java – 如何设置始终显示的警报？

现在,我只想在用户访问应用程序时获得某种电池状态指示.例如,如果设备已插入,则设备应该说充电和它的电平.如果设备已拔下,则不应显示任何内容.如果设备未充电且电池电量不足,则应显示电池电量不足指示.

我设置了大部分代码,但问题是,例如,如果我运行应用程序并且设备已插入,屏幕上会显示充电指示.如果我拔下设备,则不再显示充电但如果我重新插入设备,则仍然无法再显示充电.当设备插入或拔出,??电池电量不足或电量不足时,应始终显示电池警报.应始终显示信息更改.

所以这是我的广播接收器：

private BroadcastReceiver mBatInfoReceiver = new BroadcastReceiver()  {

        @Override
        public void onReceive(Context arg0,Intent intent) {

            //Battery level
            int level = intent.getIntExtra("level",0);

            //Plugged in Status
            int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED,-1);

            //Battery Status
            int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS,-1);

            //If the device is charging or contains a full status,it's charging
            boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                    status == BatteryManager.BATTERY_STATUS_FULL;

            //If the device isCharging and plugged in,then show that the battery is charging
            TextView batteryTextView = ((TextView) findViewById(R.id.charging));
            TextView batteryLowTextView = ((TextView) findViewById(R.id.low_battery));
            ImageView batteryLowImageView= ((ImageView) findViewById(R.id.low_battery_icon));
            ImageView batteryImageView =((ImageView) findViewById(R.id.charging_battery_icon));

            if (isCharging && plugged == BatteryManager.BATTERY_PLUGGED_AC || plugged == BatteryManager.BATTERY_PLUGGED_USB) {


                //Gets the 'last synced' string and sets to datetime of the last sync
                Resources resources = context.getResources();
                String chargingString = String.format(resources.getString(R.string.charging),level);

                //Dynamically sets the value of the battery level
                batteryLowTextView.setVisibility(TextView.INVISIBLE);
                batteryLowImageView.setVisibility(ImageView.INVISIBLE);
                batteryTextView.setText(chargingString + "%");

            } else if (level < LOW_BATTERY_LEVEL && !isCharging) {

                Resources resources = context.getResources();
                String lowBatteryString = String.format(resources.getString(R.string.low_battery));

                batteryTextView.setVisibility(TextView.INVISIBLE);
                batteryImageView.setVisibility(ImageView.INVISIBLE);
                batteryLowTextView.setText(lowBatteryString);

            } else if (!isCharging && level > LOW_BATTERY_LEVEL) {

                //do nothing
                batteryTextView.setVisibility(TextView.GONE);
                batteryImageView.setVisibility(ImageView.GONE);

            }

        }

    };

在我的OnCreate方法中,我打电话

//calls registerReceiver to receive the broadcast for the state of battery
            this.registerReceiver(this.mBatInfoReceiver,new
                    IntentFilter(Intent.ACTION_BATTERY_CHANGED));

所以,我想知道我做错了什么？是bools吗？

if (isCharging) {

            //Gets the 'last synced' string and sets to datetime of the last sync
            Resources resources = context.getResources();
            String chargingString = String.format(resources.getString(R.string.charging),level);

            //Dynamically sets the value of the battery level
            batteryLowTextView.setVisibility(TextView.INVISIBLE);
            batteryLowImageView.setVisibility(ImageView.INVISIBLE);
            batteryTextView.setText(chargingString + "%");
            batteryTextView.setVisibility(TextView.VISIBLE);
            batteryImageView.setVisibility(ImageView.VISIBLE);

        } else if (level <= LOW_BATTERY_LEVEL) {

            Resources resources = context.getResources();
            String lowBatteryString = String.format(resources.getString(R.string.low_battery));

            batteryTextView.setVisibility(TextView.INVISIBLE);
            batteryImageView.setVisibility(ImageView.INVISIBLE);
            batteryLowTextView.setText(lowBatteryString);
            batteryLowTextView.setVisibility(TextView.VISIBLE);
            batteryLowImageView.setVisibility(ImageView.VISIBLE);

        } else {

            //show nothing
            batteryTextView.setVisibility(TextView.GONE);
            batteryImageView.setVisibility(ImageView.GONE);
            batteryLowTextView.setVisibility(TextView.GONE);
            batteryLowImageView.setVisibility(ImageView.GONE);
        }