Android Fragment与Frangment交互传值

前言

Fragment与Fragment主要用接口回调的方式进行交互，简单介绍一下本文的实现流程。首先一个MainActivity，两个Fragment(HomeFragment,MyFragment),两个Fragment依附与MainActivity,点击按钮要将HomeFragment输入框里的值展示在MyFragment页面:

1.定义一个接口类  FragmentListener

2.在MainActivity实现接口

3.在HomeFragment调用接口，传入EditText的输入内容

4.在MainActivity接收到值，调用MyFragment方法，传入值

5.在MyFragment展示传过来的值

先上效果

 定义一个接口类  FragmentListener

interface FragmentListener {

    void setText(String text);
}

Activity代码 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">


    <androidx.viewpager.widget.ViewPager
        android:id="@+id/main_viewpage"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1" />

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/main_tablayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="9" />

</LinearLayout>

public class MainActivity extends AppCompatActivity implements FragmentListener {

    private TabLayout mTabLayout;
    private ViewPager mViewPage;
    private ArrayList<String> mList = new ArrayList<>();
    private ArrayList<Fragment> mFragmentList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTabLayout = findViewById(R.id.main_tablayout);
        mViewPage = findViewById(R.id.main_viewpage);

        //添加标题
        mList.add("首页");
        mList.add("我的");
        mFragmentList.add(new HomeFragment());
        mFragmentList.add(new MyFragment());

        //设置ViewPage适配器
        mViewPage.setAdapter(new MyViewPageAdapter(getSupportFragmentManager()));
        //设置Tablayout联动
        mTabLayout.setupWithViewPager(mViewPage);

    }

    @Override
    public void setText(String text) {
        //获取MyFragment
        MyFragment fragment = (MyFragment) mFragmentList.get(1);
        //调用MyFragment中的setText传值
        if (text != null) {
            fragment.getText(text);
        }
    }

    //TabLayout适配器
    private class MyViewPageAdapter extends FragmentStatePagerAdapter {

        public MyViewPageAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

        @Override
        public int getCount() {
            return mList.size();
        }

        @Nullable
        @Override
        public CharSequence getPageTitle(int position) {
            return mList.get(position);
        }

    }
}

HomeFragment代码 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".HomeFragment">

    <EditText
        android:id="@+id/home_edit"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginLeft="15dp"
        android:layout_marginTop="20dp"
        android:layout_marginRight="15dp" />

    <Button
        android:id="@+id/home_bt"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginLeft="15dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="15dp"
        android:text="发送" />

</LinearLayout>

public class HomeFragment extends Fragment {

    private FragmentListener listener;
    private View inflate;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        inflate = inflater.inflate(R.layout.fragment_home, container, false);
        //初始化控件
        Button mBt = inflate.findViewById(R.id.home_bt);
        EditText mEdit = inflate.findViewById(R.id.home_edit);
        //点击按钮获取输入框内容调用接口方法传值
        mBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String text = mEdit.getText().toString().trim();
                if (listener != null && text != null) {
                    listener.setText(text);
                }
            }
        });
        return inflate;
    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        listener = (FragmentListener) context;
    }
}

MyFragment代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MyFragment">

    <TextView
        android:id="@+id/my_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:gravity="center"
        android:text="接受值"
        android:textColor="@color/black"
        android:textSize="16sp" />
</LinearLayout>

public class MyFragment extends Fragment {

    private View inflate;
    private TextView mText;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        inflate = inflater.inflate(R.layout.fragment_my, container, false);
        //初始化控件
        mText = inflate.findViewById(R.id.my_text);
        return inflate;
    }

    //获取到HomeFragment输入框的值赋值
    public void getText(String text) {
        mText.setText(text);
    }
    
}