无法在Android中打开数据库（预创建）

我已经将我的sqlite数据库文件放在“assets”文件夹中，并且我编写了一个DataManager类来从数据库中获取数据，但是我得到了运行时错误。。我使用调试工具查看在

CreateDataBase（）

错误引发时确切了解的位置。。请帮我解决这个问题

这是我的Datamanager类。我正在为android预创建数据库，但我得到文件未找到异常，请帮助我。我已经在下面显示了我的日志

（数据管理器类）

日志：

11-30 16:02:18.908: E/SQLiteLog(968): (14) cannot open file at line 30176 of [00bb9c9ce4]
11-30 16:02:18.938: E/SQLiteLog(968): (14) os_unix.c:30176: (2) open(/data/data/com.example.applicationdatabase/databasesdatabase) - 
11-30 16:02:18.948: E/SQLiteDatabase(968): Failed to open database '/data/data/com.example.applicationdatabase/databasesdatabase'.
11-30 16:02:18.948: E/SQLiteDatabase(968): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.checkDataBase(DataBaseManager.java:102)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.createDataBase(DataBaseManager.java:69)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.<init>(DataBaseManager.java:39)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.instance(DataBaseManager.java:55)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DBActivity.onCreate(DBActivity.java:35)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.Activity.performCreate(Activity.java:5104)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.os.Looper.loop(Looper.java:137)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.main(ActivityThread.java:5039)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at java.lang.reflect.Method.invokeNative(Native Method)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at java.lang.reflect.Method.invoke(Method.java:511)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at dalvik.system.NativeStart.main(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968): FATAL EXCEPTION: main
11-30 16:02:19.008: E/AndroidRuntime(968): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.applicationdatabase/com.example.applicationdatabase.DBActivity}: java.lang.NullPointerException
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.os.Looper.loop(Looper.java:137)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.main(ActivityThread.java:5039)
11-30 16:02:19.008: E/AndroidRuntime(968):  at java.lang.reflect.Method.invokeNative(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968):  at java.lang.reflect.Method.invoke(Method.java:511)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-30 16:02:19.008: E/AndroidRuntime(968):  at dalvik.system.NativeStart.main(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968): Caused by: java.lang.NullPointerException
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:188)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.createDataBase(DataBaseManager.java:79)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.<init>(DataBaseManager.java:39)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.instance(DataBaseManager.java:55)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DBActivity.onCreate(DBActivity.java:35)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.Activity.performCreate(Activity.java:5104)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
11-30 16:02:19.008: E/AndroidRuntime(968):  ... 11 more

11-30 16:02:18.908:E/SQLiteLog（968）：（14）无法打开[00bb9c9ce4]第30176行的文件
11-30 16:02:18.938:E/SQLiteLog（968）：（14）os_unix.c:30176:（2）打开（/data/data/com.example.applicationdatabase/databasesdatabase）-
11-30 16:02:18.948:E/SQLiteDatabase（968）：无法打开数据库“/data/data/com.example.applicationdatabase/databasesdatabase”。
11-30 16:02:18.948:E/SQLiteDatabase（968）：android.database.sqlite.SQLiteCantOpenDatabaseException:未知错误（代码14）：无法打开数据库
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnection.nativeOpen（本机方法）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnection.open（SQLiteConnection.java:209）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnection.open（SQLiteConnection.java:193）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnectionPool.openConnectionLocked（SQLiteConnectionPool.java:463）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnectionPool.open（SQLiteConnectionPool.java:185）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteConnectionPool.open（SQLiteConnectionPool.java:177）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteDatabase.openInner（SQLiteDatabase.java:804）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteDatabase.open（SQLiteDatabase.java:789）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteDatabase.openDatabase（SQLiteDatabase.java:694）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.database.sqlite.SQLiteDatabase.openDatabase（SQLiteDatabase.java:669）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.example.applicationdatabase.DataBaseManager.checkDataBase（DataBaseManager.java:102）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.example.applicationdatabase.DataBaseManager.createDataBase（DataBaseManager.java:69）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.example.applicationdatabase.DataBaseManager.（DataBaseManager.java:39）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.example.applicationdatabase.DataBaseManager.instance（DataBaseManager.java:55）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.example.applicationdatabase.DBActivity.onCreate（DBActivity.java:35）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.Activity.performCreate（Activity.java:5104）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1080）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2144）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2230）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.ActivityThread.access$600（ActivityThread.java:141）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.ActivityThread$H.handleMessage（ActivityThread.java:1234）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.os.Handler.dispatchMessage（Handler.java:99）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.os.Looper.loop（Looper.java:137）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于android.app.ActivityThread.main（ActivityThread.java:5039）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于java.lang.reflect.Method.invokenactive（本机方法）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于java.lang.reflect.Method.invoke（Method.java:511）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:793）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:560）
11-30 16:02:18.948:E/SQLiteDatabase（968）：位于dalvik.system.NativeStart.main（本机方法）
11-30 16:02:19.008:E/AndroidRuntime（968）：致命异常：主
11-30 16:02:19.008:E/AndroidRuntime（968）：java.lang.RuntimeException:无法启动活动组件信息{com.example.applicationdatabase/com.example.applicationdatabase.DBActivity}:java.lang.NullPointerException
11-30 16:02:19.008:E/AndroidRuntime（968）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2180）
11-30 16:02:19.008:E/AndroidRuntime（968）：在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2230）
11-30 16:02:19.008:E/AndroidRuntime（968）：在android.app.ActivityThread.access$600（ActivityThread.java:141）
11-30 16:02:19.008:E/AndroidRuntime（968）：在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1234）
11-30 16:02:19.008:E/AndroidRuntime（968）：位于android.os.Handler.dispatchMessage（Handler.java:99）
11-30 16:02:19.008:E/AndroidRuntime（968）：在android.os.Looper.loop（Looper.java:137）
11-30 16:02:19.008:E/AndroidRuntime（968）：位于android.app.ActivityThread.main（ActivityThread.java:5039）
11-30 16:02:19.008:E/AndroidRuntime（968）：位于java.lang.reflect.Method.Invokenactive（本机方法）
11-30 16:02:19.008:E/AndroidRuntime（968）：在java.lang.reflect.Method.invoke（Method.java:511）
11-30 16:02:19.008:E/AndroidRuntime（968）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:793）
11-30 16:02:19.008:E/AndroidRuntime（968）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:560）
11-30 16:02:19.008:E/AndroidRuntime（968）：在dalvik.system.NativeSta
11-30 16:02:18.908: E/SQLiteLog(968): (14) cannot open file at line 30176 of [00bb9c9ce4]
11-30 16:02:18.938: E/SQLiteLog(968): (14) os_unix.c:30176: (2) open(/data/data/com.example.applicationdatabase/databasesdatabase) - 
11-30 16:02:18.948: E/SQLiteDatabase(968): Failed to open database '/data/data/com.example.applicationdatabase/databasesdatabase'.
11-30 16:02:18.948: E/SQLiteDatabase(968): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.checkDataBase(DataBaseManager.java:102)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.createDataBase(DataBaseManager.java:69)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.<init>(DataBaseManager.java:39)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DataBaseManager.instance(DataBaseManager.java:55)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.example.applicationdatabase.DBActivity.onCreate(DBActivity.java:35)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.Activity.performCreate(Activity.java:5104)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.os.Looper.loop(Looper.java:137)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at android.app.ActivityThread.main(ActivityThread.java:5039)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at java.lang.reflect.Method.invokeNative(Native Method)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at java.lang.reflect.Method.invoke(Method.java:511)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-30 16:02:18.948: E/SQLiteDatabase(968):  at dalvik.system.NativeStart.main(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968): FATAL EXCEPTION: main
11-30 16:02:19.008: E/AndroidRuntime(968): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.applicationdatabase/com.example.applicationdatabase.DBActivity}: java.lang.NullPointerException
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.os.Looper.loop(Looper.java:137)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.main(ActivityThread.java:5039)
11-30 16:02:19.008: E/AndroidRuntime(968):  at java.lang.reflect.Method.invokeNative(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968):  at java.lang.reflect.Method.invoke(Method.java:511)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-30 16:02:19.008: E/AndroidRuntime(968):  at dalvik.system.NativeStart.main(Native Method)
11-30 16:02:19.008: E/AndroidRuntime(968): Caused by: java.lang.NullPointerException
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:188)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.createDataBase(DataBaseManager.java:79)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.<init>(DataBaseManager.java:39)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DataBaseManager.instance(DataBaseManager.java:55)
11-30 16:02:19.008: E/AndroidRuntime(968):  at com.example.applicationdatabase.DBActivity.onCreate(DBActivity.java:35)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.Activity.performCreate(Activity.java:5104)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
11-30 16:02:19.008: E/AndroidRuntime(968):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
11-30 16:02:19.008: E/AndroidRuntime(968):  ... 11 more

public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "mydb.sqlite";

    protected Context context;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String sqlStatement;
        try {
            InputStream in = context.getResources().openRawResource(R.raw.mydbqueries);
            DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            Document doc = builder.parse(in, null);
            NodeList statements = doc.getElementsByTagName("statement");
            for (int i=0; i<statements.getLength(); i++) {
                sqlStatement = statements.item(i).getChildNodes().item(0).getNodeValue();
                db.execSQL(sqlStatement);
            }
        } catch (Throwable t) {
        }
    }

    SQLiteDatabase sqliteDB = null;
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        onCreate(db);
    }

    public SQLiteDatabase open() throws SQLException
    {
        sqliteDB = this.getWritableDatabase();
        return sqliteDB;
    }
}

<?xml version="1.0" encoding="UTF-8"?><!-- <?xml version="1.0" encoding="utf-8"?> -->
<!-- database queries -->
<sql>
<!-- Meta data table -->
<!-- <statement> CREATE TABLE "android_metadata" ("locale" TEXT DEFAULT 
    'en_US') </statement> Meta data table <statement> INSERT INTO "android_metadata" 
    VALUES('en_US') </statement> -->

<statement>
    sql statement
</statement>
</sql>  

package net.learn2develop.Databases;

import java.io.IOException;

import android.app.Activity;

import android.database.Cursor;
import android.database.SQLException;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class DatabasesActivity extends Activity {

    protected static final String TAG = null;
    private Button insertButton;
    private Button updateButton;
    private Button deleteButton;
    private Button displayButton;
    boolean status = false;

    private EditText name;
    private EditText email;
    protected int value1;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        DBAdapter myDbHelper = new DBAdapter(null);
        myDbHelper = new DBAdapter(this);

        insertButton = (Button) findViewById(R.id.btnInsert);
        updateButton = (Button) findViewById(R.id.btnUpdate);
        deleteButton = (Button) findViewById(R.id.btnDelete);
        displayButton = (Button) findViewById(R.id.btnDisplay);
        name = (EditText) findViewById(R.id.edit_name);
        email = (EditText) findViewById(R.id.edit_email);

        // --- inserting ------
        insertButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (name.getText().toString().trim().length() == 0)
                {
                    Toast msg = Toast.makeText(getBaseContext(),
                            "Please Enter Name ", Toast.LENGTH_LONG);
                    msg.show();
                }
                else if (email.getText().toString().trim().length() == 0)
                {
                    Toast msg = Toast.makeText(getBaseContext(),
                            "Please Enter Email", Toast.LENGTH_LONG);
                    msg.show();
                }
                else

                    insertRecord();
            }
        });

        // --------Deleting the Records -----------
        deleteButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                deleteRecord();
            }
        });

        // --- Displaying the Records -------
        displayButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                DisplayRecord();
            }
        });

        updateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (name.getText().toString().trim().length() == 0)
                {
                    Toast msg = Toast.makeText(getBaseContext(),
                            "Please Enter Name ", Toast.LENGTH_LONG);
                    msg.show();
                }
                else if (email.getText().toString().trim().length() == 0)
                {
                    Toast msg = Toast.makeText(getBaseContext(),
                            "Please Enter Email", Toast.LENGTH_LONG);
                    msg.show();
                }
                else
                {
                    updateRecord();
                }
            }
        });

        try {
            myDbHelper.createDataBase();
        } catch (IOException ioe) {
            throw new Error("Unable to create database");
        }

        try {
            myDbHelper.openDataBase();
        } catch (SQLException sqle) {
            throw sqle;
        }

    }

    protected void DisplayRecord() {
        DBAdapter myDbHelper1 = new DBAdapter(null);
        myDbHelper1.openDataBase();
        Cursor c = myDbHelper1.getAllContacts();

        if (c.moveToFirst()) {
            do {
                DisplayContact(c);
            } while (c.moveToNext());
        }
        myDbHelper1.close();
    }

    protected void updateRecord() {

        String Name = fetchName();
        String Email = fetchEmail();

        DBAdapter myDbHelper1 = new DBAdapter(null);
        myDbHelper1.openDataBase();
        if (myDbHelper1.updateContact(1, Name, Email))
        {
            Toast msg = Toast.makeText(getBaseContext(),
                    "Update Successfully ", Toast.LENGTH_LONG);
            msg.show();
        }
        else
        {
            Toast msg = Toast.makeText(getBaseContext(),
                    "Update Failed ", Toast.LENGTH_LONG);
            msg.show();
        }
        myDbHelper1.close();

    }

    protected void deleteRecord() {
        DBAdapter myDbHelper1 = new DBAdapter(null);

        myDbHelper1.openDataBase();
        if (myDbHelper1.deleteContact(27))
        {
            Toast msg = Toast.makeText(getBaseContext(),
                    "Delete Successfully ", Toast.LENGTH_LONG);
            msg.show();
        }
        else
        {
            Toast msg = Toast.makeText(getBaseContext(),
                    "Delete Failed ", Toast.LENGTH_LONG);
            msg.show();
        }
        myDbHelper1.close();

    }

    protected void insertRecord() {
        String Name = fetchName();
        String Email = fetchEmail();

        DBAdapter myDbHelper1 = new DBAdapter(null);
        myDbHelper1.openDataBase();
        long id = myDbHelper1.insertContact(Name, Email);
        myDbHelper1.close();
        Toast msg = Toast.makeText(getBaseContext(),
                "Record: " + id + " Successfully inserted", Toast.LENGTH_LONG);
        msg.show();
        name.setText("");
        email.setText("");

    }

    public void DisplayContact(Cursor c) {
        Toast.makeText(
                this,
                "id: " + c.getString(0) + "\n" + "Name: " + c.getString(1)
                        + "\n" + "Email: " + c.getString(2), Toast.LENGTH_LONG)
                .show();
    }

    public String fetchName()
    {
        String Name = name.getText().trim().toString();
        if (Name.contentEquals(name.getHint()))
        {

            return " ";
        }
        else
        {
            return Name;
        }
    }

    public String fetchEmail()
    {
        String Email = email.getText().trim().toString();
        if (Email.contentEquals(email.getHint()))
        {
            return " ";
        }
        else
        {
            return Email;
        }
    }

}

SQLiteDatabase db;

db = getWritableDatabase();

if (db != null) {
    b.close();
}
copyDatabase();