logcat 说这里的数据库类中的“表”一词附近有一个 SQLite 错误。我查看了这段代码,没有看到任何语法错误,我错过了什么吗?
数据库类
public class Database {
public static final String DATABASE = "tester";
public static final int DATABASE_VERSION = 1;
public static final String TABLENAME = "table";
public static final String _ID = "_id";
// collumns
public static final String SAMPLE = "sample";
private static final String SCRIPT_CREATE_TABLE =
"CREATE TABLE IF NOT EXISTS " + TABLENAME + " (" + _ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
SAMPLE + " TEXT)";
SQLiteDatabase sqLiteDatabase;
SQLiteHelper sqLiteHelper;
Context context;
public Database(Context c){
context = c;
}
public void openToRead() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, DATABASE, null, DATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getReadableDatabase();
}
public void openToWrite() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, DATABASE, null, DATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getWritableDatabase();
}
public void close(){
sqLiteHelper.close();
}
public void deleteDB(){
context.deleteDatabase(DATABASE);
}
public void insert(){
ContentValues contentValues = new ContentValues();
contentValues.put(SAMPLE, "TEST ONE");
sqLiteDatabase.insert(TABLENAME, null, contentValues);
}
public String get(){
String returnString = "";
Cursor cursor = sqLiteDatabase.query(TABLENAME, new String[]{SAMPLE}, null, null, null, null, null);
if(cursor!=null){
cursor.moveToFirst();
returnString = cursor.getString(cursor.getColumnIndex(SAMPLE));
}
return returnString;
}
public class SQLiteHelper extends SQLiteOpenHelper {
public SQLiteHelper(Context context, String name,
CursorFactory factory, int version) {
super(context, name, factory, version);
}
// onCreate of the SQLiteOpenhelper only called if the database does not already exist
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SCRIPT_CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + SCRIPT_CREATE_TABLE);
onCreate(db);
}
}
}
MainActivity 类
public class MainActivity extends Activity {
TextView textViewOne;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textViewOne = (TextView) findViewById(R.id.textView1);
Database db = new Database(this);
db.openToWrite();
db.insert();
db.close();
db.openToRead();
String getStr = db.get();
db.close();
textViewOne.setText(getStr);
}
}