通过Ibinder类Bind service

Binder is like RPC in java. It enables multi-processes communication. Now we will talking about how to bind service using IBinder class.

总共有3种bind service方法：

1.使用IBinder class

2.使用Messanger class

3.使用AIDL

这里只讨论IBinder class方法。

用IBinder class 来bind service分以下几步：

Service创建步骤：

1.创建一个新的工程名字为“BindServiceUsingBinderClass”；

2.在创建的Application中创建一个Service.java继承Service；

3.在Service.java中创建一个LocalBinder内部类继承Binder；

4.实现service中onBind()方法并返回“LocalBinder的实例。

Activity创建步骤：

1.创建Client Activity,并创建一个”ServiceConnection"接口的instance。

2.实现该接口的两个方法-onServiceConnected()和onServiceDisconnected().

3.在onServiceConnected()方法中，把iBinder instance cast成localBinder类。

4.实现onStart() 方法并用bindService()绑定服务。

5.实现onStop() 方法，并用unbindService()解除绑定。

Service.java代码如下：

//Service.java
public class Service extends Service{

 IBinder mBinder = new LocalBinder();

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

 public class LocalBinder extends Binder {
  public Server getServerInstance() {
   return Server.this;
  }
 }

 public String getTime() {
  SimpleDateFormat mDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  return mDateFormat.format(new Date());
 }
}

　　Client.java

//Client.java
public class Client extends Activity {

 boolean mBounded;
 Server mServer;
 TextView text;
 Button button;
 
 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        text = (TextView)findViewById(R.id.text);
        button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new OnClickListener() {
   
   public void onClick(View v) {
    text.setText(mServer.getTime());
   }
  });
    }

 @Override
 protected void onStart() {
  super.onStart();
  Intent mIntent = new Intent(this, Server.class);
        bindService(mIntent, mConnection, BIND_AUTO_CREATE);
 };
 
 ServiceConnection mConnection = new ServiceConnection() {
  
  public void onServiceDisconnected(ComponentName name) {
   Toast.makeText(Client.this, "Service is disconnected", 1000).show();
   mBounded = false;
   mServer = null;
  }
  
  public void onServiceConnected(ComponentName name, IBinder service) {
   Toast.makeText(Client.this, "Service is connected", 1000).show();
   mBounded = true;
   LocalBinder mLocalBinder = (LocalBinder)service;
   mServer = mLocalBinder.getServerInstance();
  }
 };
 
 @Override
 protected void onStop() {
  super.onStop();
  if(mBounded) {
   unbindService(mConnection);
   mBounded = false;
  }
 };
}