Bindler机制传输对象

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系统提供了AIDL方式来实现Bindler机制。

1.创建AIDL接口

创建一个aidl类型文件，这里我们创建IBookManager.aidl

interface IBookManager {
    void addBook(in Book book);
    List<Book> getBookList();
}

Buid后，系统在build/generated/下创建BookManager.java文件，也就是BookManager类。

/*
 * This file is auto-generated.  DO NOT MODIFY.
 * Original file: /Users/wangliang/workspace/Study/app/src/main/aidl/com/moreunion/study/book/IBookManager.aidl
 */
package com.moreunion.study.book;
// 定义的一个接口，里面有两个方法:getBookList和addtBook
// getBookList用于从远程服务端获取图书列表
// addBook用于向远程服务端添加一本图书

public interface IBookManager extends android.os.IInterface {

/** Local-side IPC implementation stub class. */
public static abstract class Stub extends android.os.Binder implements com.moreunion.study.book.IBookManager {
private static final java.lang.String DESCRIPTOR = "com.moreunion.study.book.IBookManager";
/** Construct the stub at attach it to the interface. */

public Stub() {
    this.attachInterface(this, DESCRIPTOR);
}

/**
 * Cast an IBinder object into an com.moreunion.study.book.IBookManager interface,
 * generating a proxy if needed.
 */
public static com.moreunion.study.book.IBookManager asInterface(android.os.IBinder obj) {
    if ((obj == null)) {
        return null;
    }
    android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
    if (((iin!=null)&&(iin instanceof com.moreunion.study.book.IBookManager))) {
        return ((com.moreunion.study.book.IBookManager)iin);
    }
    return new com.moreunion.study.book.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<com.moreunion.study.Book> _result = this.getBookList();
            reply.writeNoException();
            reply.writeTypedList(_result);
            return true;
        }
        case TRANSACTION_addBook: {
            data.enforceInterface(descriptor);
            com.moreunion.study.Book _arg0;
            if ((0!=data.readInt())) {
                _arg0 = com.moreunion.study.Book.CREATOR.createFromParcel(data);
            } else {
                _arg0 = null;
            }
            this.addBook(_arg0);
            reply.writeNoException();
            return true;
        }
        default: {
            return super.onTransact(code, data, reply, flags);
        }
    }
}

private static class Proxy implements com.moreunion.study.book.IBookManager {

private android.os.IBinder mRemote;

Proxy(android.os.IBinder remote) {
    mRemote = remote;
}

@Override 
public android.os.IBinder asBinder() {
    return mRemote;
}

public java.lang.String getInterfaceDescriptor() {
    return DESCRIPTOR;
}

@Override 
public java.util.List<com.moreunion.study.Book> getBookList() throws android.os.RemoteException {

android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
java.util.List<com.moreunion.study.Book> _result;
    try {
        _data.writeInterfaceToken(DESCRIPTOR);
        mRemote.transact(Stub.TRANSACTION_getBookList, _data, _reply, 0);
        _reply.readException();
        _result = _reply.createTypedArrayList(com.moreunion.study.Book.CREATOR);
    } finally {
        _reply.recycle();
        _data.recycle();
    }
    return _result;
}

@Override 
public void addBook(com.moreunion.study.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);
    }
    mRemote.transact(Stub.TRANSACTION_addBook, _data, _reply, 0);
    _reply.readException();
} finally {
    _reply.recycle();
    _data.recycle();
}
}
}
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 java.util.List<com.moreunion.study.Book> getBookList() throws android.os.RemoteException;
public void addBook(com.moreunion.study.Book book) throws android.os.RemoteException;
}

客户端跟服务端都需要生成IBookManager类

内部静态类Study（就是一个Bindler类）以及Study的内部静态类Proxy（一个IBookManger类）。

Study类

/** Local-side IPC implementation stub class. */
public static abstract class Stub extends android.os.Binder implements com.moreunion.study.book.IBookManager
{
private static final java.lang.String DESCRIPTOR = "com.moreunion.study.book.IBookManager";
/** Construct the stub at attach it to the interface. */
public Stub()
{
this.attachInterface(this, DESCRIPTOR);
}
/**
 * Cast an IBinder object into an com.moreunion.study.book.IBookManager interface,
 * generating a proxy if needed.
 */
public static com.moreunion.study.book.IBookManager asInterface(android.os.IBinder obj)
{
if ((obj==null)) {
return null;
}
android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
if (((iin!=null)&&(iin instanceof com.moreunion.study.book.IBookManager))) {
return ((com.moreunion.study.book.IBookManager)iin);
}
return new com.moreunion.study.book.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<com.moreunion.study.Book> _result = this.getBookList();
reply.writeNoException();
reply.writeTypedList(_result);
return true;
}
case TRANSACTION_addBook:
{
data.enforceInterface(descriptor);
com.moreunion.study.Book _arg0;
if ((0!=data.readInt())) {
_arg0 = com.moreunion.study.Book.CREATOR.createFromParcel(data);
}
else {
_arg0 = null;
}
this.addBook(_arg0);
reply.writeNoException();
return true;
}
default:
{
return super.onTransact(code, data, reply, flags);
}
}

Proxy类

private static class Proxy implements com.moreunion.study.book.IBookManager {
    private android.os.IBinder mRemote;

    Proxy(android.os.IBinder remote){
        mRemote = remote;
    }

    @Override 
    public android.os.IBinder asBinder() {
        return mRemote;
    }

    public java.lang.String getInterfaceDescriptor() {
        return DESCRIPTOR;
    }

    @Override 
    public java.util.List<com.moreunion.study.Book> getBookList() throws android.os.RemoteException {
        android.os.Parcel _data = android.os.Parcel.obtain();
        android.os.Parcel _reply = android.os.Parcel.obtain();
        java.util.List<com.moreunion.study.Book> _result;
        try {
            _data.writeInterfaceToken(DESCRIPTOR);
            mRemote.transact(Stub.TRANSACTION_getBookList, _data, _reply, 0);
            _reply.readException();
            _result = _reply.createTypedArrayList(com.moreunion.study.Book.CREATOR);
        } finally {
            _reply.recycle();
            _data.recycle();
        }
        return _result;
    }

    @Override 
    public void addBook(com.moreunion.study.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);
            }
            mRemote.transact(Stub.TRANSACTION_addBook, _data, _reply, 0);
            _reply.readException();
        } finally {
            _reply.recycle();
            _data.recycle();
        }
    }
}

IBookManager类

public interface IBookManager extends android.os.IInterface {
    public java.util.List<com.moreunion.study.Book> getBookList() throws android.os.RemoteException;
    public void addBook(com.moreunion.study.Book book) throws android.os.RemoteException;
}

服务端需要实现Study抽象类，在onBinder()方法中返回Study类的对象。

客户端绑定服务，成功后，服务端返回一个Binder对象（继承Study类的对象）给客户端，客户端把Bindler对象当作参数调用Study类中的静态方法asInterface()返回一个IBookManager对象。

就这样我们使用IBindler机制完成了进程间通信。