我的代碼有問題。我已經創建了一個從 MySQL 數據庫填充的微調器。PHP 代碼似乎完全沒有問題，因為我運行鏈接“localhost/latihan1/menu/php”，將顯示 json 字符串。json顯示如下：{"result":[{"username":"haha","name":"Bus Bisnis","course":"math","session":"20119"},{"username":"hihi", "name":"Bus Ace","course":"fizik","session":"12817"},{"username":"m_ridwan","name":"Ridwan","course":"Komputer" ,"session":"1920"},{"username":"m_iqbal","name":"Iqbal","course":"Sains","session":"2021"}]}但是當我打開應用程序時，微調器不顯示數據。我不知道為什么。下面是我的代碼JAVA公共類 MainActivity 擴展 AppCompatActivity 實現 Spinner.OnItemSelectedListener{<?php require_once "koneksi.php"; $query = mysqli_query($con, "SELECT * FROM kendaraan ORDER BY id ASC"); $students = array(); while($row = mysqli_fetch_array($query)){ array_push($students,array( 'username'=>$row['username'], 'name'=>$row['name'], 'course'=>$row['course'], 'session'=>$row['session'] )); } echo json_encode(array('result'=>$students)); mysqli_close($con);?>
1 回答
呼如林
TA貢獻1798條經驗 獲得超3個贊
我在我的 android studio 中執行了你的代碼。我看起來您的網絡調用無法獲取數據（結果仍然為空）。檢查我的代碼以供參考。我用靜態數據替換了您的網絡調用。
package com.attiq.testapp;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public class Main5Activity extends AppCompatActivity implements Spinner.OnItemSelectedListener {
private Spinner spinner;
private ArrayList<String> students;
//JSON Array
private JSONArray result;
private TextView textViewName;
private TextView textViewCourse;
private TextView textViewSession;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main5);
//Initializing the ArrayList
students = new ArrayList<String>();
spinner = findViewById(R.id.spinner);
spinner.setOnItemSelectedListener(this);
textViewName = findViewById(R.id.textViewName);
textViewCourse = findViewById(R.id.textViewCourse);
textViewSession = findViewById(R.id.textViewSession);
getData();
}
private void getData(){
String json= "{\"result\":[{\"username\":\"haha\",\"name\":\"Bus Bisnis\",\"course\":\"math\",\"session\":\"20119\"},{\"username\":\"hihi\",\"name\":\"Bus Ace\",\"course\":\"fizik\",\"session\":\"12817\"},{\"username\":\"m_ridwan\",\"name\":\"Ridwan\",\"course\":\"Komputer\",\"session\":\"1920\"},{\"username\":\"m_iqbal\",\"name\":\"Iqbal\",\"course\":\"Sains\",\"session\":\"2021\"}]}";
try {
JSONObject jsonObject = new JSONObject(json);
result= jsonObject.getJSONArray("result");
getStudents(result);
} catch (Exception e){
e.printStackTrace();
}
}
private void getStudents(JSONArray j) {
for (int i = 0; i < j.length(); i++) {
try {
JSONObject json = j.getJSONObject(i);
students.add(json.getString(Config.TAG_USERNAME));
} catch (JSONException e) {
e.printStackTrace();
}
}
spinner.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, students));
}
private String getName(int position) {
String name = "";
try {
JSONObject json = result.getJSONObject(position);
name = json.getString(Config.TAG_NAME);
} catch (JSONException e) {
e.printStackTrace();
}
return name;
}
private String getCourse(int position) {
String course = "";
try {
JSONObject json = result.getJSONObject(position);
course = json.getString(Config.TAG_COURSE);
} catch (JSONException e) {
e.printStackTrace();
}
return course;
}
private String getSession(int position) {
String session = "";
try {
JSONObject json = result.getJSONObject(position);
session = json.getString(Config.TAG_SESSION);
} catch (JSONException e) {
e.printStackTrace();
}
return session;
}
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
//Setting the values to textviews for a selected item
textViewName.setText(getName(position));
textViewCourse.setText(getCourse(position));
textViewSession.setText(getSession(position));
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
textViewName.setText("");
textViewCourse.setText("");
textViewSession.setText("");
}
}
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