我正在尝试从异步任务设置我的工具栏标题。我在这一行中得到了一个无法解析方法getActivity（）：
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(name);
我的代码如下所示：
/**
* 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();
}
}
我觉得我需要使用我带来的上下文c，但我尝试的每一个组合都让我失望。
答案 0 :(得分：1)
使用上下文：
((ActionBarActivity)context).getSupportActionBar().setTitle(name);
答案 1 :(得分：1)
首先，您应该使用doInBackground方法执行所有耗时的操作。这还包括解析JSON数据。在onPreExecute和onPostExecute方法中，您只应该执行GUI操作。
请勿在{{1}}课程中直接使用活动或活动上下文。将侦听器与AsyncTask一起使用以更改GUI内容。例如：
WeakReference答案 2 :(得分：0)
定义一个静态的actvity实例，在excute()
public static ActionBarActivity instance = null;
：
onCreate(Bundle bundle){
GetBeerDataJSON2 task = new GetBeerDataJSON2() ;
task.instance = this;
task.excute();
}
另一个解决方法是将this作为context的{{1}}传递给GetBeerDataJSON2并将其投放到ActionBarActivity
无论如何，更好的方法是使用像volley这样的库来获取json而不是构建方向盘
答案 3 :(得分：0)
在Activity代码中创建GetBeerDataJSON2（Context，Stirng）实例时在构造函数中组合答案会将'this'作为第一个参数传递。
并将其视为：
((ActionBarActivity) context).getSupportActionBar().setTitle(name);
而不是：
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(name);
错误因为没有为AsynchTask定义getActivity（）方法。