I can use Parcelable in Activity but I don't know how to use it in Fragment.
I have a ListFragment in FragmentGet to display all rows database in ListView, I want to get details of ListView in another Fragment when it's clicked, I use Parcelable to passing data between Fragments.
This is my Test.java:
import android.os.Parcel;
import android.os.Parcelable;
public class Test implements Parcelable {
private int studentNumber;
private String studentName;
private String studentFamily;
public int getStudentNumber() {
return studentNumber;
}
public void setStudentNumber(int studentNumber) {
this.studentNumber = studentNumber;
}
public String getStudentName() {
return studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public String getStudentFamily() {
return studentFamily;
}
public void setStudentFamily(String studentFamily) {
this.studentFamily = studentFamily;
}
public Test() {
}
public Test(Parcel read) {
studentNumber = read.readInt();
studentName = read.readString();
studentFamily = read.readString();
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel write, int flags) {
write.writeInt(studentNumber);
write.writeString(studentName);
write.writeString(studentFamily);
}
public static final Parcelable.Creator<Test> CREATOR =
new Parcelable.Creator<Test>() {
@Override
public Test createFromParcel(Parcel source) {
return new TestP(source);
}
@Override
public Test[] newArray(int size) {
return new TestP[size];
}
};
}
In FragmentSend.java I want to send data to FragmentGet.java, this is the code:
public class FragmentSend extends ListFragment {
// Classes
TestReadData readData;
TestDataSource dataSource;
private List<Test> listTest;
public FragmentSend() {
// Required empty public constructor
}
@TargetApi(Build.VERSION_CODES.M)
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.fragment_send, container, false);
readData = new TestReadData(getContext());
dataSource = new TestDataSource(getContext());
refreshStudentList(inflater);
return layout;
}
public void refreshStudentList(LayoutInflater inflater) {
listTest = readData.getAllStudentRows();
ArrayAdapter<Test> testAdapter = new TestFragmentListAdapter(inflater.getContext(), listTest);
setListAdapter(testAdapter);
}
@Override
public void onResume() {
super.onResume();
dataSource.open();
}
@Override
public void onPause() {
super.onPause();
dataSource.close();
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
Test model = listTest.get(position);
// this three line code is for Activity not Fragment!
Intent intent = new Intent(getContext(), FragmentGet.class);
intent.putExtra("Student", model);
// startActivity(intent);
// I use this code for fragment
Fragment fragmentGet = new FragmentGet();
fragmentGet.setArguments(intent.getExtras());
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_container, fragmentGet);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
In the FragmentGet.java I get data like this:
public class FragmentGet extends Fragment {
// Classes
Test model;
// Variables
private List<Test> listTest;
public FragmentGet () {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View layout = inflater.inflate(R.layout.fragment_get, container, false);
// Classes Associated
model = new Test(Parcel.obtain());
Bundle bundle = getActivity().getIntent().getExtras();
model = bundle.getParcelable("Student");
return layout;
}
When I run the app, I will get this error:
Attempt to invoke virtual method 'android.os.Parcelable android.os.Bundle.getParcelable(java.lang.String)' on a null object reference
how can I fix this error?
Create Parcelable class without plugin in Android Studioimplements Parcelable in your class and then put cursor on "implements Parcelable" and hit Alt+Enter and select Add Parcelable implementation (see image). that's it.
Suppose you have a class Foo implements Parcelable properly, to put it into Intent in an Activity: Intent intent = new Intent(getBaseContext(), NextActivity. class); Foo foo = new Foo(); intent. putExtra("foo ", foo); startActivity(intent);
To actually pass the data between fragments, we need to create a ViewModel object with an activity scope of both the fragments, initialize the ViewModel , and set the value of the LiveData object.
Parcelable is a serialization mechanism provided by Android to pass complex data from one activity to another activity.In order to write an object to a Parcel, that object should implement the interface “Parcelable“.
Passing data to Fragments
is carried by using Bundles
but not Intents
.
In FragmentSend
change
Intent intent = new Intent(getContext(), FragmentGet.class);
intent.putExtra("Student", model);
Fragment fragmentGet = new FragmentGet();
fragmentGet.setArguments(intent.getExtras());
to this
Fragment fragmentGet = new FragmentGet();
Bundle bundle = new Bundle();
bundle.putParcelable("Student", model);
fragmentGet.setArguments(bundle);
And to receive the data in FragmentGet
change
Bundle bundle = getActivity().getIntent().getExtras();
model = bundle.getParcelable("Student");
to
Bundle bundle = this.getArguments();
if (bundle != null) {
model = bundle.getParcelable("Student");
}
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