Question

我是Android新手编程的新手，我正在尝试创建一个应用程序，用户可以从2个微调器中选择一些选项，点击搜索按钮后，应用程序将根据所选的选项搜索数据库结果会显示出来。问题是我不确定要使用所选微调器选项的值进行db.rawQuery搜索的参数。我试着在下面粗略猜测，但它不起作用，我不知道如何使用这两个标准进行搜索。

以下是微调器的编码：

public class First extends Activity {

private Spinner foodSpinner, locationSpinner;
private Button btnSubmit;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.first);
    addListenerOnButton();
}
public void addListenerOnButton() {

    foodSpinner = (Spinner) findViewById(R.id.foodSpinner);
    locationSpinner = (Spinner) findViewById(R.id.locationSpinner);
    btnSubmit = (Button) findViewById(R.id.btnSubmit);

    btnSubmit.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            Intent intent = new Intent(First.this.getApplicationContext(), MainActivity.class);
            intent.putExtra("FOODSPINNER", foodSpinner.getSelectedItem().toString());
            intent.putExtra("LOCATIONSPINNER", locationSpinner.getSelectedItem().toString());
            First.this.startActivity(intent);

        }

    });

}

以下是搜索的编码：

public class MainActivity extends ListActivity {

    protected SQLiteDatabase db;
    protected Cursor cursor;
    protected ListAdapter adapter;
    protected String foodItemChosen;
    protected String locationItemChosen;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Bundle extras = getIntent().getExtras();
        foodItemChosen = getIntent().getExtras().getString("FOODSPINNER");
        locationItemChosen = extras.getString("LOCATIONSPINNER");
        db = (new DatabaseHelper(this)).getWritableDatabase();
    }


    public void onListItemClick(ListView parent, View view, int position, long id) {
        Intent intent = new Intent(this, ResultDetails.class);
        Cursor cursor = (Cursor) adapter.getItem(position);
        intent.putExtra("FOOD_ID", cursor.getInt(cursor.getColumnIndex("_id")));
        startActivity(intent);
    }

    public void search(View view) {
        cursor = db.rawQuery("SELECT _id, name, address FROM database WHERE food LIKE ?", 
                new String[]{"%" '+foodItemChosen+' "%"});
        adapter = new SimpleCursorAdapter(
                this, 
                R.layout.result_list_item, 
                cursor, 
                new String[] {"name", "address"}, 
                new int[] {R.id.name, R.id.address});
        setListAdapter(adapter);
    }
}

Answer 1

然后最好使用query方法而不是rawQuery。它提供了从数据库中选择项目的灵活方式。

一些有用的文章

http://www.vogella.com/articles/AndroidSQLite/article.html

http://www.codeproject.com/Articles/119293/Using-SQLite-Database-with-Android

使用微调器值搜索数据库

1 个答案: