看下总体流程图：
ServerApplication工程：
1.服务端ServerApplication 创建AIDL文件：
在包名cn.umbrella.aidl下右键-->new-->AIDL-->AIDL File，创建aidl文件IUmBrellaService,android studio会把aidl文件统一自动放到main/aidl目录下
IUmBrellaService.aidl:
// IUmBrellaService.aidl
package cn.umbrella.aidl;
// Declare any non-default types here with import statements
interface IUmBrellaService {
String umbrellaEevent(String client_str);
}
重新rebuild工程下，这个aidl文件就会自动生成IUmBrellaService.java文件，在build/generated/source/aidl/debug/目录下：
public interface IUmBrellaService extends android.os.IInterface {
public static abstract class Stub extends android.os.Binder implements IUmBrellaService {
private static final String DESCRIPTOR = "cn.umbrella.aidl.IUmBrellaService";
public Stub() {
this.attachInterface(this, DESCRIPTOR);
}
public static IUmBrellaService asInterface(android.os.IBinder obj) {
...
return new Stub.Proxy(obj);
}
@Override
public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException {
switch (code) {
case TRANSACTION_umbrellaEevent: {
data.enforceInterface(DESCRIPTOR);
String _arg0;
_arg0 = data.readString();
String _result = this.umbrellaEevent(_arg0);
reply.writeNoException();
reply.writeString(_result);
return true;
}
}
return super.onTransact(code, data, reply, flags);
}
private static class Proxy implements IUmBrellaService {
private android.os.IBinder mRemote;
Proxy(android.os.IBinder remote) {
mRemote = remote;
}
@Override
public String umbrellaEevent(String client_str) throws android.os.RemoteException {
android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
String _result;
try {
_data.writeInterfaceToken(DESCRIPTOR);
_data.writeString(client_str);
mRemote.transact(Stub.TRANSACTION_umbrellaEevent, _data, _reply, 0);
_reply.readException();
_result = _reply.readString();
} finally {
_reply.recycle();
_data.recycle();
}
return _result;
}
}
static final int TRANSACTION_umbrellaEevent = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
}
public String umbrellaEevent(String client_str) throws android.os.RemoteException;
}
这个java包括了静态抽象Stub类，以及私有Proxy，这是客户端client和服务端Service 通过binder驱动通讯用。
2、提供外部绑定的service以及在XML上声明权限：
ServerService.java:
public class ServerService extends Service {
private IBinder mBinder;
@Nullable
@Override
public IBinder onBind(Intent intent) {
mBinder = new IUmBrellaImpl();
return mBinder;
}
public class IUmBrellaImpl extends IUmBrellaService.Stub{
@Override
public String umbrellaEevent(String client_str) throws RemoteException {
Log.d("ServerService","client_str=" + client_str);
String serverString = "server string is from server";
return serverString;
}
}
}
其中onBind返回的对象IBinder给客户端client 绑定服务成功回调函数onServiceConnected。
XML声明permission和action:
<service
android:name=".service.ServerService"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.ServerService"/>
</intent-filter>
</service>
这样服务端server就完毕，接下来我们看客户端client如何绑定：
3、客户端client同样需要创建一样的aidl文件，并且路径都一致，重新rebuild下，也会自动在build/generated/source/aidl/debug/生成IUmBrellaService.java文件，内容都一致。
绑定bindservice：
private Context mContext;
private IBinder mBinder;
IUmBrellaService mServerSerivce;
private void connect(){
Intent intent = new Intent("android.intent.action.ServerService");
ComponentName cpName = new ComponentName("cn.umbrella.server","cn.umbrella.server.service.ServerService");
intent.setComponent(cpName);
mContext.bindService(intent,mServiceConnection,Service.BIND_AUTO_CREATE);
}
ServiceConnection mServiceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder binder) {
try {
mBinder = service;
mServerSerivce = IUmBrellaService.Stub.asInterface(binder);
mBinder.linkToDeath(mDeatRecipient,0);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
};
IBinder.DeathRecipient mDeatRecipient = new IBinder.DeathRecipient() {
@Override
public void binderDied() {
Log.d("","远程进程died");
}
};
其中onServiceConnected(ComponentName name, IBinder binder) 的参数binder就是客户端绑定服务端ServerService 成功后onBinder返回的对象，在这边把binder改造成IUmBrellaService.Stub的Proxy类，即 mServerSerivce = IUmBrellaService.Stub.asInterface(binder);
这样绑定成功后，客户端client就可以调用服务端server提供的接口即：
try {
String is = mServerSerivce.umbrellaEevent("umbrella event is from client");
} catch (RemoteException e) {
e.printStackTrace();
}
对比startservice，使用bindservice相对来说中度耦合，可短时间内密集通讯，识别呼叫端、可回传实行结果及listener回调、service进程crash，呼叫端可以收到died，容错处理，bindservice成功后，调用接口就不会再通过ActivityManagerService了。
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