Service想要与Activity进行数据交互，首先Activity先得绑定Service.bound service是service 的实现,它允许其他应用程序绑定到它并与之交互。要提供bound service,我们必须实现onBind()回调方法。这个方法返回一个内部对象定义的编程接口,Activity可以使用与Service进行交互。那么具体该如何实现呢，首先我们还是一样先创建一个MyService继承Service。然后如何设置:呢。（1）在你的Service,创建一个Binder实例,返回当前的Service实例以及一个Activity可以调用公共方法。（2）返回这个实例的Binder在onBind()回调方法。（3）在Activity里创建ServiceConnection,在onServiceConnected()回调方法接受Binder,并得到服务器的实例。讲的比较啰嗦哦，我们还是看代码来细细品味吧。
Service的代码
package com.example.f22_service02;
import java.util.Random;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteException;
import android.util.Log;
public class HelloService extends Service {
private MyBinder binder=new MyBinder();
public class MyBinder extends Binder{
public HelloService getService(){
return HelloService.this;
//返回Service实例，使主程序能调用该方法
}
@Override
protected boolean onTransact(int code, Parcel data, Parcel reply,
int flags) throws RemoteException {
// TODO Auto-generated method stub
Log.i("TAG", "------>"+data.readInt());
Log.i("TAG", "------>"+data.readString());
reply.writeInt(2);
reply.writeString("Rose");
return super.onTransact(code, data, reply, flags);
}
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return binder; //回掉方法
}
public int getRandom(){
return new Random().nextInt(100);
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
Log.i("TAG", "------>Create");
super.onCreate();
}
@Override
public boolean onUnbind(Intent intent) {
// TODO Auto-generated method stub
Log.i("TAG", "------>Unbind");
return super.onUnbind(intent);
}
}
Activity的方法
package com.example.f22_service02;
import com.example.f22_service02.HelloService.MyBinder;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteException;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
@SuppressLint("Recycle")
public class MainActivity extends Activity implements OnClickListener {
private Button button, button2, button3;
private MyBinder binder;
private HelloService helloService;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) this.findViewById(R.id.button1);
button2 = (Button) this.findViewById(R.id.button2);
button3 = (Button) this.findViewById(R.id.button3);
button.setOnClickListener(this);
button2.setOnClickListener(this);
button3.setOnClickListener(this);
}
private ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) {
// TODO Auto-generated method stub
Log.i("ACTIVITY", "---------〉失去绑定");
}
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
// TODO Auto-generated method stub
binder = (MyBinder) service; // 绑定Service，并获得Service实例，接下来就可以调用Service中的方法了
helloService = binder.getService();
Log.i("ACTIVITY", "---------〉绑定成功");
}
};
@SuppressLint("Recycle")
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.button1:
//绑定Service
Intent intent=new Intent(MainActivity.this,HelloService.class);
bindService(intent, connection, Context.BIND_AUTO_CREATE);//第三个参数是一个标志显示选项绑定
break;
case R.id.button2:
//实现Activity与Service的数据交互
//Parcel是一个容器，能包含消息(数据和对象引用),可以通过一个IBinde发送
Parcel data=Parcel.obtain();
data.writeInt(helloService.getRandom());
data.writeString("jack");
Parcel reply=Parcel.obtain();
try {
binder.transact(IBinder.LAST_CALL_TRANSACTION, data, reply, 0);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.i("ACTIVITY", "----Service回传的值---->"+reply.readInt());
Log.i("ACTIVITY", "----Service回传的值---->"+reply.readString());
break;
case R.id.button3:
//解除绑定
unbindService(connection);
break;
}
}
}