java - (Android) 片段 onCreate 不运行整个方法
问题描述
我正在开发一个 android 项目,我从 JSON 转储中获取数据。我有一个片段,我从另一个公共 Java 类调用 Asynctask。由于某种原因,我的片段不会运行它的整个 onCreateView,并且在我调用 Asynctask 之后,它会停止运行其余的 onCreateView。有一个重要的 for 循环,它不会运行。
该片段看起来像这样,您可以在我的评论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 所在的公共 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;
}
}
解决方案
如果您研究过 AsyncTask 它在后台 UI 上运行。
尽管您在此方法之后调用 Loop,但 Loop 位于 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 完成工作后执行
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