使用SQLite數據庫更新微調器

Question

我需要在添加它所顯示的數據後不斷更新我的微調器。我的代碼
部分：

public class MainActivity extends AppCompatActivity { 
ArrayAdapter<String> adapter; 
Spinner spinner; 

protected void onCreate(Bundle savedInstanceState) { 
ArrayList<String> categories = databaseHelper.getAllCategories(); 
spinner = (Spinner) findViewById(R.id.spinner); 
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, categories); 
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
spinner.setAdapter(adapter); 
} 

在DatabaseHelper類，我做簡單的查詢，它選擇一列。

Answer 1

public class MainActivity extends AppCompatActivity { 
ArrayAdapter<String> adapter; 
Spinner spinner; 
ArrayList<String> categories; 

protected void onCreate(Bundle savedInstanceState) { 
categories = databaseHelper.getAllCategories(); 
spinner = (Spinner) findViewById(R.id.spinner); 
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, categories); 
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
spinner.setAdapter(adapter); 
} 

private function updateSpinner(){ 
    categories.clear(); 
    categories.addAll(databaseHelper.getAllCategories()); 
    adapter.notifyDataSetChanged(); 
}