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Asynctask getActivity

由 女生的网名这么多〃 提交于 2019-12-25 07:58:40

问题


I am trying to set my toolbar title from an async task. I am getting a cannot resolve method getActivity() in this line:

        ((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(name);

My code looks like this:

/**
 * Created by Mike on 2/28/15.
 */
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.preference.PreferenceManager;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RatingBar;
import android.widget.TextView;
import android.widget.Toast;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

/**
 * Created by Mike on 4/26/14.
 */
public class GetBeerDataJSON2 extends AsyncTask<String, Void, String> {

    Context c;
    String id;
    private ProgressDialog Dialog;


    public GetBeerDataJSON2 (Context context, String beerID)
    {
        c = context;
        id = beerID;
        Dialog = new ProgressDialog(c);
    }

    @Override
    protected String doInBackground(String... arg0) {
        // TODO Auto-generated method stub
        return readJSONFeed(arg0[0]);
    }

    protected void onPreExecute() {
        Dialog.setMessage("Getting beer information");

        Dialog.setTitle("Loading");
        Dialog.show();
    }

    protected void onPostExecute(String result){
        //decode json here
        try{

            JSONObject o = new JSONObject(result);

            //get beer details



            //todo: lets get things from our new JSON

            String name = o.getString("name");
            String beerDescription = o.getString("description");
            String abv = o.getString("abv");
            String ibu = o.getString("ibu");
            String image = o.getString("icon");
            String glass = o.getString("glass");
            String beerBreweryStyle = o.getString("style");
            String beerBreweryName = o.getString("brewery");
            String status = o.getString("status");
            String rating = o.getString("rating");
            String food = o.getString("food");




            int beerRate = 0;
            beerRate = o.getInt("userRating");



            //prepare buttons
            //Button buttonBrewery = (Button) ((Activity) c).findViewById(R.id.buttonBrewery);
            //Button buttonStyle = (Button) ((Activity) c).findViewById(R.id.buttonStyle);

            TextView tv_breweryName = (TextView) ((Activity) c).findViewById(R.id.beerBreweryName);
            TextView tv_styleName = (TextView) ((Activity) c).findViewById(R.id.beerStyleName);

            SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(c);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putString("styleName",beerBreweryStyle);
            editor.putString("beerName",name);
            editor.putString("lastBeer",name);
            editor.putString("breweryName",beerBreweryName);
            editor.putString("styleName",beerBreweryStyle);
            editor.commit();

            ((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(name);


            //create text views
            TextView styleTitle = (TextView) ((Activity) c).findViewById(R.id.beerTitle);
            styleTitle.setText(name);

            TextView textABV = (TextView) ((Activity) c).findViewById(R.id.abv);
            textABV.setText(abv);

            TextView textIBU = (TextView) ((Activity) c).findViewById(R.id.IBU);
            textIBU.setText(ibu);

            TextView textGlass = (TextView) ((Activity) c).findViewById(R.id.glass);
            textGlass.setText(glass);

            TextView textDescription= (TextView) ((Activity) c).findViewById(R.id.beerDescription);
            textDescription.setText(beerDescription);

            String breweryButton = "Brewery: ";
            String styleButton = "Style: ";

            //todo: add beer name to shared prefs

            tv_breweryName.setText(beerBreweryName);
            tv_styleName.setText(beerBreweryStyle);

            //get user id
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(c);
            String userName = prefs.getString("userName", null);
            final String userID = prefs.getString("userID", null);

            //check if user has beer
            String url = "http://www.beerportfolio.com/app_checkBeer.php?";
            String userURLComp = "u=" + userID;
            final String beerID = "&b=" + id;

            url = url + userURLComp + beerID;
            //new CheckBeerJSON(c,id,userID).execute(url);

            //todo: add code for check beer here

            if(status.equals("no")){




                //clear loader image
                LinearLayout ll = (LinearLayout) (LinearLayout)((Activity) c).findViewById(R.id.addBeerLayout);
                ll.removeAllViews();

                //Add beer add button
                LayoutInflater mInflater = (LayoutInflater)c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                LinearLayout addButton = (LinearLayout)((Activity) c).findViewById(R.id.addBeerLayout);
                addButton.addView(mInflater.inflate(R.layout.addbeerbutton_layout, null));

                //add on click listener here
                Button bt4 = (Button)((Activity) c).findViewById(R.id.button1);
                bt4.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        // do whatever stuff you wanna do here



                        //get beer details
                        String url2 = "http://www.beerportfolio.com/app_addBeer.php?";
                        String urlUserID = "u=" + userID;
                        String urlBeerID = "&bID=" + id;


                        Log.d("url", id);
                        //construct url for adding beer
                        url2 = url2 + urlUserID + urlBeerID;



                        Log.d("url", url2);

                        //execute async on url to add to brewery
                        new AddBeer(c).execute(url2);

                        //to do: change to start rater
                        LinearLayout ll = (LinearLayout) ((Activity) c).findViewById(R.id.addBeerLayout);
                        ll.removeAllViews();

                        //add rater

                        LayoutInflater inflater = (LayoutInflater)((Activity) c).getSystemService(((Activity) c).LAYOUT_INFLATER_SERVICE);
                        LinearLayout addButton = (LinearLayout)((Activity) c).findViewById(R.id.addBeerLayout);
                        addButton.addView(inflater.inflate(R.layout.addrate_layout, null));


                        //add listener to rate button todo
                        //add listener to bar
                        addListenerOnRatingBar(c);




                    }
                });


            }

            else{


                //clear loader image
                LinearLayout ll = (LinearLayout) (LinearLayout)((Activity) c).findViewById(R.id.addBeerLayout);
                ll.removeAllViews();

                //inflate star rater
                LayoutInflater mInflater = (LayoutInflater)c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                LinearLayout addButton = (LinearLayout)((Activity) c).findViewById(R.id.addBeerLayout);
                addButton.addView(mInflater.inflate(R.layout.addrate_layout, null));

                RatingBar r = (RatingBar) ((Activity) c).findViewById(R.id.beerRatingBar);

                //get user data


                //get beer rating with async task and update rate bar
                String url2 = "http://www.beerportfolio.com/app_getRating.php?";
                String userURLComp2 = "u=" + userID;
                String beerID2 = "&b=" + beerID;

                url = url + userURLComp2 + beerID2;



                //new GetUserRating(c,r).execute(url2);
                r.setRating(beerRate);

                //add listener to bar
                addListenerOnRatingBar(c);



            }

            //end code here

            //todo: get rate code goes here


            TextView tv1 = (TextView) ((Activity) c).findViewById(R.id.beerRating);

            tv1.setText(rating + " / 5");

            //end rate code


            String url2 = "http://beerportfolio.com/app_beerDetails2.php?u="+ userID + "&b=" + beerID;
            //new GetBeerRateJSON(c,id).execute(url2);

            ImageView im1 = (ImageView) ((Activity) c).findViewById(R.id.image);
            if(image.equals("N/A")){
                //set image as png
                im1.setImageResource( R.drawable.noimage);
            }

            else{
                ImageDownloadTask imageD = new ImageDownloadTask(im1);
                imageD.execute(image);
            }


            //tdo: add food paring

            if (food.equals("N/A")){


            }




            Dialog.dismiss();







        }
        catch(Exception e){

        }

    }

    private void addListenerOnRatingBar(Context view) {
        RatingBar ratingBar = (RatingBar) ((Activity) view).findViewById(R.id.beerRatingBar);

        ratingBar.setOnRatingBarChangeListener(new RatingBar.OnRatingBarChangeListener() {
            public void onRatingChanged(RatingBar ratingBar, float rating,
                                        boolean fromUser) {

                //next async task to update online database
                float stars = ratingBar.getRating();

                //get user details
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(c);
                String userID = prefs.getString("userID", null);

                //get beer id
                String beerID = id;

                //get rating
                String urlRate = "r=" + String.valueOf(ratingBar.getRating());
                String urlUserID = "&u=" + userID;
                String urlBeerID = "&b=" + beerID;

                //construct url
                String url2 = "http://www.beerportfolio.com/app_rateUpdate.php?";

                url2 = url2 + urlRate + urlUserID + urlBeerID;


                //async task to update rating in database
                new UpdateRating(c).execute(url2);





            }
        });
    }

    public String getName(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getString("name");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getABV(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getString("abv");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getIBU(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getString("ibu");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getImage(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getJSONObject("labels").getString("large");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getGlass(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getJSONObject("glass").getString("name");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getBreweryName(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getJSONArray("breweries").getJSONObject(0).getString("name");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getBreweryStyle(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getJSONObject("style").getString("name");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }

    public String getDescription(JSONObject json){
        String holder;

        try{
            holder = json.getJSONObject("data").getString("description");

        } catch (JSONException e) {
            holder = "N/A";
        }

        return holder;

    }




    public String readJSONFeed(String URL) {
        StringBuilder stringBuilder = new StringBuilder();
        HttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(URL);
        try {
            HttpResponse response = httpClient.execute(httpGet);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            if (statusCode == 200) {
                HttpEntity entity = response.getEntity();
                InputStream inputStream = entity.getContent();
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(inputStream));
                String line;
                while ((line = reader.readLine()) != null) {
                    stringBuilder.append(line);
                }
                inputStream.close();
            } else {
                Log.d("JSON", "Failed to download file");
            }
        } catch (Exception e) {
            Log.d("readJSONFeed", e.getLocalizedMessage());
        }
        return stringBuilder.toString();
    }

}

I feel like I need to use the context c that I bring in, but every combination I have tried has failed me.


回答1:


Use context:

((ActionBarActivity)context).getSupportActionBar().setTitle(name);



回答2:


At first you should do all time consuming operation in a doInBackground method. This also include parsing JSON data. In onPreExecute and onPostExecute method you should do only GUI things.

Don't use activity or activity context directly in AsyncTask class. Use listeners together with WeakReference to change GUI things. For example:

public class MyAsyncTask extends AsyncTask<String, Void, String> {
  public interface TaskListener {
    void onTitleReceived(String title);
  }

  private final WeakReference<TaskListener> mTaskListenerRef;    

  public MyAsyncTask(TaskListener listener) {
    this.mTaskListenerRef = new WeakReference<>(listener);
  }

  public void notifyTitleReceived(String title) {
    TaskListener listener = mTaskListenerRef.get();
    if (listener != null) {
      listener.onTitleReceived(title);
    }
  }

  protected void onPostExecute(String result){
    ...
    notifyTitleReceived(newTitle);
    ...
  }
}

public class MyActivity extends ActionBarActivity implements MyAsyncTask.TaskListener {
    @Override
    public void onTitleReceived(String title) {
      getSupportActionBar().setTitle(title);
    }

    private void runTask() {
      new MyTask(this).execute();
    }
}



回答3:


define an static instance of actvity , set it before excute()

in your GetBeerDataJSON2 class

public static ActionBarActivity instance = null;

in your ActionBarActivity class :

onCreate(Bundle bundle){
GetBeerDataJSON2 task = new GetBeerDataJSON2() ; 
task.instance = this;
task.excute();
}

another solotion is passing this as the contextin your constructor of GetBeerDataJSON2 and cast it to ActionBarActivity

anyway better way of doing this is using libraries like volley to get json rather than building the wheel




回答4:


Combining answers in constructor while creating instance of GetBeerDataJSON2(Context, Stirng) in Activity code pass 'this' as first argument.

And cast it as :

((ActionBarActivity) context).getSupportActionBar().setTitle(name);

Instead of :

((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(name);

Error Because there is no method getActivity() defined for AsynchTask.



来源：https://stackoverflow.com/questions/28955810/asynctask-getactivity

标签
android
android-asynctask
android-toolbar
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