问题
I have some problem about setting and getting id from data that showed with volley JSon array request.
I've tried to do this, but it fail.
ChildTidur.java
public class ChildTidur extends AppCompatActivity implements TidurAdapter.ContactsAdapterListener {
private static final String TAG = ChildTidur.class.getSimpleName();
private RecyclerView recyclerView;
private List<Story> storyList;
private TidurAdapter mAdapter;
private SearchView searchView;
private TextView noFavtsTV;
private AppPreferences appPreferences;
// CONNECTION_TIMEOUT and READ_TIMEOUT are in milliseconds
public static final int CONNECTION_TIMEOUT = 2000;
public static final int READ_TIMEOUT = 2000;
final String KEY_SAVED_RADIO_BUTTON_INDEX = "SAVED_RADIO_BUTTON_INDEX";
// url to fetch contacts json
private static final String URL = "https://api.kafeinkode.com/childtidur.json";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.child_tidur);
AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);
SwipeRefreshLayout pullToRefresh = findViewById(R.id.pullToRefresh);
pullToRefresh.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
finish();
startActivity(getIntent());
}
});
//toolbar logo and desc
Toolbar topToolBar = (Toolbar) findViewById(R.id.toolbarTidur);
setSupportActionBar(topToolBar); //munculkan menu ke toolbar
getSupportActionBar().setDisplayHomeAsUpEnabled(true); //this line shows back button
recyclerView = findViewById(R.id.recycler_view);
noFavtsTV = findViewById(R.id.no_favt_text);
storyList = new ArrayList<>();
mAdapter = new TidurAdapter(this, storyList, this, appPreferences);
// white background notification bar
whiteNotificationBar(recyclerView);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.addItemDecoration(new TidurDekor(this, DividerItemDecoration.VERTICAL, 36));
recyclerView.setAdapter(mAdapter);
//Make call to AsyncTask
new AsyncLogin().execute();
//Get radio button value
LoadPreferences();
} //OnCreate
private void showNoFavtText(boolean show) {
noFavtsTV.setVisibility(show ? View.VISIBLE : View.GONE); //jika data yang ditampilkan tidak ada, maka show noFavsTv
recyclerView.setVisibility(show ? View.GONE : View.VISIBLE); //jika data yang ditampilkan tidak ada, maka don't show rV
}
private void LoadPreferences(){
LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View contentView = inflater.inflate(R.layout.activity_settings, null,false);
RadioGroup radioGroup = (RadioGroup)contentView.findViewById(R.id.radioSex);
SharedPreferences sharedPreferences = getSharedPreferences("MY_SHARED_PREF", MODE_PRIVATE);
int savedRadioIndex = sharedPreferences.getInt(KEY_SAVED_RADIO_BUTTON_INDEX, 0);
RadioButton savedCheckedRadioButton = (RadioButton)radioGroup.getChildAt(savedRadioIndex);
savedCheckedRadioButton.setChecked(true);
RadioGroup genderGroup = (RadioGroup) contentView.findViewById(R.id.radioSex);
RadioButton male = (RadioButton) contentView.findViewById(R.id.theme1);
RadioButton female = (RadioButton) contentView.findViewById(R.id.theme2);
if (genderGroup.getCheckedRadioButtonId() == -1) {
Toolbar tb = (Toolbar) findViewById(R.id.toolbarTidur);
tb.setBackgroundColor(getResources().getColor(R.color.colorPrimaryDark));
}
else {
if (male.isChecked()) { // one of the radio buttons is checked
Toolbar tb1 = (Toolbar) findViewById(R.id.toolbarTidur);
tb1.setBackgroundColor(getResources().getColor(R.color.colorPrimaryDark));
}
else if (female.isChecked()) {
Toolbar tb2 = (Toolbar) findViewById(R.id.toolbarTidur);
tb2.setBackgroundColor(getResources().getColor(R.color.colorAccent));
}
}
}
private class AsyncLogin extends AsyncTask<String, String, String> {
ProgressDialog pdLoading = new ProgressDialog(ChildTidur.this);
HttpURLConnection conn;
java.net.URL url = null;
@Override
protected void onPreExecute() {
super.onPreExecute();
//this method will be running on UI thread
showNoFavtText(false);
pdLoading.setMessage("\tMencoba terhubung ke internet...");
pdLoading.setCancelable(false);
pdLoading.show();
}
@Override
protected String doInBackground(String... params) {
try {
// Enter URL address where your json file resides
// Even you can make call to php file which returns json data
url = new URL("https://api.kafeinkode.com/childtidur.json");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return e.toString();
}
try {
// Setup HttpURLConnection class to send and receive data from php and mysql
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(READ_TIMEOUT);
conn.setConnectTimeout(CONNECTION_TIMEOUT);
conn.setRequestMethod("GET");
// setDoOutput to true as we recieve data from json file
conn.setDoOutput(true);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
return e1.toString();
}
try {
int response_code = conn.getResponseCode();
// Check if successful connection made
if (response_code == HttpURLConnection.HTTP_OK) {
// Read data sent from server
InputStream input = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
StringBuilder result = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
// Pass data to onPostExecute method
return (result.toString());
} else {
return("koneksi gagal");
}
} catch (IOException e) {
e.printStackTrace();
return e.toString();
} finally {
conn.disconnect();
}
}
/**
* fetches json by making http calls
*/
protected void onPostExecute(String result) {
JsonArrayRequest request = new JsonArrayRequest(URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
pdLoading.dismiss();
Log.d(TAG, response.toString());
if (response.length() > 0) {
// Parsing json
List<Story> items = new Gson().fromJson(response.toString(), new TypeToken<List<Story>>() {
}.getType());
// adding contacts to contacts list
storyList.clear();
storyList.addAll(items);
// refreshing recycler view
mAdapter.notifyDataSetChanged();
for (int i=0; i<storyList.size(); i++) {
Story story = new Story();
story.setIdStory(String.valueOf(i));
}
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
pdLoading.dismiss();
// error in getting json
Log.e(TAG, "Error: " + error.getMessage());
Toast.makeText(getApplicationContext(), "Tidak bisa menampilkan data. Periksa kembali sambungan internet Anda", Toast.LENGTH_LONG).show();
AlertDialog alertDialog = new AlertDialog.Builder(ChildTidur.this).create();
alertDialog.setTitle("Error");
alertDialog.setMessage("Data Tidak bisa ditampilkan. Periksa kembali sambungan internet Anda");
alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
alertDialog.show();
showNoFavtText(true);
}
});
TidurSearch.getInstance().addToRequestQueue(request);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.search_tidur, menu);
getMenuInflater().inflate(R.menu.menu_main, menu);
// Associate searchable_tidur configuration with the SearchView
SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
searchView = (SearchView) menu.findItem(R.id.action_search2).getActionView();
searchView.setSearchableInfo(searchManager
.getSearchableInfo(getComponentName()));
searchView.setMaxWidth(Integer.MAX_VALUE);
// listening to search query text change
searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String query) {
// filter recycler view when query submitted
mAdapter.getFilter().filter(query);
return false;
}
@Override
public boolean onQueryTextChange(String query) {
// filter recycler view when text is changed
mAdapter.getFilter().filter(query);
return false;
}
});
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_search2) {
return true;
}
//Menu
if (id == R.id.action_settings) {
startActivity(new Intent(this, SettingsActivity.class));
return true;
}
else
if (id == R.id.about_us) {
startActivity(new Intent(this, AboutUs.class));
return true;
}
else
if (id == R.id.favlist) {
startActivity(new Intent(this, ShowFavouriteList.class));
return true;
}
switch (item.getItemId()) {
case android.R.id.home:
this.finish();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onBackPressed() {
// close search view on back button pressed
if (!searchView.isIconified()) {
searchView.setIconified(true);
return;
}
super.onBackPressed();
}
private void whiteNotificationBar(View view) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
int flags = view.getSystemUiVisibility();
flags |= View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR;
view.setSystemUiVisibility(flags);
getWindow().setStatusBarColor(Color.WHITE);
}
}
@Override
public void onContactSelected(Story story) {
Toast.makeText(getApplicationContext(), "Selected: " + story.getName(), Toast.LENGTH_LONG).show();
}
}
TidurAdapter.java
public void onClick(View view) {
// Another problem lays here when I get id of data
Story story = storyList.get(getLayoutPosition());
int ambilId = Integer.parseInt(story.getIdStory());
if ( 0 == ambilId ) {
Intent myIntent = new Intent(view.getContext(), DoaMauTidur.class);
view.getContext().startActivity(myIntent);
}
else if ( 1 == getAdapterPosition() )
{
Intent myIntent = new Intent(view.getContext(), DoaBangunt.class);
view.getContext().startActivity(myIntent);
}
else if ( 2 == getAdapterPosition() )
{
Intent myIntent = new Intent(view.getContext(), DoaJimak.class);
view.getContext().startActivity(myIntent);
}
}
This is a full code:
Story.java
public Story(){}
String name;
String nomor;
private String idStory;
private int isLiked;
public String getName() {
return name;
}
public String getNomor() { return nomor; }
public void setIdStory(String isStory) {
this.idStory = isStory;
}
public String getIdStory() {
return idStory;
}
public void setIsLiked(int isLiked) {
this.isLiked = isLiked;
}
public int getIsLiked() {
return isLiked;
}
}
ChildTidur.java
/**
* fetches json by making http calls
*/
protected void onPostExecute(String result) {
JsonArrayRequest request = new JsonArrayRequest(URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
pdLoading.dismiss();
Log.d(TAG, response.toString());
if (response.length() > 0) {
// Parsing json
List<Story> items = new Gson().fromJson(response.toString(), new TypeToken<List<Story>>() {
}.getType());
// adding contacts to contacts list
storyList.clear();
storyList.addAll(items);
// refreshing recycler view
mAdapter.notifyDataSetChanged();
for (int i=0; i<storyList.size(); i++) {
Story story = new Story();
story.setIdStory(String.valueOf(i));
}
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
pdLoading.dismiss();
// error in getting json
Log.e(TAG, "Error: " + error.getMessage());
Toast.makeText(getApplicationContext(), "Tidak bisa menampilkan data. Periksa kembali sambungan internet Anda", Toast.LENGTH_LONG).show();
AlertDialog alertDialog = new AlertDialog.Builder(ChildTidur.this).create();
alertDialog.setTitle("Error");
alertDialog.setMessage("Data Tidak bisa ditampilkan. Periksa kembali sambungan internet Anda");
alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
alertDialog.show();
showNoFavtText(true);
}
});
TidurSearch.getInstance().addToRequestQueue(request);
}
}
TidurAdapter.java
public class TidurAdapter extends RecyclerView.Adapter<TidurAdapter.TidurViewHolder> implements Filterable {
private Context context;
private List<Story> storyList;
private List<Story> storyListFiltered;
private ContactsAdapterListener listener;
private int changedItemPosition;
public boolean isLiked;
private AppPreferences appPreferences;
Boolean checked = false;
public TidurAdapter(Context context, List<Story> storyList, ContactsAdapterListener listener, AppPreferences appPreferences) {
this.context = context;
this.listener = listener;
this.storyList = storyList;
this.storyListFiltered = storyList;
this.appPreferences = appPreferences;
}
@Override
public TidurViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.child_row_item_tidur, parent, false);
return new TidurViewHolder(itemView);
}
@Override
public void onBindViewHolder(@NonNull TidurViewHolder holder, int position) {
final Story story = storyListFiltered.get(position);
holder.name.setText(story.getName());
holder.nomor.setText(story.getNomor());
holder.setViewData(storyList.get(position), holder.getAdapterPosition());
}
@Override
public int getItemCount() {
return storyListFiltered.size();
}
public interface ContactsAdapterListener {
void onContactSelected(Story story);
}
//ViewHolder
public class TidurViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public TextView nomor;
public ImageView mFavorite;
private CheckBox likeCheckBox;
final String KEY_SAVED_RADIO_BUTTON_INDEX = "SAVED_RADIO_BUTTON_INDEX";
public TidurViewHolder(View view) {
super(view);
name = view.findViewById(R.id.name);
nomor = view.findViewById(R.id.nomor);
likeCheckBox = itemView.findViewById(R.id.like_button_cb);
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// get id of data
Story story = storyList.get(getLayoutPosition());
int ambilId = Integer.parseInt(story.getIdStory());
if ( 0 == ambilId ) {
Intent myIntent = new Intent(view.getContext(), DoaMauTidur.class);
view.getContext().startActivity(myIntent);
}
else if ( 1 == getAdapterPosition() )
{
Intent myIntent = new Intent(view.getContext(), DoaBangunt.class);
view.getContext().startActivity(myIntent);
}
else if ( 2 == getAdapterPosition() )
{
Intent myIntent = new Intent(view.getContext(), DoaJimak.class);
view.getContext().startActivity(myIntent);
}
}
});
//Get radio button value
LayoutInflater inflater = (LayoutInflater) view.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View cV = inflater.inflate(R.layout.activity_settings, null,false);
RadioGroup radioGroup = (RadioGroup)cV.findViewById(R.id.radioSex);
SharedPreferences sharedPreferences = view.getContext().getSharedPreferences("MY_SHARED_PREF", Activity.MODE_PRIVATE);
int savedRadioIndex = sharedPreferences.getInt(KEY_SAVED_RADIO_BUTTON_INDEX, 0);
RadioButton savedCheckedRadioButton = (RadioButton)radioGroup.getChildAt(savedRadioIndex);
savedCheckedRadioButton.setChecked(true);
RadioGroup genderGroup = (RadioGroup) cV.findViewById(R.id.radioSex);
RadioButton male = (RadioButton) cV.findViewById(R.id.theme1);
RadioButton female = (RadioButton) cV.findViewById(R.id.theme2);
if (genderGroup.getCheckedRadioButtonId() == -1) {
nomor.setBackgroundColor(view.getResources().getColor(R.color.colorPrimaryDark));
} else {
if (male.isChecked()) { // one of the radio buttons is checked
nomor.setBackgroundDrawable(ContextCompat.getDrawable(view.getContext(), R.drawable.rounded_drawable));
}
else if (female.isChecked()) {
nomor.setBackgroundDrawable(ContextCompat.getDrawable(view.getContext(), R.drawable.rounded_drawable_red));
}
}
} //TidurViewHolder(View view)
public void setViewData(final Story story, final int adapterPosition) {
if (story.getIsLiked() == 1) {
likeCheckBox.setChecked(true);
}
else {
likeCheckBox.setChecked(false);
}
likeCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
changedItemPosition = adapterPosition;
if (buttonView.isPressed()) {
if (isChecked) {
isLiked = true;
updateLikes();
appPreferences.saveFavouriteCard(story);
Toast.makeText(context, "Saved", Toast.LENGTH_SHORT).show();
}
else {
isLiked = false;
updateLikes();
appPreferences.deleteCard(story.getIdStory());
Toast.makeText(context, "Removed", Toast.LENGTH_SHORT).show();
}
}
}
});
} //setviewdata
public void updateLikes() {
if (isLiked && storyList.get(changedItemPosition).getIsLiked() == 0) { //jika dilakukan like (pada posisi hati kosong) di halaman home
storyList.get(changedItemPosition).setIsLiked(1); //maka jadikan hati berwarna merah di halaman favourite list
notifyItemChanged(changedItemPosition, ACTION_LIKE_IMAGE_CLICKED);
}
else if (!isLiked && storyList.get(changedItemPosition).getIsLiked() == 1) { //jika like dicabut (pada posisi hati yang sedang merah) di halaman home
storyList.get(changedItemPosition).setIsLiked(0); //maka cabut juga warna merah di halaman favourite list
notifyItemChanged(changedItemPosition, ACTION_LIKE_IMAGE_CLICKED);
}
} //updateLikes
}//Class TidurViewHolder
}
The error result is, it is showing null... Which mean no ID that can be obtained.
回答1:
In your for loop you are not setting id of your List, but your new Story.
Instead of:
for (int i=0; i<storyList.size(); i++) {
Story story = new Story();
story.setIdStory(String.valueOf(i));
}
Use this:
for (int i=0; i<storyList.size(); i++) {
storyList.get(i).setIdStory(String.valueOf(i));
}
Also because your index i=0 starts from zero, you should change for loop index i to start from 1 like this:
for (int i=1; i<=storyList.size(); i++) {
storyList.get(i).setIdStory(String.valueOf(i));
}
Check this main activity:
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
// CONNECTION_TIMEOUT and READ_TIMEOUT are in milliseconds
private ArrayList<Story> storyList;
// url to fetch contacts json
private static final String URL = "https://api.kafeinkode.com/childtidur.json";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
storyList = new ArrayList<>();
//Fetch JSON data
fetchData();
}
private void fetchData(){
JsonArrayRequest request = new JsonArrayRequest(URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
if (response.length() > 0) {
// Parsing json
List<Story> items = new Gson().fromJson(response.toString(), new TypeToken<List<Story>>() {}.getType());
// adding contacts to contacts list
storyList.clear();
storyList.addAll(items);
for (int i=0; i<storyList.size(); i++) {
storyList.get(i).setIdStory(String.valueOf(i + 1));
}
Log.d("StoryLid: ", storyList.toString());
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// error in getting json
Log.e(TAG, "Error: " + error.getMessage());
}
});
VolleyService.getInstance(this).getRequestQueue().add(request);
}
}
As a result you have response:
来源：https://stackoverflow.com/questions/56739408/how-do-we-set-id-for-data-that-showed-with-volley-json-array-request