我正在尝试在用户等待来自Web服务的响应时出现“加载...”消息。

我已经看过各种其他类似的问题/答案以及我在网上找到的教程但却无法让它正常运行。

任何帮助将非常感谢!

代码在这里:

public class SunriseSunset extends Activity implements OnClickListener {

    public Button getLocation;
    public Button setLocationJapan;
    public TextView LongCoord;
    public TextView LatCoord;
    public double longitude;
    public double latitude;
    public LocationManager lm;
    public Spinner Locationspinner;
    public DateDialogFragment frag;
    public Button date;
    public Calendar now;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sunrisesunset);
        // Show the Up button in the action bar.
                setupActionBar();

        //Setting onClickListener for Calculate Sunrise/Sunset Button
        findViewById(R.id.CalculateSunriseSunset).setOnClickListener(this);

        //Sets up LocationManager to enable GPS data to be accessed.
        lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1,
                new MyLocationListener());

        //Declares Latitude and Longitude TextViews
        LatCoord = (TextView) findViewById(R.id.LatCoord);
        LongCoord = (TextView) findViewById(R.id.LongCoord);

        //Declares for Location Spinner/Dropdown
        addListenerOnSpinnerItemSelection();

        //Date shit
        now = Calendar.getInstance();
        date = (Button)findViewById(R.id.date_button);
        date.setText(DateFormat.format("dd MMMM yyyy", Calendar.getInstance()));
        date.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDialog();
            }
        });

    }
    /**
     * Set up the {@link android.app.ActionBar}.
     */
    private void setupActionBar() {

        getActionBar().setDisplayHomeAsUpEnabled(true);

    }

    // More date shit
    @SuppressLint("CommitTransaction")
    public void showDialog() {  
        FragmentTransaction ft = getFragmentManager().beginTransaction(); //get the fragment   
        frag = DateDialogFragment.newInstance(this, new DateDialogFragmentListener(){      

        public void updateChangedDate(int year, int month, int day){                     
        now.set(year, month, day);
        date.setText(DateFormat.format("dd MMMM yyyy", now));             
        }  
          }, now);
        frag.show(ft, "DateDialogFragment");     }



    public interface DateDialogFragmentListener{
        //this interface is a listener between the Date Dialog fragment and the activity to update the buttons date
        public void updateChangedDate(int year, int month, int day);
    }

    public void addListenerOnSpinnerItemSelection() {
        Locationspinner = (Spinner) findViewById(R.id.Locationspinner);
        Locationspinner
                .setOnItemSelectedListener(new CustomOnItemSelectedListener(
                        this));
    }


    protected void showCurrentLocation() {
        // TODO Auto-generated method stub
        // This is called to find current location based on GPS data and sends
        // these values to the LongCoord and LatCoord TextViews
        Location location = lm
                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
        latitude = location.getLatitude();
        longitude = location.getLongitude();

        LongCoord.setText(Double.toString(longitude));
        LatCoord.setText(Double.toString(latitude));
    }

    @Override
    public void onClick(View arg0) {
        Button b = (Button) findViewById(R.id.CalculateSunriseSunset);
        b.setClickable(false);
        new LongRunningGetIO().execute();
    }

    public class LongRunningGetIO extends AsyncTask<Void, Void, String> {
        //Reads in the web service
        protected String getASCIIContentFromEntity(HttpEntity entity)
                throws IllegalStateException, IOException {
            InputStream in = entity.getContent();
            StringBuffer out = new StringBuffer();
            int n = 1;
            while (n > 0) {
                byte[] b = new byte[4096];
                n = in.read(b);
                if (n > 0)
                    out.append(new String(b, 0, n));
            }
            return out.toString();
        }

        @SuppressLint("SimpleDateFormat")
        @Override
        protected String doInBackground(Void... params) {
            HttpClient httpClient = new DefaultHttpClient();
            HttpContext localContext = new BasicHttpContext();

            // Finds todays date and adds that into the URL in simple date format DD/MM
            SimpleDateFormat df = new SimpleDateFormat("dd/MM");
            String formattedDate = df.format(now.getTime());

            String finalURL = "http://www.earthtools.org/sun/"
                    + LatCoord.getText().toString().trim() + "/"
                    + LongCoord.getText().toString().trim() + "/"
                    + formattedDate + "/99/0";
            HttpGet httpGet = new HttpGet(finalURL);
            String text = null;

            try {
                HttpResponse response = httpClient.execute(httpGet,
                        localContext);
                HttpEntity entity = response.getEntity();
                text = getASCIIContentFromEntity(entity);
            } catch (Exception e) {
                return e.getLocalizedMessage();
            }
            return text;
        }

        protected void onPostExecute(String results) {
            if (results != null) {
                try {

                    DocumentBuilderFactory dbFactory = DocumentBuilderFactory
                            .newInstance();
                    DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
                    InputSource s = new InputSource(new StringReader(results));
                    Document doc = dBuilder.parse(s);
                    doc.getDocumentElement().normalize();
                    TextView tvSunrise = (TextView) findViewById(R.id.Sunrise);
                    TextView tvSunset = (TextView) findViewById(R.id.Sunset);
                    tvSunrise.setText(doc.getElementsByTagName("sunrise").item(0).getTextContent());
                    tvSunset.setText(doc.getElementsByTagName("sunset").item(0).getTextContent());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            Button b = (Button) findViewById(R.id.CalculateSunriseSunset);
            b.setClickable(true);
        }
    }



    class MyLocationListener implements LocationListener {
        @Override
        public void onLocationChanged(Location location) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub
        }
    }
}

任何帮助将非常感激:) x

===============>>#1 票数:3 已采纳

如果您还没有阅读过,请阅读AsyncTask

此类允许执行后台操作并在UI线程上发布结果,而无需操作线程和/或处理程序。

您可以在其中使用的功能很少。 例如:onPreExecute,doInBackground,onProgressUpdate和onPostExecute。

在onPreExecute()上,使用以下命令声明一个对话框并显示一个loading ...框:

private final ProgressDialog dialog = new ProgressDialog(YourClass.this);

protected void onPreExecute() {
   this.dialog.setMessage("loading...");
   this.dialog.show();
}

然后在doInBackground中,您可以完成任务。 即调用webservice并等待响应(这样你就可以在后台线程中等待而无需锁定UI)。

protected Boolean doInBackground(final Void unused) {
  // call your web service here and do other stuff(wait).
  // return true when success else false
}

上面的函数返回boolean,它被接受为onPostExecute OnpostExecute()中的参数,停止对话框并显示其他事项,如成功等。如下所示:

protected void onPostExecute(final Boolean result) {
   if (this.dialog.isShowing()) { // if dialog box showing = true
      this.dialog.dismiss(); // dismiss it
   }
   if (result.booleanValue()) {
      //also show register success dialog
   }
}

同时检查这个帖子。 希望这可以帮助。

===============>>#2 票数:0

在执行AsyncTask时尝试显示进度对话框,并在AsyncTask的后执行时关闭对话框。 此外:

private ProgressDialog progressDialog;

@Override
    public void onClick(View arg0) {
        Button b = (Button) findViewById(R.id.CalculateSunriseSunset);
        b.setClickable(false);
        progressDialog = ProgressDialog.show(SunriseSunset.this, "Loading",
                "Please wait while fetching data");
        new LongRunningGetIO().execute();
    }

...

protected void onPostExecute(String results) {
progressDialog.dismiss();
                if (results != null) {
                    try {

  ask by Athoul translate from so

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