android,a Receiver intent is null

this is my receiver.viewChanger is my original class .

public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
            viewChanger vc = new viewChanger();

        if(action.equals("android.intent.action.TIME_TICK")){
            vc.setDateView(context);

        }else if(action.equals("android.intent.action.BATTERY_CHANGED")){
            int level = intent.getIntExtra("level", 0);
            vc.setBatteryView(level, context);

        }else if(action.equals(Intent.ACTION_POWER_CONNECTED)){
            int charging = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
            vc.setAcusbView(charging, context);

        }else if(action.equals(Intent.ACTION_POWER_DISCONNECTED)){
            vc.setAcusbNullView(context);
        }

    }

my trouble is

int charging = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);

this intent seems to be empty,charging get to be "-1" what is wrong for me?

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