使用Fragment发送数据-Android

Question

I have a pager view and in the below method we instruct pager what to display based on the selected position.

This method return the fragment for the every position in the View Pager

 @Override
    public Fragment getItem(int position) {

        if(position == 0) 
        {
            Tab1 tab1 = new Tab1();
            return tab1;
        }
        else   if(position == 1)         
        {
            Tab2 tab2 = new Tab2();
            return tab2;
        }
        else  if(position == 2) {
            Tab3 tab3 = new Tab3();
            return tab3;
        }

        else  if(position == 3) {
            Tab4 tab4 = new Tab4();
            return tab4;
        }
        else  if(position == 4) {
            Tab5 tab5 = new Tab5();
            return tab5;
        }
        else {
            Tab6 tab6 = new Tab6();
            return tab6;
        }

    }

I want to sent argument with the Tab1 so that i can display data based on parameter

public class Tab1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v =inflater.inflate(R.layout.tab_1,container,false);
        return v;
    }
}

Please help

Answer 1

How to put data in Fragment

You can use Bundle to send data to Fragment

Tab1 someFragment = new Tab1();
Bundle bundle = new Bundle();
bundle.putInt(key, value);
someFragment.setArguments(bundle);

How to retrieve data from Fragment

In your Fragment, retrieve the data:

Bundle bundle = this.getArguments();
int myDataInt = bundle.getInt(key, defaultValue);

Read more about Bundle

Also, you can put your Entity classes in bundle, if your class implements Parcelable , in this way you can send class objects to-an-from Fragment

Answer 2

I would suggest you to make you fragment code to look something like this

public class Tab1 extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;


    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment Tab1.
     */
    // TODO: Rename and change types and number of parameters
    public static Tab1 newInstance(String param1, String param2) {
        Tab1 fragment = new Tab1();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    public Tab1() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_tab1, container, false);
    }


}

and in the view pager code you can pass as many number of parameters you need in you fragment. Above fragment uses 2 parameters for instance.

    if(position == 0) 
                {
                    Tab1 tab1 = Tab1.newInstance("param1","param2");
                    return tab1;
                }

Answer 3

Here's an example of a good standard Fragment with the ability to add arguments easily, by using newInstance()

public class MyFragment extends Fragment {

    public static MyFragment newInstance(int someInt, String someString, MyClass myClass){
        MyFragment myFrgament = new MyFragment();

        Bundle bundle = new Bundle();
        bundle.putInt("SomeIntKey", someInt);
        bundle.putString("SomeStringKey", someString);
        bundle.putSerializable("SomeSerializableKey", someSerializable);

        myFragment.setArguments(bundle);

        return myFragment;
    }



    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        Bundle arguments = getArguments();
        if (arguments != null){
            int someInt = arguments.getInt("SomeIntKey");
            String someString = arguments.getString("SomeStringKey");
            MyClass myClass = arguments.getSerializable("SomeSerializableKey");
        }

        // Normal Fragment onCreateView Code
    }
}

And you can create your fragment instance by calling

MyFragment fragment = MyFragment.newInstance(999, "Some String", new MyClass());

If you're passing in an instance of a class, make sure that class is implementing Serializable .