Question

我要做的是在用户点击一个名为location_Button的按钮后获取用户的位置，然后显示一个显示有关其位置信息的框。我试过这样的：

Button location_Button=(Button) findViewById(R.id.location_button);
    location_Button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Define a listener that responds to location updates
           progressDialog = ProgressDialog.show(Settings.this, "", "Loading...");

            final LocationListener locationListener = new LocationListener() {

                public void onLocationChanged(Location location) {
                    // Called when a new location is found by the network location provider.

                    lat =location.getLatitude();
                    lon = location.getLongitude();
                    try{

                        addresses=(geocoder.getFromLocation(lat, lon, 1));
                        if (addresses.size() > 0) {
                            String city = addresses.get(0).getAddressLine(1);
                            String id = city.substring(0,city.length()-5);
                            String state1=String.valueOf(id.charAt(id.length()-3));
                            String state2=String.valueOf(id.charAt(id.length()-2));
                            String STATE = state1+state2;

                            locationManager.removeUpdates(this);
                            progressDialog.dismiss();

                            //alert dialog is established and displayed here



                        }
                        else {
                            //tv.setText("Oops...");
                        }

                    }catch(IOException e){
                        e.printStackTrace();
                    }

                }

                public void onStatusChanged(String provider, int status, Bundle extras) {}

                public void onProviderEnabled(String provider) {}

                public void onProviderDisabled(String provider) {}
            };

问题是进度对话框永远不会被解雇。按下按钮时没有进度对话框，它会搜索然后显示该框，进度对话框继续说明加载并且永远不会被解除。我的目标是在建立位置后取消进度对话框，同时应弹出警告对话框，但事实并非如此。进度对话框的位置不正确？

Answer 1

仅仅因为Android始终是异步的，您必须使用线程来使用进度对话框。一个例子：

在您的代码中，当您想要启动对话框时，请调用异步类：

Button location_Button=(Button) findViewById(R.id.location_button);
    location_Button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            LocationChanged locationChanged = new LocationChanged(MainActivity.this, "Loading...");
            locationChanged.execute();
        }

现在您需要创建LocationChanged.java：

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;

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

    private ProgressDialog progressDialog;
    private Context context;
        private String message;

    public LocationChanged (Context context, String message) {
        this.context = context;
                this.message = message;
        }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = ProgressDialog.show (context, null, message);
    }

    @Override
    protected Void doInBackground( Void... params ) {
            // Here you add your code. 

            return null;
    }

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

        progressDialog.dismiss();

          // You can add code to be executed after the progress (may be a result).
    }

}

进度对话框不会被忽略

1 个答案: