怎么让那个返回值不为空

Question

下面是我想获取电池电量信息的代码：

package com.android.infocolle;
import java.util.ArrayList;
import java.util.HashMap;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.util.Log;

public class BatteryDetailInfo {

private static ArrayList<HashMap<String,Object>> mBatteryList = new ArrayList<HashMap<String,Object>>();
private static HashMap<String, Object> mBatteryMap = new HashMap<String, Object>();

public static ArrayList<HashMap<String, Object>> getBatteryDetail(Intent intent,Context context) { 

    /* 创建广播接收器 */  
    BroadcastReceiver onBatteryInfoReceiver  = new BroadcastReceiver()   
    {  
        private int BatteryN;       //目前电量  
        private int BatteryV;       //电池电压  
        private double BatteryT;        //电池温度  
        private String BatteryStatus;   //电池状态  
        private String BatteryTemp;     //电池使用情况  

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

            String action = intent.getAction();  
            /* 
             * 如果捕捉到的action是ACTION_BATTERY_CHANGED， 就运行onBatteryInfoReceiver() 
             */  
            if (Intent.ACTION_BATTERY_CHANGED.equals(action))   
            {  
                BatteryN = intent.getIntExtra("level", 0);    //目前电量  
                BatteryV = intent.getIntExtra("voltage", 0);  //电池电压  
                BatteryT = intent.getIntExtra("temperature", 0);  //电池温度  

                switch (intent.getIntExtra("status", BatteryManager.BATTERY_STATUS_UNKNOWN))   
                {  
                case BatteryManager.BATTERY_STATUS_CHARGING:  
                    BatteryStatus = "充电状态";  
                    break;  
                case BatteryManager.BATTERY_STATUS_DISCHARGING:  
                    BatteryStatus = "放电状态";  
                    break;  
                case BatteryManager.BATTERY_STATUS_NOT_CHARGING:  
                    BatteryStatus = "未充电";  
                    break;  
                case BatteryManager.BATTERY_STATUS_FULL:  
                    BatteryStatus = "充满电";  
                    break;  
                case BatteryManager.BATTERY_STATUS_UNKNOWN:  
                    BatteryStatus = "未知道状态";  
                    break;  
                }  

                switch (intent.getIntExtra("health", BatteryManager.BATTERY_HEALTH_UNKNOWN))   
                {  
                case BatteryManager.BATTERY_HEALTH_UNKNOWN:  
                    BatteryTemp = "未知错误";  
                    break;  
                case BatteryManager.BATTERY_HEALTH_GOOD:  
                    BatteryTemp = "状态良好";  
                    break;  
                case BatteryManager.BATTERY_HEALTH_DEAD:  
                    BatteryTemp = "电池没有电";  
                    break;  
                case BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE:  
                    BatteryTemp = "电池电压过高";  
                    break;  
                case BatteryManager.BATTERY_HEALTH_OVERHEAT:  
                    BatteryTemp =  "电池过热";  
                    break;  
                }   

                mBatteryMap.clear();
                mBatteryMap.put("BatteryN", BatteryN);
                mBatteryMap.put("BatteryV", BatteryV);
                mBatteryMap.put("BatteryT", BatteryT);
                mBatteryMap.put("BatteryStatus", BatteryStatus);
                mBatteryMap.put("BatteryTemp", BatteryTemp);
                Log.i("20171012liqin mBatteryMap : ", String.valueOf(mBatteryMap));
            }  
            mBatteryList.clear();
            mBatteryList.add(mBatteryMap);

            Log.i("20171012liqin (BroadcastReceiver) mBatteryMap : ", String.valueOf(mBatteryMap));
            Log.i("20171012liqin (BroadcastReceiver) mBatteryList : ", String.valueOf(mBatteryList));
        }  
    };  

    context.registerReceiver(onBatteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 
    Log.i("20171012liqin (getBatteryDetail) mBatteryList : ", String.valueOf(mBatteryList)); 
    return mBatteryList;
}

}

当我在activity里面调用BatteryDetailInfo.getBatteryDetail 时返回的 mBatteryList 值总是为空，具体log如下

20171012liqin (getBatteryDetail) mBatteryList : : []
20171012liqin mBatteryMap : : {BatteryStatus=充电状态, BatteryT=308.0, BatteryTemp=状态良好, BatteryV=4317, BatteryN=100}
20171012liqin (BroadcastReceiver) mBatteryMap : : {BatteryStatus=充电状态, BatteryT=308.0, BatteryTemp=状态良好, BatteryV=4317, BatteryN=100}
20171012liqin (BroadcastReceiver) mBatteryList : : [{BatteryStatus=充电状态, BatteryT=308.0, BatteryTemp=状态良好, BatteryV=4317, BatteryN=100}]

虽然registerReceiver是在return mBatteryList前面执行，但是onBatteryInfoReceiver里面的onReceive确实还没执行，mBatteryList就已经返回了

    context.registerReceiver(onBatteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED)); 
    Log.i("20171012liqin (getBatteryDetail) mBatteryList : ", String.valueOf(mBatteryList)); 
    return mBatteryList;

求大神指点一下，这代码要怎么修改才能返回不为空的值，万谢！****

Answer 1

很明显是onBatteryInfoReceiver还没执行完就return mBatteryList