Question

我正在研究一个android项目，我从JSON转储中获取数据。我有一个片段，其中我从另一个公共Java类调用Asynctask。由于某种原因，我的片段不会全部运行在onCreateView上，在我调用Asynctask之后，它将停止运行其余的onCreateView。有一个重要的for循环，它将不会运行。

该片段看起来像这样，您可以在我的注释中看到它停止运行的位置。

public class DataTabelFragment extends Fragment {

private TextView sensor1;

jsonAsynctask jsonasynctask = new jsonAsynctask();


public DataTabelFragment() {
    // Required empty public constructor
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate( R.layout.fragment_data_tabel, container, false );

    sensor1 = (TextView) view.findViewById( R.id.sensor1Box );

    new jsonAsynctask().execute(); //THIS IS THE LAST CODE RUNNING

    //NOT RUNNING CODE AFTER THIS

    System.out.println( jsonasynctask.allDevice );

    for (int i = 0; i < jsonasynctask.allId.size(); i++) {

        // String date_time = allDate_time.get( i );
        // String date = date_time.substring( 0, date_time.indexOf( "T" ) );
        // String time = date_time.substring( date_time.indexOf( "T" ) + 1, date_time.indexOf( "+" ) );
        // textView2.append( allId.get( i ) + "  " + allTemp.get( i ) + "  " + allHum.get( i ) + "  " + allBat.get( i ) + "  " + allMode.get( i ) + "  " + date + "  " + time + "  " + allLux.get( i ) + "\n\n" );
        sensor1.append( jsonasynctask.allId.get( i ) + " | " + jsonasynctask.allDevice.get( i ) + " | " + jsonasynctask.allTemp.get( i ) + " | " + jsonasynctask.allHum.get( i ) + " | " + jsonasynctask.allBat.get( i ) + " | " + jsonasynctask.allMode.get( i ) + " | " + jsonasynctask.allLux.get( i ) + " | " + jsonasynctask.allDate_time.get( i ) + "\n\n" );

    }

    return view;

    }

}

这是Asynctask在其中的公共Java类：

public class jsonAsynctask extends AsyncTask<Void, Void, Void> {

JSONObject deviceArray;
JSONObject tempArray;
JSONObject humArray;
JSONObject batArray;
JSONObject modeArray;
JSONObject date_timeArray;
JSONObject luxArray;

JSONArray json2;

List<String> allId = new ArrayList<String>();
List<String> allDevice = new ArrayList<String>();
List<String> allTemp = new ArrayList<String>();
List<String> allHum = new ArrayList<String>();
List<String> allBat = new ArrayList<String>();
List<String> allMode = new ArrayList<String>();
List<String> allDate_time = new ArrayList<String>();
List<String> allLux = new ArrayList<String>();

String basicAuth;
String line;
String json_string;
String json;
String cxwebURL;
String credentials;
String password;
String username;

Gson gson;
ProgressDialog pd;
String data = "";
//HttpsURLConnection connection;
HttpURLConnection connection;
BufferedReader bufferedReader;

String id = "";
JSONObject idArray;

URL url;


private static String encodeBase64URLSafeString(byte[] binaryData) {

    return android.util.Base64.encodeToString( binaryData, android.util.Base64.URL_SAFE );

}

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

        username = "xxx";

        password = "xxx";

        credentials = username + ":" + password;

        cxwebURL = "https://" + credentials + "@xxx.com/fetch.php?device=xxx";

        try {

            url = new URL( cxwebURL );

            connection = (HttpsURLConnection) url.openConnection();

            basicAuth = "Basic " + new String( encodeBase64URLSafeString( credentials.getBytes() ) );

            connection.setRequestProperty( "Authorization", basicAuth );
            connection.setRequestMethod( "GET" );
            connection.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded" );
            connection.setRequestProperty( "Content-Language", "en-US" );
            connection.setUseCaches( false );
            connection.setDoInput( true );
            connection.setDoOutput( true );
            connection.connect();

            InputStream stream = connection.getInputStream();

            bufferedReader = new BufferedReader( new InputStreamReader( stream ) );

            line = "";

            while (line != null) {
                line = bufferedReader.readLine();
                data = data + line;
            }

            json2 = new JSONArray( data );

            for (int i = 0; i < json2.length(); i++) {
                idArray = json2.getJSONObject( i );
                deviceArray = json2.getJSONObject( i );
                tempArray = json2.getJSONObject( i );
                humArray = json2.getJSONObject( i );
                batArray = json2.getJSONObject( i );
                modeArray = json2.getJSONObject( i );
                date_timeArray = json2.getJSONObject( i );
                luxArray = json2.getJSONObject( i );
                id = idArray.getString( "id" );

                String temp = tempArray.getString( "temp" );
                String device = deviceArray.getString( "device" );

                String hum = humArray.getString( "hum" );

                String bat = batArray.getString( "bat" );

                String mode = modeArray.getString( "mode" );

                String date_time = date_timeArray.getString( "time" );

                String lux = luxArray.getString( "light" );

                allId.add( id );
                allDevice.add( device );
                allTemp.add( temp );
                allHum.add( hum );
                allBat.add( bat );
                allMode.add( mode );
                allDate_time.add( date_time );
                allLux.add( lux );


            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

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

    @Override
    public void onPostExecute(Void result) {
        super.onPostExecute( result );

        gson = new Gson();

        json = gson.toJson( data );

        json_string = data;


        }
    }

Answer 1

如果您已经研究过AsyncTask，它将在后台UI上运行。

尽管您在此方法之后调用Loop，但是Loop在Main UI上，因此它在AsyncTask完成之前执行。

所以感觉循环没有执行

将循环放入AsynTask的onPost（）方法中，以便在AsyncTask完成工作后立即执行

（Android）片段onCreate未运行整个方法

1 个答案: