Question

我有第二个查询在线数据库的活动，我想设置TextView的文本，但我不能。当我启动应用程序时，TextView为空。

这是第二项活动的代码：

 public class sendQuery extends main  {
/////////// Public method to send Query ///////////
public static String send(String query, Activity sendQuery) {
String result = "0";
InputStream is = null;
String weekDayVal=null;
String provola=null;
//the query to send
ArrayList<NameValuePair> querySend = new ArrayList<NameValuePair>();

querySend.add(new BasicNameValuePair("querySend",query));

//http post
try{
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://locali.altervista.org/php/locali.php");
    httppost.setEntity(new UrlEncodedFormEntity(querySend));
    HttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    is = entity.getContent();
}catch(Exception e){
    Log.e("log_tag", "Error in http connection "+e.toString());
}

//convert response to string
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();
    result=sb.toString();
    try{
        JSONArray weekDetails = new JSONArray ( result); // Your response string
        for(int index=0;index < 1/*weekDetails.length()*/;index++)
        {
        JSONObject tempWeekDetail = weekDetails.getJSONObject(index);
        weekDayVal = tempWeekDetail.getString("Lunedi");// Value for Monday
        //added this Log which you can view from LogCat. also changed above variable name
        Log.i("Resp Value","Moday Value "+weekDayVal);
        JSONObject provino = weekDetails.getJSONObject(index);
        provola = provino.getString("Martedi");// Value for Monday
        //added this Log which you can view from LogCat. also changed above variable name
        Log.i("Resp Value","Moday Value "+provola);
        }
        TextView text = (TextView) sendQuery.findViewById(R.id.textView10);
        text.setText(provola);
        }
        catch(Exception e)
        {


        }
}catch(Exception e){
    Log.e("log_tag", "Error converting result: "+e.toString());
}

Log.i("SendQUERY", result);
return result;
}
}

主要活动如下：

 public class main extends Activity {
 /** Called when the activity is first created. */
 @Override

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

TextView resLayout = (TextView) findViewById(R.id.res);


String res = sendQuery.send("SELECT * FROM contatti", null);

resLayout.append(res);



}
}

到目前为止还没有人能够帮助我，我无法弄清楚我错在哪里。感谢

修改

问题在于第二个活动，这里TextView text =（TextView）sendQuery.findViewById（R.id.textView10）; text.setText（provola）;

Answer 1

将resLayout.append(res);更改为resLayout.setText(res);

Answer 2

 setText() is a method that you have to call when you want to set some text in textview.
 so you have to use

 resLayout.setText(res);
 if you are getting any exception,error or nothing is set on your view.then you have to check your string value for null or empty.

    if(!res.equalignorecase("null" && !res.equalignorecase(""))){
       resLayout.setText(res);
    }else{
       resLayout.setText("set some dummy text");
  }

Answer 3

更改

resLayout.append(res);

到

resLayout.setText(res);

在TextView中添加文本

3 个答案: