how to pass List<NameOfClassObject> from activity to fragment

Question

here is my code for retrieving data from database using databasehelper class

 public List<Hospitals> getHospitals(Context context){
    Hospitals hospitals = null;
    List<Hospitals> hospitalList = new ArrayList<>();
    openDatabase(context);
    Cursor cursor = database.rawQuery("SELECT * FROM buildings WHERE category_id = 1", null);
    cursor.moveToFirst();
    while(!cursor.isAfterLast()){
        hospitals = new Hospitals(cursor.getInt(0), cursor.getString(1), cursor.getFloat(2), cursor.getFloat(4));
        hospitalList.add(hospitals);
        cursor.moveToNext();
    }
    cursor.close();
    closeDatabase();

    return hospitalList;
}

And Here is my Class Hospital

public class Hospitals {
private int id;
private String name;
private Float latitude;
private Float longhitude;

public Hospitals(int id, String name, Float latitude, Float longhitude ){
    this.id = id;
    this.name = name;
    this.latitude = latitude;
    this.longhitude = longhitude;

}

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public Float getLatitude() {
    return latitude;
}

public void setLatitude(Float latitude) {
    this.latitude = latitude;
}

public Float getLonghitude() {
    return longhitude;
}

public void setLonghitude(Float longhitude) {
    this.longhitude = longhitude;
}

}

and here is my code in main activity to pass List<> to fragment

List<Hospitals> result = databaseHelper.getHospitals(this);
        Bundle bundle = new Bundle();
        bundle.putParcelableArrayList("valuesArray", result);
        GmapFragment gmapFragment = new GmapFragment();
        gmapFragment.setArguments(bundle);
        fragmentManager.beginTransaction().replace(R.id.mainLayout, gmapFragment).commit();

I got 2nd arguments in putParcelableArrayList() - Wrong 2nd argument type. Found: 'java.util.List', required: 'java.util.ArrayList

how to solve that error?

Answer 1

Wrong 2nd argument type. Found: 'java.util.List', required: 'java.util.ArrayList

At first Covert LIST to ARRAYLIST .

 List<Hospitals> result = databaseHelper.getHospitals(this);
 ArrayList<Hospitals> al_HOSPITAL = new ArrayList<>(result.size());
 al_HOSPITAL.addAll(result);

Then

Bundle bundle = new Bundle();
bundle.putSerializable("valuesArray", al_HOSPITAL);

You should use Parcelable .

AFAIK Using Parcelable better than Serializable .

• Parcelable is time-consuming and error-prone process .

Interface for classes whose instances can be written to and restored from a Parcel. Classes implementing the Parcelable interface must also have a non-null static field called CREATOR of a type that implements the Parcelable.Creator interface.

public class Hospitals implements Parcelable {

Finally Clean-Rebuild-Run . Hope this helps .

Answer 2

Implement Serializable in your model like this:

public class Hospitals implements Serializable {
    private int id;
    private String name;
    private Float latitude;
    private Float longhitude;

    public Hospitals(int id, String name, Float latitude, Float longhitude )
    {
       this.id = id;
       this.name = name;
       this.latitude = latitude;
       this.longhitude = longhitude;
    }
  ....
}

and put serializable into bunle:

List<Hospitals> result = databaseHelper.getHospitals(this);
    Bundle bundle = new Bundle();
    bundle.putSerializable("valuesArray", result);
    GmapFragment gmapFragment = new GmapFragment();
    gmapFragment.setArguments(bundle);
    fragmentManager.beginTransaction().replace(R.id.mainLayout, gmapFragment).commit();