如何为具有相同内容的多个片段创建片段模板（具有变量和方法的类、布局）？答案

【问题标题】：How do I create a fragment template(class with variables and methods, layout) for multiple fragments with the same content?如何为具有相同内容的多个片段创建片段模板（具有变量和方法的类、布局）？
【发布时间】：2021-03-26 22:05:59
【问题描述】：

在主屏幕上，我有 7 个按钮（天）和一个片段。对于一周中的每一天，我想生成一个带有一些 EditTexts 和一个 ListView 的片段，但是创建 7 个具有相同布局和几乎相同类内容的片段似乎太重复了。我只在星期一和星期二这样做。

MondayFragment 和 TuesdayFragment 之间的唯一区别是，在 TuesdayFragment 中，我将变量 mondayTV 重命名为 tuesdayTV，在布局中，我更改了提交按钮和 ListView 的 ID。 Bundle 的键也不同。我认为不值得发布它，因为它与 MondayFragment 非常相似。

我想知道是否可以创建一个片段模板并使用它为给定我编写的这段代码的活动的每个按钮生成一个片段。在功能方面还有很多工作要做，但我无法摆脱这个想法。

MainActivity.java

package com.example.dietmanagement;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    public Button monday, tuesday, wednesday, thursday, friday, saturday, sunday;

    final MondayFragment mondayFragment = new MondayFragment();
    final TuesdayFragment tuesdayFragment = new TuesdayFragment();

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

        /*Intent i = getIntent();
        String current_user = i.getStringExtra("current_user");
        TextView current_user_txtview = findViewById(R.id.current_user);
        current_user_txtview.setText("Welcome, " + current_user);*/

        monday = (Button)findViewById(R.id.monday_btn);
        tuesday = (Button)findViewById(R.id.tuesday_btn);
        wednesday = (Button)findViewById(R.id.wednesday_btn);
        thursday = (Button)findViewById(R.id.thursday_btn);
        friday = (Button)findViewById(R.id.friday_btn);
        saturday = (Button)findViewById(R.id.saturday_btn);
        sunday = (Button)findViewById(R.id.sunday_btn);

        monday.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openFragment(mondayFragment);
                getDay(mondayFragment, "monday", (String) monday.getContentDescription());
            }
        });


        tuesday.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openFragment(tuesdayFragment);
                getDay(tuesdayFragment, "tuesday", (String) tuesday.getContentDescription());
            }
        });

    }

    private void openFragment(final Fragment fragment){
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.daysfragment, fragment);
        transaction.addToBackStack(null);
        transaction.commit();
    }

    public void getDay(final Fragment fragment, String key, String value)
    {
        Bundle bnd = new Bundle();
        bnd.putString(key, value);
        fragment.setArguments(bnd);
    }

}

Activity_main.xml

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/background_green"
    tools:context=".MainActivity">


    <Button
        android:id="@+id/tuesday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:contentDescription="@string/tuesday_context"
        android:text="@string/tuesday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.194"
        app:layout_constraintStart_toEndOf="@+id/monday_btn"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.017" />

    <TextView
        android:id="@+id/main_title"
        android:layout_width="147dp"
        android:layout_height="93dp"
        android:fontFamily="sans-serif-medium"
        android:text="@string/welcome_label"
        android:textColor="#FFFFFF"
        android:textSize="70sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.414"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.049" />

    <Button
        android:id="@+id/monday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:contentDescription="@string/monday_context"
        android:text="@string/monday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.16"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.017" />

    <Button
        android:id="@+id/thursday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:text="@string/thursday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.018"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.172" />

    <Button
        android:id="@+id/sunday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:text="@string/sunday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="28sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.786"
        app:layout_constraintStart_toEndOf="@+id/saturday_btn"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.172" />

    <Button
        android:id="@+id/saturday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:text="@string/saturday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="28sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.225"
        app:layout_constraintStart_toEndOf="@+id/friday_btn"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.172" />

    <Button
        android:id="@+id/friday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:text="@string/friday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.137"
        app:layout_constraintStart_toEndOf="@+id/thursday_btn"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.172" />

    <Button
        android:id="@+id/wednesday_btn"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:background="@drawable/button_states"
        android:text="@string/wednesday"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.369"
        app:layout_constraintStart_toEndOf="@+id/tuesday_btn"
        app:layout_constraintTop_toBottomOf="@+id/main_title"
        app:layout_constraintVertical_bias="0.017" />

    <ImageView
        android:id="@+id/logo"
        android:layout_width="52dp"
        android:layout_height="58dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="52dp"
        android:contentDescription="@string/app_name"
        app:layout_constraintStart_toEndOf="@+id/main_title"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_logo" />

    <TextView
        android:id="@+id/current_user"
        android:layout_width="362dp"
        android:layout_height="27dp"
        android:text="@string/current_user"
        android:textAlignment="viewEnd"
        android:textSize="18sp"
        app:layout_constraintBottom_toTopOf="@+id/main_title"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.938"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.318" />

    <FrameLayout
        android:id="@+id/daysfragment"
        android:layout_width="match_parent"
        android:layout_height="460dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

MondayFragment.java

    package com.example.dietmanagement;

import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;


public class MondayFragment extends Fragment {

    public TextView mondayTV;
    public ArrayList<String> hour_food;
    public ArrayAdapter<String> listViewAdapter;
    public ListView listView;
    public EditText input_meal;
    public EditText input_time;
    public Button submit;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_monday, container, false);

        mondayTV = (TextView) v.findViewById(R.id.day);
        Bundle bndMon = getArguments();
        String day = bndMon.getString("monday");
        mondayTV.setText(day);

        hour_food = new ArrayList<String>();
        listViewAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, hour_food);
        listView = (ListView)v.findViewById(R.id.monday_list_item);

        listView.setAdapter(listViewAdapter);

        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                hour_food.remove(position);
                Toast.makeText(getActivity(), "Meal Removed", Toast.LENGTH_SHORT).show();
                listViewAdapter.notifyDataSetChanged();
                return true;
            }
        });

        input_meal = v.findViewById(R.id.input_meal);
        input_time = v.findViewById(R.id.input_time);

        submit = (Button) v.findViewById(R.id.submit_food_btn);
        submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(TextUtils.isEmpty(input_time.getText())) {
                    Toast.makeText(getActivity(), "Empty time input", Toast.LENGTH_SHORT).show();
                } else if(TextUtils.isEmpty(input_meal.getText())){
                    Toast.makeText(getActivity(), "Empty meal input", Toast.LENGTH_SHORT).show();
                }
                else
                {
                    hour_food.add(String.format("%s - %s", input_meal.getText().toString(), input_time.getText().toString()));
                    listViewAdapter.notifyDataSetChanged();
                    input_meal.setText("");
                    input_time.setText("");
                }
            }
        });

        return v;
    }
}

fragment_monday.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/background_green"
    tools:context=".MondayFragment">

    <TextView
        android:id="@+id/day"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="@string/day" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/input_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:autofillHints="@string/time"
            android:hint="@string/time"
            android:inputType="time" />

        <EditText
            android:id="@+id/input_meal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:autofillHints="@string/meal"
            android:hint="@string/meal"
            android:inputType="textAutoCorrect|textCapSentences" />

    </LinearLayout>

    <Button
        android:id="@+id/submit_food_btn_monday"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/submit"
        android:background="@color/white"
        android:textColor="@color/background_green"
        android:layout_gravity="end"
        android:layout_marginTop="10dp"/>


    <ListView
        android:id="@+id/monday_list_item"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
</LinearLayout>

字符串.xml

【问题讨论】：

也许看看抽象类
为什么你的片段有不同的布局？似乎每个人都可能是 DayOfTheWeekFragment 的一个实例。

标签： java android android-layout android-fragments

【解决方案1】：

创建DayFragment 并仅布局一天。传递Fragment 的额外信息并使用该额外信息处理不同日期的情况（在您的情况下，看起来只有捆绑包中的String 不同）。

fragment_day.xml

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

    <TextView
        android:id="@+id/day"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="@string/day" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/input_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:autofillHints="@string/time"
            android:hint="@string/time"
            android:inputType="time" />

        <EditText
            android:id="@+id/input_meal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:autofillHints="@string/meal"
            android:hint="@string/meal"
            android:inputType="textAutoCorrect|textCapSentences" />

    </LinearLayout>

    <Button
        android:id="@+id/submit_food_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/submit"
        android:background="@color/white"
        android:textColor="@color/background_green"
        android:layout_gravity="end"
        android:layout_marginTop="10dp"/>

    <ListView
        android:id="@+id/list_item"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</LinearLayout>

DayFragment.java

public class DayFragment extends Fragment {

    private TextView dayTV;
    private ArrayList<String> hour_food;
    private ArrayAdapter<String> listViewAdapter;
    private ListView listView;
    private EditText input_meal;
    private EditText input_time;
    private Button submit;
    private String text;

    public DayFragment(String text) {
        this.text = text;
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_day, container, false);

        dayTV = v.findViewById(R.id.day);
        dayTV.setText(text);

        hour_food = new ArrayList<>();
        listViewAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, hour_food);
        listView = v.findViewById(R.id.list_item);

        listView.setAdapter(listViewAdapter);

        listView.setOnItemLongClickListener((parent, view, position, id) -> {
            hour_food.remove(position);
            Toast.makeText(getActivity(), "Meal Removed", Toast.LENGTH_SHORT).show();
            listViewAdapter.notifyDataSetChanged();
            return true;
        });

        input_meal = v.findViewById(R.id.input_meal);
        input_time = v.findViewById(R.id.input_time);

        submit = v.findViewById(R.id.submit_food_btn);
        submit.setOnClickListener(v1 -> {
            if (TextUtils.isEmpty(input_time.getText())) {
                Toast.makeText(getActivity(), "Empty time input", Toast.LENGTH_SHORT).show();
            } else if (TextUtils.isEmpty(input_meal.getText())) {
                Toast.makeText(getActivity(), "Empty meal input", Toast.LENGTH_SHORT).show();
            } else {
                hour_food.add(String.format("%s - %s", input_meal.getText().toString(), input_time.getText().toString()));
                listViewAdapter.notifyDataSetChanged();
                input_meal.setText("");
                input_time.setText("");
            }
        });

        return v;
    }
}

使用构造函数传递信息。

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        Button monday = findViewById(R.id.monday_btn),
                tuesday = findViewById(R.id.tuesday_btn),
                wednesday = findViewById(R.id.wednesday_btn),
                thursday = findViewById(R.id.thursday_btn),
                friday = findViewById(R.id.friday_btn),
                saturday = findViewById(R.id.saturday_btn),
                sunday = findViewById(R.id.sunday_btn);

        openFragment(monday);
        openFragment(tuesday);
        openFragment(wednesday);
        openFragment(thursday);
        openFragment(friday);
        openFragment(saturday);
        openFragment(sunday);
    }

    private void openFragment(Button btn) {
        btn.setOnClickListener(v -> {
            String contentDescription = btn.getContentDescription().toString();
            getSupportFragmentManager().beginTransaction()
                    .replace(R.id.daysfragment, new DayFragment(contentDescription))
                    .addToBackStack(null)
                    .commit();
        });
    }
}

在MainActivity openFragment() 方法中采用Button 参数和Button 并将onClickListener 设置为Button。当您单击任何Button 时，它会从该Button 获取内容描述并将其传递给Fragment 并使用该内容描述打开该Fragment。

【讨论】：