我尝试使用适配器在listview中显示我的sqlitedatabase中的数据但是找不到错误表和nullpointerexception，请快速回复..谢谢
`package utils;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class DBhelper extends SQLiteOpenHelper {
private final static String DATABASE_NAME = "dataofg.sqlite";
private String DATABASE_PATH = "data/data/com.example.gindicator/databases/";
private final static int DATABASE_VERSION = 4;
private Context mContext;
private SQLiteDatabase sqliteDatabase = null;
public DBhelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
mContext = context;
// TODO Auto-generated constructor stub
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
} else {
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private boolean checkDataBase() {
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
sqliteDatabase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
}
if (sqliteDatabase != null) {
sqliteDatabase.close();
}
return sqliteDatabase != null ? true : false;
}
private void copyDataBase() throws IOException {
InputStream myInput = mContext.getAssets().open(DATABASE_NAME);
String outFileName = DATABASE_PATH + DATABASE_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
String myPath = DATABASE_PATH + DATABASE_NAME;
sqliteDatabase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
public DBhelper open() throws SQLException {
sqliteDatabase = getWritableDatabase();
return this;
}
@Override
public synchronized void close() {
if (sqliteDatabase != null)
sqliteDatabase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
public void GetStationData() {
String StrQuery = "Select * from tblStations";
Constant.ArrStationName.clear();
open();
Cursor cursor = sqliteDatabase.rawQuery(StrQuery, null);
//Log.e("cursor", "" + cursor.getCount());
if (cursor.getCount() > 0) {
cursor.moveToFirst();
do {
// Log.i("City","" +
cursor.getString(cursor.getColumnIndex("strStationName")));
Constant.ArrStationName.add(cursor.getString(cursor
.getColumnIndex("strStationName")));
} while (cursor.moveToNext());
}
cursor.close();
close();
}`
这是DBhelper calss，下面是我定义的数组
`package utils;
import java.util.ArrayList;
public class Constant {
public static ArrayList<String> ArrStationName = new ArrayList<String>();
}
` 适配器类
`package com.gindicator.adapter;
import com.example.gindicator.R;
import utils.Constant;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
public class CitybusAdapter extends BaseAdapter {
Context context;
LayoutInflater LI;
public CitybusAdapter(Context contextpara) {
context = contextpara;
LI = LayoutInflater.from(contextpara);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return Constant.ArrStationName.size();
}
@Override
public int getViewTypeCount() {
// TODO Auto-generated method stub
return Constant.ArrStationName.size();
}
@Override
public int getItemViewType(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if (convertView == null) {
convertView = LI.inflate(R.layout.city_raw, null);
TextView txtCityRaw = (TextView) convertView
.findViewById(R.id.txtCityRaw);
txtCityRaw.setText(Constant.ArrStationName.get(position));
}
return convertView;
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
}`
主要类，我在数据库中显示数据
`package com.example.gindicator;
import java.io.IOException;
import com.gindicator.adapter.CitybusAdapter;
import utils.Constant;
import utils.DBhelper;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;
public class Citybusbtn1 extends Activity{
public static DBhelper myDbHelper;
ListView lst ;
CitybusAdapter cityobject;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.citybusbtn1);
cityobject = new CitybusAdapter(Citybusbtn1.this);
DBhelper myDbHelper = new DBhelper(this);
try {
myDbHelper.createDataBase();
// myDbHelper.openDataBase();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
myDbHelper.GetStationData();
Initialization();
}
private void Initialization() {
// TODO Auto-generated method stub
if (Constant.ArrStationName.size() > 0) {
lst=(ListView)findViewById(R.id.hotellist);
lst.setAdapter(cityobject);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
`
当我第一次运行程序时，它会在第1页中运行时在日志和停止程序中显示错误
04-16 11:27:45.702: D/dalvikvm(14822): GC_CONCURRENT freed 0K, 7% free
16033K/17223K,
paused 1ms+1ms, total 34ms
04-16 11:27:45.702: D/dalvikvm(14822): WAIT_FOR_CONCURRENT_GC blocked 15ms
04-16 11:27:45.706: E/SQLiteLog(14822): (14) cannot open file at line 30174 of
[00bb9c9ce4]
04-16 11:27:45.706: E/SQLiteLog(14822): (14) os_unix.c:30174: (2)
open(//data/data/com.example.gindicator/databases/dataofg.sqlite) -
04-16 11:27:45.709: E/SQLiteDatabase(14822): Failed to open database
'data/data/com.example.gindicator/databases/dataofg.sqlite'.
04-16 11:27:45.709: E/SQLiteDatabase(14822):
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could
not
open database
之后显示错误就像这个logcat whwn我点击按钮显示数据列表视图
04-16 11:15:02.925: V/Provider/Setting(14024): from settings cache , name =
sound_effects_enabled value = 0
04-16 11:15:02.986: D/AbsListView(14024): checkAbsListViewlLogProperty get invalid
command
04-16 11:15:03.002: E/SQLiteLog(14024): (1) no such table: tblStations
04-16 11:15:03.002: D/AndroidRuntime(14024): Shutting down VM
04-16 11:15:03.003: W/dalvikvm(14024): threadid=1: thread exiting with uncaught
exception (group=0x40f61908)
04-16 11:15:03.011: E/AndroidRuntime(14024): FATAL EXCEPTION: main
04-16 11:15:03.011: E/AndroidRuntime(14024): java.lang.RuntimeException: Unable to
start activity
ComponentInfo{com.example.gindicator/com.example.gindicator.Citybusbtn1}:
android.database.sqlite.SQLiteException: no such table: tblStations (code 1): ,
while compiling: Select * from tblStations
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2189)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2216)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread.access$600(ActivityThread.java:149)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1305)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.os.Handler.dispatchMessage(Handler.java:99)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.os.Looper.loop(Looper.java:153)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread.main(ActivityThread.java:5000)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
java.lang.reflect.Method.invokeNative(Native Method)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
java.lang.reflect.Method.invoke(Method.java:511)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
dalvik.system.NativeStart.main(Native Method)
04-16 11:15:03.011: E/AndroidRuntime(14024): Caused by:
android.database.sqlite.SQLiteException: no such table: tblStations (code 1): , while
compiling: Select * from tblStations
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteConnection.acquirePreparedStatement
(SQLiteConnection.java:882
)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteDirectCursorDriver.query
(SQLiteDirectCursorDriver.java:44)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
utils.DBhelper.GetStationData(DBhelper.java:123)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
com.example.gindicator.Citybusbtn1.onCreate(Citybusbtn1.java:40)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.Activity.performCreate(Activity.java:5020)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-16 11:15:03.011: E/AndroidRuntime(14024): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
04-16 11:15:03.011: E/AndroidRuntime(14024): ... 11 more
04-16 11:15:04.696: I/Process(14024): Sending signal. PID: 14024 SIG: 9
谢谢你的朋友
答案 0 :(得分：0)
尝试从其他表中获取数据。如果它正常工作删除表并重新创建。如果没有，请检查数据库的安全性和Android项目的身份验证。