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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:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | //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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | //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 ; } }; } |