Android列表视图显示单行项目



我制作了一个自定义适配器,其中一个textview和一个webview作为listview中的行项目。我正在从服务器获取数据。但我不知道为什么它只显示一行,而应该有两行。

活动类别

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;
    }
}

我确信会有一个小问题,但我无法得到这个问题,并花了几个小时来解决这个错误。

你好,我认为你在public List<PatientUtility> parseData(String jsonStringData) {..} function中犯了错误。请参阅初始化错误。
patientUtilityArrayList = new ArrayList<>();

在for循环中初始化的数组列表。这就是为什么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;
    } 

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,现在您正在每个循环中创建新的ArrayList对象。因此,它不是将数据添加到以前的列表中,而是每次创建一个新的列表并添加到该列表中。

这是关于您的编码风格的答案。Google建议我们应该像这样覆盖BaseAdaptergetView

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    if (convertView == null){
        convertView = inflater.inflate(R.layout.list_row_patient_utility_section, null);
        holder = new ViewHolder();
        holder.tv = (TextView) convertView.findViewById(R.id.titleTextView);
        holder.wv = (WebView) convertView.findViewById(R.id.dataTextView);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder)converview.getTag();
    }
    PatientUtility p = list.get(position);
    holder.tv.setText(p.getTitle());
    holder.wv.loadData(p.getData(), "text/html", "utf-8");
    return convertView;
}
public class ViewHolder{
    TextView tv;
    WebView wv;
}

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