我在 Android 中创建表时遇到问题。
我有这张桌子，但它是旧版本，所以我不得不放弃它。在此之后，我无法让它创建另一个表，我不知道为什么。我收到错误“没有这样的表 user_login”
这是我的数据库类
public class Database extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DB_name = "aeglea";
private static final String TABLE_NAME = "user_login";
//private static final String KEY_ID = "id";
private static final String KEY_UID = "uid";
private static final String KEY_NAME = "name";
private static final String KEY_LAST = "last";
private static final String KEY_EMAIL = "email";
private static final String KEY_USERNAME = "username";
public Database(Context context) {
super(context, DB_name, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db) {
String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_NAME + "("
+ KEY_UID + " INTEGER PRIMARY KEY,"
+ KEY_NAME + " TEXT,"
+ KEY_LAST + " TEXT,"
+ KEY_EMAIL + " TEXT UNIQUE,"
+ KEY_USERNAME + " TEXT UNIQUE" + ")";
db.execSQL(CREATE_LOGIN_TABLE);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
// Create tables again
onCreate(db);
}
public void addUser(int uid, String name, String last, String email, String username) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_UID, uid); // user id
values.put(KEY_NAME, name); // Name
values.put(KEY_LAST, last); //last
values.put(KEY_EMAIL, email); // Email
values.put(KEY_USERNAME, username); // User name
// Inserting Row
db.insert(TABLE_NAME, null, values);
db.close(); // Closing database connection
}
public void resetTables(){
SQLiteDatabase db = this.getWritableDatabase();
// Delete All Rows
db.delete(TABLE_NAME, null, null);
db.close();
}
/**
* Getting user data from database
* */
public HashMap<String, String> getUserDetails(){
HashMap<String,String> user = new HashMap<String,String>();
String query = "SELECT * FROM " + TABLE_NAME;//make query
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);//do query
// Move to first row
cursor.moveToFirst();
if(cursor.getCount() > 0){
user.put("uid", cursor.getString(1));
user.put("name", cursor.getString(2));
user.put("last",cursor.getString(3));
user.put("email", cursor.getString(4));
user.put("username", cursor.getString(5));
}
cursor.close();
db.close();
// return user
return user;
}
/**
* Getting user login status
* return true if rows are there in table
* */
public int getRowCount() {
String countQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int rowCount = cursor.getCount();
db.close();
cursor.close();
// return row count
return rowCount;
}
}
这是我使用数据库的主要类（看底部）
public class login2 extends Activity {
private EditText un,pw;
TextView error;
Button ok;
private JSONObject jo2;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
un=(EditText)findViewById(R.id.et_un);
pw=(EditText)findViewById(R.id.et_pw);
ok=(Button)findViewById(R.id.btn_login);
error=(TextView)findViewById(R.id.tv_error);
ok.setOnClickListener(new View.OnClickListener() {
private Database db = new Database(getApplicationContext());
public void onClick(View v) {
// TODO Auto-generated method stub
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("username", un.getText().toString()));
postParameters.add(new BasicNameValuePair("password", pw.getText().toString()));
//String valid = "1";
JSONObject response = null;
try {
response = CustomHttpClient.executeHttpPost("http://ironis.dyndns.org/aeglea/android/log.php", postParameters);
// String res=response.toString();
// res = res.trim();
//res= res.replaceAll("\\s+","");
//error.setText(res);
if(response.getString("success").equals("1")){
error.setText(response.getString("last"));
//store user to database in success
//reset older entries
db.resetTables();
//add user
db.addUser(Integer.parseInt(response.getString("id")), response.getString("name"), response.getString("last"), response.getString("email"), response.getString("username"));
}else{
error.setText(response.getString("error_msg"));
}
} catch (Exception e) {
un.setText(e.toString());
}
}
});
}
}