Binder的实现
一、AIDL
1. Book.java 实现Parcelable接口
package com.android.shieh.processtest.aidl;
import android.os.Parcel;
import android.os.Parcelable;
/**
* Created by GKX100187 on 2015/11/27.
*/
public class Book implements Parcelable {
public int bookId;
public String bookName;
public Book(int bookId, String bookName){
this.bookId = bookId;
this.bookName = bookName;
}
private Book(Parcel in) {
bookId = in.readInt();
bookName = in.readString();
}
public static final Creator<Book> CREATOR = new Creator<Book>() {
@Override
public Book createFromParcel(Parcel in) {
return new Book(in);
}
@Override
public Book[] newArray(int size) {
return new Book[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(bookId);
dest.writeString(bookName);
}
}
2. Book.aidl 将Book类在AIDL中声明
package com.android.shieh.processtest.aidl; parcelable Book;//声明Book类
3.BookManager.aidl 定义接口
// IBookManager.aidl
package com.android.shieh.processtest.aidl;
// Declare any non-default types here with import statements
import com.android.shieh.processtest.aidl.Book;//在同一个包中也要import该类
interface IBookManager {
/**
* Demonstrates some basic types that you can use as parameters
* and return values in AIDL.
*/
List<Book> getBookList();
void addBook(in Book book);
}
IDE会根据该接口自动生成相应的.java类，类似手动创建中的BookManagerImpl类
二、手动创建
1.AIDL性质的接口声明IBookManager.java
package com.android.shieh.processtest.manualbinder;
import android.os.IBinder;
import android.os.IInterface;
import android.os.RemoteException;
import com.android.shieh.processtest.aidl.Book;
import java.util.List;
/**
* Created by GKX100187 on 2015/11/30.
*/
public interface IBookManager extends IInterface {
static final String DESCRIPTOR //Binder的唯一标识符，一般用当前Binder类名表示
= "com.android.shieh.processtest.manualbinder.IBookManager";
static final int TRANSACTION_getBookList = IBinder//对应方法的id
.FIRST_CALL_TRANSACTION + 0;
static final int TRANSACTION_addBook = IBinder
.FIRST_CALL_TRANSACTION + 1;
public List<Book> getBookList() throws RemoteException;
public void addBook(Book book) throws RemoteException;
}
2.实现Stub类和Stub类中的代理类
package com.android.shieh.processtest.manualbinder;
import android.os.Binder;
import android.os.IBinder;
import android.os.IInterface;
import android.os.Parcel;
import android.os.RemoteException;
import com.android.shieh.processtest.aidl.Book;
import java.util.List;
/**
* Created by GKX100187 on 2015/11/30.
*/
public class BookManagerImpl extends Binder implements IBookManager{
public BookManagerImpl() {
//接口黏合
this.attachInterface(this,DESCRIPTOR);
}
/**用于将服务端的Binder对象转换成客户端所需要AIDL接口类型的对象
*客户端与服务端处于同一进程，返回的是服务端Stub本身
* 否则返回的是系统封装后的Stub.proxy（代理Stub，供客户端使用）
*/
public static IBookManager asInterface(IBinder obj){
if(obj == null){
return null;
}
IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
if(((iin != null) && (iin instanceof IBookManager))){
return ((IBookManager)iin);
}
return new BookManagerImpl.Proxy(obj);
}
/**
* 返回当前的Binder对象
* */
@Override
public IBinder asBinder() {
return this;
}
/**
* 该方法运行在服务端Binder线程池，
* 服务端通过code确定客户端所请求的方法，
* data中取出所需参数
* reply写入返回值
* 返回false表示可能客户端请求失败
* */
@Override
protected boolean onTransact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException {
switch (code){
case INTERFACE_TRANSACTION:
reply.writeString(DESCRIPTOR);
return true;
case TRANSACTION_getBookList:
data.enforceInterface(DESCRIPTOR);
List<Book> result = this.getBookList();
reply.writeNoException();
reply.writeTypedList(result);
return true;
case TRANSACTION_addBook:
data.enforceInterface(DESCRIPTOR);
Book arg0;
if(data.readInt()!=0){
arg0 = Book.CREATOR.createFromParcel(data);
}else {
arg0 = null;
}
reply.writeNoException();
return true;
}
return super.onTransact(code, data, reply, flags);
}
@Override
public List<Book> getBookList() throws RemoteException {
return null;
}
@Override
public void addBook(Book book) throws RemoteException {
}
private static class Proxy implements IBookManager{
private IBinder mRemote;
Proxy(IBinder remote){
mRemote = remote;
}
@Override
public IBinder asBinder() {
return mRemote;
}
public String getInterfaceDescriptor() {
return DESCRIPTOR;
}
/**
* 运行在客户端
* */
@Override
public List<Book> getBookList() throws RemoteException {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
List<Book> result;
try {
data.writeInterfaceToken(DESCRIPTOR);
//发送远程调用请求,阻塞等待，调用服务端的onTransact()返回后继续执行
mRemote.transact(TRANSACTION_getBookList,data,reply,0);
//此时服务端已经处理完客户端的请求
reply.readException();//客户端取出返回值
result = reply.createTypedArrayList(Book.CREATOR);
}finally {
reply.recycle();
data.recycle();
}
return result;
}
@Override
public void addBook(Book book) throws RemoteException {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
try{
data.writeInterfaceToken(DESCRIPTOR);
if((book != null)) {
data.writeInt(1);
book.writeToParcel(data, 0);
} else {
data.writeInt(0);
}
mRemote.transact(TRANSACTION_addBook,data,reply,0);
reply.readException();
}finally {
reply.recycle();
data.recycle();
}
}
}
}
三、Binder的死亡代理 DethRecipient
private IBinder.DeathRecipient mDeathRecipient = new IBinder.DeathRecipient(){
@Override
public void binderDied() {
if(mBookManager == null){
return ;
}
mBookManager.asBinder().unlinkToDeath(mDeathRecipient,0);
mBookManager = null;
//再重新绑定远程Service
}
};
客户端绑定远程服务,给Binder设置死亡代理
mService = IMessageBoxManager.Stub.asInterface(binder); binder.linkToDeath(mDeathRecipient);