AIDL学习

源于《Android开发艺术探索》,作者讲的跨进程通信之AIDL。
作者是在同一个moudle下写的aidl,我为了模拟真实情况,所以在两个不同的app下面使用了。
说一些注意的点吧。

首先Aidl支持的类型

.基本数据类型
.String 和CharSequence
.ArrayList
.HashMap
.Parcelable
.AIDL
比如例子中用到了Book。Book实现了Parcelable接口。
并且要为Book专门创建一个Aidl
Book.aidl(创建的时候似乎会提示需要唯一名称,可以先创建其他名称然后重命名)

package com.example.lps.aidlserver;
parcelable Book;

然后就是接口什么的,

package com.example.lps.aidlserver;
import com.example.lps.aidlserver.Book;
import com.example.lps.aidlserver.IOnNewBookArrivedListener;
// Declare any non-default types here with import statements
interface IMyAidlInterface {
 List getBookList();
 void addBook(in Book book);
 void regisiterListener(IOnNewBookArrivedListener listener);
 void unregisiterListener(IOnNewBookArrivedListener listener);
 }

然后编译一下就会在

AIDL学习_第1张图片
image.png

这里生成代码。
然后服务端创建Service

package com.example.lps.aidlserver;

import android.app.Service;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Binder;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteCallbackList;
import android.os.RemoteException;
import android.support.annotation.Nullable;

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Created by lps on 2017/7/3.
 *
 * @version 1
 *  @see
 * @since 2017/7/3 17:11
 */


public class BookManagerService extends Service {
@Override
public void onCreate() {
    super.onCreate();
    mBookList.add(new Book("Android开发艺术探索", "任玉刚"));
    mBookList.add(new Book("Android高级进阶", "未知"));
    mBookList.add(new Book("疯狂android讲义", "李刚"));
    new Thread(new ServiceWorker()).start();
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}

private static final String TAG = "BookManagerService";
private AtomicBoolean mIsServiceDestroyed = new AtomicBoolean(false);
private CopyOnWriteArrayList mBookList = new CopyOnWriteArrayList<>();
private RemoteCallbackList mRemoteCallbackList=new RemoteCallbackList<>();
private CopyOnWriteArrayList mIOnNewBookArrivedListeners = new CopyOnWriteArrayList<>();
private Binder mBinder = new IMyAidlInterface.Stub() {
    @Override
    public List getBookList() throws RemoteException {
        return mBookList;
    }

    @Override
    public void addBook(Book book) throws RemoteException {
        mBookList.add(book);
    }

    @Override
    public boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException {
        int mPermission = checkCallingOrSelfPermission("com.example.lps.aidlserver.permission.ACCESS_BOOK_SERVICE");
        if (mPermission== PackageManager.PERMISSION_DENIED){//权限验证(似乎一直返回的-1)
            return false;
        }
        String packname=null;
        String[] mPackagesForUid = getPackageManager().getPackagesForUid(getCallingUid());
        if (mPackagesForUid!=null&&mPackagesForUid.length>0){
            packname = mPackagesForUid[0];
        }
if (!packname.startsWith("com.example")){
return false;
}

        return super.onTransact(code, data, reply, flags);
    }

    @Override
    public void regisiterListener(IOnNewBookArrivedListener listener) throws RemoteException {
//            if (!mIOnNewBookArrivedListeners.contains(listener)) {
  //                mIOnNewBookArrivedListeners.add(listener);
//            } else {
//                throw new RemoteException(" listener already exists");
//            }
        mRemoteCallbackList.register(listener);
    }

    @Override
    public void unregisiterListener(IOnNewBookArrivedListener listener) throws RemoteException {
//            if (mIOnNewBookArrivedListeners.contains(listener))//false
//                mIOnNewBookArrivedListeners.remove(listener);
        mRemoteCallbackList.unregister(listener);
    }
};


private class ServiceWorker implements Runnable {

    @Override
    public void run() {
        while (!mIsServiceDestroyed.get()) {
            try {
                Thread.sleep(5000);
            } catch (InterruptedException mE) {
                mE.printStackTrace();
            }
            int bookId = mBookList.size() + 1;
            Book newBook = new Book("newbook" + bookId, bookId + "");
            try {
                onNewBookArrived(newBook);
            } catch (RemoteException mE) {
                mE.printStackTrace();
            }
        }
    }
}

private void onNewBookArrived(Book mNewBook) throws RemoteException {
    mBookList.add(mNewBook);
  //        for (int i = 0; i < mIOnNewBookArrivedListeners.size(); i++) {
//            mIOnNewBookArrivedListeners.get(i).onNewBookArrived(mNewBook);
//        }
        int mBroadcast = mRemoteCallbackList.beginBroadcast();
        for (int i = 0; i < mBroadcast; i++) {
        IOnNewBookArrivedListener mBroadcastItem = mRemoteCallbackList.getBroadcastItem(i);
        if (mBroadcastItem!=null){
            mBroadcastItem.onNewBookArrived(mNewBook);
        }
    }
    mRemoteCallbackList.finishBroadcast();
}
}

在吧app作为client端
app需要拷贝aidl相关的东西。并且编译一下生成同样的代码。
代码大致如下

 private static final String TAG = "MainActivity";
IMyAidlInterface mAidlInterface;

IOnNewBookArrivedListener mIOnNewBookArrivedListener=new IOnNewBookArrivedListener.Stub() {
@Override
public void onNewBookArrived(Book newBook) throws RemoteException {
    Log.e(TAG, "onNewBookArrived() called with: newBook = [" + newBook + "]");
}

};
private ServiceConnection mConnection = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        mAidlInterface = IMyAidlInterface.Stub.asInterface(service);
        try {
            List mBookList = mAidlInterface.getBookList();
            Log.e(TAG, "onServiceConnected() called with: name = [" + name + "], service = [" + service + "]");
            Log.e(TAG, "onServiceConnected: mbooklist" + mBookList);
            Book newBook = new Book("从你的全世界路过", "张嘉jia");
            mAidlInterface.addBook(newBook);
            List mnewBooklist = mAidlInterface.getBookList();
            Log.e(TAG, "onServiceConnected: mnewBooklist" + mnewBooklist);
            mAidlInterface.regisiterListener(mIOnNewBookArrivedListener);
        } catch (RemoteException mE) {
            mE.printStackTrace();
        }
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {

    }
};


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent mIntent = new Intent("BookManagerService");
    bindService(mIntent, mConnection, Context.BIND_AUTO_CREATE);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    if (mAidlInterface!=null&&mAidlInterface.asBinder().isBinderAlive()){
        try {
            mAidlInterface.unregisiterListener(mIOnNewBookArrivedListener);
        } catch (RemoteException mE) {
            mE.printStackTrace();
        }
    }
    unbindService(mConnection);
}

需要注意的是,如作者所说对于IOnNewBookArrivedListener
之前用的CopyOnWriteArrayList存储,进行注册和解除注册。实际收到的不是同一个对象。换为RemoteCallbackList处理。具体都在代码中。

后面作者还提到了权限认证。
在服务端定义permission。客户端注册权限。发现似乎权限不能随意命名。前面需要接包名+permission.权限名。我之前随意命名如(lps.BOOK_SERVICE)在onTransact的checkCallingOrSelfPermission返回始终为-1.认证失败。后面改为com.example.lps.aidlserver.permission.ACCESS_BOOK_SERVICE就可以了。
还有第二种根据包名判断的也在代码里面了。
这样暂且算是AIDL入门吧。
跨进程和BInder确实需要慢慢理解。略深奥。

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