[原]IPC机制之Binder连接池
cuiran发表于 2016-09-19 11:51:34
AIDL典型的使用流程
首先是创建一个Service和一个AIDL接口,接着创建一个类继承自AIDL接口中的Stub 并实现Stub中的抽象方法，在Service的onBind方法返回这个类的对象,然后客户端就可以绑定服务端的Service，建立连接之后可以访问远程服务端的方法.
Binder连接池
但是如果公司的项目越来越大，有很多个业务模块需要使用AIDL来进行进程间通信，如果按照之前的就需要创建多个service,但是service是系统四大组件之一，过多使用会造成性能资源消耗。 因此，这个时候有必要使用Binder连接池。
流程大致是：
每个业务模块创建自己的AIDL接口并实现此接口，这个时候不同业务模块之间不能有耦合的，所有实现细节我们要单独开来，然后向服务端提供一个属于自己的key和其对应的对象；那么服务端只需要一个Service然后提供一个查询的queryBinder接口，然后根据业务模块来返回对应的Binder。工作原理如图所示
具体可以通过代码来实现一下。
Example代码
新建AIDL ISecurityCenter
声明如下
// ISecurityCenter.aidl
package com.cayden.collect.study.binder;
// Declare any non-default types here with import statements
interface ISecurityCenter {
String encrypt(String content);
String decrypt(String password);
}
再新建一个提供计算的AIDL ICompute
// ICompute.aidl
package com.cayden.collect.study.binder;
// Declare any non-default types here with import statements
interface ICompute {
int add(int a,int b);
}
然后需要build工程 再对上面2个AIDL接口做具体的实现操作
package com.cayden.collect.study.binder;
import android.os.RemoteException;
/**
* Created by cuiran
* Time 16/9/18 14:24
* Email cuiran2001@163.com
* Description
*/
public class SecurityCenterImpl extends ISecurityCenter.Stub {
private static final char SECRET_CODE='^';
@Override
public String encrypt(String content) throws RemoteException {
char[] chars=content.toCharArray();
for(int i=0;i<chars.length;i++){
chars[i]^=SECRET_CODE;
}
return new String(chars);
}
@Override
public String decrypt(String password) throws RemoteException {
return encrypt(password);
}
}
package com.cayden.collect.study.binder;
import android.os.RemoteException;
/**
* Created by cuiran
* Time 16/9/18 14:28
* Email cuiran2001@163.com
* Description
*/
public class ComputeImpl extends ICompute.Stub {
@Override
public int add(int a, int b) throws RemoteException {
return a+b;
}
}接着需要为连接池创建一个AIDL接口 IBinderPool
// IBinderPool.aidl
package com.cayden.collect.study.binder;
// Declare any non-default types here with import statements
interface IBinderPool {
IBinder queryBinder(int binderCode);
}
然后创建连接池
package com.cayden.collect.study.binder;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Log;
import java.util.concurrent.CountDownLatch;
/**
* Created by cuiran
* Time 16/9/18 14:36
* Email cuiran2001@163.com
* Description
*/
public class BinderPool {
private static final String TAG="BinderPool";
public static final int BINDER_NONE=-1;
public static final int BINDER_COMPUTE=0;
public static final int BINDER_SECRITY_CENTER=1;
private Context mContext;
private IBinderPool mBinderPool;
private static volatile BinderPool sInstance;
private CountDownLatch mCountDownLatch;
private BinderPool(Context context){
mContext=context.getApplicationContext();
connectBinderPoolService();
}
public static BinderPool getInstance(Context context){
if(sInstance==null){
synchronized (BinderPool.class){
if(sInstance==null){
sInstance=new BinderPool(context);
}
}
}
return sInstance;
}
private synchronized void connectBinderPoolService(){
mCountDownLatch=new CountDownLatch(1);
Intent service=new Intent(mContext,BinderPoolService.class);
mContext.bindService(service,mBinderPoolConnection,Context.BIND_AUTO_CREATE);
try{
mCountDownLatch.await();
}catch (InterruptedException e){
e.printStackTrace();
}
}
public IBinder queryBinder(int binderCode){
IBinder binder=null;
try{
if(mBinderPool!=null){
binder=mBinderPool.queryBinder(binderCode);
}
}catch (RemoteException e){
e.printStackTrace();
}
return binder;
}
private ServiceConnection mBinderPoolConnection=new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
mBinderPool=IBinderPool.Stub.asInterface(iBinder);
try{
mBinderPool.asBinder().linkToDeath(mBinderPoolDeathRecipient,0);
}catch (RemoteException e){
e.printStackTrace();
}
mCountDownLatch.countDown();
}
@Override
public void onServiceDisconnected(ComponentName componentName) {
}
};
private IBinder.DeathRecipient mBinderPoolDeathRecipient=new IBinder.DeathRecipient() {
@Override
public void binderDied() {
Log.d(TAG,"binder died");
mBinderPool.asBinder().unlinkToDeath(mBinderPoolDeathRecipient,0);
mBinderPool=null;
connectBinderPoolService();
}
};
public static class BinderPoolImpl extends IBinderPool.Stub{
public BinderPoolImpl(){
super();
}
@Override
public IBinder queryBinder(int binderCode) throws RemoteException {
IBinder binder=null;
switch (binderCode){
case BINDER_SECRITY_CENTER:{
binder=new SecurityCenterImpl();
break;
}
case BINDER_COMPUTE:{
binder=new ComputeImpl();
break;
}
default:
break;
}
return binder;
}
}
}
接着需要实现远程service
package com.cayden.collect.study.binder;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.support.annotation.Nullable;
/**
* Created by cuiran
* Time 16/9/18 14:33
* Email cuiran2001@163.com
* Description
*/
public class BinderPoolService extends Service {
private static final String TAG="BinderPoolService";
private Binder mBinderPool=new BinderPool.BinderPoolImpl();
@Override
public void onCreate() {
super.onCreate();
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return mBinderPool;
}
@Override
public void onDestroy() {
super.onDestroy();
}
}
最后执行 验证一下
需要在Activity的线程里面调用方法
ISecurityCenter securityCenter;
ICompute mCompute;
private void doWork(){
Log.d(TAG,"doWork.......");
BinderPool binderPool=BinderPool.getInstance(getActivity());
IBinder securityBinder=binderPool.queryBinder(BinderPool.BINDER_SECRITY_CENTER);
securityCenter=(ISecurityCenter) SecurityCenterImpl.asInterface(securityBinder);
Log.d(TAG,"访问ISecurityCenter");
String msg="HelloWorld ,I'm cayden";
Log.d(TAG,"content="+msg);
try {
String password=securityCenter.encrypt(msg);
Log.d(TAG,"password="+password);
Log.d(TAG,"decrypt="+securityCenter.decrypt(password));
}catch (Exception e){
e.printStackTrace();
}
Log.d(TAG,"访问ICompute");
IBinder computeBinder=binderPool.queryBinder(BinderPool.BINDER_COMPUTE);
mCompute=(ICompute) ComputeImpl.asInterface(computeBinder);
try {
Log.d(TAG,"3+5="+mCompute.add(3,5));
}catch (Exception e){
e.printStackTrace();
}
}执行结果如下
09-19 11:46:56.080 7923-9643/com.cayden.collect D/MessengerFragment: doWork.......
09-19 11:46:56.132 7923-9643/com.cayden.collect D/MessengerFragment: 访问ISecurityCenter
09-19 11:46:56.132 7923-9643/com.cayden.collect D/MessengerFragment: content=HelloWorld ,I'm cayden
09-19 11:46:56.132 7923-9643/com.cayden.collect D/MessengerFragment: password=;221 1,2:~ry3~=?':;0
09-19 11:46:56.132 7923-9643/com.cayden.collect D/MessengerFragment: decrypt=HelloWorld ,I'm cayden
09-19 11:46:56.132 7923-9643/com.cayden.collect D/MessengerFragment: 访问ICompute
09-19 11:46:56.136 7923-9643/com.cayden.collect D/MessengerFragment: 3+5=8
这样Binder的连接池的demo版就结束了
源码地址:代码地址
最后需要注明内容参考自大神的书《Android开发艺术探索》，在这里做个笔记进行整理 也是对这部分有更好的掌握。