java - 安卓/MySQL : Populate Spinner from database with Initial Set Text "Please Select"

Question

我想询问我的代码。我成功创建了一个微调器，列出了数据库中的数据。

就我而言，此微调器将填充表“factory”中“fac_name”列的数据。现在，在微调器的初始列表中，我想显示文本“请选择”，文本下方将显示数据库中的填充数据。下面是我的代码。

Java

public static final String TAG_FAC_NAME = "fac_name";

public static final String JSON_ARRAY = "result";
private JSONArray result;
private ArrayList<String> factoryList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_task);

    factoryList = new ArrayList<>();
    spFactory = findViewById(R.id.spFactory);
    spFactory.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    getData();

}

private void getData(){
    StringRequest stringRequest = new StringRequest(URLs.URL_SPINNER_FACTORY,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    JSONObject j = null;

                    try {
                        j = new JSONObject(response);

                        result = j.getJSONArray(JSON_ARRAY);

                        getFactory(result);
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                }
            });

    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(stringRequest);
}

private void getFactory(JSONArray j){
    for(int i=0;i<j.length();i++){
        try {
            JSONObject json = j.getJSONObject(i);

            factoryList.add(json.getString(TAG_FAC_NAME));
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

    spFactory.setAdapter(new ArrayAdapter<String>(AddTask.this, android.R.layout.simple_spinner_dropdown_item, factoryList));
}

URL_SPINNER_FACTORY (spinner_factory.php)

<?php 

    require_once "../config/configPDO.php";

    $query = $conn->prepare("SELECT * FROM ot_factory ORDER BY fac_id ASC");
    $query->execute();

    $factoryList = array();

    while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
        array_push($factoryList,array(

            'fac_name'=>$row['fac_name'],

            )
        );
    }

    echo json_encode(array('result'=>$factoryList));

?>

有人可以帮我解决这个问题吗？谢谢..

Answer 1

您可以使用 XML 代码来完成此操作。喜欢

`<Spinner
  android:id="@+id/R.id.spFactory"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_marginStart="20dp"
  android:layout_marginLeft="20dp"
  android:layout_marginTop="15dp"
  android:layout_marginBottom="15dp"
  android:prompt="Please Select" />`