I'm trying my first Parcelable transfer and it doesn't go fine. This is my Parcelable class :
public class Element implements Parcelable, Serializable {
private static final long serialVersionUID = 1L;
String name;
String id;
byte[] password;
public static final Parcelable.Creator<Element> CREATOR = new Parcelable.Creator<Element>() {
public Element createFromParcel(Parcel source) {
return new Element(source);
}
public Element[] newArray(int size) {
return new Element[size];
}
};
private Element(Parcel in){
name = in.readString();
id = in.readString();
password = new byte[in.readInt()];
in.readByteArray(password);
}
public Element(String name,String id,byte[] password){
this.name=name;
this.id=id;
this.password=password;
}
#Override
public String toString() {
return name;
}
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeString(id);
dest.writeInt(password.length);
dest.writeByteArray(password);
}
}
As you see, it's a simple Parcelable with 2 String fields and 1 byteArray.
Now I send it to the second activity via my main one :
//Inside the main activity
Intent i = new Intent(MainActivity.this, DisplayActivity.class);
i.putExtra("element", (Parcelable)adapter.getItem(pos));
startActivity(i);
And then, I receive the Parcelable in the second activity :
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.display);
Element e = getIntent().getExtras().getParcelable("element");
//this line makes my app crash. No idea why.
Try it this way:
Element obj = new Element();
//set your data here before send
Intent i = new Intent(this, MyActivity.class);
i.putExtra("com.package.Element", obj);
startActivity(i);
Then to retrieve it:
public class MyActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle b = getIntent().getExtras();
Element obj = b.getParcelable("com.package.Element");
}
}
I was also struggling with the same issue. In your manifest in the MyActivity activity add:
android:launchMode="singleTop"
It solved the issue for me.
<activity android:name="com.example.myapp.MyActivity"
android:label="#string/title_myactivity"
android:launchMode="singleTop">
</activity>
Why would you implement both Parcelable and Serializable?
Related
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
I have a class called Service, which is used to create Service objects using this constructor
public Service(int id, String service_name, String service_code) {
this.id = id;
this.service_name = service_name;
this.service_code = service_code;
}
then I create a list call service list as with the following signature
List<Service> serviceList = new ArrayList<Service>
I have try to pass this ArrayList through Intent Object like this
Intent i = new Intent(Classname.this, anotherClass.class);
i.putExtras("serviceList",serviceList);
startActivity(i);
But it fails. What is the way I pass through intent with ArrayList object.
Your custom class has to implement Parcelable or Serializable in order to serialize/de-serialize within an Intent.
Your class Service has to look like this for example (used a generator http://www.parcelabler.com/)
public class Service implements Parcelable {
private int id;
private String service_name;
private String service_code;
public Service(int id, String service_name, String service_code) {
this.id = id;
this.service_name = service_name;
this.service_code = service_code;
}
protected Service(Parcel in) {
id = in.readInt();
service_name = in.readString();
service_code = in.readString();
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(id);
dest.writeString(service_name);
dest.writeString(service_code);
}
#SuppressWarnings("unused")
public static final Parcelable.Creator<Service> CREATOR = new Parcelable.Creator<Service>() {
#Override
public Service createFromParcel(Parcel in) {
return new Service(in);
}
#Override
public Service[] newArray(int size) {
return new Service[size];
}
};
}
Then you can use getIntent().getParcelableArrayListExtra() with casting
ArrayList<Service> serviceList= intent.<Service>getParcelableArrayList("list"));
For sending you use it like this
intent.putParcelableArrayListExtra("list", yourServiceArrayList);
Note that the yourServiceArrayList should be an ArrayList
if it is List the you can pass through
intent.putParcelableArrayListExtra("list", (ArrayList<? extends Parcelable>) yourServiceArrayList);
You can use parcelable interface for 'Service' class, and send object through
intent using 'putParcelableArrayListExtra' method and to retrive data you can use
'getParcelableArrayListExtra'.
For your reference
refer this link
Implement object class with Serializable .
eg.
class abc implements Serializable{
//your code
}
then try this code
ArrayList<abc> fileList = new ArrayList<abc>();
Intent intent = new Intent(MainActivity.this, secondActivity.class);
intent.putSerializable("arraylisty",filelist);
startActivity(intent);
and on other side receive intent like
your arraylist objact=intent.getSerializableExtra(String name)
I have a class that I'm using for parsing data from a csv file (called CSVReader), inside of that there is some methods for the parsing as well as a couple of strings and a list that is of a custom object type (List allRecords).
What I'm doing is when the app loads, parsing all the data into that list and then trying to pass that information along to the next activity but inside the next activity I keep getting allRecords as being null.
LoginActivity
CSVReader data = new CSVReader();
data.populateRecords(this);
Intent intent = new Intent(LoginActivity.this, Find.class);
Bundle bundle = new Bundle();
bundle.putParcelable("list", data);
intent.putExtra("bundle", bundle);
startActivity(intent);
I've gone through the debugger and the bundle definitely has the data in there.
Find
Intent intent = getIntent();
Bundle bundle = intent.getBundleExtra("bundle");
data = (CSVReader) bundle.getParcelable("list");
Using the debugger still, and mMap (in the bundle) is now null and so is data.
Am I doing something wrong? Both classes DummyData and CSVReader implement Parcelable.
EDIT: Adding custom class CSVReader:
List<DummyData> allRecords;
private String base;
private String location;
private String partner;
public static Creator<CSVReader> CREATOR = new Creator<CSVReader>(){
#Override
public CSVReader createFromParcel(Parcel source){
return new CSVReader(source);
}
#Override
public CSVReader[] newArray(int size) {
return new CSVReader[size];
}
};
private CSVReader(Parcel in){
allRecords = new ArrayList<DummyData>();
in.readTypedList(allRecords, DummyData.CREATOR);
base = in.readString();
location = in.readString();
partner = in.readString();
}
...
...
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(base);
dest.writeString(location);
dest.writeString(partner);
dest.writeList(allRecords);
}
[EDIT]
I was looking over your code again, and noticed you're writing the List to the parcel LAST and reading the list from the parcel FIRST. You have to read items from the parcel in the order they are written. Try putting dest.writeList(allRecords) at the top of the method so it is the first item written, or you can put in.readList(allRecords, DummyData.class.getClassLoader()) at the bottom of the list in that method.
Give it a shot.
//////////////////////////////////////////////
From the docs,
public final void readTypedList (List<T> list, Creator<T> c)
Read into the given List items containing a particular object type
that were written with writeTypedList(List) at the current
dataPosition(). The list must have previously been written via
writeTypedList(List) with the same object type.
You're using writeList() to write the data to the parcel. Try using writeTypedList(). You could also try changing readTypedList() with readList() I believe. Something like:
in.readList(allRecords, CSVReader.class.getClassLoader());
Hope this helps.
If you plan to pass data to another activity, you need to use objects of classes that implement Parcelable. Here is an example,
package com.weather.model;
import java.util.ArrayList;
import java.util.List;
import android.os.Parcel;
import android.os.Parcelable;
public class Forcast implements Parcelable {
private String id;
private String code;
private String message;
private City city;
private String count;
private List<Weather> weatherList = new ArrayList<Weather>();
public Forcast(){
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public City getCity() {
return city;
}
public void setCity(City city) {
this.city = city;
}
public String getCount() {
return count;
}
public void setCount(String count) {
this.count = count;
}
public List<Weather> getWeatherList() {
return weatherList;
}
public void setWeatherList(List<Weather> weather) {
this.weatherList = weather;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(id);
dest.writeString(code);
dest.writeString(message);
dest.writeParcelable(city, flags);
dest.writeString(count);
dest.writeList(weatherList);
}
public static final Parcelable.Creator<Forcast> CREATOR = new Parcelable.Creator<Forcast>() {
#Override
public Forcast createFromParcel(Parcel source) {
return new Forcast(source);
}
#Override
public Forcast[] newArray(int size) {
return new Forcast[size];
}
};
protected Forcast(Parcel in){
id = in.readString();
code = in.readString();
message = in.readString();
city = (City)in.readParcelable(City.class.getClassLoader());
count = in.readString();
in.readList(weatherList, Weather.class.getClassLoader());
}
}
I included City model so you can see how it goes for an object in comparison to list of objects. Assume you have a Forcast instance with all the values as 'forcast' ( Forcast forcast = new Forcast() or something similar)
Intent intent = new Intent(this, SomeActivity.class);
intent.putExtra(com.weather.model,forcast)
startActivity(intent)
I hope that helps
You need to put bundle object by using putExtras method. Then you can get the bundle by using getIntent().getExtras().
Intent intent = new Intent(LoginActivity.this, Find.class);
Bundle bundle = new Bundle();
bundle.putParcelable("list", data);
intent.putExtras( bundle);
startActivity(intent);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
data = (CSVReader) bundle.getParcelable("list");
I'm trying to pass array lists between activities in Android. The lists contains strings. I've read a lot about Parcelable. Would I need to create a Parcelable to pass a String array list? As of now I am using putStringArrayListExtra() and getSringArrayListExtra() to pass the lists through intents.
Here is some of my code.
Intent load = new Intent(getApplicationContext(), HelloTabWidget.class);
load.putStringArrayListExtra("albums", albums);
load.putStringArrayListExtra("songs", songs);
load.putStringArrayListExtra("artists", artists);
load.putStringArrayListExtra("fileName", fileName);
This is my onCreate method for the acticity which obtains the array list.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.songlist);
Bundle extras = getIntent().getExtras();
isArtists = extras.getBoolean("artists");
isAlbums = extras.getBoolean("albums");
isSongs = extras.getBoolean("songs");
Intent get = getIntent();
songs = get.getStringArrayListExtra("songs");
artists = get.getStringArrayListExtra("artists");
albums = get.getStringArrayListExtra("albums");
fileName = get.getStringArrayListExtra("fileName");
if(isArtists == true)
updateArtistsList();
else if(isAlbums == true)
updateAlbumsList();
else if(isSongs == true)
updateSongList();
}
The class which retrieves the list is supposed to create a listView from the data in the lists. Whenever I run the code i get nullPointerExceptions when trying to make the lists. I know that my listView code works, so I have narrowed down the problem to the intents which pass the array lists.
Thanks in advance.
EDIT:
Here are the first few lines from the logcat.
12-28 03:03:42.313: E/AndroidRuntime(873): FATAL EXCEPTION: main
12-28 03:03:42.313: E/AndroidRuntime(873): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.adam.mediaplayer/com.adam.mediaplayer.HelloTabWidget}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.adam.mediaplayer/com.adam.mediaplayer.MakeListActivity}: java.lang.NullPointerException
It depends on the type of arraylist
putIntegerArrayListExtra(String name, ArrayList<Integer> value)
putParcelableArrayListExtra(String name, ArrayList<? extends Parcelable> value)
putStringArrayListExtra(String name, ArrayList<String> value)
putCharSequenceArrayListExtra(String name, ArrayList<CharSequence> value)
Then you can read from you next activity by replacing put with get with key string as argument,eg
myIntent.getStringArrayListExtra("arrayListName");
Here is how you can pass an ArrayList :
MyListClass.java - Custom class
public class MyListClass implements Parcelable{
private int test;
public MyListClass()
{}
public MyListClass(Parcel read){
test = read.readInt();
}
public int getTest() {
return test;
}
public void setTest(int test) {
this.test = test;
}
public static final Parcelable.Creator<MyListClass> CREATOR =
new Parcelable.Creator<MyListClass>() {
#Override
public MyListClass createFromParcel(Parcel source) {
return new MyListClass(source);
}
#Override
public MyListClass[] newArray(int size) {
return new MyListClass[size];
}
};
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel arg0, int arg1) {
arg0.writeInt(test);
}
}
MyParcelable.java
public class MyParcelable implements Parcelable {
private List<MyListClass> arrList = new ArrayList<MyListClass>();
private int myInt = 0;
private String str = null;
public String getStr() {
return str;
}
public void setStr(String str) {
this.str = str;
}
public List<MyListClass> getArrList() {
return arrList;
}
public void setArrList(List<MyListClass> arrList) {
this.arrList = arrList;
}
public int getMyInt() {
return myInt;
}
public void setMyInt(int myInt) {
this.myInt = myInt;
}
MyParcelable() {
// initialization
arrList = new ArrayList<MyListClass>();
}
public MyParcelable(Parcel in) {
myInt = in.readInt();
str = in.readString();
in.readTypedList(arrList, MyListClass.CREATOR);
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel outParcel, int flags) {
outParcel.writeInt(myInt);
outParcel.writeString(str);
outParcel.writeTypedList(arrList);
}
public static final Parcelable.Creator<MyParcelable> CREATOR = new Parcelable.Creator<MyParcelable>() {
#Override
public MyParcelable createFromParcel(Parcel in) {
return new MyParcelable(in);
}
#Override
public MyParcelable[] newArray(int size) {
return new MyParcelable[size];
}
};
}
MainAcitivty.java
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
arrList.add(new MyListClass());
arrList.get(0).setTest(200);
MyParcelable object = new MyParcelable();
object.setMyInt(100);
object.setArrList(arrList);
Intent intent = new Intent(MainActivity.this,ReceiverParcel.class);
intent.putExtra("parcel", object);
startActivity(intent);
}
ReceiverParcel.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle b = getIntent().getExtras();
MyParcelable object = b.getParcelable("parcel");
System.out.println(object.getArrList().get(0).getTest());
System.out.println(object.getMyInt());
}
I have the following three classes.
Cricketers
public class Cricketers implements Parcelable {
private String name;
private String address;
private int age;
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;
}
#Override
public int describeContents() {
return 0;
}
public Cricketers() {
}
#Override
public void writeToParcel(Parcel dest, int flag) {
dest.writeString(name);
dest.writeString(address);
dest.writeInt(age);
}
public Cricketers(Parcel in) {
this.name = in.readString();
this.address = in.readString();
this.age = in.readInt();
}
#SuppressWarnings("unchecked")
public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
public Cricketers createFromParcel(Parcel in) {
return new Cricketers(in);
}
public Cricketers[] newArray(int size) {
return new Cricketers[size];
}
};
}
Activity1
public class Activity1 extends Activity {
private ArrayList<Cricketers> cricketers;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
cricketers = new ArrayList<Cricketers>();
Cricketers object = new Cricketers();
object.setName("Sachin");
object.setAddress("Mumbai");
object.setAge(37);
cricketers.add(object);
Cricketers object1 = new Cricketers();
object1.setName("Sourav");
object1.setAddress("Kolkata");
object1.setAge(38);
cricketers.add(object1);
Cricketers object2 = new Cricketers();
object2.setName("Dravid");
object2.setAddress("Bengaluru");
object2.setAge(38);
cricketers.add(object2);
Intent intent = new Intent(this, Activity2.class);
intent.putExtra("cricketers", cricketers);
startActivity(intent);
cricketers = null;
}
Activity2
public class Activity2 extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
Cricketers cricketers = bundle.getParcelable("cricketers");
}
}
I am retrieving the data on Activity2 , but its returning cricketers = null .
Within the Activity1 class , the data "cricketers" is being properly added to the Intent.
Kindly provide your inputs.
Thanks in advance.
I have solved the issue ....
Changes need to done to the Activity2 class
public class Activity2 extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
ArrayList<Cricketers> data = new ArrayList<Cricketers>();
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
data = bundle.getParcelableArrayList("cricketers");
for (int count = 0; count < data.size(); count++) {
Cricketers cric = (Cricketers) data.get(count);
String name = cric.getName();
String address = cric.getAddress();
int age = cric.getAge();
}
}
}
I found some problem with AIDL cache ... if you change all your code abour the parcelable, or simple you refactor the name of the class. if you reinstall the app, or clear the app cache, the AIDL is still working and searching fot that refactored class.
I fix this task rebooting the device. It a crap to change code in the parcelable class but not see it works when reinstall the app, you MUST to reboot the device... or thats whar I do.
Thanks for the example dude ;) the activit2 was a bless!!