I have PatientList class that extends fragment and other AddPatient class that extends ActionBarActivity. Now i want to pass static string from PatientList to AddPatient then its getting null.Where is the problem?? Why it is getting null???
not sure if I'm understanding but you can add a method in AddPatient and within PatientList call ((AddPatient) getActivity()).yourmethod(string)
in AddPatient:
public receiveString(String mystring)
{
// do whatever with mystring
}
in PatientList where needed e.g. onClick or something
((AddPatient) getActivity()).receiveString("hello")
if you want to pass data to an Activity you are starting with startActivity() instead you should do something like (if you are inside a fragment)
Intent intent = new Intent(getActivity(), AddPatient.class);
intent.putExtra("param_string", mystring)
getActivity().startActivity(intent);
in AddPatient
private String mMyString;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.yourlayout);
mMyString = getIntent().getStringExtra("param_string");
}
you can add Integer, Strings and Serializable stuff, multiple times
Instead of some dark magic proposed by #sherpya you should check how it is done by google at http://developer.android.com/training/basics/fragments/communicating.html
You should create an interface that is for that instead of creating dependency upon concrete Activity. What if you decide later to reuse this fragment in another Activity ?
In same cases you can use some event bus http://square.github.io/otto/
Related
How can I receive a custom ArrayList from another Activity via Intent? For example, I have this ArrayList in Activity A:
ArrayList<Song> songs;
How could I get this list inside Activity B?
The first part to understand is that you pass information from Activity A to Activity B using an Intent object, inside which you can put "extras". The complete listing of what you can put inside an Intent is available here: https://developer.android.com/reference/android/content/Intent.html (see the various putExtra() methods, as well as the putFooExtra() methods below).
Since you are trying to pass an ArrayList<Song>, you have two options.
The first, and the best, is to use putParcelableArrayListExtra(). To use this, the Song class must implement the Parcelable interface. If you control the source code of Song, implementing Parcelable is relatively easy. Your code might look like this:
Intent intent = new Intent(ActivityA.this, ActivityB.class);
intent.putParcelableArrayListExtra("songs", songs);
The second is to use the version of putExtra() that accepts a Serializable object. You should only use this option when you do not control the source code of Song, and therefore cannot implement Parcelable. Your code might look like this:
Intent intent = new Intent(ActivityA.this, ActivityB.class);
intent.putSerializableExtra("songs", songs);
So that's how you put the data into the Intent in Activity A. How do you get the data out of the Intent in Activity B?
It depends on which option you selected above. If you chose the first, you will write something that looks like this:
List<Song> mySongs = getIntent().getParcelableArrayListExtra("songs");
If you chose the second, you will write something that looks like this:
List<Song> mySongs = (List<Song>) getIntent().getSerializableExtra("songs");
The advantage of the first technique is that it is faster (in terms of your app's performance for the user) and it takes up less space (in terms of the size of the data you're passing around).
Misam is sending list of Songs so it can not use plain putStringArrayList(). Instead, Song class has to implement Parcelable interface. I already explained how to implement Parcelable painless in post here.
After implementing Parcelable interface just follow Uddhavs answer with small modifications:
// First activity, adding to bundle
bundle.putParcelableArrayListExtra("myArrayListKey", arrayList);
// Second activity, reading from bundle
ArrayList<Song> list = getIntent().getParcelableArrayListExtra("myArrayListKey");
I hope this helps you.
1. Your Song class should be implements Parcelable Class
public class Song implements Parcelable {
//Your setter and getter methods
}
2. Put your arraylist to putParcelableArrayListExtra()
public class ActivityA extends AppCompatActivity {
ArrayList<Song> songs;
#Override
protected void onCreate(Bundle savedInstanceState) {
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(), ActivityB.class)
.putParcelableArrayListExtra("songs", (ArrayList<? extends Parcelable>) songs));
}
});
}
3. In the ActivityB
public class ActivityB extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
Intent intent = getIntent();
final ArrayList<Song> songs = intent.getParcelableArrayListExtra("songs");
//Check the value in the console
buttonCheck.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
for (Song value : songs) {
System.out.println(value.getTitle());
}
}
});
}
to send a string arrayList in Java you can use,
intent.putStringArrayListExtra("key", skillist <- your arraylist);
and
List<String> listName = getIntent().getStringArrayListExtra("key");
Please note, bundle is one of the key components in Android system that is used for inter-component communications. All you have to think is how you can use put your Array inside that bundle.
Sending side (Activity A)
Intent intent1 = new Intent(MainActivity.this, NextActivity.class);
Bundle bundle = new Bundle();
Parcelable[] arrayList = new Parcelable[10];
/* Note: you have to use writeToParcel() method to write different parameters values of your Song object */
/* you can add more string values in your arrayList */
bundle.putParcelableArray("myParcelableArray", arrayList);
intent1.putExtra("myBundle", bundle);
startActivity(intent1);
Receiving side (Activity B)
Bundle bundle2 = getIntent().getBundleExtra("myBundle"); /* you got the passsed bundle */
Parcelable[] arrayList2 = bundle.getParcelableArray("myParcelableArray");
I have three activities A,B and C. I need to pass some data from activity A to activity C. But the navigation is from A to B to C i.e. I can't go to activity C from activity A directly. I don't want to pass my data to activity B from A and I don't want to use any external storage like sqlite or shared preferences. Can it be done through intent ? If yes , how ? If no, is there any other way ?
use Interface to communicate with other Activity.
or you can make your variable public static on Activity1
The problem is that your third activity has no way of knowing which activity sent the bundle. You need to add a field that identifies what type of bundle this is so you can process accordingly. For instance, in activity 1:
Intent i = new Intent(ActivityOne.this, ActivityTwo.class);
i.putExtra("activity", (int)1);
i.putExtra("key", value);
startActivity(i);
Then in 3rd activity:
Bundle extras = getIntent().getExtras();
if(extras !=null) {
int typeAct = extras.getInt("activity");
if (typeAct == 1) {
//do something with data
}
There are various ways to send the data from one activity to other activity,
Now as you can not use intent so I would suggest you to go with either Application class or create a Global singleton class to hold your data.
Please refer following link
https://androidresearch.wordpress.com/2012/03/22/defining-global-variables-in-android/
Following are the steps to create an application class:
Step 1: Create any class and extend it with the Application class:
public class Globals extends Application{
private int data=200;
public int getData(){
return this.data;
}
public void setData(int d){
this.data=d;
}
}
Step 2: Defining the application class in the manifest file:
<application
android:name=".Globals"
.... />
Step 3:Now by calling getApplication() in any of the activity you get your application class. Just typecast it and call the methods required.
Globals g = (Globals)getApplication();
int data=g.getData();
I hope this will help.
make one interface :
public interface PassData {
public void data(String data);
}
if you want to pass the data from activity A to activity C then :
from Activity A you need to pass the data like this:then on Activity A.
PassData passData;// make it global variable
passData.data("Your DATA WHICH YOU WANT TO SEND TO ACTIVITY C");
In Activity C :
ActivityC extends AppCompatActivity implements PassData{
//onCreate Stuff
#Override
public void data(String data) {
// print this data and see it's coming or not
}
yes sure.
for example in your Activity
class ActivityA extend Activity{
public static String abc = "hello";
}
in ActivityC
ActivityC extend Activity{
onCreate(){
String a = ActivityA.abc;
Log.d("test",a);
}
}
Im trying to figure a way how to call an activity that an adapter has started. Is there a way to get the instance of the activity from startactivity and make a method call into the activity ?
I'ved got an adapter that has a list
public class LanguageDownloadRVAdapter extends RecyclerView.Adapter<LanguageDownloadRVAdapter.DownloadViewHolder>{
And in this adapter, it starts a particular activity called MainActivity
context.startActivity(new Intent(context, MainActivity.class));
((Activity)context).finish();
Here is the MainActivity that it starts
public class MainActivity extends AppCompatActivity implements IabBroadcastListener{
How can I make a call from the adapter to a method in the MainActivity. (im just trying to perform inapp purchase which is implemented in the MainActivity). so how can i do something like this.
mainactivity.perform_inapp_purchase();
Try to use EventBus for passing data between activity and list adapter. You can do it in the same way for passing data between activity and fragment.
This work the same way as storing data in global variable (in a fancier way)
In the adapter:
Add a new Field private Context mContext;
In the adapter Constructor add one more parameter as below, and assign it into class level variable:
public LanguageDownloadRVAdapter(......,Context context){
//your code.
this.mContext=context;
}
In the Adapter where you want to call Activity's perform_inapp_purchase() method:
if(mContext instanceof MainActivity){
((MainActivity) mContext).perform_inapp_purchase();
}
More Generalized Approach:
If you need to use this same adapter for more than one activity then :
Create an Interface
public interface InAppPerchaceInterface{
void perform_inapp_purchase();
}
Implement this interface in activities
Then in Adapter, call like below:
if(mContext instanceof InAppPerchaceInterface){
((InAppPerchaceInterface) mContext).perform_inapp_purchase();
}
You can store the instance in the application class, but you should be careful about the memory leaks.
In the onCreate of your activity
protected void onCreate(Bundle savedInstanceState)
{
// get the instance using this and store it in the application class or in the place that you want to call from it
}
From where will you call your method?
I didn't understand the situation.
I searched in site and there were similar questions as mine but none of theme were not my answer
look at this picture:
so it is clear that i want to start CrimeActivity by sending an intent from CrimeListFragment + an extra in its intent
the book that i read for android programming its author said:
Starting an activity from a fragment works nearly the same as starting an activity from another activity.
You call the Fragment.startActivity(Intent) method, which calls the corresponding Activity
method behind the scenes
CrimeListFragment.java :
public void onListItemClick(ListView l, View v, int position, long id) {
// Get the Crime from the adapter
Crime c = ((CrimeAdapter)getListAdapter()).getItem(position);
// Start CrimeActivity
Intent i = new Intent(getActivity(), CrimeActivity.class);
i.putExtra(CrimeFragment.EXTRA_CRIME_ID, c.getId());
startActivity(i);
}
the second part is now retrieving the intent and its extra and the author said about that:
There are two ways a fragment can access data in its activity’s intent: an easy, direct shortcut and a
complex, flexible implementation. First, you are going to try out the shortcut. Then you will implement
the complex and flexible solution that involves fragment arguments.
and my problem is about the first way, the shortcut
In the shortcut, CrimeFragment will simply use the getActivity() method to access the
CrimeActivity’s intent directly. Return to CrimeFragment and add the key for the extra. Then, in
onCreate(Bundle), retrieve the extra from CrimeActivity’s intent and use it to fetch the Crime
CrimeFragment.java :
public class CrimeFragment extends Fragment {
public static final String EXTRA_CRIME_ID =
"com.bignerdranch.android.criminalintent.crime_id";
private Crime mCrime;
...
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mCrime = new Crime();
UUID crimeId = (UUID)getActivity().getIntent()
.getSerializableExtra(EXTRA_CRIME_ID);
mCrime = CrimeLab.get(getActivity()).getCrime(crimeId);
}
The downside to direct retrieval
Having the fragment access the intent that belongs to the hosting activity makes for simple code.
However, it costs you the encapsulation of your fragment. CrimeFragment is no longer a reusable
building block because it expects that it will always be hosted by an activity whose Intent defines an
extra named EXTRA_CRIME_ID.
This may be a reasonable expectation on CrimeFragment’s part, but it
means that CrimeFragment, as currently written, cannot be used with
just any activity.
My question and problem is the last sentence, why this Fragment (CrimeFragment) cannot be used with just any Activity???
The author explains it. Your CrimeFragment, in its onCreate() method, gets its hosting activity (through getActivity()) and then attempts to get an UUID from the Intent used to start that Activity.
This means that any activity containing your CrimeFragment now has to obey this rule, i.e. its intent should have (in it) an extra defined by the name EXTRA_CRIME_ID. If that activity does not comply, you'll see an exception being thrown in CrimeFragment's onCreate().
Try having this fragment in a new activity created by yourself to see what happens.
retrieval in onActivityCreated()
#Override
public void onActivityCreated(Bundle savedInstanceState) {
if (savedInstanceState != null) {
....
}
else {
UUID crimeId = (UUID)getActivity().getIntent().getSerializableExtra(EXTRA_CRIME_ID);
}
}
I have two activities says Activity A and Activity B.
Activity A contains Fragments AF1,AF2.
Activity B contains Fragments BF1,BF2.
Currently I am in AF1.
How can we pass data(bundle) from AF1 to AF2?
How can we pass data (bundle) from AF1 to BF2?
The first approach is to use interfaces. Here is a breakdown of the steps:
Create an interface in your AF1 fragment - a method in that interface will be called and the data passed back through the arguments passed to it. In your activity, you implement that interface and override the method. Once the method is called, you could create another method in AF2 which you can easily call and pass the corresponding values.
The above described process has been shown in this tutorial: how to communicate between fragments and activities
FragmentOne.java
public class FragmentOne extends Fragment{
private Activity activity;
#Override
public void onAttach(Activity act){
super.onAttach(act);
activity = act;
}
#Override
public View onCreateView(..........){
/* somethind was clicked here*/
try{
((OnSomethingClickedListener) activity).updateActivity(position);
}catch(ClassCastException e){}
return view;
}
public interface OnSomethingCllickedListener{
void updateActivity(int position);
}
}
In your activity, implement the interface and override the method above:
public class ActivityOne extends Activity implements FragmentOne.OnSomethingCllickedListener{
#Override
public void onCreate(Bundle saveInstanceState){
/* as usual here */
}
#Override
public void updateActivity(int position){
/* call FragmentTwo's method here to update the view based on the position of item clicked here*/
FragmentTwo.updateView(position);
}
}
Secondly, to decouple your activities from your fragments, use EventBus library. This is quite simple and goes like this:
Download the jar file and add it to your project.
Create an Event class
Register for Events in your activities (unregister inside onDestroy)
When you want to notify the activity of the events, just call EventBus' post method and pass back the respective data.
Inside your activity, you need a method onEvent(YourEventClassName event) then you can pass the values respectively to your fragments as needed.
I hope this helps.
Code to pass and retrieve data:
Bundle bundle =new Bundle();
bundle.putString("message", message);
Frag1 _fragment = new Frag1();
fragmentTransaction.replace(android.R.id.content, _fragment);
fragmentTransaction.commit();
Bundle bundle=getArguments(); //get data
if(bundle!=null)
{
message=bundle.getString("message") ;
}