如何从SQLITE数据库中获取用户ID(ROWID)并在TextView(Android)中显示

Question

我进行了sqlite登录并注册应用程序。成功登录后，我希望用户看到他/她看到" Welcome user_name "one_answers"您的ID-number： user_id 。以及 user_id的文本视图。我想看rowid。

这是 databaseHelper 的一些代码：

public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "UserManager.db";
private static final String TABLE_USER = "user";
private static final String COLUMN_USER_ID = "user_id";
private static final String COLUMN_USER_NAME = "user_name";
private static final String COLUMN_USER_EMAIL = "user_email";
private static final String COLUMN_USER_PASSWORD = "user_password";
private String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USER + "("
        + COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + COLUMN_USER_NAME + " TEXT,"
        + COLUMN_USER_EMAIL + " TEXT," + COLUMN_USER_PASSWORD + " TEXT" + ")";
public long getUserId (String email){
    long userId = 0;
    SQLiteDatabase db = this.getWritableDatabase();
    String[] columns = {
            COLUMN_USER_ID
    };
    String selection = COLUMN_USER_EMAIL + " = ?";
    String[] selectionArgs = { email };
    Cursor cursor = db.query(TABLE_USER,
            columns,
            selection,
            selectionArgs,
            null,
            null,
            null);
    int cursorCount = cursor.getCount();
    cursor.moveToFirst();
    userId = cursor.getLong(0);
    cursor.close();
    db.close();
    if (cursorCount > 0){
        return userId;
    }
    return userId;
}

在 loginactivity 中，我希望在单击登录后获取用户名和用户ID的值。这是一些代码：

if (databaseHelper.checkUser(textInputEditTextEmail.getText().toString().trim()
            , textInputEditTextPassword.getText().toString().trim())){
        Intent accountsIntent = new Intent(activity, UsersActivity.class);
        accountsIntent.putExtra("NAME", databaseHelper.getUserName(textInputEditTextEmail.getText().toString().trim()));
        Intent idIntent = new Intent(activity, UsersActivity.class);
        String ID = String.valueOf(databaseHelper.getUserId(textInputEditTextEmail.getText().toString().trim()));
        idIntent.putExtra("ID", ID);
        emptyInputEditText();
        startActivity(accountsIntent);
    } else {
        Snackbar.make(nestedScrollView, getString(R.string.error_valid_email_password), Snackbar.LENGTH_LONG).show();
    }

最后，我希望将其显示在 userActivity 中：

textViewName = (TextView) findViewById(R.id.text1);
    String nameFromIntent = getIntent().getStringExtra("NAME");
    textViewName.setText("Welcome " + nameFromIntent);
    textViewId = (TextView) findViewById(R.id.text2);
    String idFromIntent = getIntent().getStringExtra("ID");
    textViewId.setText("Your Id-Number: " + idFromIntent);

但是，使用用户名，一切都可以正常工作，但是用户ID被弄乱了。它向我展示了"您的ID-number：null"

我在网上找不到任何解决方案，所以我在此处发布。我如何获得用户ID，该用户ID必须是整数主键自动启动并显示为字符串。但是，为了使其更加复杂，我还需要用户ID作为INT/long来进行进一步的功能（转换为二进制代码，...）。

Answer 1

您的数据库Helper有一些错误和无关紧要的代码结构。

替换您的数据库Helper，如下面的代码。

   public class DatabaseHelper  {
    private static final String TAG = "DatabaseHelper";
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "UserManager";
    private static final String TABLE_USER = "user";
    private static final String COLUMN_USER_ID = "user_id";
    private static final String COLUMN_USER_NAME = "user_name";
    private static final String COLUMN_USER_EMAIL = "user_email";
    private static final String COLUMN_USER_PASSWORD = "user_password";
    private static final String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USER + "("
            + COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," 
            + COLUMN_USER_NAME + " TEXT,"
            + COLUMN_USER_EMAIL + " TEXT,"
            + COLUMN_USER_PASSWORD + " TEXT" + ")";

    private final Context context;
    private AppDatabaseHelper appDB;
    private SQLiteDatabase db;
    public DatabaseHelper(Context ctx) {
        this.context = ctx;
        appDB = new AppDatabaseHelper(context);
    }
    // Open the database connection.
    public DatabaseHelper open() {
        db = appDB.getWritableDatabase();
        return this;
    }
    public boolean checkIfUserExit(String tableName,String emailId) {
        String where = COLUMN_USER_EMAIL+" LIKE '%"+emailId+"%'";
        Cursor c = db.query(true, tableName, null,
                where, null, null, null, null, null);
        if(c.getCount()>0)
            return true;
        else
            return false;
    }
    public int GetUserID(String tableName,String emailId) {
        String where = COLUMN_USER_EMAIL+" LIKE '%"+emailId+"%'";
        Cursor c = db.query(true, tableName, null,
                where, null, null, null, null, null);
        if(c.getCount()>0)
            return c.getInt(0);
        else
            return 0;
    }
    public String GetUserUserName(String tableName,String emailId) {
        String where = COLUMN_USER_EMAIL+" LIKE '%"+emailId+"%'";
        Cursor c = db.query(true, tableName, null,
                where, null, null, null, null, null);
        if(c.getCount()>0)
            return c.getString(1);
        else
            return null;
    }

    public static class AppDatabaseHelper extends SQLiteOpenHelper {
        AppDatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }
        @Override
        public void onCreate(SQLiteDatabase _db) {
            _db.execSQL(CREATE_USER_TABLE);
        }
        @Override
        public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading application's database from version " + oldVersion
                    + " to " + newVersion + ", which will destroy all old data!");
            // Destroy old database:
            _db.execSQL("DROP TABLE IF EXISTS " + TABLE_USER);
            // Recreate new database:
            onCreate(_db);
        }
    }
}

您必须像这样的活动中调用数据库helper

private DatabaseHelper databaseHelper;
databaseHelper = new DatabaseHelper(context.getApplicationContext());
            databaseHelper.open();

从您的本地DB获取值

if (databaseHelper.checkIfUserExit(databaseHelper.TABLE_USER , textInputEditTextEmail.getText().toString().trim())){
        Intent accountsIntent = new Intent(activity, UsersActivity.class);
        accountsIntent.putExtra("NAME",    
 databaseHelper.GetUserUserName(databaseHelper.TABLE_USER ,textInputEditTextEmail.getText().toString().trim()));
        String ID = String.valueOf(databaseHelper.GetUserID(databaseHelper.TABLE_USER ,textInputEditTextEmail.getText().toString().trim()));
        accountsIntent.putExtra("ID", ID);
        emptyInputEditText();
        startActivity(accountsIntent);
    } else {
        Snackbar.make(nestedScrollView, getString(R.string.error_valid_email_password), Snackbar.LENGTH_LONG).show();
    }

Answer 2

尝试以下：

替换

cursor.getLong(0);

cursor.getLong(cursor.getColumnIndex(COLUMN_USER_ID));

upd。：也尝试删除此问题：

Intent idIntent = new Intent(activity, UsersActivity.class);

并更换

idIntent.putExtra("ID", ID);

accountIntent.putExtra("ID", ID);