I have a problem with with sharing data between two different activities. I have data like :
int number
String name
int number_2
int time
int total
I'm trying to make something like order list with this set of data . So it will take one set of data , then back to previous activity , move forward and again add data to it .
I have an idea of making it in array of object - but data inside was cleared after changing activity.
How can I make it ?
I don't know if and how to add Array of object to SharedPreferences , and get value of one element from there.
You should have a look at the documentation of the Intent(s) if you want to do that on the fly associating a key to the value(s) that you want to pass to your second activity.
Anyway, you can think any(sharedpref, database,...) way to pass your parameters but for those kind of things it's a convention and a good practice to follow that.
Don't used share preferences for this...Use the singleton pattern, extend Application, or just make a class with static variables and update them...
You can use .putExtra but since you are communicating with more than one activity the above suggestions are probably the best.
public class ShareData {
private String s;
private int s;
private static ShareData shareData = new ShareData();
private ShareData(){}
public static ShareData getInstance(){ return shareData}
//create getters and setters;
}
Why not to use Intents
Intent intent = new Intent(FirstActivity.this, (destination activity)SecondActivity.class);
intent.putExtra("some_key", value);
intent.putExtra("some_other_key", "a value");
startActivity(intent);
in the second activity
Bundle bundle = getIntent().getExtras();
int value = bundle.getInt("some_key");
String value2 = bundle.getString("some_other_key");
EDIT if you want to read more about adding array to shared preferences check this
Is it possible to add an array or object to SharedPreferences on Android
also this
http://www.sherif.mobi/2012/05/string-arrays-and-object-arrays-in.html
Related
I'm trying to transfer ArrayList between activities, but nothing I've tried works as well.
This was my best shot, but this didn't work either.
I'm calling the external action here:
getComics getComicInfo = new getComics(charName, pageNum);
getComicInfo.execute();
getIntentData()
and here i'm trying to put data, but the problem is due the fact that this is an external action, so I can't shift through activits.
if(counter == comicInfoObject.length()){
Log.v("check arr length =>" , Integer.toString(comicList.size()));
Intent i = new Intent();
i.putExtra("comicArrayList", (ArrayList<Comics>)comicList);
}
and here i'm tring to retrive the data, but it doesn't get inside the "if"
public void getIntentData(){
Intent i = getIntent();
if(i != null && i.hasExtra("comicArrayList")){
comicList2 = i.getParcelableExtra("comicArrayList");
int size = comicList2.size();
}
}
first code is where I call an external class that using api and in the bottom line creates the arrayList
second code is inside the external class, where I'm trying to pass the arrayList with putExtra
third code is where i'm tring to retrive the data after getIntentData().
Pack at the sender Activity
intent.putParcelableArrayListExtra(<KEY>, ArrayList<Comics extends Parcelable> list);
startActivity(intent);
Extract at the receiver Activity
getIntent().getParcelableArrayListExtra(<KEY>);
You need make a Comics class that implements Parcelable, then use put ParcelableArrayListExtrato pass arraylist.
Here is a sample link for Pass data between activities implements Parcelable
However be careful if your array list too big, you could get intent exception, for this case you could think about a static reference to store your array list.
I have created an application that takes in user name and other details for a transaction and then fills them in a database. At times the application shows odd behavior by filling the SAME details in the database twice as two transactions. Even though the new values are read but not STORED in the static variables.
Therefore I needed help in flushing the values of all my static variables at the end of each activity to avoid overriding of the previous values in a fresh transaction.
EDIT :
public class One
{
static String var;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
var="blah";
}
}
public class Two
{
static String variable = One.var;
// This is where i am accessing the value of the variables from previous activities.
//CODE
}
May these help you..
Using Static Variables is like a nightmare in any activity as it stores memory through out the activity..
I think you can try some other memory store to overcome your problem of passing value from one activity to another..
In my opinion u can store values in SharedPreference or either you can pass value through intent to other activity where ever it is required..
Hope these will help you..
EDIT:
Intent in = new Intent(MainActivity.this,SecondActivity.class);
You can use more than one putExtra() method to put several values and can fetch then in Second Activity
in.putStringArrayListExtra(String name, ArrayList<String> value);
StartActivity(in);
In Second Activity:
Intent in = getIntent();
ArrayList<String> Roleids = new ArrayList<String>;
RoleId = in.getStringArrayListExtra(String name, ArrayList<String> value)
I'd like to pass a custom Object from one activity to another, the Object consists of a String and a List of another custom Object which consists of an array of strings and an array of ints. I've read https://stackoverflow.com/a/2141166/830104, but then I've found this answer https://stackoverflow.com/a/7842273/830104. Which is better to use Bundle or Parcelable? What is the difference? When should I use this each? Thanks for your replies, Dan
Parcelable and Bundle are not exclusive concepts; you can even deploy both on your app at a time.
[1] Term Parcelable comes with Serialization concept in Java (and other high-level language such as C#, Python,...). It ensures that an object - which remains in RAM store - of such Parcelable class can be saved in file stream such as text or memory (offline status) then can be reconstructed to be used in program at runtime (online status).
In an Android application, within 2 independent activities (exclusively running - one starts then other will have to stop):
There will be NO pointer from current activity to refer to previous one and its members - because previous activity is stopped and cleared out form memory; so that to maintain object's value passed to next activity (called from Intent) the object need to be parcelable (serializable).
[2] While Bundle is normally the Android concept, denotes that a variable or group of variables. If look into lower level, it can be considered as HashMap with key-value pairs.
Conclusion:
Bundle is to store many objects with related keys, it can save any object in native types, but it doesn't know how to save a complex object (which contains an ArrayList for example)
Parcelable class is to ensure a complex instance of it can be serialized and de-serialized during runtime. This object can contains complex types such as ArrayList, HashMap, array, or struct,...
[UPDATED] - Example:
//Class without implementing Parcelable will cause error
//if passing though activities via Intent
public class NoneParcelable
{
private ArrayList<String> nameList = new ArrayList<String>();
public NoneParcelable()
{
nameList.add("abc");
nameList.add("xyz");
}
}
//Parcelable Class's objects can be exchanged
public class GoodParcelable implements Parcelable
{
private ArrayList<String> nameList = new ArrayList<String>();
public GoodParcelable()
{
nameList.add("Can");
nameList.add("be parsed");
}
#Override
public int describeContents()
{
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags)
{
// Serialize ArrayList name here
}
}
In source activity:
NoneParcelable nonePcl = new NoneParcelable();
GoodParcelable goodPcl = new GoodParcelable();
int count = 100;
Intent i = new Intent(...);
i.putExtra("NONE_P",nonePcl);
i.putExtra("GOOD_P",goodPcl);
i.putExtra("COUNT", count);
In destination activity:
Intent i = getIntent();
//this is BAD:
NoneParcelable nP = (NoneParcelable)i.getExtra("NONE_P"); //BAD code
//these are OK:
int count = (int)i.getExtra("COUNT");//OK
GoodParcelable myParcelableObject=(GoodParcelable)i.getParcelableExtra("GOOD_P");// OK
I have an activity that contain a list of data (TextView), i need to save this data that have been choose (onClick) in the list and been able to get and read it in another activity(history)
I understand that is exist a possibility with the "serializable" but i did not success to understand how it could help me.
i will be happy if someone can clarify this subject for me,example?.
Thank you for helping!!
If you're trying to pass a String to another activity, you can do this with putExtra and getStringExtra:
Intent intent = new Intent(this, OtherActivity.class);
intent.putExtra("parameter", myStringParameter);
startActivity(intent);
and then read it in OtherActivity's onCreate method:
String parameter = getIntent().getStringExtra("parameter");
The Serializable interface is useful for marshalling more complicated objects; you don't need this if you're just dealing with String.
Edit - if you need to store small amounts of data persistently you could use SharedPreferences:
final String TAG = "MyApplication";
SharedPreferences prefs = getSharedPreferences(TAG, MODE_PRIVATE);
prefs.edit().putString("parameter", myStringParameter).commit();
and then to read the preferences:
final String TAG = "MyApplication";
SharedPreferences prefs = getSharedPreferences(TAG, MODE_PRIVATE);
String parameter = prefs.getString("parameter", null);
This data will be available even after your application closes.
Yes, use classes that implement Serializable. See my answer on this question: How to pass several variables of different types from one function to another on android?
Create some model classes which will hold data:
public class Page implements Serializable {
private String name;
private String description;
//and so on...
public Page(String name, String description) {
this.name = name;
this.description = description;
}
public String getName() {
return name;
}
public String getDescription() {
return description;
}
}
Now you can create a Page object and fill it with data(name, description) via the constructor. Optionally make some setters.
Page p = new Page("James", "Hello World");
startActivity(new Intent(context, MyActivity.class).putExtra("Page", p));
Retrieve your Page in MyActivity in its onCreate method:
Page p = (Page)getIntent().getExtras().getSerializable("Page");
Toast.makeText(this, "Name: " + p.getName() + ", Description:" + p.getDescription(), Toast.LENGTH_LONG).show();
I am aware about the methods mentioned above. But just for alternative thoughts, since you are mentioning the history word, how about using SQLite for this purpose?
In first activity, you can save the data, and in second activity, retrieve the data.
You can share data between your activities in various ways depending on how much data you need to save and how long the data needs to be saved.
Intents : Useful when transferring small bits of data between 2-3 screens
Singleton / Static data store classes : useful when sharing lot of data between various activities
SQLite DB : Large amount of data to be shared , also useful to save the same between app launches
Shared Preferences : Small amount of data , between app launches.
For your use-case its best to use intents unless the data is shared between more than 2-3 activities where option 2 would be a better solution
Sending immutable stateful objects between activities (messaging) is commendable, IMHO. It can be argued that OOP is about messaging, not objects. Two suggestions. 1) use the fully qualified name for the name:value pair so do:
private void launchManagePassword() {
Intent i= new Intent(this, ManagePassword.class); // no param constructor
PasswordState outState= new PasswordState(lengthKey,timeExpire,isValidKey,timeoutType,"",model.getIsHashPassword());
Bundle b= new Bundle();
b.putSerializable("jalcomputing.confusetext.PasswordState", outState);
i.putExtras(b);
startActivityForResult(i,REQUEST_MANAGE_PASSWORD); // used for callback
}
This will minimize runtime casting errors.
2) When you have the app working well and the object interface is stabilized consider refactoring the code to a Parcel for speed.
JAL
EDIT: AS REQUESTED Code
I would like to be able to transfer data from one activity to another activity. How can this be done?
Through the below code we can send the values between activities
use the below code in parent activity
Intent myintent=new Intent(Info.this, GraphDiag.class).putExtra("<StringName>", value);
startActivity(myintent);
use the below code in child activity
String s= getIntent().getStringExtra(<StringName>);
There are couple of ways by which you can access variables or object in other classes or Activity.
A. Database
B. shared preferences.
C. Object serialization.
D. A class which can hold common data can be named as Common Utilities it depends on you.
E. Passing data through Intents and Parcelable Interface.
It depend upon your project needs.
A. Database
SQLite is an Open Source Database which is embedded into Android. SQLite supports standard relational database features like SQL syntax, transactions and prepared statements.
Tutorials -- http://www.vogella.com/articles/AndroidSQLite/article.html
B. Shared Preferences
Suppose you want to store username. So there will be now two thing a Key Username, Value Value.
How to store
// Create object of SharedPreferences.
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
//now get Editor
SharedPreferences.Editor editor = sharedPref.edit();
//put your value
editor.putString("userName", "stackoverlow");
//commits your edits
editor.commit();
Using putString(),putBoolean(),putInt(),putFloat(),putLong() you can save your desired dtatype.
How to fetch
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
String userName = sharedPref.getString("userName", "Not Available");
http://developer.android.com/reference/android/content/SharedPreferences.html
C. Object Serialization
Object serlization is used if we want to save an object state to send it over network or you can use it for your purpose also.
Use java beans and store in it as one of his fields and use getters and setter for that
JavaBeans are Java classes that have properties. Think of
properties as private instance variables. Since they're private, the only way
they can be accessed from outside of their class is through methods in the class. The
methods that change a property's value are called setter methods, and the methods
that retrieve a property's value are called getter methods.
public class VariableStorage implements Serializable {
private String inString ;
public String getInString() {
return inString;
}
public void setInString(String inString) {
this.inString = inString;
}
}
Set the variable in you mail method by using
VariableStorage variableStorage = new VariableStorage();
variableStorage.setInString(inString);
Then use object Serialzation to serialize this object and in your other class deserialize this object.
In serialization an object can be represented as a sequence of bytes that includes the object's data as well as information about the object's type and the types of data stored in the object.
After a serialized object has been written into a file, it can be read from the file and deserialized that is, the type information and bytes that represent the object and its data can be used to recreate the object in memory.
If you want tutorial for this refer this link
http://javawithswaranga.blogspot.in/2011/08/serialization-in-java.html
Get variable in other classes
D. CommonUtilities
You can make a class by your self which can contain common data which you frequently need in your project.
Sample
public class CommonUtilities {
public static String className = "CommonUtilities";
}
E. Passing Data through Intents
Please refer this tutorial for this option of passing data.
http://shri.blog.kraya.co.uk/2010/04/26/android-parcel-data-to-pass-between-activities-using-parcelable-classes/
When you passing data from one activity to another activity perform like this
In Parent activity:
startActivity(new Intent(presentActivity.this, NextActivity.class).putExtra("KEY_StringName",ValueData));
or like shown below in Parent activity
Intent intent = new Intent(presentActivity.this,NextActivity.class);
intent.putExtra("KEY_StringName", name);
intent.putExtra("KEY_StringName1", name1);
startActivity(intent);
In child Activity perform as shown below
TextView tv = ((TextView)findViewById(R.id.textViewID))
tv.setText(getIntent().getStringExtra("KEY_StringName"));
or do like shown below in child Activity
TextView tv = ((TextView)findViewById(R.id.textViewID));
TextView tv1 = ((TextView)findViewById(R.id.textViewID1))
/* Get values from Intent */
Intent intent = getIntent();
String name = intent.getStringExtra("KEY_StringName");
String name1 = intent.getStringExtra("KEY_StringName1");
tv.setText(name);
tv.setText(name1);
Passing data from one activity to other in android
Intent intent = new Intent(context, YourActivityClass.class);
intent.putExtra(KEY, <your value here>);
startActivity(intent);
Retrieving bundle data from android activity
Intent intent = getIntent();
if (intent!=null) {
String stringData= intent.getStringExtra(KEY);
int numberData = intent.getIntExtra(KEY, defaultValue);
boolean booleanData = intent.getBooleanExtra(KEY, defaultValue);
char charData = intent.getCharExtra(KEY, defaultValue); }
Hopefully you will find the answer from here Send Data to Another Activity - Simple Android Login
You just have to send extras while calling your intent
like this:
Intent intent = new Intent(getApplicationContext(), SecondActivity.class); intent.putExtra("Variable Name","Value you want to pass"); startActivity(intent);
Now on the OnCreate method of your SecondActivity you can fetch the extras like this
If the value u sent was in "long"
long value = getIntent().getLongExtra("Variable Name which you sent as an extra", defaultValue(you can give it anything));
If the value u sent was a "String"
String value = getIntent().getStringExtra("Variable Name which you sent as an extra");
If the value u sent was a "Boolean"
Boolean value = getIntent().getStringExtra("Variable Name which you sent as an extra",defaultValue);
Your Purpose
Suppose You want to Go From Activity A to Activity B.
So We Use an Intent to switch activity
the typical code Looks Like this -
In Activity A [A.class]
//// Create a New Intent object
Intent i = new Intent(getApplicationContext(), B.class);
/// add what you want to pass from activity A to Activity B
i.putExtra("key", "value");
/// start the intent
startActivity(i);
In Activity B [B.class]
And to Get the Data From the Child Activity
Intent i = getIntent();
if (i!=null) {
String stringData= i.getStringExtra("key");
}
This works best:
Through the below code we can send the values between activities
use the below code in parent activity(PARENT CLASS/ VALUE SENDING CLASS)
Intent myintent=new Intent(<PARENTCLASSNAMEHERE>.this,<TARGETCLASSNAMEHERE>.class).putExtra("<StringName>", value);
startActivity(myintent);
use the below code in child activity(TARGET CLASS/ACTIVITY)
String s= getIntent().getStringExtra(<StringName>);
Please see here that "StringName" is the name that the destination/child activity catches while "value" is the variable name, same as in parent/target/sending class.