    }
    @Override
    public android.os.IBinder asBinder() {
      return null;
    }
  }
  /** Local-side IPC implementation stub class. */
  public static abstract class Stub extends android.os.Binder implements com.example.helloaidl.IBookManager
  {
    private static final java.lang.String DESCRIPTOR = "com.example.helloaidl.IBookManager";
    
    /**
   * Stub构造函数
   */
    public Stub()
    {
      this.attachInterface(this, DESCRIPTOR);
    }
    /**
     * 将IBinder 转换为BookManagerService interface
     */
    public static com.example.helloaidl.IBookManager asInterface(android.os.IBinder obj)
    {
      if ((obj==null)) {
        return null;
      }
      android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
      if (((iin!=null)&&(iin instanceof com.example.helloaidl.IBookManager))) {
        return ((com.example.helloaidl.IBookManager)iin);
      }
      return new com.example.helloaidl.IBookManager.Stub.Proxy(obj);
    }
    @Override public android.os.IBinder asBinder()
    {
      return this;
    }
    @Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
    {
      java.lang.String descriptor = DESCRIPTOR;
      switch (code)
      {
        case INTERFACE_TRANSACTION:
        {
          reply.writeString(descriptor);
          return true;
        }
        case TRANSACTION_getBookList:
        {
          data.enforceInterface(descriptor);
          java.util.List _result = this.getBookList();
          reply.writeNoException();
          reply.writeTypedList(_result);
          return true;
        }
        case TRANSACTION_addBook:
        {
          data.enforceInterface(descriptor);
          com.example.helloaidl.Book _arg0;
          if ((0!=data.readInt())) {
            _arg0 = com.example.helloaidl.Book.CREATOR.createFromParcel(data);
          }
          else {
            _arg0 = null;
          }
          this.addBook(_arg0);
          reply.writeNoException();
          return true;
        }
        default:
        {
          return super.onTransact(code, data, reply, flags);
        }
      }
    }
    /**
    * 代理
    */
    private static class Proxy implements com.example.helloaidl.IBookManager
    {
      private android.os.IBinder mRemote;
      
      /**
      * Proxy构造函数
      */
      Proxy(android.os.IBinder remote)
      {
        mRemote = remote;
      }
      @Override public android.os.IBinder asBinder()
      {
        return mRemote;
      }
      public java.lang.String getInterfaceDescriptor()
      {
        return DESCRIPTOR;
      }
      //获取图书列表

      @Override public java.util.List getBookList() throws android.os.RemoteException
      {
        android.os.Parcel _data = android.os.Parcel.obtain();
        android.os.Parcel _reply = android.os.Parcel.obtain();
        java.util.List _result;
        try {
          _data.writeInterfaceToken(DESCRIPTOR);
          boolean _status = mRemote.transact(Stub.TRANSACTION_getBookList, _data, _reply, 0);
          if (!_status && getDefaultImpl() != null) {
            return getDefaultImpl().getBookList();
          }
          _reply.readException();
          _result = _reply.createTypedArrayList(com.example.helloaidl.Book.CREATOR);
        }
        finally {
          _reply.recycle();
          _data.recycle();
        }
        return _result;
      }
      
      //添加图书
      @Override public void addBook(com.example.helloaidl.Book book) throws android.os.RemoteException
      {
        android.os.Parcel _data = android.os.Parcel.obtain();
        android.os.Parcel _reply = android.os.Parcel.obtain();
        try {
          _data.writeInterfaceToken(DESCRIPTOR);
          if ((book!=null)) {
            _data.writeInt(1);
            book.writeToParcel(_data, 0);
          }
          else {
            _data.writeInt(0);
          }
          boolean _status = mRemote.transact(Stub.TRANSACTION_addBook, _data, _reply, 0);
          if (!_status && getDefaultImpl() != null) {
            getDefaultImpl().addBook(book);
            return;
          }
          _reply.readException();
        }
        finally {
          _reply.recycle();
          _data.recycle();
        }
      }
      public static com.example.helloaidl.IBookManager sDefaultImpl;
    }
    static final int TRANSACTION_getBookList = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
    static final int TRANSACTION_addBook = (android.os.IBinder.FIRST_CALL_TRANSACTION + 1);
    public static boolean setDefaultImpl(com.example.helloaidl.IBookManager impl) {
      if (Stub.Proxy.sDefaultImpl == null && impl != null) {
        Stub.Proxy.sDefaultImpl = impl;
        return true;
      }
      return false;
    }
    public static com.example.helloaidl.IBookManager getDefaultImpl() {
      return Stub.Proxy.sDefaultImpl;
    }
  }
  // 鑾峰彇鍥句功鍒楄〃

  public java.util.List getBookList() throws android.os.RemoteException;
  //娣诲姞鍥句功

  public void addBook(com.example.helloaidl.Book book) throws android.os.RemoteException;
}

3.编写远程服务代码 BookManagerService，为了演示进程间的通信机制，故需要将Service与Activity处于不同的进程，需要在AndroidManifest.xml中，把service配置成android:process=":remote"

class BookManagerService : Service() {
    private val TAG = BookManagerService::class.java.simpleName

    //使用CopyOnWriteArrayList来支持并发读写
    private val mBookList = CopyOnWriteArrayList()

    override fun onBind(intent: Intent): IBinder? {
        return mBinder
    }


    private val mBinder = object : IBookManager.Stub() {
        override fun addBook(book: Book) {
            mBookList.add(book)
        }

        override fun getBookList(): List {
            return mBookList
        }

    }

}

客户端

创建Activity，在manifest中注册，完整代码如下：

class BookManagerActivity : AppCompatActivity() {

    private val TAG = BookManagerActivity::class.java.simpleName

    private var mRemoteBookManager: IBookManager? = null
    private var boookId = 1

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        bindService()
        initListener()
    }

    //绑定远程服务端
    private fun bindService() {
        val intent = Intent(this, BookManagerService::class.java)
        intent.setPackage(packageName)
        bindService(intent, mConnection, Context.BIND_AUTO_CREATE)
    }

    //注册按钮监听，调用远程耗时方法需要开启线程
    private fun initListener() {
        btnGetBookList.setOnClickListener {
            Toast.makeText(this, "GetBookList", Toast.LENGTH_SHORT).show()
            Thread {
                try {
                    mRemoteBookManager?.let { mRemoteBookManager ->
                        val list = mRemoteBookManager.bookList
                        Log.i(TAG, "query book list: $list")
                    }
                } catch (e: RemoteException) {
                    e.printStackTrace()
                }
            }.start()
        }
        btnAddBook.setOnClickListener {
            Toast.makeText(this, "AddBook", Toast.LENGTH_SHORT).show()
            Thread {
                try {
                    mRemoteBookManager?.apply {
                        val newBook = Book( boookId++, "Book$boookId")
                        Log.i(TAG, "add book: $newBook")
                        addBook(newBook)
                    }
                } catch (e: RemoteException) {
                    e.printStackTrace()
                }
            }.start()
        }
    }

    override fun onDestroy() {
        unBindService()
        super.onDestroy()
    }

    private fun unBindService() {
        unbindService(mConnection)
    }

    //服务端连接状态回调
    private var mConnection = object : ServiceConnection {
        override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
            Log.e(TAG, "onServiceConnected: $mRemoteBookManager")
            //将服务端返回的Binder对象转换为aidl对象
            mRemoteBookManager = IBookManager.Stub.asInterface(service)
            Log.e(TAG, "onServiceConnected: $mRemoteBookManager")
        }

        override fun onServiceDisconnected(name: ComponentName?) {
            Log.i(TAG, "onServiceDisconnected ThreadName: ${Thread.currentThread().name}")
            mRemoteBookManager = null
        }
    }

}

点击获取Demo

AIDL基本使用

Server端

客户端

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