String（JSONArray）类型未定义add（String）方法

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使用MySQL查询从PHP文件中提取数据后，我想用数据填充两个数组。第一个数组的工作原理：String（JSONArray）类型未定义add（String）方法

results.add((String) json_data.get("product") + "\n" + json_data.get("owner"));

但是当我添加第二个数组：

mysql_id.add((String) json_data.get("id"));

Eclipse显示一个错误：

The method add(String) is undefined for the type String

有一个没有可用的建议，我不知道问题。我有“mysql_id”随处可见“结果”，但它不起作用！

感谢您的帮助！

以下是完整的代码：

package de.maartenfricke.coffeebar; 

import java.io.BufferedInputStream; 
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.lang.reflect.Array; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.net.URLConnection; 
import java.util.ArrayList; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.NameValuePair; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.entity.UrlEncodedFormEntity; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import android.app.Activity; 
import android.content.Context; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.Menu; 
import android.widget.CheckBox; 
import android.widget.CompoundButton; 
import android.widget.CompoundButton.OnCheckedChangeListener; 
import android.widget.LinearLayout; 
import android.widget.ScrollView; 
import android.widget.Toast; 

public class Overview extends Activity { 
    InputStream is; 
    ArrayList<String> results = new ArrayList<String>(); 
    ArrayList<String> mysql_id = new ArrayList<String>(); 
    JSONObject json_data; 
    JSONObject json_data_2; 
    Boolean dataComplete = false; 

@Override 
public void onCreate(Bundle savedInstanceState) {     
    super.onCreate(savedInstanceState); 

    Bundle zielkorb = getIntent().getExtras(); 
    String text2 = zielkorb.getString("datenpaket1"); 

    Context context = getApplicationContext(); 
    CharSequence text = "Sie haben soeben einen " + text2 + " bestellt"; 
    int duration = Toast.LENGTH_LONG; 
    Toast toast = Toast.makeText(context, text, duration); 
    toast.show(); 


    getData();   
    while(!this.dataComplete) {// es soll solange gewartet werden bis die ArrayList ganz gefüllt ist und die Abfrage beendet wurde 
     //ProgressDialog pd = ProgressDialog.show(Overview.this,"Loading...","Frage Daten von Server ab..."); 
    try { 
     Thread.sleep(50); 
    } catch (InterruptedException e) { 
    // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
    } 
    //pd.demiss(); 
    this.fillList(); 



} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.activity_overview, menu); 
    return true; 
} 

public void getData() { 
    Thread t = new Thread() { //Setzte Tread 
    private String result = ""; //Setze Variable String für die Ergebnisse 
    private String mysql_id = ""; //Setze Variable mysql_id für mysql_id 
    public void run() { 
     ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); //Definiere Arrayliste 
    try { 
     HttpClient httpclient = new DefaultHttpClient(); //http client ünterstützt das indirekte verbinden mit webseiten ohne Browser und upload, download etc. 
     HttpPost httppost = new HttpPost("http://192.168.178.35/getAllOrders.php"); //Rufe Link auf 
     httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 
     HttpResponse response = httpclient.execute(httppost); 
     HttpEntity entity = response.getEntity(); 
     is = entity.getContent(); 
    } 
    catch(Exception e) { //Wenn ein Fehler auftritt: 
     Log.e("log_tag", "Fehler bei der http Verbindung "+e.toString()); 
    } 

    try { 
     BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8); 
     StringBuilder sb = new StringBuilder(); 
     String line = null; 
     while ((line = reader.readLine()) != null) { 
      sb.append(line + "n"); 
     } 
     is.close(); 
     mysql_id=sb.toString(); 
     result=sb.toString(); 

    } 
    catch(Exception e) { //Wenn ein Fehler auftritt: 
     Log.e("log_tag", "Error converting result "+e.toString()); 
    } 

    try { 
     JSONArray jArray = new JSONArray(result); 
     for(int i=0;i<jArray.length();i++) { 
      json_data = jArray.getJSONObject(i); 
      results.add((String) json_data.get("product") + "\n" + json_data.get("owner")); 
      //mysql_id.add((String) json_data.get("id")); 
     }  
     dataComplete = true; 
    } 
    catch(JSONException e) { //Wenn ein Fehler auftritt: 
    Log.e("log_tag", "Error parsing data "+e.toString()); 
    } 
}  
}; 
t.start(); 
} 

public void fillList() { 
    //this.setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, results)); 

    ScrollView sv = new ScrollView(this); 
    LinearLayout ll = new LinearLayout(this); 
    ll.setOrientation(LinearLayout.VERTICAL); 
    sv.addView(ll); 

    for (int i = 0; i < results.size(); i++) { 
     String tag = results.get(i); 
     final CheckBox cb = new CheckBox(this); 
     cb.setText(tag); 
     cb.setTag("checkbox"); 
     cb.setOnCheckedChangeListener(new OnCheckedChangeListener() { 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { 
       // TODO Auto-generated method stub 
       if (buttonView.isChecked()) { 
        try { 
         setOrderFinish(cb.getId()); 
        } catch (IOException e) { 
         // TODO Auto-generated catch block 
         e.printStackTrace(); 
        } 
       } else { 
        Toast.makeText(getBaseContext(), "UnChecked: " + buttonView + isChecked, 
        Toast.LENGTH_SHORT).show(); 
       } 
      } 
     }); 
     ll.addView(cb); 
    } 
    this.setContentView(sv); 
} 

public void setOrderFinish(int product_id) throws IOException { 
    URL url = new URL("http://192.168.178.35/setOrderAsFinished.php?id="+product_id); 
    URLConnection urlConnection = url.openConnection(); 
    InputStream in = new BufferedInputStream(urlConnection.getInputStream()); 
    try { 
     Context context = getApplicationContext(); 
     CharSequence text = "Finished: " + product_id; 
     int duration = Toast.LENGTH_LONG; 
     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 
    } finally { 
     in.close(); 
    } 
} 
}

来源

2012-09-27 user1703084

这是来自你的重复问题，我提到那里发布一些代码。你没有做那里，并且你做了新的问题..http：//stackoverflow.com/questions/12620166/the-method-addstring-is-undefined-for-the-type-string-jsonobject-2nd-array/ 12620244＃12620244 –

您mysql_id被redifined用作匿名的线程中的一员：

private String mysql_id = ""; //Setze Variable mysql_id für mysql_id

，并作为这样的，太

mysql_id=sb.toString();

使用不同的变量名称（例如给你的数组赋予复数名称）

来源

2012-09-27 12:48:41 njzk2

ArrayList<String> results = new ArrayList<String>();在我看来像结果是类型arrayList不是字符串。这就是为什么你可以调用它的add方法。

mysql_id是字符串类型，它不支持add方法。改变它的键入ArrayList的

来源

2012-09-27 12:49:24

在这里你声明为字符串

public void getData() { 
Thread t = new Thread() { //Setzte Tread 
private String result = ""; //Setze Variable String für die Ergebnisse 
private String mysql_id = "";

实际上它应该是ArrayList的

ArrayList<String> results = new ArrayList<String>(); 
ArrayList<String> mysql_id = new ArrayList<String>();

来源

2012-09-27 12:49:49

尝试使用的getString（）而不是get（）方法：

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 
import org.json.JSONTokener; 
... 
for (int i = 0; i < array.length(); i++) {            
    JSONObject obj = array.getJSONObject(i);         
    String product= (obj.getString("product")); 
    results.add(product); 
    ... 
}

来源

2012-09-27 12:57:42

String（JSONArray）类型未定义add（String）方法

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