为什么在接听电话时会有这么多LogCat消息？

Question

我正在尝试检测用户何时接收呼叫，何时呼叫某人，何时呼叫结束。有人能解释一下为什么我在接到电话和呼叫时会有这么多日志消息吗？

我在Android Manifest中的接收器

<receiver android:name="com.prjct3.amadey.myapplication3.MyReceiver">
            <intent-filter>
                <action android:name="android.intent.action.PHONE_STATE"/>
                </intent-filter>
            </receiver>

这是我的代码。

public class MyReceiver extends BroadcastReceiver {
    PhoneStateListener listener;
    String incoming_nr;
    private int prev_state;
    String TAG="Point_1";
    @Override
    public void onReceive(final Context context, Intent intent) {
        Log.i("Point","onReceive");
        TelephonyManager tm = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);

        listener=new PhoneStateListener(){
            @Override
            public void onCallStateChanged(int state, String incomingNumber) {
                // TODO Auto-generated method stub

                super.onCallStateChanged(state, incomingNumber);
                 switch(state){
                case TelephonyManager.CALL_STATE_RINGING:
                    Log.d(TAG, "CALL_STATE_RINGING");
                        prev_state=state;
                        break;
                case TelephonyManager.CALL_STATE_OFFHOOK:
                Log.d(TAG, "CALL_STATE_OFFHOOK");
                prev_state=state;
                break;
                case TelephonyManager.CALL_STATE_IDLE:
                    Log.d(TAG, "CALL_STATE_IDLE==>"+incomingNumber);
                    if((prev_state==TelephonyManager.CALL_STATE_OFFHOOK)){
                        prev_state=state;
                        //Answered Call which is ended
                    }
                    if((prev_state==TelephonyManager.CALL_STATE_RINGING)){
                        prev_state=state;
                        //Rejected or Missed call
                    }
                    break;

            }
            }

        };
        tm.listen(listener, PhoneStateListener.LISTEN_CALL_STATE);
    }
}

还有我的LogCat

06-19 11:13:26.580    7519-7519/? D/Point_1﹕ CALL_STATE_IDLE==>null
06-19 11:13:26.705    7519-7519/? D/Point_1﹕ CALL_STATE_IDLE==>null
06-19 11:13:26.706    7519-7519/? D/Point_1﹕ CALL_STATE_IDLE==>null
06-19 11:19:05.669    7704-7704/? D/Point_1﹕ CALL_STATE_RINGING
06-19 11:19:05.669    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:08.471    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>+76398291345
06-19 11:19:08.523    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>+76398291345
06-19 11:19:08.524    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:32.053    7704-7704/? D/Point_1﹕ CALL_STATE_OFFHOOK
06-19 11:19:32.053    7704-7704/? D/Point_1﹕ CALL_STATE_OFFHOOK
06-19 11:19:32.076    7704-7704/? D/Point_1﹕ CALL_STATE_OFFHOOK
06-19 11:19:32.076    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:39.248    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:39.271    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:39.288    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:39.333    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>
06-19 11:19:39.333    7704-7704/? D/Point_1﹕ CALL_STATE_IDLE==>

谢谢。

Answer 1

当您的广播接收器的onReceive()被调用时，每次您尝试收听一个新的PhoneStateListener.You时，只需要执行一次。

if (phoneStateListener == null) {
phoneStateListener = new ThePhoneStateListener(arg0);
}

检查电话状态监听器是否为空，然后进行初始化。