我想让手机在锁屏状态下继续监听onSignalStrengthsChanged，用wakelock为什么不能实现？

Question

重要代码： private class MyPhoneStateListener extends PhoneStateListener { /* 从得到的信号强度,每个tiome供应商有更新 */ @Override public void onSignalStrengthsChanged(SignalStrength signalStrength) { acquire1(); //acquire(true); super.onSignalStrengthsChanged(signalStrength); Toast.makeText(getApplicationContext(), "手机信号强度asu为 " + String.valueOf(signalStrength.getGsmSignalStrength()), Toast.LENGTH_SHORT).show();  Log.i(DISPLAY_SERVICE, "operator name =周周周周周装置周周周周周 "); asu=signalStrength.getGsmSignalStrength(); getSystemService(Context.POWER_SERVICE); PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);   boolean isScreen=pm.isScreenOn(); if(dbm==1&&isScreen!=true&&asu<29) { dbm=0; acquire(true); TextView2.setText("你liang"); Intent it=new Intent("tw.android.MY_BROADCAST");//调用广播 sendBroadcast(it); } } }; public void acquire1() {  //release();  PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);  int mode = PowerManager.PARTIAL_WAKE_LOCK; if(mWakeLock==null) {mode=mode|PowerManager.ON_AFTER_RELEASE; mWakeLock = pm.newWakeLock(mode, "");  Log.i(DISPLAY_SERVICE, "重中之重重中之重"); mWakeLock.acquire(); } }  public void release() {  if (mWakeLock != null) {      mWakeLock.release();      mWakeLock = null;  }  }