android - 开始 Activity

Question

当我尝试开始 Activity 时，手机停止响铃并且它一直强制关闭。

所以这是我的广播接收器

public class Incoming extends BroadcastReceiver {


    @Override
    public void onReceive(Context arg0, Intent arg1) {
        // TODO Auto-generated method stub

         MyPhoneStateListener phoneListener=new MyPhoneStateListener();  
            TelephonyManager telephony = (TelephonyManager)   
            arg0.getSystemService(Context.TELEPHONY_SERVICE);
         phoneListener.context = arg0;
            telephony.listen(phoneListener,PhoneStateListener.LISTEN_CALL_STATE);  
    }

}

这应该开始 Activity

public class MyPhoneStateListener extends PhoneStateListener {  

    int prevstate;


    public void onCallStateChanged(int state,String incomingNumber){  


        if(prevstate==TelephonyManager.CALL_STATE_OFFHOOK && state == TelephonyManager.CALL_STATE_IDLE){

              Log.i("PARm","Here the activity should start");
          }
        else if(prevstate==TelephonyManager.CALL_STATE_RINGING && state == TelephonyManager.CALL_STATE_IDLE){ 

            Log.i("PARM","Here the activity should start");

        }



    switch(state){  
        case TelephonyManager.CALL_STATE_IDLE:  
          Log.d("DECallNoteActivity.get getContext();BUG", "IDLE"); 
          prevstate = state;
        break;  
        case TelephonyManager.CALL_STATE_OFFHOOK:  
          Log.d("DEBUG", "OFFHOOK");
          prevstate = state;
        break;  
        case TelephonyManager.CALL_STATE_RINGING:  
          Log.d("DEBUG", "RINGING");
          prevstate = state;
        break;  
        }

      } 


    } 

如果您能告诉我在这种情况下如何获取上下文以启动 Activity 或如何启动它的其他方式，我会很高兴。

谢谢。

Answer 1

广播接收器的上下文仅在 onReceive 调用期间有效:您无法保存它并在以后重用它。如果您需要以这种方式启动 Activity，您需要的是从 BroadcastReceiver 的 onReceive 方法启动一个 Service，并让该服务创建电话状态监听器并启动所需的 Activity:启动 Activity 后，它可以自行停止。