Question

我正在创建一个包含动态ListView的应用，它应该在Button点击后从服务器获取数据并在获得响应后绑定它们。我已经完成了收到回复。但是不知道如何将数据绑定到ListView。我还创建了一个用于绑定的适配器。但不知道通过适配器绑定数据的方式。谁能帮我？我已经在下面提供了我的代码供参考..

主要Activity.java（来自onCreate）：

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

    list = (ListView) findViewById(R.id.take_payment_list);
    adapter = new CustomListAdapter(this, notifications);
    list.setAdapter(adapter);

    refresh_btn = (Button) findViewById(R.id.refresh_btn);

    refresh_btn.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            HttpHandler httpHandler1 = new HttpHandler();
            String res = null;


            try {

                Log.d("edwLog", TAG + " get_payment_notifications " + HttpHandler.API_URL + "get_payment_notifications/" + AuthToken + "/");
                res = httpHandler1.makeServiceCall(HttpHandler.API_URL + "get_payment_notifications/" + AuthToken + "/", HttpHandler.GET);
                Log.d("edwLog", TAG + " response > " + res);
                if (res != null) {
                    JSONObject jsonObject = new JSONObject(res);
                    String responseType = jsonObject.getString("type");
                    if (responseType.equals("success")) {
                        if (jsonObject.has("response")) {

                            JSONArray jsonArray = jsonObject.getJSONArray("response");
                            for (int i = 0; i < jsonArray.length(); i++) {
                                notificationsresponse.add(jsonArray.getJSONObject(i));
                            }


                        }
                    }
                }



            } catch (Exception e) {
                e.printStackTrace();
                Log.d("edwLog", TAG + " IOException > " + e.toString());
            }

            adapter.notifyDataSetChanged();
        }
    });

适配器类：

public class CustomListAdapter extends BaseAdapter {

private final Activity activity;
private LayoutInflater inflater;
private List<Users> notifications;

ImageLoader imageLoader = AppController.getInstance().getImageLoader();

public CustomListAdapter(Activity activity, List<Users> notifications) {
    this.activity = activity;
    this.notifications = notifications;
}

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

@Override
public Object getItem(int location) {
    return notifications.get(location);
}

@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.custom_rows, null);

    if (imageLoader == null)
        imageLoader = AppController.getInstance().getImageLoader();

    NetworkImageView thumbNail = (NetworkImageView) convertView.findViewById(R.id.thumbnail);


    TextView name = (TextView) convertView.findViewById(R.id.txt_customer_name4);
    TextView time = (TextView) convertView.findViewById(R.id.txt_notification_time4);

    // getting notifications data for the row
    Users m = notifications.get(position);

    // thumbnail image
    thumbNail.setImageUrl(m.getThumbnailurl(), imageLoader);

    // name
    name.setText(m.getName());

    // notification time
    /*time.setText(String.valueOf(m.getTime()));*/
    CharSequence timeAgo = DateUtils.getRelativeTimeSpanString(
            Long.parseLong(m.getTime()), System.currentTimeMillis(), DateUtils.SECOND_IN_MILLIS);
            time.setText(timeAgo);


    return convertView;
}



}

Answer 1

首先创建一个你已经完成的适配器：

list = (ListView) findViewById(R.id.take_payment_list);
adapter = new CustomListAdapter(this, notifications);
list.setAdapter(adapter);

但是在第二行列表项缺失，休息一切正常：

adapter = new CustomListAdapter(this,<<listItem>>, notifications);

现在收到回复

将您的项目添加到notifications数组，然后更改适配器以获得新的通知数组：

notifications.add("data");
adapter = new CustomListAdapter(this,<<listItem>>, notifications);

Answer 2

执行简单的步骤：

适配器中的覆盖方法：

public void notifyDataSetChanged(List<Users> notifications){
   this.notifications = notifications;
   super.notifyDataSetChanged();
}

现在，而不是打电话：

adapter.notifyDataSetChanged();

称之为：

adapter.notifyDataSetChanged(notificationsresponse);

此外，从服务器获取数据的方法也不正确。当您尝试在主UI线程上获取数据时，这将减慢用户体验。您应该只在异步线程中调用服务器/数据库调用，并在UI线程上更新该响应。

Answer 3

首先，永远不要在主线程上调用Web服务，在AsyncTask中调用它们。 AsyncTask将是您的Activity / Fragment类的内部类。

private class WebServiceCaller extends AsyncTask<String, Void, JSONObject> {

    @Override
    protected JSONObject doInBackground(String... params) {
        //Call your web service here
        }
        return response; //the json response you get
    }

    @Override
    protected void onPostExecute(JSONObject result) {
        //here bind the data using your adapter to the listview
        //Parse the JSONObject you get as the response and add them to the list of Your User
        //now call the adapter
        adapter= new CustomListAdapter(MainActiviy.this,List);
        listView.setAdapter(adapter);
    }

    @Override
    protected void onPreExecute() {}

    @Override
    protected void onProgressUpdate(Void... values) {}
}

Answer 4

如果您希望再次使用获取的数据，请先将其存储在 Sqlite数据库中，否则请使用 ArrayAdapter 将数据绑定到listView。

参考this链接。

Answer 5

在你们的帮助下成功找到它。它只是在获得响应后添加这3行代码。对于我的应用程序，它是这样的：

adapter = new CustomListAdapter(TakePayment.this, R.layout.custom_rows, (ArrayList<JSONObject>) notificationsresponse);
list.setAdapter(adapter);
adapter.notifyDataSetChanged();

如何在android中获取响应后绑定ListView中的数据？

5 个答案: