从另一个片段中调用元素

Question

如何从片段1到片段2调用回收器视图？因此我可以在片段1的recyclerview中添加项目，并从片段1的视图而不是片段2的视图识别recyclerview。

当我单击fab时，onClickListener无法正常工作，并且没有任何动作。

我要做的是，当我单击fragment2中的晶圆厂时，将在片段1的回收站视图中添加一个项目。

这是片段1的JAVA代码

package com.example.admin.test2;


import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;


/**
 * A simple {@link Fragment} subclass.
 */
public class MainScreen extends Fragment {

    private ArrayList<ExampleItem> mExampleList;

    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        View view = inflater.inflate (R.layout.fragment_main_screen, container, false);

        mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);

            mExampleList = new ArrayList <>();
            //   mExampleList.add(new ExampleItem(R.drawable.ic_library_add_black_24dp, "", "", "ADD EXPENSES"));


            mRecyclerView = view.findViewById(R.id.recyclerView);
            mRecyclerView.setHasFixedSize(true);
            mLayoutManager = new LinearLayoutManager(getContext());
            mAdapter = new ExampleAdapter(mExampleList);

            mRecyclerView.setLayoutManager(mLayoutManager);
            mRecyclerView.setAdapter(mAdapter);

        return view;
    }

}

这是片段2的JAVA代码

package com.example.admin.test2;


import android.app.DatePickerDialog;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Context;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Spinner;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

public class Expense extends Fragment {


    public Expense() {
        // Required empty public constructor
    }
    //SPINNER
    Spinner sp1;
    CustomAdapter adapter;
    String[] names = {"Food & Drink", "Shopping", "Transportation", "Home", "Bills & Fees", "Entertainment", "Healthcare", "Education", "Beauty", "Others"};
    int[] images = {R.drawable.food, R.drawable.shopping, R.drawable.transportation, R.drawable.home, R.drawable.bills, R.drawable.entertainment, R.drawable.medical, R.drawable.education, R.drawable.beauty, R.drawable.others};

    //DATE PICKER
    private EditText mDisplayDate;
    private DatePickerDialog.OnDateSetListener mDateSetListener;

    //FOR THE ADD ITEM
    FloatingActionButton fab;
    private ArrayList<ExampleItem> mExampleList;
    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private RecyclerView.LayoutManager mLayoutManager;

    EditText amount;
    EditText detail;

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


        //spinner
        sp1 = (Spinner)view.findViewById(R.id.customSpinner);

        adapter = new CustomAdapter(getActivity(), names, images);
        sp1.setAdapter(adapter);

        //fab onClick - sending values to the recycler view
        fab = (FloatingActionButton) view.findViewById(R.id.fabs);
        amount = (EditText) view.findViewById(R.id.textAmountt);
        detail = (EditText) view.findViewById(R.id.textDetailss);

        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String amountValue = amount.getText().toString();
                String detailValue = detail.getText().toString();

                mExampleList.add(0, new ExampleItem(R.drawable.entertainment, "Entertainment", detailValue, "₱ " + amountValue));
                mAdapter.notifyDataSetChanged();
            }
        });

        View view2 = inflater.inflate (R.layout.fragment_main_screen, container, false);
        mExampleList = new ArrayList <>();
        //   mExampleList.add(new ExampleItem(R.drawable.ic_library_add_black_24dp, "", "", "ADD EXPENSES"));

        mRecyclerView = view2.findViewById(R.id.recyclerView);
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new LinearLayoutManager(getContext());
        mAdapter = new ExampleAdapter(mExampleList);
        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerView.setAdapter(mAdapter);

        int pos = sp1.getSelectedItemPosition();








        //date picker
        mDisplayDate = (EditText) view.findViewById(R.id.datePick);

        mDisplayDate.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Calendar cal = Calendar.getInstance();
                int year = cal.get(Calendar.YEAR);
                int month = cal.get(Calendar.MONTH);
                int day = cal.get(Calendar.DAY_OF_MONTH);

                DatePickerDialog dialog = new DatePickerDialog(getActivity(),
                        android.R.style.Theme_Holo_Light_Dialog_MinWidth,
                        mDateSetListener,
                        year, month, day);
                dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                dialog.show();

            }
        });

        mDateSetListener = new DatePickerDialog.OnDateSetListener() {
            @Override
            public void onDateSet(DatePicker view, int year, int month, int day) {
                //Calendar calendar = Calendar.getInstance();
                //String currentDate = DateFormat.getDateInstance().format(calendar.getTime());

                month = month + 1;
                String date = month + "-" + day + "-" + year;
                mDisplayDate.setText(date);


            }
        };

        return view;
    }

}

这是活动JAVA

package com.example.admin.test2;

import android.graphics.Color;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.Window;
import android.view.WindowManager;


public class ScreenOne extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener{


    BottomNavigationView bottomNavigationView;

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

        bottomNavigationView = findViewById (R.id.Navbot);

        bottomNavigationView.setOnNavigationItemSelectedListener (this);
        bottomNavigationView.setSelectedItemId (R.id.home);


    }

    Income incomeFragment = new Income ();
    Expense expenseFragment = new Expense ();
    Savings savingsFragment = new Savings ();
    MainScreen mainFragment = new MainScreen ();
    Charts chartsFragment = new Charts ();

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId ()){
            case R.id.home:
                getSupportFragmentManager ().beginTransaction ().setCustomAnimations (R.anim.fade_in, R.anim.fade_out).replace (R.id.replaceLayout, mainFragment).commit ();
                updateStatusBarColor("#77dd77");
                return true;

            case R.id.income:
                getSupportFragmentManager ().beginTransaction ().setCustomAnimations (R.anim.fade_in, R.anim.fade_out).replace (R.id.replaceLayout, incomeFragment).commit ();
                updateStatusBarColor("#779ecb");
                return true;

            case R.id.expense:
                getSupportFragmentManager ().beginTransaction ().setCustomAnimations (R.anim.fade_in, R.anim.fade_out).replace (R.id.replaceLayout, expenseFragment).commit ();
                updateStatusBarColor("#ff6961");
                return true;

            case R.id.savings:
                getSupportFragmentManager ().beginTransaction ().setCustomAnimations (R.anim.fade_in, R.anim.fade_out).replace (R.id.replaceLayout, savingsFragment).commit ();
                updateStatusBarColor("#77dd77");
                return true;

            case R.id.chart:
                getSupportFragmentManager ().beginTransaction ().setCustomAnimations (R.anim.fade_in, R.anim.fade_out).replace (R.id.replaceLayout, chartsFragment).commit ();
                updateStatusBarColor("#77dd77");
                return true;

        }

        return false;
    }

    public void updateStatusBarColor(String color){// Color must be in hexadecimal fromat
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(Color.parseColor(color));
        }
    }
}

Answer 1

您可以使用EventBus来组织片段/活动之间的通信。

Answer 2

在应用程序中创建一个接口。

public interface MyInterface {
void updateFragment(Example value);// you can pass your object also in the arguments 
}

在“活动”中实现此界面。

public class ScreenOne extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener ,MyInterface  {

@Override
public void updateFragmnt(Example value){// if you pass arguments then call the method of fragment which recycle view you have to update

// update your Fragment Recycle view here .
  expenseFragment.updateData(value);
}

}

从onclick添加项目时，在fragment上执行这些操作。

   fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String amountValue = amount.getText().toString();
            String detailValue = detail.getText().toString();

           ExampleItem example = new ExampleItem(R.drawable.entertainment, "Entertainment", detailValue, "₱ " + amountValue);

           ((getActivity())MyInterface).updateFragmnt(example);
        }
    });

最终在Expense片段中添加方法...

public class Expense extends Fragment {

public void updateData(Example example){

// add this data in your arraylist 
// notify your adapter
// and magic begin 

}

}