Android Studio用sqlite实现一个简单的登陆注册功能

在Android Studio中，您可以使用SQLite数据库来实现一个简单的登录注册功能。以下是实现这一功能的步骤和示例代码：

1. 创建数据库和表：

public class UserDbHelper extends SQLiteOpenHelper {
 
    private static final String TABLE_NAME = "users";
    private static final String COL_ID = "id";
    private static final String COL_USERNAME = "username";
    private static final String COL_PASSWORD = "password";
 
    public UserDbHelper(Context context) {
        super(context, "UserDatabase.db", null, 1);
    }
 
    @Override
    public void onCreate(SQLiteDatabase db) {
        String createTableStatement = "CREATE TABLE " + TABLE_NAME + " (" + COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COL_USERNAME + " TEXT, " + COL_PASSWORD + " TEXT)";
        db.execSQL(createTableStatement);
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Implement schema migration logic if needed
    }
}

2. 实现注册功能：

public boolean registerUser(String username, String password) {
    SQLiteDatabase db = dbHelper.getWritableDatabase();
    ContentValues cv = new ContentValues();
    cv.put(UserDbHelper.COL_USERNAME, username);
    cv.put(UserDbHelper.COL_PASSWORD, password);
 
    long result = db.insert(UserDbHelper.TABLE_NAME, null, cv);
    return result != -1;
}

3. 实现登录功能：

public boolean loginUser(String username, String password) {
    SQLiteDatabase db = dbHelper.getReadableDatabase();
    String[] selectionArgs = {username, password};
    Cursor cursor = db.query(UserDbHelper.TABLE_NAME, new String[]{UserDbHelper.COL_USERNAME, UserDbHelper.COL_PASSWORD}, UserDbHelper.COL_USERNAME + "=? AND " + UserDbHelper.COL_PASSWORD + "=?", selectionArgs, null, null, null);
 
    if (cursor.moveToFirst()) {
        cursor.close();
        return true;
    }
 
    cursor.close();
    return false;
}

4. 在Activity中使用这些方法：

UserDbHelper dbHelper = new UserDbHelper(this);
 
// 注册方法调用
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