Android 利用广播接收器启动服务

public class MainActivity extends Activity {

    private Button bt ;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
            bt = (Button)findViewById(R.id.bt);
            
            IntentFilter filter = new IntentFilter("BT");
            Receiver recerver = new Receiver();
            getApplicationContext().registerReceiver(recerver, filter);
                
            bt.setOnClickListener(new OnClickListener(){
                public void onClick(View arg0) {
                    Intent intent = new Intent("BT");
                    intent.setPackage(getPackageName());
                    Bundle bundle = new Bundle();
                    bundle.putString("say",    "Hello,I'm activity!");
                    intent.putExtras(bundle);
                    sendBroadcast(intent);
                }
            });
    }

}

public class Receiver extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent) {
            String bd=intent.getStringExtra("say");
            Toast.makeText(context,bd+ "I'm Receiver.I will send Intent!!!", Toast.LENGTH_LONG).show();
            intent.setAction("myservice");
            context.startService(intent);
    }

}

public class MyService extends Service {

    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }
    
    public void onCreate(){
        Toast.makeText(MyService.this, "onCreate()", Toast.LENGTH_LONG).show();
    }
    public void onStart(Intent intent,int startId){
        Toast.makeText(MyService.this, "onStart()", Toast.LENGTH_LONG).show();
        
    }
    public void onDestroy(){
        Toast.makeText(MyService.this, "onDestroy()", Toast.LENGTH_LONG).show();
    }
}

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".MyService">
            <intent-filter >
                <action android:name="myservice" />
            </intent-filter>
        </service>
    </application>