使用Android從editext中檢索數據MySQL

Question

我試圖從MySQL數據庫（我通過phpMyAdmin訪問）檢索數據並嘗試在EditText中顯示數據。我不知道我在哪裏犯了一個錯誤，但想要擺脫這個問題。

日誌貓的錯誤表明沒有城市值。我知道我犯了錯，但我是Android新手。下面是我的代碼：

MainActivity.java

public class MainActivity extends Activity { 

    private ProgressDialog pDialog; 
    String id; 
    Button btn; 
    EditText txt1,txt2; 
    JSONParser jsonParser = new JSONParser(); 
    ArrayList<HashMap<String,String>> result; 
    private static final String url = "http://10.0.2.2/letstry/value.php"; 
    private static final String tag_success = "success"; 
    private static final String tag_cities = "cities"; 
    private static final String tag_id = "id"; 
    private static final String tag_city = "city_name"; 

    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     btn=(Button)findViewById(R.id.select); 

     result = new ArrayList<HashMap<String,String>>(); 

     btn.setOnClickListener(new View.OnClickListener() 
     { 
      @Override 
      public void onClick(View v) 
      { 
       new loadresult().execute(); 
      } 
     }); 
    } 

    class loadresult extends AsyncTask<String,String,String> 
    { 

     @Override 
     protected String doInBackground(String... args) { 
      // TODO Auto-generated method stub 
      int success; 
      try { 

       // Building Parameters 
       List<NameValuePair> params = new ArrayList<NameValuePair>(); 
       params.add(new BasicNameValuePair("id", id)); 

       // getting product details by making HTTP request 
       // Note that product details url will use GET request 
       JSONObject json = jsonParser.makeHttpRequest(
         url, "GET", params); 

       // check your log for json response 
       Log.d("Single Product Details", json.toString()); 

       // json success tag 
       success = json.getInt(tag_success); 
       if (success == 1) { 
        // successfully received product details 
        JSONArray listObj = json 
          .getJSONArray(tag_cities); // JSON Array 

        // get first product object from JSON Array 
        JSONObject list = listObj.getJSONObject(0); 

        // product with this pid found 
        // Edit Text 
        txt1 = (EditText) findViewById(R.id.one1); 
        txt2 = (EditText) findViewById(R.id.two1); 

        // display product data in EditText 
        txt1.setText(list.getString(tag_id)); 
        txt2.setText(list.getString(tag_city)); 

       }else{ 
        // product with pid not found 
       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 
      return null; 
     } 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 
     if (id == R.id.action_settings) { 
      return true; 
     } 
     return super.onOptionsItemSelected(item); 
    } 
} 

PHP腳本

<?php 

$con = mysql_connect("localhost","root","12345"); 
$db = mysql_select_db("search",$con); 

    $query = mysql_query("Select * from cities where Id=2"); 
if(mysql_num_rows($query)>0) 
{ 
    while($result=mysql_fetch_array($query)) 
    { 
     $list=array(); 
     $list['Id']=$result['Id']; 
     $list['city_name']=$result['city_name']; 

     $response['list']=array(); 

     array_push($response["list"], $list); 
    } 
    $response["success"] = 1; 
    echo json_encode($response); 
} else { 
    // no products found 
    $response["success"] = 0; 
    $response["message"] = "No products found"; 

    // echo no users JSON 
    echo json_encode($response); 
} 

?> 

Answer 1

你需要使用一個線程處理程序，因爲在Android中你不能改變視圖元素（在主線程中運行）來自在另一個線程中運行的方法。

這是一個不錯的axample從文檔。 另一個很好的例子已經得到解答here

希望它有幫助。