Develop Reference

Pass Objects between Activities

I'm devlopping an Android app made of multiple Activities and I have to pass ab Object between them, but I can't pass it by using intents because the class of the object doesn't implement serializable, how can I do it?
I CAN'T MODIFY THE SOURCE CODE OF MY CLASS
Thanks :)
public class MyClass { //stuff }
//I can't modify this source code
MyClass m = new MyClass(); //object I have to pass

Suppose there is a data object class named StudentDataObject having some data types.
StudentDataObject studentDataObject = new StudentDataObject();
Gson gson = new Gson();
String studentDataObjectAsAString = gson.toJson(studentDataObject);
Now we are passing it from one activity to another activity using intent.
Intent intent = new Intent(FromActivity.this, ToActivity.class);
intent.putExtra("MyStudentObjectAsString", studentDataObjectAsAString);
startActivity(intent);
Now we are in new activity, we get that object here using following line.
Gson gson = new Gson();
String studentDataObjectAsAString = getIntent().getStringExtra("MyStudentObjectAsString");
StudentDataObject studentDataObject = gson.fromJson(studentDataObjectAsAString, StudentDataObject.class);
Activity itself know where from I am called, so we can directly write getIntent() method.
Here we only need to add one dependency of GSON we can add it using following line in build.gradle file.
compile 'com.google.code.gson:gson:2.6.2'
And one thing is that implement StudentDataObject as a Parcelable and if showing error then just press alt+Enter and implement methods.
Try this once, Hope it will work.
Sample Example for StudentDataObject should be like :-
public class StudentDataObject implements Parcelable {
// fields
//empty constructor
//parameterised constructor
//getters and setters
//toString method
//last implement some Parcelable methods
}

First of all create Parcelable data model.
public class DataModel implements Parcelable {
private int mData;
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel out, int flags) {
out.writeInt(mData);
}
public static final Parcelable.Creator<DataModel> CREATOR
= new Parcelable.Creator<DataModel>() {
public DataModel createFromParcel(Parcel in) {
return new DataModel(in);
}
public DataModel[] newArray(int size) {
return new DataModel[size];
}
};
private DataModel(Parcel in) {
mData = in.readInt();
}
}
put object into intent
intent.putExtra("KEY", object);
get object from intent
object = getIntent().getExtras().getParcelable("KEY");

This code may help you:
public class EN implements Serializable {
//... you don't need implement any methods when you implements Serializable
}
FirstActivity
EN enumb = new EN();
Intent intent = new Intent(getActivity(), NewActivity.class);
intent.putExtra("en", enumb); //second param is Serializable
startActivity(intent);
SecandActivity
Bundle extras = getIntent().getExtras();
if (extras != null) {
en = (EN)getIntent().getSerializableExtra("en"); //Obtaining data
}
Passing data through intent using Serializable

Here is my object class Book.java
import android.os.Parcel;
import android.os.Parcelable;
public class Book implements Parcelable {
// book basics
private String title;
private String author;
// main constructor
public Book(String title, String author) {
this.title = title;
this.author = author;
}
// getters
public String getTitle() { return title; }
public String getAuthor() { return author; }
// write object values to parcel for storage
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(title);
dest.writeString(author);
}
public Book(Parcel parcel) {
title = parcel.readString();
author = parcel.readString();
}
public static final Parcelable.Creator<Book> CREATOR = new Parcelable.Creator<Book>() {
#Override
public Book createFromParcel(Parcel parcel) {
return new Book(parcel);
}
#Override
public Book[] newArray(int size) {
return new Book[0];
}
};
public int describeContents() {
return hashCode();
}
}
Now you can pass object like this
Button button = (Button) findViewById(R.id.submit_button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Book book = new Book(mBkTitle.getText().toString(),
mBkAuthor.getText().toString());
Intent intent = new Intent(MainActivity.this, BookActivity.class);
intent.putExtra("Book", book);
startActivity(intent);
}
});
Now object will be received like this in receiving ReceivingActivity.java
Intent intent = getIntent();
Book book = intent.getParcelableExtra("Book");
mBkTitle.setText("Title:" + book.getTitle());
mBkAuthor.setText("Author:" + book.getAuthor());

You need to implement parcelable and then pass it via intent. Dont use Serializable cause is way slower than parcelable.
Read here how to make your object parcelable: https://developer.android.com/reference/android/os/Parcelable.html
after you dont it, pass your object like this:
intent.putExtra("KEY", your_object);
to read it:
getIntent().getExtras().getParcelable("KEY");

Extend the class and implement serializable or parcelable in the inherited class and use its objects as in other answers.
Class NewClass extends MyClass implements serializable {
//Create a constructor matching super
}
Use objects of this class instead of my class

You can pass a custom object from one activity to another through intent in 2 ways.
By implements Serializable
By implements Parcelable
(1) By implements Serializable no need to do anything just implement Serializable
into your class like
public class Note implements Serializable {
private int id;
private String title;
}
(2) By implementing Parcelable (you have to follow the Parcel write and read with same order)
public class Note implements Parcelable {
private int id;
private String title;
public Note() {
}
Note(Parcel in){
this.id = in.readInt();
this.title = in.readString();
}
public void setId(int id) {
this.id = id;
}
public int getId() {
return id;
}
public void setTitle(String title) {
this.title = title;
}
public String getTitle() {
return title;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(id);
dest.writeString(title);
}
public static final Parcelable.Creator<Note> CREATOR = new Parcelable.Creator<Note>(){
#Override
public Note createFromParcel(Parcel source) {
return new Note(source);
}
#Override
public Note[] newArray(int size) {
return new Note[size];
}
};
}
and then in your activity
Activity A
intent.putExtra("NOTE", note);
Activity B
Note note = (Note) getIntent().getExtras().get("NOTE");
Imp: Parcelable is 10 times faster than Serializable

Which way is better for pass a large list of data from one activity to another activity - android?

I need to pass a large list of data from one activity to another activity,which way is better?
First way(for example):
ArrayList<myModel> myList = new ArrayList<myModel>();
intent.putExtra("mylist", myList);
Second way(for example) :
ActivityTwo act = new ActivityTwo();
act.getDataMethod(listValues);
Intent i = new Intent(this, ActivityTwo.class);
startActivity(i);
And in another activity(ActivityTwo) I get data from getDataMethod.

If the data you want to send is really big (around 1MB). The best way to pass it is to store it in persistent storage in ActivityA and access it in ActivityB.
The approach with passing it via Parcerable/Serializable is risky as you may end up with TransactionTooLargeException when trying to pass around 1MB of data.
The approach with passing it via Singleton class is even worse as when you are in ActivityB and application is recreated (it was long in background/memory was low) you will loose data from singleton (process is recreated) and nobody will set it, ActivityB will be launched and it wont have data from AcitvityA (as it was never created).
In general you shouldn't pass data through intents, you should pass arguments/identifiers which then you can use to fetch data from db/network/etc.

Best way to pass large data list from one Activity to another in Android is Parcelable . You first create Parcelable pojo class and then create Array-List and pass into bundle like key and value pair and then pass bundle into intent extras.
Below I put one sample User Pojo class that implements Parcelable interface.
import android.os.Parcel;
import android.os.Parcelable;
/**
* Created by CHETAN JOSHI on 2/1/2017.
*/
public class User implements Parcelable {
private String city;
private String name;
private int age;
public User(String city, String name, int age) {
super();
this.city = city;
this.name = name;
this.age = age;
}
public User(){
super();
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
#SuppressWarnings("unused")
public User(Parcel in) {
this();
readFromParcel(in);
}
private void readFromParcel(Parcel in) {
this.city = in.readString();
this.name = in.readString();
this.age = in.readInt();
}
public int describeContents() {
return 0;
}
public final Parcelable.Creator<User> CREATOR = new Parcelable.Creator<User>() {
public User createFromParcel(Parcel in) {
return new User(in);
}
public User[] newArray(int size) {
return new User[size];
}
};
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(city);
dest.writeString(name);
dest.writeInt(age);
}
}
ArrayList<User> info = new ArrayList<User>();
info .add(new User("kolkata","Jhon",25));
info .add(new User("newyork","smith",26));
info .add(new User("london","kavin",25));
info .add(new User("toranto","meriyan",30));
Intent intent = new Intent(MyActivity.this,NextActivity.class);
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("user_list",info );
intent.putExtras(bundle);`
startActivity(intent );

To me serialized objects/list is better way.
`Intent intent = ....
Bundle bundle = new Bundle();
ArrayList<String> myList = new ArrayList<String>();
bundle.putSerializable("mylist", myList);
intent.putExtras(bundle);`

Use the first approach. However you will need to use the following method call to put it into the Intent:
ArrayList<String> myList = new ArrayList<String>();
intent.putStringArrayListExtra("mylist",myList);
The to get the list out of the intent in the receiving Activity:
ArrayList<String> myList = getIntent().getStringArrayListExtra("mylist");

If you have a huge list of data it is better way to save the data in Singleton java class and use set/get to save & get the data in application level.
Sharing large data as intent bundle may chances to lose data.
Application.class
add this in you manifest file
<application
android:name=".App"
-----
</application>
public class App extends Application {
public ArrayList<Object> newsList;
#Override
public void onCreate() {
super.onCreate();
}
public void setHugeData(ArrayList<Object> list){
this.newsList = list;
}
public ArrayList<Object> getHugeData(){
return newsList;
}
}
in ActivityA.class
ArrayList<Object> info = new ArrayList<>();
// save data
((App)getApplication()).setHugeData(info);
in ActvityB.class
ArrayList<Object> info = new ArrayList<>();
// get the data
info = ((App)getApplication()).getHugeData();

You can use such libraries as Eventbus to pass models through activities or you can put your model in ContentValues (https://developer.android.com/reference/android/content/ContentValues.html) class - it is parcable and you can pass it through intent. A good practice is to implement two methods in your Model class - toContentValues() and fromContentValues().
Something like this:
public class DealShort extends BaseResponse implements ContentValuesProvider {
#SerializedName("id")
#Expose
private long id = -1;
#SerializedName("full_price")
#Expose
private double fullPrice;
public static DealShort fromContentValues(ContentValues cv) {
DealShort deal = new DealShort();
deal.id = cv.getAsLong(DbContract.Product.SERVER_ID);
deal.fullPrice = cv.getAsLong(DbContract.CategoriesProducts.CATEGORY_ID);
}
public ContentValues toContentValues() {
ContentValues cv = new ContentValues();
cv.put(DbContract.Product.SERVER_ID, id);
cv.put(DbContract.Product.FULL_PRICE, fullPrice);
return cv;
}
}

1,You can use Singleton class,like below code:
public class MusicListHolder {
private ArrayList<MusicInfo> musicInfoList;
public ArrayList<MusicInfo> getMusicInfoList() {
return musicInfoList;
}
public void setMusicInfoList(ArrayList<MusicInfo> musicInfoList) {
this.musicInfoList = musicInfoList;
}
private static final MusicListHolder holder = new MusicListHolder();
public static MusicListHolder getInstance() {
return holder;
}
}
it's easy and useful!
2,You can use Application,just put your data in Application before you use it!
3,You can use Eventbus
4,You can put your data in a file/sqlite/...,maybe it's slow and conflict,but it's workable

Put interface in bundle to start a new activity

I need to start an activity from 2 different screens that have two different models but, both models have some shared information which is the one that I need in the new activity. The problem is that I cannot make those models to extend from the same parent, as one of the models already extends one parent. I have thought about creating an interface that contains the shared methods but, if I do that, then how can I put that interface in the bundle required to start the next activity?
I add some simplified code in order to clarify my situation:
public class A extends Model implements CustomInterface {
String name;
String address;
public String getName(){
return name;
}
public String getAddress() {
return address;
}
}
public class B implements CustomInterface {
String name;
public String getName() {
return name;
}
}
public interface CustomInterface {
String getName();
}
My problem is that I need to start an activity with a bundle with the shared information between both models. So, I would like to put CustomInterface in a bundle. How could I do that?
Thanks in advance.

So, I would like to put CustomInterface in a bundle
you could let CustomInterface extend Parcelable. E.g.
public interface CustomInterface extends Parcelable {
String getName();
}
this way the classes implementing CustomInterface will have to implements the method defined in the Parcelable interface. If implemented correctly, you will be able to pass those objects around without problems

Create a singleton class, then you can share data without passing it:
public class MySingleton
{
private static MySingleton instance;
public String customVar;
public static MySingleton getInstance()
{
if (instance == null)
{
// Create the instance
instance = new MySingleton();
}
// Return the instance
return instance;
}
private MySingleton()
{
// Constructor hidden because this is a singleton
}
public void getSomeData()
{
return something;
}
public void getSomeOtherData()
{
return somethingelse;
}
}
Then in your classes:
public class A extends Model {
String name;
String address;
public String getName(){
return name;
}
public String getAddress() {
return address;
}
public String doSomethingWithSharedData(){
MySingleton model = MySingleton.getInstance();
String somedata = model.getSomeData();
}
}
public class B {
String name;
public String getName() {
return name;
}
public String doSomethingDifferentWithSharedData(){
MySingleton model = MySingleton.getInstance();
String somedata = model.getSomeOtherData();
}
}

Not Serializable Exception on custom class - Android

So I'm trying to pass an instance of a class I create by intent to a new activity.
public class Room implements Serializable{
/**
*
*/
private static final long serialVersionUID = 6857044522819206055L;
int roomID;
String roomName;
ArrayList<MarkerHolder> markerHolders = new ArrayList<MarkerHolder>();
public int getRoomID() {
return roomID;
}
public void setRoomID(int roomID) {
this.roomID = roomID;
}
public String getRoomName() {
return roomName;
}
public void setRoomName(String roomName) {
this.roomName = roomName;
}
public ArrayList<MarkerHolder> getMarkerHolders() {
return markerHolders;
}
public void setMarkerHolders(ArrayList<MarkerHolder> markerHolders) {
this.markerHolders = markerHolders;
}
}
public class MarkerHolder implements Serializable{
/**
*
*/
private static final long serialVersionUID = -7334724625702415322L;
String marker;
String markerTag;
public String getMarker() {
return marker;
}
public void setMarker(String marker) {
this.marker = marker;
}
public String getMarkerTag() {
return markerTag;
}
public void setMarkerTag(String markerTag) {
this.markerTag = markerTag;
}
}
And I try to pass that class by
Intent svc = new Intent(this, RoomUploader.class);
svc.putExtra("room", room);
try{
startService(svc);
}catch (Exception e){
e.printStackTrace();
}
and I keep getting a Not Serializable Exception which I can't figure out. Both classes implement serializable and have serial Ids. The member variables are just strings, ints, and an array of another class that is also serializable that contains only strings. As far as I know all these things should be serializable, what else could cause this error? Thanks in advance.

Are those classes inner classes of your activity or another class? If so, they have a reference to their outer class (which may or may not be serializable), and you can solve this by making those classes static.
Example:
public static class Room implements Serializable
{
//your implementation
}
public static class MarkerHolder implements Serializable
{
//your implementation
}

Try changing ArrayList to a native array of MarkerHolder:
MarkerHolder[] markerHolders;
Update: My bad. I've always used native array for serialization so not aware ArrayList is indeed serialzable.
Your code looks right. What was the exact error message printed in the logcat (i.e. which class threw the serialization exception)?
Another solution (more work) is to make your objects implement the Parcable interface.

Try to use getApplicationContext() or context instaed of this.

Transferring object data from one activity to another activity

I am having a class EmployeeInfo as the following:
public class EmployeeInfo {
private int id; // Employee ID
private String name; // Employee Name
private int age;// Employee Age
public int getEmployeeID() {
return id;
}
public void setEmployeeID(int id) {
this.id = id;
}
public String getEmployeeName() {
return name;
}
public void setEmployeeName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age= age;
}
}
ArrayList<EmployeeInfo> employeeInfo object contains the emplyoyee info data for multiple employees.
I want to transfer the data( ArrayList employeeInfo ) from Activity1 to Activity2.
Is using Parcelable the only way to transfer the data from Activity1 to Activity2?
If not , what are the alternatives.
If yes ,kindly provide the prototype code of Parcelable along with the sample code on how to transfer the object data from Activity1 to Activity2.

Here is my implementation of Parceleble:
public class ProfileData implements Parcelable {
private int gender;
private String name;
private String birthDate;
public ProfileData(Parcel source) {
gender = source.readInt();
name = source.readString();
birthDate = source.readString();
}
public ProfileData(int dataGender, String dataName, String dataBDate) {
gender = dataGender;
name = dataName;
birthDate = dataBDate;
}
// Getters and Setters are here
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel out, int flags) {
out.writeInt(gender);
out.writeString(name);
out.writeString(birthDate);
}
public static final Parcelable.Creator<ProfileData> CREATOR
= new Parcelable.Creator<ProfileData>() {
public ProfileData createFromParcel(Parcel in) {
return new ProfileData(in);
}
public ProfileData[] newArray(int size) {
return new ProfileData[size];
}
};
}
and how I transfer data:
Intent parcelIntent = new Intent().setClass(ActivityA.this, ActivityB.class);
ProfileData data = new ProfileData(profile.gender, profile.getFullName(), profile.birthDate);
parcelIntent.putExtra("profile_details", data);
startActivity(parcelIntent);
and take data:
Bundle data = getIntent().getExtras();
ProfileData profile = data.getParcelable("profile_details");

You can simply let your EmployeeInfo class implement Serializable. Or you can send data like this
intent.putExtra("id", employInfo.getEmployeeID());
intent.putExtra("name", employInfo.getEmployeeName());
intent.putExtra("age", employInfo.getAge());
If you need to transfer a list of your custom classes, i'd use the first approach. So you would be able to put entire list as Serializable.
However they said that everyone should use Parcelable instead because it's "way faster". Tbh, I'd never used it, because it needs more effort and I doubt somebody can realize the difference in speed in a regular application w/o a load of data sending via intent

Good question. Looking at the docs and doing armchair coding:
It may be possible to pass an object between Activities by calling putExtras(Bundle) and myBundle.putSerializable. The object and the entire object tree would need to implement serializable.
JAL
EDIT: The answer is yes:
It is possible to pass an immutable object between Activities by calling putExtras(Bundle) and myBundle.putSerializable. The object and the entire object tree would need to implement serializable. This is a basic tenet of Object Oriented Programming, passing of stateful messages.
First we create the immutable object by declaring a new class:
package jalcomputing.confusetext;
import java.io.Serializable;
/*
* Immutable messaging object to pass state from Activity Main to Activity ManageKeys
* No error checking
*/
public final class MainManageKeysMessage implements Serializable {
private static final long serialVersionUID = 1L;
public final int lengthPassword;
public final long timeExpire;
public final boolean isValidKey;
public final int timeoutType;
public MainManageKeysMessage(int lengthPassword, long timeExpire, boolean isValidKey, int timeoutType){
this.lengthPassword= lengthPassword;
this.timeExpire= timeExpire;
this.isValidKey= isValidKey;
this.timeoutType= timeoutType;
}
}
Then we create an immutable stateful instance of the class, a message, in the parent activity, and send it in an intent as in:
private void LaunchManageKeys() {
Intent i= new Intent(this, ManageKeys.class); // no param constructor
// push data (4)
MainManageKeysMessage message= new MainManageKeysMessage(lengthPassword,timeExpire,isValidKey,timeoutType);
Bundle b= new Bundle();
b.putSerializable("jalcomputing.confusetext.MainManageKeysMessage", message);
i.putExtras(b);
startActivityForResult(i,REQUEST_MANAGE_KEYS); // used for callback
}
Finally, we retrieve the object in the child activity.
try {
inMessage= (MainManageKeysMessage) getIntent().getSerializableExtra("jalcomputing.confusetext.MainManageKeysMessage");
lengthPassword= inMessage.lengthPassword;
timeoutType= inMessage.timeoutType;
isValidKey= inMessage.isValidKey;
timeExpire= inMessage.timeExpire;
} catch(Exception e){
lengthPassword= -1;
timeoutType= TIMEOUT_NEVER;
isValidKey= true;
timeExpire= LONG_YEAR_MILLIS;
}

Well there is another way to transfer an object.We can use application to transfer object and this is way is far better way in my opinion.
First of all create your custom application in your main package.
public class TestApplication extends Application {
private Object transferObj;
#Override
public void onCreate() {
super.onCreate();
// ACRA.init(this);
}
public Object getTransferObj() {
return transferObj;
}
public void setTransferObj(Object transferObj) {
this.transferObj = transferObj;
}
}
Now use setTransfer and get transfer methods to move abjects from one activity to other like:
To Transfer:
((TestApplication) activity.getApplication()).setTransferObj(Yous object);
ToRecieve:
Object obj=((TestApplication) activity.getApplication()).getTransferObj();
NOTE
Always remember to make entry of this application in manifest application tag:
<application
android:name=".TestApplication">
</application>

You can convert your object to jsonstring using Gson or Jakson and pass using intent as string and read the json in another activity.