没有这样的表：联系人（代码1）:,编译时：INSERT INTO联系人（姓名，邮件）VALUES（？，？）

Question

我试图在我的数据库中添加一些信息时遇到问题。 这是我的DateBase类：

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper  extends SQLiteOpenHelper{

    public static final int DATABASE_VERSION = 1;
    public static final String DATABASE_NAME = "contactDb";
    public static final String TABLE_CONTACTS = "contacts";

    public static final String KEY_ID = "_id";
    public static final String KEY_NAME = "name";
    public static final String KEY_MAIL = "mail";

    public DBHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + TABLE_CONTACTS + " (" + KEY_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_NAME + " TEXT NOT NULL, " + KEY_MAIL + " TEXT NOT NULL);");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("drop table if exists " + TABLE_CONTACTS);

        onCreate(db);

    }
}

这是我的课程，我试图在表格中添加信息：

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    Button btnAdd, btnRead, btnClear;
    EditText etName, etEmail;

    DBHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btnAdd = (Button) findViewById(R.id.btnAdd);
        btnAdd.setOnClickListener(this);

        btnRead = (Button) findViewById(R.id.btnRead);
        btnRead.setOnClickListener(this);

        btnClear = (Button) findViewById(R.id.btnClear);
        btnClear.setOnClickListener(this);

        etName = (EditText) findViewById(R.id.etName);
        etEmail = (EditText) findViewById(R.id.etEmail);

        dbHelper = new DBHelper(this);
    }

    @Override
    public void onClick(View v) {

        String name = etName.getText().toString();
        String email = etEmail.getText().toString();

        SQLiteDatabase database = dbHelper.getWritableDatabase();

        ContentValues contentValues = new ContentValues();


        switch (v.getId()) {

            case R.id.btnAdd:
                contentValues.put(DBHelper.KEY_NAME, name);
                contentValues.put(DBHelper.KEY_MAIL, email);

                database.insert(DBHelper.TABLE_CONTACTS, null, contentValues);
                break;

            case R.id.btnRead:
                Cursor cursor = database.query(DBHelper.TABLE_CONTACTS, null, null, null, null, null, null);

                if (cursor.moveToFirst()) {
                    int idIndex = cursor.getColumnIndex(DBHelper.KEY_ID);
                    int nameIndex = cursor.getColumnIndex(DBHelper.KEY_NAME);
                    int emailIndex = cursor.getColumnIndex(DBHelper.KEY_MAIL);
                    do {
                        Log.d("mLog", "ID = " + cursor.getInt(idIndex) +
                                ", name = " + cursor.getString(nameIndex) +
                                ", email = " + cursor.getString(emailIndex));
                    } while (cursor.moveToNext());
                } else
                    Log.d("mLog","0 rows");

                cursor.close();
                break;

            case R.id.btnClear:
                database.delete(DBHelper.TABLE_CONTACTS, null, null);
                break;
        }
        dbHelper.close();
    }
}

这是完整的错误文字：

E/SQLiteLog: (1) no such table: contacts
E/SQLiteDatabase: Error inserting name=hey mail=hey@mail.ru
                  android.database.sqlite.SQLiteException: no such table: contacts (code 1): , while compiling: INSERT INTO contacts(name,mail) VALUES (?,?)
                      at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                      at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
                      at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
                      at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                      at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
                      at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
                      at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1472)
                      at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1343)
                      at com.lol.sqlite.MainActivity.onClick(MainActivity.java:67)
                      at android.view.View.performClick(View.java:5610)
                      at android.view.View$PerformClick.run(View.java:22265)
                      at android.os.Handler.handleCallback(Handler.java:751)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6077)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

很高兴看到任何答案