AIDL基本使用3—-in out inout的用

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在AIDL中客户端和服务端传入参数是可以设置流向.仅限参数不包含返回值
1. in :客户端可以传入参数到服务到(默认方法)
2. out:服务端修改客户端传入参数对象会影响客户端的传入实例
3. inout:服务端即可接受客户端参数也可以修改对其客户端实例影响

这个标签在哪?

这里用AIDL基本使用2的Demo作为案例:AIDL基本使用2

在AIDL基本使用2案例中 IMyAidlInterface.aidl 用来作为客户端和服务端交互的接口.

// IMyAidlInterface.aidlpackage com.ucoupon.myservice;import com.ucoupon.myservice2.Book;interface IMyAidlInterface {    String bookIn(in Book mbook);    String bookOut(out Book mbook);    String bookInout(inout Book mbook);}

看上面的代码中可以知道.in out inout是用来修饰aidl接口中传入参数.

我们在复习下Book.java 里面有什么

package com.ucoupon.myservice2;import android.os.Parcel;import android.os.Parcelable;/** * Created by FMY on 2017/5/18. */public class Book implements Parcelable {    String name;    int id;    public Book(String name, int id) {        this.name = name;        this.id = id;    }    protected Book(Parcel in) {        name = in.readString();        id = in.readInt();    }    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.writeString(name);        dest.writeInt(id);    }}

一个很普通的类有两个字段

来编译看看
编译出错,出错于自动生成接口java文件.new Book()无法被实例化.
因为根本没有这个构造方法.

为什么我们在AIDL基本使用的2中没有报错?
继续查看源码

这里写图片描述

如果被修饰方法参数为out那么会自动创建修饰参数的空构造方法
在本例中有如下方法被out修饰:
String bookOut(out Book mbook);

解决办法:创建一个空构造方法

继续编译
编译又报错

可以看到Book实例化调用readFromParcel方法.可是book没有这个方法.

解决办法:
在Book类中添加此方法.此方法是用于客户端用了out或者inout修饰的方法中读取服务端修改后的对象的数值在赋值给客户端

package com.ucoupon.myservice2;import android.os.Parcel;import android.os.Parcelable;/** * Created by FMY on 2017/5/18. */public class Book implements Parcelable {....    public void readFromParcel(Parcel reply) {        name = reply.readString();        id = reply.readInt();    }    .....}

修改后编译通过;

然后把文件拷贝到客户端进行绑定操作这一步略过

in测试

来看服务段代码

package com.ucoupon.myservice;import android.app.Service;import android.content.BroadcastReceiver;import android.content.Intent;import android.content.ServiceConnection;import android.os.IBinder;import android.os.RemoteException;import android.support.annotation.Nullable;import android.util.Log;import com.ucoupon.myservice2.Book;public class MyService extends Service {    public MyService() {    }    @Override    public void onCreate() {        super.onCreate();        Log.d(TAG, "onCreate() called");    }    //绑定的时候回调    @Nullable    @Override    public IBinder onBind(Intent intent) {        Log.d(TAG, "onBind() called with: intent = [" + intent + "]");        return new MyAidlInterface();    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Log.d(TAG, "onStartCommand() called with: intent = [" + intent + "], flags = [" + flags + "], startId = [" + startId + "]");        return super.onStartCommand(intent, flags, startId);    }    @Override    public void unbindService(ServiceConnection conn) {        Log.d(TAG, "unbindService() called with: conn = [" + conn + "]");        super.unbindService(conn);    }    @Override    public void onRebind(Intent intent) {        Log.d(TAG, "onRebind() called with: intent = [" + intent + "]");        super.onRebind(intent);    }    @Override    public boolean onUnbind(Intent intent) {        Log.d(TAG, "onUnbind() called with: intent = [" + intent + "]");        return super.onUnbind(intent);    }    @Override    public void unregisterReceiver(BroadcastReceiver receiver) {        Log.d(TAG, "unregisterReceiver() called with: receiver = [" + receiver + "]");        super.unregisterReceiver(receiver);    }    @Override    public void onDestroy() {        super.onDestroy();        Log.d(TAG, "onDestroy() called");    }    @Override    public void onStart(Intent intent, int startId) {        Log.d(TAG, "onStart() called with: intent = [" + intent + "], startId = [" + startId + "]");        super.onStart(intent, startId);    }    private static final String TAG = "MyService";    class MyAidlInterface extends IMyAidlInterface.Stub{        @Override        public String bookIn(Book mbook) throws RemoteException {            Log.d(TAG, "bookIn() called with: mbook = [" + mbook + "]");            mbook.id = 233;            return null;        }        @Override        public String bookOut(Book mbook) throws RemoteException {            Log.d(TAG, "bookout() called with: mbook = [" + mbook + "]");            mbook.id = 233;            return null;        }        @Override        public String bookInout(Book mbook) throws RemoteException {            Log.d(TAG, "bookInout() called with: mbook = [" + mbook + "]");            mbook.id = 233;            return null;        }    }}

客户端:

package com.ucoupon.aidlstudy;import android.content.ComponentName;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.os.RemoteException;import android.support.v7.app.AppCompatActivity;import android.util.Log;import com.ucoupon.myservice.IMyAidlInterface;import com.ucoupon.myservice2.Book;public class MainActivity extends AppCompatActivity {    private Myconnect myconnect;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //连接管理        myconnect = new Myconnect();        //意图        Intent intent = new Intent();        intent.setClassName("com.ucoupon.myservice","com.ucoupon.myservice.MyService");        startService(intent);        //开始绑定服务        bindService(intent,myconnect,BIND_AUTO_CREATE);    }    private static final String TAG = "MainActivity";    class Myconnect implements ServiceConnection {        //连接的成功的时候回调        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            Log.d(TAG, "onServiceConnected() called with: name = [" + name + "], service = [" + service + "]");            IMyAidlInterface iMyAidlInterface = IMyAidlInterface.Stub.asInterface(service);            Book mBook = new Book("客户端", -1);            try {                Log.e("fmy","客户端没有调用 bookin方法前mBook: name = "+mBook.name+","+" id"+mBook.id);                iMyAidlInterface.bookIn(mBook);                Log.e("fmy","客户端调用后 bookin方法后mBook: name = "+mBook.name+","+" id"+mBook.id);            } catch (RemoteException e) {                e.printStackTrace();            }            //解绑服务//            unbindService(myconnect);        }        //断开连接的时候回调        @Override        public void onServiceDisconnected(ComponentName name) {            Log.d(TAG, "onServiceDisconnected() called with: name = [" + name + "]");        }    }}

结果预测:
根据前言in 可以让客户端传入一个对象给服务端.但是服务端拿到对象后修改对客户端实例是没有效果

运行结果:
客户端:

E/fmy: 客户端没有调用 bookin方法前mBook: name = 客户端, id-1客户端调用后 bookin方法后mBook: name = 客户端, id-1

服务端:

 mbook = [Book{name='客户端', id=-1}]

从上面的日志可以发现客户端调用前后book实例是没有任何变化.
服务端也正确读取到客户端发送book实例信息.
回过头来再看看bookIn方法.

  @Override        public String bookIn(Book mbook) throws RemoteException {            Log.d(TAG, "bookIn() called with: mbook = [" + mbook + "]");            mbook.id = 233;            return null;        }

方法中bookIn对传入的book对象修改了id为233.但是客户端在调用后并有没有影响自身book对象.

out测试

客户端代码和上面in测试差不多,只改变调用bookout方法而已
客户端:

Book mBook = new Book("客户端", -1); try {     Log.e("fmy","客户端没有调用 bookout方法前mBook: name = "+mBook.name+","+" id"+mBook.id);     iMyAidlInterface.bookOut(mBook);     Log.e("fmy","客户端调用后 bookout方法后mBook: name = "+mBook.name+","+" id"+mBook.id); } catch (RemoteException e) {     e.printStackTrace(); }

预期结果:
out定义:服务端无法读取从客户端传入的参数,但可以改变传入的对象,然后对客户端的实例对象有影响

客户端没有调用 bookout方法前mBook: name = 客户端, id-1客户端调用后 bookout方法后mBook: name = null, id233

服务端:

mbook = [Book{name='null', id=0}]

判断正确:因为out是客户端无法传入参数给服务端,所以服务端的book参数都为默认值.
这时服务端修改book的id为233.然后把服务端的book传回.所以调用后客户端的name为空 id为233

AIDL基本使用4—-linkToDeath和unlinkToDeath

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