Question

在尝试从MySQL服务器获取一行数据之前，我使用了一个专栏并设法通过教程将其转换为listView。但是为了从表中连续获取数据，我无法将其放入listView。

所以我要做的就是将后台工作者的“转移”放到列表视图中。

PHP SQL查询：

$sql = "SELECT id, employee, hours FROM selected_shifts WHERE day = '$day';";

主要活动的导航抽屉：

if (items[0].equals(mExpandableListTitle.get(groupPosition))) {
                if (items[0].equals(mExpandableListTitle.get(childPosition))) {
                    String day = "Monday";
                    OnChoice(day);
                } else if (items[1].equals(mExpandableListTitle.get(childPosition))) {
                    String day= "Tuesday";
                    OnChoice(day);
                } else if (items[2].equals(mExpandableListTitle.get(childPosition))) {
                    String day = "Wednesday";
                    OnChoice(day);
                } else if (items[3].equals(mExpandableListTitle.get(childPosition))) {
                    String day = "Thursday";
                    OnChoice(day);
                } else if (items[4].equals(mExpandableListTitle.get(childPosition))) {
                    String day = "Friday";
                    OnChoice(day);
                }
            }

            mDrawerLayout.closeDrawer(GravityCompat.START);
            return false;
        }
    });
}

public void OnChoice(String day) {
    String type = "choice";
    BackgroundWorker backgroundWorker = new BackgroundWorker(this);
    backgroundWorker.execute(type, day);
}

后台工作者（从MySQL服务器获取数据）：

public class BackgroundWorker extends AsyncTask<String,Void,String> {
Context context;
AlertDialog alertDialog;
BackgroundWorker (Context ctx) {
    context = ctx;
}
@Override
protected String doInBackground(String... params) {
    String type = params[0];
    String shifts_url = "***PHP LINK***";
    if(type.equals("choice")) {
        try {
            String day = params[1];
            URL url = new URL(shifts_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("day","UTF-8")+"="+URLEncoder.encode(day,"UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
            String shift="";
            String line="";
            while((line = bufferedReader.readLine())!= null) {
                shift += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return shift;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return null;
}

@Override
protected void onPreExecute() {
    alertDialog = new AlertDialog.Builder(context).create();
    alertDialog.setTitle("Status");
}

@Override
protected void onPostExecute(String shift) {
    //Toast the data as json
    Toast.makeText(context, shift, Toast.LENGTH_LONG).show();
}

@Override
protected void onProgressUpdate(Void... values)
{
    super.onProgressUpdate(values);


   }
}

修改

将其放入ListView：

public void onTaskCompleted(String shift) {
    try {
        loadIntoListView(shift);
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

private void loadIntoListView(String shift) throws JSONException {
    JSONArray jsonArray = new JSONArray(shift);
    String[] list = new String[jsonArray.length()];
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject obj = jsonArray.getJSONObject(i);
        list[i] = obj.getString(shift);
    }
    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
    listView.setAdapter(arrayAdapter);
}

Answer 1

在result处，您应该将“shift”添加到适配器中的dataSet。

Answer 2

那么你想要传递public interface TaskListener { void onTaskCompleted(String shift); }的方法是使用自定义的“监听器”。

创建此

BackgroundWorker

在你的TaskListener taskListener; BackgroundWorker(Context context, TaskListener taskListener){ this.context = context; this.taskListener = taskListener; }上更改构造函数如下：

onPostExecute

然后在taskListener.onTaskCompleted(shift)方法上，执行BackgroundWorker。

当您调用this构造函数传递BackgroundWorker backgroundWorker = new BackgroundWorker(this, this)作为第二个参数时：

TaskListener

然后在Main上实现... MainActivity implements TaskListener ... @override onTaskCompleted(String shift) { // You have your `shift` here to do with as you please }并实现该方法。像这样：

{{1}}

将来自后端服务的数据行放入ListView

2 个答案: