无法从警报服务访问 sqlite 数据库

Question

我想从警报服务访问我的 sqlite 数据库。还想向数据库添加新记录。我尝试了很多，但出现异常。请帮帮我..你可以在下面找到整个代码

public class MyAlarmService extends Service  {

DatabaseManager database;

    String ename;
    int id;
    DateFormat d;
    RestClient obj;
    private Context context;
    Long timstpAtFive;
    private String posturl = "http://infinitsolutions.in/attendance/api/attendance";

    public MyAlarmService(){}

    public MyAlarmService(Context context, Long tlong ){
        this.context = context;
        this.timstpAtFive=tlong;



    }




    @Override
    public IBinder onBind(Intent arg0)
    {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void onCreate()
    {
        // TODO Auto-generated method stub
        super.onCreate();
    }

    @Override
    public void onStart(Intent intent, int startId)
    {

    super.onStart(intent, startId);
            d = DateFormat.getDateInstance();
            obj = new RestClient((android.app.Activity) context);
            try {

                String stat = "signed in";
                ArrayList<DataRecord>autoList = database.executeQuery("select employee_Id from attendance where date='" + d.format(new Date()) + "' and status = '" + stat + "'");

                int size = autoList.size();
                for (int i = 0; i < size; i++) {

                          id = autoList.get(i).getInt("employee_Id");
        ArrayList<DataRecord> list = database.executeQuery("select status from attendance where employee_Id ='" + id + "'and date='" + d.format(new Date()) + "'");
                        int n = list.size();
                        if (list.get(n - 1).equals("signed in")) {

                        ArrayList<DataRecord> list1 = database.executeQuery("select employee_name from employee where employee_Id ='" + id + "'");
                        ename = list1.get(0).getString("employee_name");
                        methodemployee(id, ename);

                    }
                }
            }catch(NullPointerException e){
                    e.printStackTrace();
            } catch(Exception e){
                e.printStackTrace();
            }
 private void methodemployee(int employee_id,String employee_name)
    {
        DataRecord data= new DataRecord();
        try {
            data.put("employee_name", employee_name);
            data.put("employee_Id",employee_id);
            data.put("date", d.format(new Date()));
            data.put("time",timstpAtFive);
            data.put("status", "signed out");
            data.put("type", "auto");
            database.addRecord("attendance", null, data);
        } catch (JSONException e) {
            e.printStackTrace();
        }


        ArrayList<DataRecord> attendance = database.executeQuery("select * from attendance where employee_Id ='" + employee_id + "'");
        int n=attendance.size();
        //postdata(attendance.get(n-1));

    }




    @Override
    public void onDestroy()
    {
        // TODO Auto-generated method stub
        super.onDestroy();
    }
    // Post data to server and return acknowledgement from server
    private void postdata(DataRecord dataRecord) {
        obj.POST(posturl, getJSON(dataRecord), new RestListenerJson() {
            @Override
            public void onResultJsonFormat(JSONObject jsonobject) {

            }

            @Override
            public void onResultJsonFormat(String jsonobject) {
                String result = jsonobject;

            }
        });
    }
    //Convert the datarecords to JSONString
    private String getJSON(DataRecord dataRecord)

    {
        JSONObject Jobj = new JSONObject();
        try {
            DateFormat d1 = DateFormat.getTimeInstance();
            //long time = d1.parse(dataRecord.getString("time")).getTime() / 1000;


            Jobj.put("date", dataRecord.getString("date"));
            Jobj.put("employee_Id", dataRecord.getString("employee_Id"));
            Jobj.put("time", timstpAtFive);
            Jobj.put("status", dataRecord.getString("status"));
            Jobj.put("employee_name", dataRecord.getString("employee_name"));
            Jobj.put("type", dataRecord.getString("type"));


        } catch (JSONException e) {
            e.printStackTrace();
        } //catch (ParseException e) {
        // e.printStackTrace();
        //}
        catch (NullPointerException e) {
            e.printStackTrace();
        }

        return Jobj.toString();
    }



}

你可以在下面找到logcat警告..没有错误

9-21 11:32:00.877    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ java.lang.NullPointerException
09-21 11:32:00.877    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at com.example.infinitdeveloper.myapplication.MyAlarmService.onStart(MyAlarmService.java:74)
09-21 11:32:00.877    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.app.Service.onStartCommand(Service.java:450)
09-21 11:32:00.877    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2797)
09-21 11:32:00.877    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.app.ActivityThread.access$2100(ActivityThread.java:145)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1362)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:102)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.os.Looper.loop(Looper.java:136)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5214)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:814)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:630)
09-21 11:32:00.887    4778-4778/com.example.infinitdeveloper.myapplication W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)

Answer 1

您需要从警报管理器获取上下文并将其传递给数据库管理器类以访问数据库。

编辑 您不能简单地执行数据库查询而不进行初始化。您需要制作单独的数据库管理器类。在其中编写您的函数，然后将上下文传递给该函数并从数据库中获取结果。

请查看此链接：Vogella Android Database。您没有初始化和打开数据库即时。您需要阅读一些有关 Android 数据库的信息。