android之理解Service(三)

这一节笔记是关于Transact的IPC，Transact的使用背景和Messenger一样，是在同一个APP中Client与service的IPC
相对比，使用Transact比使用Messenger简单的多。了解BinderService基础，这个就so easy

package com.vibexie.servicetransact;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteException;

public class MyService extends Service {
    @Override
    public void onCreate() {
        super.onCreate();
    }

    public MyService() {
    }

    public class MyBinder extends Binder{
        @Override
        protected boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException {
            reply.writeString(data.readString()+" and juan");
            return super.onTransact(code, data, reply, flags);
        }
    }
    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
       return new MyBinder();
    }
}

package com.vibexie.servicetransact;

import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteException;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity {
    /**
     * 与service建立连接的Binder
     */
    MyService.MyBinder myBinder;
    private Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button=(Button)this.findViewById(R.id.button);
        Intent intent=new Intent(this,MyService.class);
        bindService(intent,serviceConnection, Context.BIND_AUTO_CREATE);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                /**
                 * 向service发送的Parcel
                 */
                Parcel parcel=Parcel.obtain();
                parcel.writeString("vibexie");
                /**
                 * 用于接收service返回数据的parcel
                 */
                Parcel reply=Parcel.obtain();

                /**
                 * 与Service进行交互
                 */
                try {
                    myBinder.transact(IBinder.FIRST_CALL_TRANSACTION, parcel, reply, 0);
                } catch (RemoteException e) {
                    e.printStackTrace();
                }

                /**
                 * 获取返回数据
                 */
                Toast.makeText(MainActivity.this,reply.readString(),Toast.LENGTH_SHORT).show();
            }
        });
    }

    ServiceConnection serviceConnection=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            myBinder = (MyService.MyBinder)service;
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };
}

效果：