java - 空异常。数据库已锁定

Question

能够使用不同的适配器和数据库名称读取/写入另一个 Activity 。尝试复制粘贴并进行相应编辑。但是，出现了一些错误，例如数据库锁定。

遭遇.java

package com.example.medilearner;

import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.medilearner.database.JSONParser;
import com.medilearner.database.encounterDbAdapter;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;






public class EncounterActivity extends Activity {
    ListView list;
    TextView eid;
    TextView eclerkship;
    TextView ename;
    TextView etype;
    TextView erequiredattempts;


    // DATABASE ADAPTOR
    encounterDbAdapter patientDB;
    Context myContext;

    Button Btngetdata;
    ArrayList<HashMap<String, String>> encouterlist = new ArrayList<HashMap<String, String>>();

    //URL to get JSON Array
    private static String url = URL;

    //JSON Node Names 
    private static final String TAG_ENCOUNTERS = "encounters";
    private static final String TAG_E_ID = "e_id";
    private static final String TAG_E_CLERKSHIP = "clerkship";
    private static final String TAG_E_NAME = "encounter_name";  
    private static final String TAG_E_TYPE = "type";
    private static final String TAG_E_REQUIRED_ATTEMPTS = "required_attempts";

    JSONArray android = null;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_encounter);
        encouterlist = new ArrayList<HashMap<String, String>>();

                 new JSONParse().execute();
    }

    private class JSONParse extends AsyncTask<String, String, JSONObject> {
         private ProgressDialog pDialog;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
             eid = (TextView)findViewById(R.id.eid);
             eclerkship = (TextView)findViewById(R.id.eclerkship);
             ename = (TextView)findViewById(R.id.ename);
             etype = (TextView)findViewById(R.id.etype);
             erequiredattempts = (TextView)findViewById(R.id.erequiredattempts);
            pDialog = new ProgressDialog(EncounterActivity.this);
            pDialog.setMessage("Getting Data ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();



        }

        @Override
        protected JSONObject doInBackground(String... args) {



            JSONParser jParser = new JSONParser();

            // Getting JSON from URL
            JSONObject json = jParser.getJSONFromUrl(url);
            return json;
        }
         @Override
         protected void onPostExecute(JSONObject json) {
             pDialog.dismiss();
             try {
                    // Getting JSON Array from URL
                    android = json.getJSONArray(TAG_ENCOUNTERS);
                    for(int i = 0; i < android.length(); i++){
                    JSONObject c = android.getJSONObject(i);

                    // Storing  JSON item in a Variable
                    String eid = c.getString(TAG_E_ID);
                    String eclerkship = c.getString(TAG_E_CLERKSHIP);
                    String ename = c.getString(TAG_E_NAME);
                    String etype = c.getString(TAG_E_TYPE);     
                    String erequiredattempts = c.getString(TAG_E_REQUIRED_ATTEMPTS);


                    // Opening of database
                    patientDB = new encounterDbAdapter(myContext);
                    patientDB.open();
                    // Adding value HashMap key => value
                    patientDB.close();

                    HashMap<String, String> map = new HashMap<String, String>();

                    map.put(TAG_E_ID, eid);
                    map.put(TAG_E_CLERKSHIP, eclerkship);
                    map.put(TAG_E_NAME, ename);
                    map.put(TAG_E_TYPE, etype);
                    map.put(TAG_E_REQUIRED_ATTEMPTS, erequiredattempts);

                    encouterlist.add(map);
                    list=(ListView)findViewById(R.id.list);     



                    ListAdapter adapter = new SimpleAdapter(EncounterActivity.this, encouterlist,
                            R.layout.list_v,
                            new String[] { TAG_E_ID, TAG_E_CLERKSHIP, TAG_E_NAME, TAG_E_TYPE, TAG_E_REQUIRED_ATTEMPTS }, new int[] {
                                    R.id.eid, R.id.eclerkship, R.id.ename, R.id.etype, R.id.erequiredattempts});

                    list.setAdapter(adapter);
                    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                        @Override
                        public void onItemClick(AdapterView<?> parent, View view,
                                                int position, long id) {
                            Toast.makeText(EncounterActivity.this, "You Clicked at "+encouterlist.get(+position).get("type"), Toast.LENGTH_SHORT).show();

                        }
                    });

                    }
            } catch (JSONException e) {
                e.printStackTrace();
            }


         }
    }

}

EncounterDbAdapter.java

package com.medilearner.database;

import java.util.ArrayList;
import java.util.Locale;

import android.content.ContentValues;
import android.content.Context;

import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class encounterDbAdapter {

    private static final String DATABASE_NAME = "encounter.db";
    private static final String DATABASE_TABLE = "encounterDb";
    private static final int DATABASE_VERSION = 2;
    private SQLiteDatabase _db;
    private final Context encounterContext;



    public static final String KEY_ID = "_id";
    public static final int COLUMN_KEY_ID = 0;


    public static final String ENCOUNTER_ID = "entry_initial";
    public static final int COLUMN_INITIAL_ID = 1;
    public static final String CLERKSHIP = "entry_date";
    public static final int COLUMN_DATE_ID = 2;
    public static final String ENCOUNTER_NAME = "entry_sitelocation";
    public static final int COLUMN_SITE_ID = 3;
    public static final String TYPE = "entry_clinic";
    public static final int COLUMN_WARD_ID = 4;
    public static final String REQUIRED_ATTEMPTS = "entry_history";
    public static final int COLUMN_HISTORY_ID = 5;

    protected static final String DATABASE_CREATE = "create table "
            + DATABASE_TABLE + " (" + KEY_ID
            + " integer primary key autoincrement, " + ENCOUNTER_ID + " Text, "
            + CLERKSHIP + " text not null, " + ENCOUNTER_NAME + " Text, " 
            + TYPE + " Text, " + REQUIRED_ATTEMPTS + " Text);";

    private String encounterDBADAPTER_LOG_CAT = "MY_LOG";

    private myencounterDBOpenHelper EncounterdbHelper;

    public encounterDbAdapter(Context _context) {

        this.encounterContext = _context;
        EncounterdbHelper = new myencounterDBOpenHelper(encounterContext, DATABASE_NAME, null,
                DATABASE_VERSION);
        _db=EncounterdbHelper.getWritableDatabase();

    }

    public void close() {
            this._db.close();
            Log.w(encounterDBADAPTER_LOG_CAT, "DB closed");
    }

    public void open() throws SQLiteException {
        try{
            _db=EncounterdbHelper.getWritableDatabase();
            Log.w(encounterDBADAPTER_LOG_CAT, "DB opened as writable database");

        }catch(SQLiteException ex){
            _db=EncounterdbHelper.getReadableDatabase();
            Log.w(encounterDBADAPTER_LOG_CAT, "DB opened as readable database");
        }
    }
//insertion
    public long insertEncounterEntry(String eID, String clerkship, String encounterName, String type, String requiredAttempts) {

        //insert new task
        ContentValues newEntryValues=new ContentValues();
        newEntryValues.put(ENCOUNTER_ID,eID);
        newEntryValues.put(CLERKSHIP,clerkship);
        newEntryValues.put(ENCOUNTER_NAME,encounterName);
        newEntryValues.put(TYPE,type);
        newEntryValues.put(REQUIRED_ATTEMPTS,requiredAttempts);

        //Insert the row
        Log.w(encounterDBADAPTER_LOG_CAT, "Inserted EntryInitial="+eID+" EntryDateOfDiagnosis="+clerkship + "Inserted EntrySiteLocation="+encounterName + "Inserted EntryWardClinic="+type +  "Inserted entryPerformedHistory="+requiredAttempts +"into table"+DATABASE_TABLE);

            long Integer =  _db.insert(DATABASE_TABLE, null, newEntryValues);
            Log.w(encounterDBADAPTER_LOG_CAT, "ID:" + Integer);
            return Integer;
    }

//removal
    public boolean removeEntry(long _rowIndex) {

        if(_db.delete(DATABASE_TABLE, KEY_ID+"="+_rowIndex, null)<=0)
        {
            Log.w(encounterDBADAPTER_LOG_CAT,"Removing Entrying where id="+_rowIndex+"Failed");
            return false;
        }
        Log.w(encounterDBADAPTER_LOG_CAT,"Removing Entrying where id="+_rowIndex+"Success");
        return true;

    }

    //updating
    public boolean updateEntry(long _rowIndex,String entryInitial, String entryDateOfDiagnosis, String entrySiteLocation, String entryWardClinic, String entryPerformedHistory, String entryPerformedPhysical ) {

        return false;
    }

    //retrival 


      public Cursor retrieveAllPatientEntriesCursor()
      {
          Cursor localCursor=null;
          try
        {
//            
        localCursor = this._db.query("mediLearnerDb", null, null, null, null, null, null);

//        localCursor = this._db.query("mediLearnerDb", new String[] { "entry_initial"}, null, null, null, null, null).getString(1);
//       test = this._db.query("mediLearnerDb", new String[] { "entry_initial"}, null, null, null, null, null).getString(1);
        }
        catch (SQLException localSQLException)
        {
          Log.w(this.encounterDBADAPTER_LOG_CAT, "Retrieve fail! ");
        }
//      return null;
          return localCursor;
      }


    public class myencounterDBOpenHelper extends SQLiteOpenHelper {

        public myencounterDBOpenHelper(Context context, String name,
                CursorFactory factory, int version) {
            super(context, name, factory, version);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            db.execSQL(DATABASE_CREATE);
            Log.w(encounterDBADAPTER_LOG_CAT, "Helper : DB " + DATABASE_TABLE
                    + " Created!!");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub

        }

    } // End of myDBOpenHelper

       private void filter(String paramString)
        {
          paramString.toLowerCase(Locale.getDefault());
        }
}// End of myDBAdapter

日志猫

12-06 17:30:58.036: D/dalvikvm(14495): GC_FOR_ALLOC freed 16K, 11% free 12207K/13703K, paused 14ms, total 16ms
12-06 17:30:58.116: W/ResourceType(14495): Failure getting entry for 0x010802c1 (t=7 e=705) in package 0 (error -75)
12-06 17:30:58.161: W/ResourceType(14495): Failure getting entry for 0x010802c1 (t=7 e=705) in package 0 (error -75)
12-06 17:30:58.161: W/ResourceType(14495): Failure getting entry for 0x010802c1 (t=7 e=705) in package 0 (error -75)
12-06 17:30:58.166: D/dalvikvm(14495): GC_CONCURRENT freed 236K, 12% free 12860K/14471K, paused 12ms+18ms, total 45ms
12-06 17:30:58.196: E/SpannableStringBuilder(14495): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
12-06 17:30:58.196: E/SpannableStringBuilder(14495): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
12-06 17:30:59.041: D/AbsListView(14495): Get MotionRecognitionManager
12-06 17:30:59.061: W/ResourceType(14495): Failure getting entry for 0x010802c1 (t=7 e=705) in package 0 (error -75)
12-06 17:31:02.786: D/AndroidRuntime(14495): Shutting down VM
12-06 17:31:02.786: W/dalvikvm(14495): threadid=1: thread exiting with uncaught exception (group=0x41bc42a0)
12-06 17:31:02.786: E/AndroidRuntime(14495): FATAL EXCEPTION: main
12-06 17:31:02.786: E/AndroidRuntime(14495): java.lang.NullPointerException
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at com.medilearner.database.encounterDbAdapter.<init>(encounterDbAdapter.java:57)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at com.example.medilearner.EncounterActivity$JSONParse.onPostExecute(EncounterActivity.java:123)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at com.example.medilearner.EncounterActivity$JSONParse.onPostExecute(EncounterActivity.java:1)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.os.AsyncTask.finish(AsyncTask.java:631)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.os.AsyncTask.access$600(AsyncTask.java:177)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.os.Handler.dispatchMessage(Handler.java:99)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.os.Looper.loop(Looper.java:137)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at android.app.ActivityThread.main(ActivityThread.java:4921)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at java.lang.reflect.Method.invokeNative(Native Method)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at java.lang.reflect.Method.invoke(Method.java:511)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
12-06 17:31:02.786: E/AndroidRuntime(14495):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

我猜你的上下文是空的。

这里:patentDB = new meetDbAdapter(myContext);

解决方案:patentDB = new meetDbAdapter(EncounterActivity.this);

希望这有帮助。