Develop Reference

Current value of EditText not being passed to a function from onCreate()

I am building an android app that displays the COVID19 statistics for India, I am getting the stats in JSON format from https://api.covid19india.org/data.json , this API contains data of individual states too,
Below is the snip of Json array(contains json objects representing each state) that i am requesting
as of Now i am displaying the entire data ( all states ) at a time on my screen, However i want to give the state name as the input and display the stats of only that state For eg. in the below image in place of sample i want to write a state name and the stats of that state must be displayed on click of the button.
Here is the code of mainActivity.java, I am using Volley Library for fetching data from API
public class MainActivity extends AppCompatActivity {
private TextView result;
private RequestQueue mq;
public String value;
int flag = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
result = findViewById(R.id.textView4);
Button parse = findViewById(R.id.button);
mq = Volley.newRequestQueue(this);
EditText text = (EditText)findViewById(R.id.state_ip);
value = text.getText().toString();
parse.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
jsonParse(value);
**//How do i pass 'value' i.e the state name entered by user to jsonParse**
}
});
}
private void jsonParse(final String value) {
Log.d("val_state",value);
String url = "https://api.covid19india.org/data.json";
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("statewise");
for (int i = 0; i < jsonArray.length(); i++)
{
JSONObject st = jsonArray.getJSONObject(i);
String statename = st.getString("state");
String active = st.getString("active");
String confirmed = st.getString("confirmed");
String deaths = st.getString("deaths");
String recovered = st.getString("recovered");
if(statename.equals(value))
{
flag= 1;
}
statename = "State : " + statename;
active = "Active Cases : " + active;
confirmed = "Confirmed Cases : " + confirmed;
deaths = "Total Deaths : " + deaths;
recovered = "Total Recovered : " + recovered;
if(flag==1)
{
flag=0;
result.append(statename + "\n" + String.valueOf(active) + "\n" + String.valueOf(confirmed) + "\n" + String.valueOf(deaths) + "\n" + String.valueOf(recovered) + "\n\n\n");
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
mq.add(request);
}
}
Here , i want to pass the value of state entered by the user to the method jsonParse() so that i check the state name with the received JSON data and append it to the TextView, but when i do this , and try to log the value inside the jsonParse() method i get nothing, why is this happening , How do i implement the above ?

Your EditText value is update and has to be captured after the button is clicked.
parse.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
value = text.getText().toString();
jsonParse(value);
}
});

Correct way of getting a Json position

After the login I get this response from the webserver..
{"success":" Bem vindo lu#lu.com"}{"nomeusuario":"Lu Zimermann"}{"enderecousuario":"Rua Pedro Alves 270. Centro. Casa."}{"telefoneusuario":"(42) 3623-8052"}
Ok. Now My android code.
loginButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
request = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
JSONObject jsonObject = new JSONObject(response);
if(jsonObject.names().get(0).equals("success")){
Toast.makeText(getApplicationContext(),jsonObject.getString("success"),Toast.LENGTH_SHORT).show();
//startActivity(new Intent(getApplicationContext(),Restaurantes.class));
}else {
Toast.makeText(getApplicationContext(), jsonObject.getString("error"), Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
This code Toast the following message. "Bem vindo lu#lu.com"
What I want is:
How can I get the other infos and pass it to a String.
Email = "lu#lu.com"
Endereco = "Rua Pedro..."
Name = "Lu Zimermann"
Soo I can use it later on the app.
Thanks.

Now the response is the right way you can do this to save data..
first wirte a custion class for Preferennce
SharedPreferenceCustom
public class SharedPreferenceCustom {
private Context mContext;
private String defValue = "";
public SharedPreferenceCustom(Context context) {
this.mContext = context;
}
public void setSharedPref(String inputKey, Object inputValue) {
final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(inputKey, String.valueOf(inputValue));
editor.apply();
}
public String getSharedPref(String inputKey) {
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
return sharedPreferences.getString(inputKey, defValue);
}
}
Now for saving the data, in the activity
try {
JSONObject response = new JSONObject(new String(response_from_server))
SharedPreferenceCustom sp = new SharedPreferenceCustom(Activity.this);
sp.setSharedPref("key_1", response.getString("nomeusuario")); // use key as per needed
sp.setSharedPref("key_2", response.getString("enderecousuario"));
sp.setSharedPref("key_3", response.getString("telefoneusuario"));
sp.setSharedPref("key_4", response.getString("success"));
} catch (JSONException e) {
e.printStackTrace();
}
And for getting the data call sp.getSharedPref("key"); pass the key for getting the corresponding data
EDIT: you can also write individual function in SharedPreferenceCustion to store different data type, or you can use just this, But it might create some conflicts for certain data types,
Hope this helps :) :)

To get access to the other keys, you can use the get(key) on the jsonObject object. Here are the code changes you need to make:
try {
JSONObject jsonObject = new JSONObject(response);
if(jsonObject.names().get(0).equals("success")){
Toast.makeText(getApplicationContext(),jsonObject.getString("success"),Toast.LENGTH_SHORT).show();
{"success":" Bem vindo lu#lu.com"}{"nomeusuario":"Lu Zimermann"}{"enderecousuario":"Rua Pedro Alves 270. Centro. Casa."}{"telefoneusuario":"(42) 3623-8052"}
//here I am just getting the other properties/keys
String nomeusuario = jsonObject.getString("nomeusuario");
String enderecousuario = jsonObject.getString("enderecousuario");
String telefoneusuario = jsonObject.getString("telefoneusuario");
//here you could do whatever you like - I am just making a Toast as an example:
Toast.makeText(getApplicationContext(), nomeusuario+ ", "+enderecousuario+ ", "+telefoneusuario ,Toast.LENGTH_LONG).show();
}else {
Toast.makeText(getApplicationContext(), jsonObject.getString("error"), Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
I hope this helps you - give it a try and let me know.
By the way, I am assuming the JSON that you are getting is proper.

There are several ways you can do that.
First of all you need to store them into variable/s.
You can choose to keep it as JSON var, as HashMap or each variable separate as String.
The second action is to access it from any place. This depends on how long to you want the information alive.
If you want them live for just as long as the app is live then the I suggest to create a Global Java class with set/get of your variable.
You could also store it in SharedPreferences or sqlite database for permanent.

Try following
loginButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
request = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
if(jsonObject.names().get(0).equals("success")){
//Toast.makeText(getApplicationContext(),jsonObject.getString("success"),Toast.LENGTH_SHORT).show();
JSONObject jsonObject = new JSONObject(response);
Iterator<String> keys = jsonObject.keys();
String values = "";
while(keys.hasNext()){
String keyName = keys.next();
values = jsonObject.getString(keyName) + "\n";
}
Toast.makeText(getApplicationContext(),values,Toast.LENGTH_SHORT).show();
//startActivity(new Intent(getApplicationContext(),Restaurantes.class));
}else {
Toast.makeText(getApplicationContext(), jsonObject.getString("error"), Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}

Getting Nested JsonObjects & Arrays Using Retrofit Library

I got tired using this library, this is my first time using it and made a lot of success ways, but i'm a bit confused in getting the following Json :
{
"Guides":
{
"English": {"ArabicSony":"Test1","ArabicNexus":"Test2","ArabicSamsung":"Test3","ArabicHTC":"Test4"}
,"Arabic": {"EnglishSony":"Test1","EnglishNexus":"Test2","EnglishSamsung":"Test3","EnglishHTC":"Test4"}
}
}
Googled and saw a lot of guides and answered, and made my List like this :
public class PostItem {
List<PostItemArabic> Arabic;
List<PostItemEnglish> English;
}
class PostItemArabic{
private String ArabicSony;
private String ArabicNexus;
private String ArabicSamsung;
private String ArabicHTC;
public String getArabicSony() {
return ArabicSony;
}
public void setArabicSony(String arabicSony) {
ArabicSony = arabicSony;
}
public String getArabicNexus() {
return ArabicNexus;
}
public void setArabicNexus(String arabicNexus) {
ArabicNexus = arabicNexus;
}
public String getArabicSamsung() {
return ArabicSamsung;
}
public void setArabicSamsung(String arabicSamsung) {
ArabicSamsung = arabicSamsung;
}
public String getArabicHTC() {
return ArabicHTC;
}
public void setArabicHTC(String arabicHTC) {
ArabicHTC = arabicHTC;
}
}
class PostItemEnglish{
private String EnglishSony;
private String EnglishNexus;
private String EnglishSamsung;
private String EnglishHTC;
public String getEnglishSony() {
return EnglishSony;
}
public void setEnglishSony(String englishSony) {
EnglishSony = englishSony;
}
public String getEnglishNexus() {
return EnglishNexus;
}
public void setEnglishNexus(String englishNexus) {
EnglishNexus = englishNexus;
}
public String getEnglishSamsung() {
return EnglishSamsung;
}
public void setEnglishSamsung(String englishSamsung) {
EnglishSamsung = englishSamsung;
}
public String getEnglishHTC() {
return EnglishHTC;
}
public void setEnglishHTC(String englishHTC) {
EnglishHTC = englishHTC;
}
}
My Model :
private class Model {
private List<PostItem> Guides;
public List<PostItem> getGuides() {
return Guides;
}
public void setGuides(List<PostItem> roms_center) {
this.Guides = roms_center;
}
}
And printing the result like this :
List<PostItem> Guides = response.body().getGuides();
for(int i = 0 ; i < Guides.size() ; i ++ ) {
for (int b = 0; b < Guides.get(i).English.size() ; b++){
Log.LogInfo("English Result Is: " + Guides.get(i).English.get(i).getEnglishHTC());
Log.LogInfo("English Result Is: " + Guides.get(i).English.get(i).getEnglishNexus());
Log.LogInfo("English Result Is: " + Guides.get(i).English.get(i).getEnglishSamsung());
Log.LogInfo("English Result Is: " + Guides.get(i).English.get(i).getEnglishSony());
}
for (int b = 0; b < Guides.get(i).Arabic.size() ; b++){
Log.LogInfo("Arabic Result Is: " + Guides.get(i).Arabic.get(i).getArabicHTC());
Log.LogInfo("Arabic Result Is: " + Guides.get(i).Arabic.get(i).getArabicNexus());
Log.LogInfo("Arabic Result Is: " + Guides.get(i).Arabic.get(i).getArabicSamsung());
Log.LogInfo("Arabic Result Is: " + Guides.get(i).Arabic.get(i).getArabicSony());
}
}
My work isn't correct, and getting a lot of errors,
Here's the last error i got :
`Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 3 column 18 path $.Guides
What's the way to make it correct ? `

Based on your models when you try to get the guides list your telling retrofit to populate an array. Retrofit is then getting the data and finding that it is a single object and not array. So you need to update your model to reflect the data returned. For example:
class PostItem {
List<Language> mLanguages;
}
class Language{
String mLanguageTitle; //for example english
List<String> mData; //for this is your list of data
}
Then in your activity instead of getting guides you would get just a post item for example:
response.body().getPostItem();
Hope it helps !

First of all, you can use the retrofit Gson library.
You can handle this in two ways:
Option 1: reformat your languages in your json to be an array like Doug says.
{
"Guides":
[
{"Lang":"English","ArabicSony":"Test1","ArabicNexus":"Test2","ArabicSamsung":"Test3","ArabicHTC":"Test4"}
, {"Lang":"Arabic","EnglishSony":"Test1","EnglishNexus":"Test2","EnglishSamsung":"Test3","EnglishHTC":"Test4"}
]
}
Then you will need to redesign your class to reflect this structure.
Like Doug sayd:
class PostItem {
List<Language> mLanguages;
}
Option 2: Create a custom json desirializer in your class. this will take the Json and break it down into whatever structure you want it to be.
public class PostItem implements JsonDeserializer
#Override
public MyDesirializer deserialize(JsonElement json, Type type,
JsonDeserializationContext context) throws JsonParseException {
JsonObject jarabic = (JsonObject) json.get("Arabic");
//whatever manipulations you want to do (fill with your own code)
PostItem item = new PostItem();
item.arabic = jarabic;
...
...
return item;
}

How to store class object in android sharedPreference?

I would like to store class object in android sharedpreference. I did some basic search on that and I got some answers like make it serializable object and store it but my need is so simple. I would like to store some user info like name, address, age and boolean value is active. I made one user class for that.
public class User {
private String name;
private String address;
private int age;
private boolean isActive;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public boolean isActive() {
return isActive;
}
public void setActive(boolean isActive) {
this.isActive = isActive;
}
}
Thanks.

Download gson-1.7.1.jar from this link: GsonLibJar
Add this library to your android project and configure build path.
Add the following class to your package.
package com.abhan.objectinpreference;
import java.lang.reflect.Type;
import android.content.Context;
import android.content.SharedPreferences;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
public class ComplexPreferences {
private static ComplexPreferences complexPreferences;
private final Context context;
private final SharedPreferences preferences;
private final SharedPreferences.Editor editor;
private static Gson GSON = new Gson();
Type typeOfObject = new TypeToken<Object>(){}
.getType();
private ComplexPreferences(Context context, String namePreferences, int mode) {
this.context = context;
if (namePreferences == null || namePreferences.equals("")) {
namePreferences = "abhan";
}
preferences = context.getSharedPreferences(namePreferences, mode);
editor = preferences.edit();
}
public static ComplexPreferences getComplexPreferences(Context context,
String namePreferences, int mode) {
if (complexPreferences == null) {
complexPreferences = new ComplexPreferences(context,
namePreferences, mode);
}
return complexPreferences;
}
public void putObject(String key, Object object) {
if (object == null) {
throw new IllegalArgumentException("Object is null");
}
if (key.equals("") || key == null) {
throw new IllegalArgumentException("Key is empty or null");
}
editor.putString(key, GSON.toJson(object));
}
public void commit() {
editor.commit();
}
public <T> T getObject(String key, Class<T> a) {
String gson = preferences.getString(key, null);
if (gson == null) {
return null;
}
else {
try {
return GSON.fromJson(gson, a);
}
catch (Exception e) {
throw new IllegalArgumentException("Object stored with key "
+ key + " is instance of other class");
}
}
} }
Create one more class by extending Application class like this
package com.abhan.objectinpreference;
import android.app.Application;
public class ObjectPreference extends Application {
private static final String TAG = "ObjectPreference";
private ComplexPreferences complexPrefenreces = null;
#Override
public void onCreate() {
super.onCreate();
complexPrefenreces = ComplexPreferences.getComplexPreferences(getBaseContext(), "abhan", MODE_PRIVATE);
android.util.Log.i(TAG, "Preference Created.");
}
public ComplexPreferences getComplexPreference() {
if(complexPrefenreces != null) {
return complexPrefenreces;
}
return null;
} }
Add that application class in your manifest's application tag like this.
<application android:name=".ObjectPreference"
android:allowBackup="false"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
....your activities and the rest goes here
</application>
In Your Main Activity where you wanted to store value in Shared Preference do something like this.
package com.abhan.objectinpreference;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends Activity {
private final String TAG = "MainActivity";
private ObjectPreference objectPreference;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
objectPreference = (ObjectPreference) this.getApplication();
User user = new User();
user.setName("abhan");
user.setAddress("Mumbai");
user.setAge(25);
user.setActive(true);
User user1 = new User();
user1.setName("Harry");
user.setAddress("London");
user1.setAge(21);
user1.setActive(false);
ComplexPreferences complexPrefenreces = objectPreference.getComplexPreference();
if(complexPrefenreces != null) {
complexPrefenreces.putObject("user", user);
complexPrefenreces.putObject("user1", user1);
complexPrefenreces.commit();
} else {
android.util.Log.e(TAG, "Preference is null");
}
}
}
In another activity where you wanted to get the value from Preference do something like this.
package com.abhan.objectinpreference;
import android.app.Activity;
import android.os.Bundle;
public class SecondActivity extends Activity {
private final String TAG = "SecondActivity";
private ObjectPreference objectPreference;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
objectPreference = (ObjectPreference) this.getApplication();
ComplexPreferences complexPreferences = objectPreference.getComplexPreference();
android.util.Log.i(TAG, "User");
User user = complexPreferences.getObject("user", User.class);
android.util.Log.i(TAG, "Name " + user.getName());
android.util.Log.i(TAG, "Address " + user.getAddress());
android.util.Log.i(TAG, "Age " + user.getAge());
android.util.Log.i(TAG, "isActive " + user.isActive());
android.util.Log.i(TAG, "User1");
User user1 = complexPreferences.getObject("user", User.class);
android.util.Log.i(TAG, "Name " + user1.getName());
android.util.Log.i(TAG, "Address " + user1.getAddress());
android.util.Log.i(TAG, "Age " + user1.getAge());
android.util.Log.i(TAG, "isActive " + user1.isActive());
} }
Hope this can help you. In this answer I used your class for the reference 'User' so you can better understand. However we can not relay on this method if you opted to store very large objects in preference as we all know that we have limited memory size for each app in data directory so that if you are sure you have only limited data to store in shared preference you can use this alternative.
Any suggestions on this implement are most welcome.

the other way is to save each property by itself..Preferences accept only primitive types, so you can't put a complex Object in it

You can use the global class
public class GlobalState extends Application
{
private String testMe;
public String getTestMe() {
return testMe;
}
public void setTestMe(String testMe) {
this.testMe = testMe;
}
}
and then Locate your application tag in nadroid menifest, and add this into it :
android:name="com.package.classname"
and you can set and get the data from any of your activity by using the following code.
GlobalState gs = (GlobalState) getApplication();
gs.setTestMe("Some String");</code>
// Get values
GlobalState gs = (GlobalState) getApplication();
String s = gs.getTestMe();

You could just add some normal SharedPreferences "name", "address", "age" & "isActive" and simply load them when instantiating the class

Simple solution of how to store login value in by SharedPreferences.
You can extend the MainActivity class or other class where you will store the "value of something you want to keep". Put this into writer and reader classes:
public static final String GAME_PREFERENCES_LOGIN = "Login";
Here InputClass is input and OutputClass is output class, respectively.
// This is a storage, put this in a class which you can extend or in both classes:
//(input and output)
public static final String GAME_PREFERENCES_LOGIN = "Login";
// String from the text input (can be from anywhere)
String login = inputLogin.getText().toString();
// then to add a value in InputCalss "SAVE",
SharedPreferences example = getSharedPreferences(GAME_PREFERENCES_LOGIN, 0);
Editor editor = example.edit();
editor.putString("value", login);
editor.commit();
Now you can use it somewhere else, like other class. The following is OutputClass.
SharedPreferences example = getSharedPreferences(GAME_PREFERENCES_LOGIN, 0);
String userString = example.getString("value", "defValue");
// the following will print it out in console
Logger.getLogger("Name of a OutputClass".class.getName()).log(Level.INFO, userString);

Deserializing javabeans objects with gson

I'm trying this code, but not working
public class Main {
public static void main(String[] args) { list();}
private static void list() {
Gson gson = new Gson();
String result = "[{\"Person\":{\"id\":\"1\",\"name\":\"Prédio I\"}},{\"Person\":{\"id\":\"2\",\"name\":\"Prédio II\"}}]";
Person[] persons = gson.fromJson(result, Person[].class);
System.out.println("Qtde: " + persons.length);
for (Person pe : persons) {
System.out.println("Name: " + pe.getName());
}
}
}
see that this code takes an array of Persons, but not works, should show me javabens objects

I'm guessing that the problem is with properly binding the JSON structure to a matching Java data structure. Note that each component in the JSON array is an object that has a single property, named "Person", which is an object with two properties, named "id" and "name" -- each component in the JSON array is not a simple Person object, but a Person wrapper object.
The following demonstrates binding the JSON to a matching Java data structure.
import com.google.gson.Gson;
public class GsonFoo
{
public static void main(String[] args)
{
// [{"Person":{"id":"1","name":"Prédio I"}},{"Person":{"id":"2","name":"Prédio II"}}]
String jsonInput = "[{\"Person\":{\"id\":\"1\",\"name\":\"Prédio I\"}},{\"Person\":{\"id\":\"2\",\"name\":\"Prédio II\"}}]";
PersonWrapper[] persons = new Gson().fromJson(jsonInput, PersonWrapper[].class);
System.out.println("Qtde: " + persons.length);
for (PersonWrapper pw : persons)
{
System.out.println("Name: " + pw.Person.name);
}
// output:
// Qtde: 2
// Name: Prédio I
// Name: Prédio II
}
}
class PersonWrapper
{
Person Person;
}
class Person
{
int id;
String name;
}