BrocastReceiver在code与在xml里面注册的区别

在code里面注册，只有你的Activity或service处于当前运行的状态才能接受到消息，当Activity或service不处于活的状态，则是接不到消息的。而在xml里面注册的话，那样不管是否处于活的状态都可以接收到消息的.
code:
适用于更新UI，内部使用

public class Android_TestReceiver_registerInCodeActivity extends Activity implements OnClickListener{
    private Button registerBtn = null;
    private Button unRegisterBtn = null;
    private MySMSReceiver myreceiver = null;
    private IntentFilter ifilter  = null;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        registerBtn = (Button)findViewById(R.id.registerBtn);
        unRegisterBtn = (Button)findViewById(R.id.unRegisterBtn);

        registerBtn.setOnClickListener(this);
        unRegisterBtn.setOnClickListener(this);

        myreceiver = new MySMSReceiver();
        ifilter = new IntentFilter();
        ifilter.addAction("android.provider.Telephony.SMS_RECEIVED");


    }
    @Override
    public void onClick(View v) {
        //register
        if(v.getId() == R.id.registerBtn){
            registerReceiver(myreceiver, ifilter);
        }

        //unRegister
        if(v.getId() == R.id.unRegisterBtn){
            unregisterReceiver(myreceiver);
        }

    }

}

XML：
全局的，服务，监听其他应用

        <receiver android:name=".MyReceiver">
            <intent-filter>
                <action android:name="android.intent.action.EDIT"/>
            </intent-filter>
        </receiver>