如何在Android中的SQLiteDatabase中为搜索数据实现SearchView？

Question

我在数据库中搜索数据时遇到了很大的问题。

我想从数据库获取数据到另一个活动，您可以在其中搜索数据库中的特定数据。

在DatabaseHandler的代码下面：

public class DatabaseHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 2;
private static final String TAG = "DatabaseHandler";
private static final String DATABASE_NAME = "studentsManager",
TABLE_STUDENTS = "students",
KEY_ID = "id",
KEY_FIRSTNAME = "imie",
KEY_SURNAME = "nazwisko",
KEY_INDEKS = "indeks",
KEY_EMAIL = "email",
KEY_DEPARTMENT = "wydzial",
KEY_NUMER = "numer";

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

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("CREATE TABLE " + TABLE_STUDENTS + "(" + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_FIRSTNAME + " TEXT NOT NULL," + KEY_SURNAME + " TEXT NOT NULL," + KEY_INDEKS + " INTEGER," + KEY_EMAIL + " TEXT NOT NULL," + KEY_DEPARTMENT + " TEXT NOT NULL," + KEY_NUMER + " TEXT NOT NULL)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
            + newVersion + ", which will destroy all old data.");
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_STUDENTS);
    onCreate(db);
}

}

和向数据库添加数据的AddActivity代码。

public class AddActivity extends AppCompatActivity implements OnClickListener, AdapterView.OnItemSelectedListener {

private DatabaseHandler dbCreate;
EditText etImie, etNazwisko, etIndeks, etEmail, etTelefon, etShow;
Button btnSave, btnDisplay;
Spinner sSpinner;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    etImie = (EditText)     findViewById(R.id.etImie);
    etNazwisko = (EditText) findViewById(R.id.etNazwisko);
    etIndeks = (EditText)   findViewById(R.id.etIndeks);
    etEmail = (EditText)    findViewById(R.id.etEmail);
    etTelefon = (EditText)  findViewById(R.id.etTelefon);
    etShow = (EditText)     findViewById(R.id.etShow);

    sSpinner = (Spinner)    findViewById(R.id.sSpinner);
    sSpinner.setOnItemSelectedListener(this);


    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.departments_list, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    sSpinner.setAdapter(adapter);


    btnSave = (Button)      findViewById(R.id.btnSave);
    btnSave.setOnClickListener(this);
    btnDisplay = (Button)   findViewById(R.id.btnDisplay);
    btnDisplay.setOnClickListener(this);

    dbCreate = new DatabaseHandler(this.getApplicationContext());
}

public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_baza_stud, menu);
    return true;
}

private void insertInUserTable(String imie, String nazwisko, int indeks, String email, String wydzial, String telefon){
    SQLiteDatabase db = dbCreate.getReadableDatabase();
    ContentValues data = new ContentValues();

    data.put("imie",        imie);
    data.put("nazwisko",    nazwisko);
    data.put("indeks",      indeks);
    data.put("email",       email);
    data.put("wydzial",     wydzial);
    data.put("numer",       telefon);

    db.insertOrThrow("students", null, data);
}

public void onClick(View v) {
    if(v.getId() == R.id.btnSave) {
        try {
            String imie =       etImie.getText().toString();
            String nazwisko =   etNazwisko.getText().toString();
            String sIndex =     etIndeks.getText().toString();
            int indeks =        Integer.parseInt(sIndex);
            String email =      etEmail.getText().toString();
            String wydzial =    sSpinner.getSelectedItem().toString();
            String telefon =    etTelefon.getText().toString();

            if(imie.length() == 0 || nazwisko.length() == 0 || sIndex.length() == 0 || email.length() == 0 || wydzial.length() == 0 || telefon.length() == 0){
                Toast.makeText(getApplicationContext(),"Uzupełnij brakujące pola.", Toast.LENGTH_SHORT).show();
            }else{
                insertInUserTable(imie, nazwisko, indeks, email, wydzial, telefon);
                Toast.makeText(getApplicationContext(), "Utworzono studenta: " + imie + " " + nazwisko + " .", Toast.LENGTH_SHORT).show();
            }
        } catch (SQLiteException e) {
            System.err.println(e.toString());
        } finally {
            dbCreate.close();
        }
    }
    else if(v.getId() == R.id.btnDisplay){
        try{
            displayData();
        } catch(SQLiteException e){
            System.err.println(e.toString());
        } finally {
            dbCreate.close();
        }
    }
}// end of onClick method

private static String[] allCol = {"id","imie","nazwisko","indeks","email","wydzial","numer"};

private void displayData() {
    SQLiteDatabase db = dbCreate.getReadableDatabase();

    Cursor c = db.query("students", allCol, null, null, null, null, null);
    startManagingCursor(c);

    StringBuilder resultString;
    resultString = new StringBuilder("Studenci: ");

    while(c.moveToNext()) {
        resultString.append(" \n").append(c.getLong(0)).append(". ").append(c.getString(1));
        resultString.append(" ").append(c.getString(2)).append(", ").append(c.getInt(3));
        resultString.append(", ").append(c.getString(4)).append(", ");
        resultString.append(c.getString(5)).append(", ").append(c.getString(6));
    }
    etShow.setText(resultString);
}

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    String item = parent.getItemAtPosition(position).toString();
    Toast.makeText(getApplicationContext(),
            "Selected department: " + item, Toast.LENGTH_LONG).show();
}

@Override
public void onNothingSelected(AdapterView<?> parent) {
    Toast.makeText(getApplicationContext(),
            "Please, select department.", Toast.LENGTH_SHORT).show();
}

}