android Service和activity通信

在Android中，Service和Activity可以通过多种方式进行通信。以下是一个简单的例子，展示了如何使用Intent、Binder和Interface来实现Service和Activity之间的通信。

首先，定义一个Service并创建一个绑定器类（Binder）：

public class MyService extends Service {
    private final LocalBinder binder = new LocalBinder();
 
    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }
 
    public class LocalBinder extends Binder {
        MyService getService() {
            return MyService.this;
        }
    }
 
    public void serviceMethod() {
        // 示例方法
    }
}

然后，在Activity中绑定Service并调用Service的方法：

public class MainActivity extends AppCompatActivity {
    private MyService myService;
    private boolean bound = false;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        Intent intent = new Intent(this, MyService.class);
        bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
    }
 
    private ServiceConnection serviceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            MyService.LocalBinder binder = (MyService.LocalBinder) service;
            myService = binder.getService();
            bound = true;
        }
 
        @Override
        public void onServiceDisconnected(ComponentName name) {
            bound = false;
        }
    };
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (bound) {
            unbindService(serviceConnection);
            bound = false;
        }
    }
 
    public void callServiceMethod(View view) {
        if (bound) {
            myService.serviceMethod();
        }
    }
}

在这个例子中，MainActivity通过调用bindService()方法绑定到MyService。在ServiceConnection的onServiceConnected()回调中，它通过传递的IBinder获取MyService的实例，并可以调用MyService中定义的公开方法。当MainActivity不再需要与Service通信时，它调用unbindService()以解除绑定。

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