Question

我制作了一个自定义适配器，其中包含一个textview和一个webview作为listview中的行项。我从服务器获取数据。但我不确定它为什么只显示一行，尽管应该有两行。

活动类

import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.jsoup.Jsoup;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;


public class GoldenTipsActivity extends ActionBarActivity {

    ListView listView;
    List<PatientUtility> patientUtilityArrayList;
    CustomPatientUtilityAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_golden_tips);

        listView = (ListView) findViewById(R.id.listView);
        getData();
    }

    public void getData(){
        GetData getData = new GetData();
        getData.execute();
    }


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

    public List<PatientUtility> parseData(String jsonStringData) throws JSONException{
        JSONObject object = new JSONObject(jsonStringData);
        JSONArray array = object.getJSONArray("pat_data");

        String title;
        String data;

        PatientUtility patientUtility = null;
        for (int i = 0; i < array.length(); i++){

            patientUtilityArrayList = new ArrayList<>();
            JSONObject object1 = array.getJSONObject(i);
            title = object1.getString("title");
            data = object1.getString("data");

            patientUtility = new PatientUtility();
            patientUtility.setTitle(title);
            patientUtility.setData(data);

            Log.v("Title", patientUtility.getTitle());
            Log.v("Data", patientUtility.getData());

            patientUtilityArrayList.add(patientUtility);
        }
        return patientUtilityArrayList;
    }


    private class GetData extends AsyncTask<Void, Void, List<PatientUtility>>{

        final String LOG_TAG = GetData.class.getSimpleName();

        public String html2text(String html) {
            return Jsoup.parse(html).text();
        }


        @Override
        protected List<PatientUtility> doInBackground(Void... params) {

            // These two need to be declared outside the try/catch
            // so that they can be closed in the finally block.
            HttpURLConnection urlConnection = null;
            BufferedReader reader = null;

            // Will contain the raw JSON response as a string.
            String dataJsonString = null;

            try {

                final String BASE_URL = "http://mycityortho.com/display_golden_tips.php";
                URL url = new URL(BASE_URL);
                Log.v(LOG_TAG, url.toString());

                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestMethod("GET");
                urlConnection.connect();

                // Read the input stream into a String
                InputStream inputStream = urlConnection.getInputStream();
                StringBuffer buffer = new StringBuffer();
                if (inputStream == null) {
                    // Nothing to do.
                    return null;
                }
                reader = new BufferedReader(new InputStreamReader(inputStream));

                String line;
                while ((line = reader.readLine()) != null) {
                    // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                    // But it does make debugging a *lot* easier if you print out the completed
                    // buffer for debugging.
                    buffer.append(line + "\n");
                }

                if (buffer.length() == 0) {
                    // Stream was empty.  No point in parsing.
                    return null;
                }

                dataJsonString = buffer.toString();
                Log.v(LOG_TAG, dataJsonString);

            } catch (IOException e) {
                Log.e(LOG_TAG, "Error ", e);
                // If the code didn't successfully get the weather data, there's no point in attemping
                // to parse it.
                return null;
            } finally {
                if (urlConnection != null) {
                    urlConnection.disconnect();
                }
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (final IOException e) {
                        Log.e(LOG_TAG, "Error closing stream", e);
                    }
                }
            }

            try {
                String textData = html2text(dataJsonString);
                return parseData(textData);
            }catch (JSONException e){
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(List<PatientUtility> result) {
            if (result != null){
                adapter = new CustomPatientUtilityAdapter(GoldenTipsActivity.this ,result);
                listView.setAdapter(adapter);
            }
        }
    }

    @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();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是我的自定义适配器类

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.List;

public class CustomPatientUtilityAdapter extends BaseAdapter{

    private List<PatientUtility> list;
    private Activity activity;
    private LayoutInflater inflater;

    public CustomPatientUtilityAdapter(Activity activity, List<PatientUtility> list){
        this.activity = activity;
        this.list = list;
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if (inflater == null){
            inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        if (convertView == null){
            convertView = inflater.inflate(R.layout.list_row_patient_utility_section, null);
        }

        TextView titleTextView = (TextView) convertView.findViewById(R.id.titleTextView);
        WebView dataTextView = (WebView) convertView.findViewById(R.id.dataTextView);

        PatientUtility p = list.get(position);
        titleTextView.setText(p.getTitle());
        dataTextView.loadData(p.getData(), "text/html", "utf-8");

        return convertView;
    }
}

我确信会出现小问题，但我无法解决此问题并花费数小时来解决此错误。

Answer 1

替换此

for (int i = 0; i < array.length(); i++){

        patientUtilityArrayList = new ArrayList<>();

        .................
        .................
    }
return patientUtilityArrayList;

到这个

 patientUtilityArrayList = new ArrayList<>();

 for (int i = 0; i < array.length(); i++){


        .................
        .................
    }
return patientUtilityArrayList;

实际上你现在正在每个循环中创建新的ArrayList对象。因此，不是将数据添加到上一个列表，而是每次创建一个新列表并添加该列表。

Answer 2

嗨，我认为你在public List<PatientUtility> parseData(String jsonStringData) {..} function犯了错误。看初始化是错误的。

patientUtilityArrayList = new ArrayList<>();

在for循环中初始化的数组列表。这就是为什么你在列表视图中只有一个项目。请参阅更新的parseData函数。

public List<PatientUtility> parseData(String jsonStringData) throws JSONException{
        JSONObject object = new JSONObject(jsonStringData);
        JSONArray array = object.getJSONArray("pat_data");

        String title;
        String data;

        PatientUtility patientUtility = null;

        patientUtilityArrayList = new ArrayList<>();

        for (int i = 0; i < array.length(); i++){


            JSONObject object1 = array.getJSONObject(i);
            title = object1.getString("title");
            data = object1.getString("data");

            patientUtility = new PatientUtility();
            patientUtility.setTitle(title);
            patientUtility.setData(data);

            Log.v("Title", patientUtility.getTitle());
            Log.v("Data", patientUtility.getData());

            patientUtilityArrayList.add(patientUtility);
        } 
        return patientUtilityArrayList;
    }

Answer 3

这是关于您的编码风格的答案。 Google建议我们覆盖getView的{{1}}，如下所示：

BaseAdapter

Android listview显示单行项目

3 个答案: