To perform the operations on the SQLite, the SQLiteOpenHelper class needs to be extended. In the DatabaseHandler class, the onCreate() and onUpgrade() methods of SQLiteOpenHelper class are overridden. It provides additional methods to insert and display the labels or data.
Android SQLite Spinner Example:
In the below example, we are using the SQLite database to add and display the string content on the spinner. Here, a label is added on a button click. All the added labels are displayed on the spinner.
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <EditText android:id="@+id/input_label" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:layout_marginTop="46dp" android:hint="Name" android:ems="10" /> <Button android:id="@+id/btn_add" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/input_label" android:layout_centerHorizontal="true" android:layout_marginTop="67dp" android:text="Add Name" /> <Spinner android:id="@+id/spinner" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_below="@+id/btn_add" android:layout_marginTop="70dp" /> </RelativeLayout> |
Activity class:(File: MainActivity.java)
package com.example.radioapp; import android.content.Context; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.view.inputmethod.InputMethodManager; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.Spinner; import android.widget.Toast; import java.util.List; public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener { Spinner spinner; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); spinner = findViewById(R.id.spinner); Button btnAdd = findViewById(R.id.btn_add); final EditText inputLabel = findViewById(R.id.input_label); spinner.setOnItemSelectedListener(this); // Loading spinner data from database loadSpinnerData(); btnAdd.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { String label = inputLabel.getText().toString(); if (label.trim().length() > 0) { DbHandler db = new DbHandler(getApplicationContext()); db.insertLabel(label); // making input filed text to blank inputLabel.setText(""); // Hiding the keyboard InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE); imm.hideSoftInputFromWindow(inputLabel.getWindowToken(), 0); // loading spinner with newly added data loadSpinnerData(); } else { Toast.makeText(getApplicationContext(), "Please enter label name", Toast.LENGTH_SHORT).show(); } } }); } /** * Function to load the spinner data from SQLite database * */ private void loadSpinnerData() { DbHandler db = new DbHandler(getApplicationContext()); List<String> labels = db.getAllLabels(); // Creating adapter for spinner ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, labels); // Drop down layout style - list view with radio button dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // attaching data adapter to spinner spinner.setAdapter(dataAdapter); } @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { // On selecting a spinner item String label = parent.getItemAtPosition(position).toString(); // Showing selected spinner item Toast.makeText(parent.getContext(), "You selected: " + label, Toast.LENGTH_LONG).show(); } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } } |
DatabaseHandler class:(File: DbHandler.java)
package com.example.radioapp; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import java.util.ArrayList; import java.util.List; public class DbHandler extends SQLiteOpenHelper { private static final int DATABASE_VERSION = 1; private static final String DATABASE_NAME = "spinnerExample"; private static final String TABLE_NAME = "labels"; private static final String COLUMN_ID = "id"; private static final String COLUMN_NAME = "name"; public DbHandler(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } // Creating Tables @Override public void onCreate(SQLiteDatabase db) { // Category table create query String CREATE_ITEM_TABLE = "CREATE TABLE " + TABLE_NAME + "(" + COLUMN_ID + " INTEGER PRIMARY KEY," + COLUMN_NAME + " TEXT)"; db.execSQL(CREATE_ITEM_TABLE); } // Upgrading database @Override 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); } /** * Inserting new lable into lables table * */ public void insertLabel(String label){ SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(COLUMN_NAME, label);//column name, column value // Inserting Row db.insert(TABLE_NAME, null, values);//tableName, nullColumnHack, CotentValues db.close(); // Closing database connection } /** * Getting all labels * returns list of labels * */ public List<String> getAllLabels(){ List<String> list = new ArrayList<String>(); // Select All Query String selectQuery = "SELECT * FROM " + TABLE_NAME; SQLiteDatabase db = this.getReadableDatabase(); Cursor cursor = db.rawQuery(selectQuery, null);//selectQuery,selectedArguments // looping through all rows and adding to list if (cursor.moveToFirst()) { do { list.add(cursor.getString(1));//adding 2nd column data } while (cursor.moveToNext()); } // closing connection cursor.close(); db.close(); // returning lables return list; } } |
Output 1:
Output 2:
Output 3:
Output 4:
