Android 使用来自多个异步任务的接口
我有一个有多个微调器的有趣片段。第一个微调器根据所选内容将数据加载到第二个微调器中。它看起来像这样: 当片段第一次加载时,第一个微调器是“All”,它用所有啤酒填充listView。现在,这是我唯一可以单击项目而不强制关闭的listView。我的投资组合的代码是:Android 使用来自多个异步任务的接口,android,listview,android-fragments,interface,Android,Listview,Android Fragments,Interface,我有一个有多个微调器的有趣片段。第一个微调器根据所选内容将数据加载到第二个微调器中。它看起来像这样: 当片段第一次加载时,第一个微调器是“All”,它用所有啤酒填充listView。现在,这是我唯一可以单击项目而不强制关闭的listView。我的投资组合的代码是: public class Portfolio extends Fragment implements PortfolioGetAllBeers.OnArticleSelectedListener { String beer
public class Portfolio extends Fragment implements PortfolioGetAllBeers.OnArticleSelectedListener {
String beerId = "";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//set layout here
final View theLayout = inflater.inflate(R.layout.activity_portfolio, container, false);
setHasOptionsMenu(true);
getActivity().setTitle("Portfolio");
//get user information
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String userName = prefs.getString("userName", null);
String userID = prefs.getString("userID", null);
final Spinner portfolioType = (Spinner) theLayout.findViewById(R.id.portfolioSpinner);
portfolioType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String portfolioChoice = portfolioType.getSelectedItem().toString();
Log.d("portfolio", portfolioChoice);
if( portfolioChoice.equals("All")){
//todo: clear second spinner
LinearLayout ll = (LinearLayout) theLayout.findViewById(R.id.addSpinnerLayout);
ll.removeAllViews();
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
//construct url
String url = "myURL1";
//async task goes here
PortfolioGetAllBeers task = new PortfolioGetAllBeers(getActivity());
task.setOnArticleSelectedListener(Portfolio.this);
task.execute(url);
}
else if (portfolioChoice.equals("Brewery")){
LinearLayout ll = (LinearLayout) theLayout.findViewById(R.id.addSpinnerLayout);
ll.removeAllViews();
LayoutInflater inflater = (LayoutInflater)selectedItemView.getContext().getSystemService(selectedItemView.getContext().LAYOUT_INFLATER_SERVICE);
View v = inflater.inflate(R.layout.addspinner_layout, null); // inflate addspinner
Spinner sp = (Spinner) v.findViewById(R.id.portfolioSpinner2); //portfolioSpinner2
ll.addView(v); // add the view to the linear layout
//todo: get breweries and fill spinner
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
//construct url
String url = ""myurl2;
//async task goes here
PortfolioGetAllBeers task = new PortfolioGetAllBeers(getActivity());
task.setOnArticleSelectedListener(Portfolio.this);
task.execute(url);
}
else if (portfolioChoice.equals("Style")){
LinearLayout ll = (LinearLayout) theLayout.findViewById(R.id.addSpinnerLayout);
ll.removeAllViews();
LayoutInflater inflater = (LayoutInflater)selectedItemView.getContext().getSystemService(selectedItemView.getContext().LAYOUT_INFLATER_SERVICE);
View v = inflater.inflate(R.layout.addspinner_layout, null); // inflate addspinner
Spinner sp = (Spinner) v.findViewById(R.id.portfolioSpinner2); //portfolioSpinner2
ll.addView(v); // add the view to the linear layout
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
//construct url
String url = "myurl3";
//todo: async task goes here
new PortfolioGetAllStyles(selectedItemView.getContext()).execute(url);
}
else if (portfolioChoice.equals("Rating")){
LinearLayout ll = (LinearLayout) theLayout.findViewById(R.id.addSpinnerLayout);
ll.removeAllViews();
LayoutInflater inflater = (LayoutInflater)selectedItemView.getContext().getSystemService(selectedItemView.getContext().LAYOUT_INFLATER_SERVICE);
View v = inflater.inflate(R.layout.addspinner_layout, null); // inflate addspinner
Spinner sp = (Spinner) v.findViewById(R.id.portfolioSpinner2); //portfolioSpinner2
ll.addView(v); // add the view to the linear layout
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
//make array
//make array list for beer
final List<String> tasteList = new ArrayList<String>();
tasteList.add("1");
tasteList.add("2");
tasteList.add("3");
tasteList.add("4");
tasteList.add("5");
// Selection of the spinner
Spinner spinner = (Spinner) theLayout.findViewById(R.id.portfolioSpinner2);
// Application of the Array to the Spinner
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(selectedItemView.getContext(), android.R.layout.simple_spinner_item,tasteList );
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // The drop down view
spinner.setAdapter(spinnerArrayAdapter);
//todo: add on select for spinner 2
//add on item selected
final Spinner portfolioType = (Spinner) theLayout.findViewById(R.id.portfolioSpinner2);
portfolioType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String portfolioChoice = portfolioType.getSelectedItem().toString();
//Toast.makeText(((Activity) c).getApplicationContext(), portfolioChoice, Toast.LENGTH_LONG).show();
final ListView lv = (ListView) theLayout.findViewById(R.id.allYourBeersList);
lv.setAdapter(null);
//get brewery beers
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
try {
portfolioChoice = URLEncoder.encode(portfolioChoice, "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
//construct url
String url = "myurl4;
Log.d("portfolio" , url);
//async task goes here
new PortfolioGetAllBeers(selectedItemView.getContext()).execute(url);
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// do nothing
}
});
}
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// do nothing
}
});
// Inflate the layout for this fragment
return theLayout;
}
@Override
public void onArticleSelected(String bID, String brewery){
//code to execute on click
Fragment Fragment_one;
FragmentManager man= getFragmentManager();
FragmentTransaction tran = man.beginTransaction();
Fragment_one = new BeerPage();
final Bundle bundle = new Bundle();
bundle.putString("beerIDSent", bID);
bundle.putString("breweryIDSent", brewery);
Fragment_one.setArguments(bundle);
tran.replace(R.id.main, Fragment_one);//tran.
tran.addToBackStack(null);
tran.commit();
}
}
调用此异步任务以加载listview:
public class PortfolioGetAllBeers extends AsyncTask<String, Void, String> {
Context c;
private ProgressDialog Dialog;
public PortfolioGetAllBeers (Context context)
{
c = context;
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 beers");
Dialog.setTitle("Loading");
Dialog.setCancelable(false);
Dialog.show();
}
//***************************code for on click
OnArticleSelectedListener listener;
public interface OnArticleSelectedListener{
public void onArticleSelected(String myString , String brewery);
}
public void setOnArticleSelectedListener(OnArticleSelectedListener listener){
this.listener = listener;
}
//*****************************end code for onClick
protected void onPostExecute(String result){
//decode json here
try{
JSONArray jsonArray = new JSONArray(result);
//acces listview
ListView lv = (ListView) ((Activity) c).findViewById(R.id.allYourBeersList);
//make array list for beer
final List<ShortBeerInfo> tasteList = new ArrayList<ShortBeerInfo>();
for(int i = 0; i < jsonArray.length(); i++) {
String beer = jsonArray.getJSONObject(i).getString("beer");
String rate = jsonArray.getJSONObject(i).getString("rate");
String beerID = jsonArray.getJSONObject(i).getString("id");
String bID = jsonArray.getJSONObject(i).getString("breweryID");
//create object
ShortBeerInfo tempTaste = new ShortBeerInfo(beer, rate, beerID, bID);
//add to arraylist
tasteList.add(tempTaste);
}
//add items to listview
ShortBeerInfoAdapter adapter1 = new ShortBeerInfoAdapter(c ,R.layout.brewer_stats_listview, tasteList);
lv.setAdapter(adapter1);
//set up clicks
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
ShortBeerInfo o=(ShortBeerInfo)arg0.getItemAtPosition(arg2);
String tempID = o.id;
String tempBrewID = o.brewery;
//todo: go to beer page
listener.onArticleSelected(tempID, tempBrewID);
}
});
}
catch(Exception e){
}
Dialog.dismiss();
}
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();
}
}
在执行PortfolioGellaryStyles asyc任务时,我不确定如何将onclick设置为接口。PortfolioGetAllStyles的代码为:
public class PortfolioGetAllStyles extends AsyncTask<String, Void, String> {
Context c;
private ProgressDialog Dialog;
public PortfolioGetAllStyles (Context context)
{
c = context;
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 Brewery List");
Dialog.setTitle("Loading");
Dialog.setCancelable(false);
Dialog.show();
}
protected void onPostExecute(String result){
//decode json here
try{
JSONArray jsonArray = new JSONArray(result);
//acces listview
final ListView lv = (ListView) ((Activity) c).findViewById(R.id.allYourBeersList);
//make array list for beer
final List<String> tasteList = new ArrayList<String>();
for(int i = 0; i < jsonArray.length(); i++) {
String beer = jsonArray.getJSONObject(i).getString("style");
String bID = jsonArray.getJSONObject(i).getString("breweryID");
String rate = "na";
String beerID = "na";
//create object
ShortBeerInfo tempTaste = new ShortBeerInfo(beer, rate, beerID, bID);
//add to arraylist
tasteList.add(beer);
}
// Selection of the spinner
Spinner spinner = (Spinner) ((Activity) c).findViewById(R.id.portfolioSpinner2);
// Application of the Array to the Spinner
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(c, android.R.layout.simple_spinner_item,tasteList );
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // The drop down view
spinner.setAdapter(spinnerArrayAdapter);
//add on item selected
final Spinner portfolioType = (Spinner) ((Activity) c).findViewById(R.id.portfolioSpinner2);
portfolioType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String portfolioChoice = portfolioType.getSelectedItem().toString();
//Toast.makeText(((Activity) c).getApplicationContext(), portfolioChoice, Toast.LENGTH_LONG).show();
lv.setAdapter(null);
//get brewery beers
//get userID
//get user data
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(selectedItemView.getContext());
String userID = prefs.getString("userID", null);
try {
portfolioChoice = URLEncoder.encode(portfolioChoice, "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
//construct url
String url = "http://beerportfolio.com/app_getAllYourBeersStyle.php?u=" + userID + "&b=" + portfolioChoice;
Log.d("portfolio", url);
//async task goes here
new PortfolioGetAllBeers(selectedItemView.getContext()).execute(url);
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// do nothing
}
});
}
catch(Exception e){
}
Dialog.dismiss();
}
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();
}
}
简言之我想我需要让这些行工作起来,将公文包页面中的OnSelectedListener绑定到这个异步任务:
PortfolioGetAllBeers task = new PortfolioGetAllBeers(c);
task.setOnArticleSelectedListener(Portfolio.this);
task.execute(url);
我只是无法将Portfolio.this传递到该行,因为我们不在Portfolio中,而是从它启动了另一个异步任务 在这一行中:
new PortfolioGetAllBeers(selectedItemView.getContext()).execute(url);
您正在创建和触发异步任务,而不设置侦听器。因此,您应该执行以下操作之一:
始终在执行创建的异步任务之前设置侦听器
在调用侦听器之前,请检查其是否不为null:
if(listener != null){
listener.onArticleSelected(tempID, tempBrewID);
}
你能指出这一行吗:PortfolioGetAllBeers.java:114?这是这一行:listener.onArticleSelected(tempID,tempBrewID);这是因为我没有在这个异步任务中设置task.SetOnArticleSelectedListener。这个问题最初帮助我解决了一个问题,但并非在所有情况下都是这样:如何设置侦听器。我正在尝试设置它如果您在内部类中设置它,您可以使用这样的构造:setListener(Portfolio.this)liek this:setListener(Portfolio.this).onArticleSelected(tempID,tempBrewID);我不知道该怎么做?不,就像PortfolioGetAllBears任务=新PortfolioGetAllBeers(…);task.setListener(Portfolio.this);task.execute();这不起作用,下面是我的新代码,其中包含该更改和两个错误:
PortfolioGetAllBeers task = new PortfolioGetAllBeers(c);
task.setOnArticleSelectedListener(Portfolio.this);
task.execute(url);
new PortfolioGetAllBeers(selectedItemView.getContext()).execute(url);
if(listener != null){
listener.onArticleSelected(tempID, tempBrewID);
}