Android中Fragment通过接口回调传递数据到Activity中

MainActivity

package com.example.zhangyu.myapplication;import android.os.Bundle;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.support.v7.app.AppCompatActivity;import android.widget.TextView;public class MainActivity extends AppCompatActivity implements BlankFragment2.OnFragmentInteractionListener {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //1.创建Fragment的管理对象        FragmentManager fragmentManager = getSupportFragmentManager();        //2.获取Fragment的事务对象并且开启事务        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();        //3.调用事务中动态操作fragment的方法执行 add(添加到哪里，需要添加的fragment对象);        fragmentTransaction.add(R.id.fl_fragment, BlankFragment2.newInstance("参数1：hello1", "参数2：hello2"));        //4.提交事务        fragmentTransaction.commit();    }    @Override    public void onFragmentInteraction(String s) {        TextView tvMain =  findViewById(R.id.tv_main);        tvMain.setText(s);    }}

BlankFragment2

package com.example.zhangyu.myapplication;import android.content.Context;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;/** * A simple {@link Fragment} subclass. * Activities that contain this fragment must implement the * {@link OnFragmentInteractionListener} interface * to handle interaction events. * Use the {@link BlankFragment2#newInstance} factory method to * create an instance of this fragment. */public class BlankFragment2 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;    private OnFragmentInteractionListener mListener;    private TextView tvTest2;    public BlankFragment2() {        // Required empty public constructor    }    /**     * 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 BlankFragment2.     */    // TODO: Rename and change types and number of parameters    public static BlankFragment2 newInstance(String param1, String param2) {        BlankFragment2 fragment = new BlankFragment2();        Bundle args = new Bundle();        args.putString(ARG_PARAM1, param1);        args.putString(ARG_PARAM2, param2);        fragment.setArguments(args);        return fragment;    }    @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        View view = inflater.inflate(R.layout.fragment_blank_fragment2, container, false);        tvTest2 = view.findViewById(R.id.tv_test2);        tvTest2.append("\n" + mParam1);        tvTest2.append("\n" + mParam2);        tvTest2.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                onButtonPressed();            }        });        return view;    }    // TODO: Rename method, update argument and hook method into UI event    public void onButtonPressed() {        if (mListener != null) {            mListener.onFragmentInteraction("接口回调，Fragment传递数据到Activity");        }    }    @Override    public void onAttach(Context context) {        super.onAttach(context);        if (context instanceof OnFragmentInteractionListener) {            mListener = (OnFragmentInteractionListener) context;        } else {            throw new RuntimeException(context.toString()                    + " must implement OnFragmentInteractionListener");        }    }    @Override    public void onDetach() {        super.onDetach();        mListener = null;    }    /**     * This interface must be implemented by activities that contain this     * fragment to allow an interaction in this fragment to be communicated     * to the activity and potentially other fragments contained in that     * activity.     *      * See the Android Training lesson Communicating with Other Fragments for more information.     */    public interface OnFragmentInteractionListener {        // TODO: Update argument type and name        void onFragmentInteraction(String s);    }}

MainActivity

BlankFragment2

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