Question

我有一个带片段的viewpager。我想将JSON数据显示在我片段中的textview中。有人可以告诉我如何。我是初学者。

这是我的代码。每次我在手机上运行它都会崩溃。日志说我的文本视图中有一个空对象引用。

此代码来自我正在观看的教程。我只是在我的片段上应用它但它不起作用。帮帮我谢谢。

HttpResponse httpResponse;
TextView textView;
JSONObject jsonObject = null ;
String StringHolder = "" ;
ProgressBar progressBar;
// Adding HTTP Server URL to string variable.
String HttpURL = 
"http://192.168.1***/android_login_api/topic_conservation.php";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    textView = (TextView)getActivity().findViewById(R.id.textViewC);
    progressBar = (ProgressBar)getActivity().findViewById(R.id.progressBar);
    // Showing progress bar on button click.
    progressBar.setVisibility(View.VISIBLE);

    //Calling GetDataFromServerIntoTextView method to Set JSon MySQL data into TextView.
    new GetDataFromServerIntoTextView(getActivity()).execute();

    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_eco_conservation, container, false);
}

// Declaring GetDataFromServerIntoTextView method with AsyncTask.
public class GetDataFromServerIntoTextView extends AsyncTask<Void, Void, Void>
{
    // Declaring CONTEXT.
    public Context context;


    public GetDataFromServerIntoTextView(Context context)
    {
        this.context = context;
    }

    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... arg0)
    {

        HttpClient httpClient = new DefaultHttpClient();

        // Adding HttpURL to my HttpPost oject.
        HttpPost httpPost = new HttpPost(HttpURL);

        try {
            httpResponse = httpClient.execute(httpPost);

            StringHolder = EntityUtils.toString(httpResponse.getEntity(), "UTF-8");

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try{
            // Passing string holder variable to JSONArray.
            JSONArray jsonArray = new JSONArray(StringHolder);
            jsonObject = jsonArray.getJSONObject(0);


        } catch ( JSONException e) {
            e.printStackTrace();
        }

        catch (Exception e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
    protected void onPostExecute(Void result)
    {
        try {

            // Adding JSOn string to textview after done loading.
            textView.setText(jsonObject.getString("topicdesc"));

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        //Hiding progress bar after done loading TextView.
        progressBar.setVisibility(View.GONE);

    }
}

Answer 1

试试这个，

View view=inflater.inflate(R.layout.fragment_eco_converstion,container,false);
textview=(TextView)view.findViewById(R.id.text_view);
 return view;

片段中的PHP JSON数据到Textview

1 个答案: