Question

当尝试加载来自另一个片段布局的片段时，我的应用程序停止了。

查看logcat时出现此错误：

android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.flow/com.example.flow.displayClasses.GroupScreens.HomeGroupFragment}; have you declared this activity in your AndroidManifest.xml?
        at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2005)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1673)
        at android.app.Activity.startActivityForResult(Activity.java:4586)
        at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:767)
        at android.support.v4.app.ActivityCompat.startActivityForResult(ActivityCompat.java:234)
        at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:881)
        at android.support.v4.app.FragmentActivity$HostCallbacks.onStartActivityFromFragment(FragmentActivity.java:995)
        at android.support.v4.app.Fragment.startActivity(Fragment.java:1084)
        at android.support.v4.app.Fragment.startActivity(Fragment.java:1073)
        at com.example.flow.displayClasses.GroupScreens.GroupsFragment$1.onItemClick(GroupsFragment.java:170)
        at android.widget.AdapterView.performItemClick(AdapterView.java:318)
        at android.widget.AbsListView.performItemClick(AbsListView.java:1159)
        at android.widget.AbsListView$PerformClick.run(AbsListView.java:3136)
        at android.widget.AbsListView$3.run(AbsListView.java:4052)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)

我来自哪里的片段：

package com.example.flow.displayClasses.GroupScreens;




import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.amigold.fundapter.BindDictionary;
import com.amigold.fundapter.FunDapter;
import com.amigold.fundapter.extractors.StringExtractor;
import com.example.flow.R;
import com.amigold.fundapter.BindDictionary;
import com.amigold.fundapter.FunDapter;
import com.amigold.fundapter.extractors.StringExtractor;
import android.content.Intent;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.example.flow.classes.Friends;
import com.example.flow.classes.Group;
import com.example.flow.classes.User;
import com.example.flow.displayClasses.FriendsScreen.FriendsFragment;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import android.view.MenuItem;
import android.support.annotation.Nullable;
import android.widget.Toast;


public class GroupsFragment extends Fragment {

    private final String TAG = this.getClass().getSimpleName();

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    private String mParam1;
    private String mParam2;

    ArrayList<Group> groups = new ArrayList<Group>();


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

    public static GroupsFragment newInstance(String param1, String param2) {
        GroupsFragment fragment = new GroupsFragment();
        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);

        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }


    }

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

        // Hardcoded for testing
        User u1 = new User("Bram", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u2 = new User("Bram1", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u3 = new User("Bram2", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u4 = new User("Bram3", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u5 = new User("Bram4", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u6 = new User("Bram5", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u7 = new User("Bram6", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u8 = new User("Bram7", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u9 = new User("Bram8", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u10 = new User("Bram9", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u11 = new User("Bram10", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u12 = new User("Bram11", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u13 = new User("Bram12", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u14 = new User("Bram13", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u15 = new User("Bram14", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u16 = new User("Bram15", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u17 = new User("Bram16", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");
        User u18 = new User("Bram17", "bram.de.plekker@student.ehb.be", "1234", "Captain Plek");

        ArrayList<User> ug1 = new ArrayList<User>();

        ug1.add(u1);
        ug1.add(u2);
        ug1.add(u3);

        ArrayList<User> ug2 = new ArrayList<User>();

        ug2.add(u4);
        ug2.add(u5);
        ug2.add(u6);
        //Collections.addAll(ug1, u4, u5, u6);

        ArrayList<User> ug3 = new ArrayList<User>();
        ug3.add(u1);
        ug3.add(u7);
        ug3.add(u8);
        ug3.add(u9);

        //Collections.addAll(ug1, u7, u8, u9);

        ArrayList<User> ug4 = new ArrayList<User>();
        Collections.addAll(ug1, u10, u11, u12);

        ArrayList<User> ug5 = new ArrayList<User>();
        Collections.addAll(ug1, u13, u14, u15);

        ArrayList<User> ug6 = new ArrayList<User>();
        Collections.addAll(ug1, u14, u5, u6);

        ArrayList<User> ug7 = new ArrayList<User>();
        Collections.addAll(ug1, u4, u10, u6, u18, u17);

        ArrayList<User> ug8 = new ArrayList<User>();
        Collections.addAll(ug1, u4, u5, u6);

        Group g1 = new Group(1, ug1, u1, "budies", u1, "date", true);
        Group g8 = new Group(2, ug1, u1, "budies", u1, "date", false);
        Group g9 = new Group(3, ug1, u1, "budies", u1, "date", true);
        Group g10 = new Group(4, ug1, u1, "budies", u1, "date", false);
        Group g11 = new Group(5, ug1, u1, "budies", u1, "date", true);
        Group g12 = new Group(6, ug1, u1, "budies", u1, "date", false);
        Group g13 = new Group(7, ug1, u1, "budies", u1, "date", false);
        Group g14 = new Group(8, ug1, u1, "budies", u1, "date", false);
        Group g15 = new Group(9, ug1, u1, "budies", u1, "date", true);
        Group g16 = new Group(10, ug1, u1, "budies", u1, "date", true);
        Group g17 = new Group(11, ug1, u1, "budies", u1, "date", true);
        Group g18 = new Group(12, ug1, u1, "budies", u1, "date", false);


        Collections.addAll(groups, g1, g8, g9, g10, g11, g12, g13, g14, g15, g16, g17, g18);

        ListView list = (ListView)RootView.findViewById(R.id.listView);
        CustomAdapter adapter = new CustomAdapter();
        list.setAdapter(adapter);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id)
            {
                Intent intent = new Intent(getActivity().getApplicationContext(), HomeGroupFragment.class);
                intent.putExtra("group", groups.get(position));

                startActivity(intent);
            }
        });

        return RootView;

    }


    class CustomAdapter extends BaseAdapter {

        int index;

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

        @Override
        public Object getItem(int position) {
            return position;
        }

        @Override
        public long getItemId(int id) {
            return id ;
        }

        public View getView(int i, View view, ViewGroup viewgroup) {

            if (groups.get(i).isPrepaid()) {
                view = getLayoutInflater().inflate(R.layout.groups_prepaid_layout, null);
            } else {
                view = getLayoutInflater().inflate(R.layout.groups_layout, null);
            }


            TextView textView = view.findViewById(R.id.Groupname);
            ImageView image = view.findViewById(R.id.member);
            String t = groups.get(i).getName();
            textView.setText(t);

            return view;
        }
    }
}

无法加载的片段：

package com.example.flow.displayClasses.GroupScreens;

import android.content.Intent;
import android.graphics.Color;
import android.graphics.Typeface;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.constraint.ConstraintLayout;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

import android.widget.Toast;

import com.amigold.fundapter.BindDictionary;
import com.amigold.fundapter.FunDapter;
import com.amigold.fundapter.extractors.StringExtractor;
import com.example.flow.Home;
import com.example.flow.R;
import com.example.flow.classes.Group;
import com.example.flow.classes.GroupExpense;
import com.example.flow.classes.UserExpense;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Objects;

public class HomeGroupFragment extends Fragment  {

    private final String TAG = this.getClass().getSimpleName();

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    private String mParam1;
    private String mParam2;

    ArrayList<GroupExpense> expense = new ArrayList<GroupExpense>();


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

    public static HomeGroupFragment newInstance(String param1, String param2) {
        HomeGroupFragment fragment = new HomeGroupFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    Group group;
    boolean status;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }

    }

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

        View RootView = inflater.inflate(R.layout.fragment_group, container, false);
/*
        super.onCreate(savedInstanceState);
        getActivity().setContentView(R.layout.fragment_group);
        ConstraintLayout layout =getActivity().findViewById(R.id.groupLayout);
        status = true;*/

        //harcoded

        UserExpense ux = new UserExpense(group.getUsers().get(2), 5.3);
        UserExpense ux1 = new UserExpense(group.getUsers().get(3), 6.91);

        ArrayList<UserExpense> uxs = new ArrayList<UserExpense>();
        Collections.addAll(uxs, ux, ux1);

        GroupExpense ex = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex1 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex2 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex3 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex4 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex5 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex6 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex7 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex8 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex9 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex10 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex11 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex12 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex13 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex14 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);
        GroupExpense ex15 = new GroupExpense(1, group.getUsers().get(1), "pitta", "voor te eten", 12.21, "13 oktober 2018", uxs);


        Collections.addAll(expense, ex, ex1, ex2, ex3, ex4, ex5, ex6, ex7, ex8, ex9, ex10, ex11, ex12, ex13, ex14, ex15);

        Intent intent = getActivity().getIntent();
        group = Objects.requireNonNull(intent.getExtras()).getParcelable("group");

        int id = intent.getIntExtra("group", -1);

        TextView t = getActivity().findViewById(R.id.Groupname);
        t.setText(group.getName());
        t.setId(group.getGroupId());

        setLayout();

    return RootView;
    }

    public void changeToMember(View view)
    {
        Button member =getActivity().findViewById(R.id.member);
        Button history =getActivity().findViewById(R.id.history);

        if (status) {
            member.setBackgroundResource(R.drawable.bottom_border_selected);
            member.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
            member.setTypeface(null, Typeface.BOLD);
            member.setTextColor(Color.parseColor("#4799E8"));

            history.setBackgroundResource(R.drawable.bottom_border);
            history.setTextSize(TypedValue.COMPLEX_UNIT_SP, 14);
            history.setTypeface(null, Typeface.NORMAL);
            history.setTextColor(Color.parseColor("#000000"));


            status = false;
            setLayout();
        }
    }

    public void changeToHistory(View view)
    {
        Button member = getActivity().findViewById(R.id.member);
        Button history =getActivity().findViewById(R.id.history);

        if (!status) {
            member.setBackgroundResource(R.drawable.bottom_border);
            member.setTextSize(TypedValue.COMPLEX_UNIT_SP, 14);
            member.setTypeface(null, Typeface.NORMAL);
            member.setTextColor(Color.parseColor("#000000"));

            history.setBackgroundResource(R.drawable.bottom_border_selected);
            history.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
            history.setTypeface(null, Typeface.BOLD);
            history.setTextColor(Color.parseColor("#4799E8"));
            status = true;
            setLayout();
        }
    }

    public void setLayout()
    {
        ListView list = getActivity().findViewById(R.id.expenseList);
        CustomAdapter ad = new CustomAdapter();
        list.setAdapter(ad);

        list.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id)
            {
                if (status) {
                    Intent intent = new Intent(getActivity().getApplicationContext(), GroupExpenseFragment.class);
                    intent.putExtra("expense", expense.get(position));
                    startActivity(intent);
                } else {
                    Intent intent = new Intent(getActivity().getApplicationContext(), Home.class);
                    intent.putExtra("group", group.getUsers().get(position));
                    startActivity(intent);
                }
            }
        });
    }

    public void leaveGroup(View view)
    {

    }

    class CustomAdapter extends BaseAdapter
    {

        @Override
        public int getCount()
        {

            return status ? expense.size() : group.getUsers().size();
        }

        @Override
        public Object getItem(int position)
        {
            return position;
        }

        @Override
        public long getItemId(int id)
        {
            return id;
        }

        public View getView(int i, View view, ViewGroup viewgroup)
        {

            if (status) {
                view = getLayoutInflater().inflate(R.layout.group_expense_layout, null);

                TextView user = view.findViewById(R.id.username);
                TextView subject = view.findViewById(R.id.subject);
                TextView amount = view.findViewById(R.id.expenseAmount);

                user.setText(expense.get(i).getCreditor().getName());
                subject.setText(expense.get(i).getName());
                amount.setText(String.valueOf(expense.get(i).getAmount()));
            } else {
                view = getLayoutInflater().inflate(R.layout.group_member_layout, null);

                TextView name = view.findViewById(R.id.nameMember);
                TextView admin = view.findViewById(R.id.privilege);
                TextView date = view.findViewById(R.id.date);

                name.setText(group.getUsers().get(i).getName());
                admin.setText("");
                date.setText("");
            }

            return view;
        }
    }
}

fragment_group.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".displayClasses.GroupScreens.HomeGroupFragment">

    <android.support.constraint.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:id="@+id/groupLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".displayClasses.GroupScreens.GroupFragment">
    <TextView
        android:id="@+id/Groupname"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:text="@string/group_name"
        android:textColor="#428EC4"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/member"
        style="@style/selected"
        android:layout_width="wrap_content"
        android:layout_marginTop="8dp"
        android:fontFamily="sans-serif"
        android:text="@string/history"
        android:textAllCaps="false"
        app:layout_constraintEnd_toStartOf="@+id/history"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/Groupname" />

    <Button
        android:id="@+id/history"
        style="@style/unselected"
        android:layout_width="wrap_content"
        android:layout_marginTop="8dp"
        android:fontFamily="sans-serif"
        android:text="@string/members"
        android:textAllCaps="false"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/member"
        app:layout_constraintTop_toBottomOf="@+id/Groupname" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:orientation="vertical"
        app:layout_constraintBottom_toTopOf="@+id/textView3"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/history">


        <ListView
            android:id="@+id/expenseList"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </ListView>
    </LinearLayout>

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="@string/leave_group"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    </android.support.constraint.ConstraintLayout>
</RelativeLayout>

group_expense_layout：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">

    <TextView
        android:id="@+id/username"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_centerVertical="true"
        android:layout_marginStart="25dp"
        android:text="Username"
        android:textSize="18sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/subject"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/username"
        android:layout_marginStart="65dp"
        android:layout_toEndOf="@+id/username"
        android:text="Name" />

    <TextView
        android:id="@+id/expenseAmount"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/username"
        android:layout_alignParentEnd="true"
        android:layout_marginStart="93dp"
        android:layout_marginEnd="25dp"
        android:layout_toEndOf="@+id/subject"
        android:text="TextView" />

</RelativeLayout>

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.flow">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label=" "
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        tools:ignore="GoogleAppIndexingWarning"
        tools:replace="android:icon,android:label">

        <activity
            android:theme="@style/AppTheme"
            android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:theme="@style/AppTheme.NoActionBar"
            android:name=".Home"
            android:parentActivityName=".displayClasses.LoginScreens.Login">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".displayClasses.LoginScreens.Login" />
        </activity>

        <activity
            android:theme="@style/AppTheme"
            android:name=".displayClasses.LoginScreens.activity_signup" />

        <activity
            android:theme="@style/AppTheme"
            android:name=".displayClasses.LoginScreens.Login" />

    </application>
</manifest>

但是据我所知，我不应该在清单中实现片段。那我需要重写Intent语句吗？是的，我该如何正确执行？我正在学习使用Android Studio的任何帮助，不胜感激。

Answer 1

android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.flow/com.example.flow.displayClasses.GroupScreens.HomeGroupFragment}; have you declared this activity in your AndroidManifest.xml?

您是否在清单中声明了活动？

编辑：

这里的代码

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id)
        {
            Intent intent = new Intent(getActivity().getApplicationContext(), HomeGroupFragment.class);
            intent.putExtra("group", groups.get(position));

            startActivity(intent);
        }

这不是初始化片段的方式。 startActivity（）用于启动活动。这就是崩溃发生的原因。

要使用香精，您必须执行碎片交易。在活动中创建一个FrameLayout，在其中添加该片段。更多信息How do I add a Fragment to an Activity with a programmatically created content view

Answer 2

您需要导入以下库：

 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;

然后在onClick中，您需要调用片段转换进行显示一个片段。目的是用于活动：

 HomeGroupFragment f = HomeGroupFragment.newInstance(position); // call the fragment you want to display with new instance
 //f.setArguments(bundle);  // if you want to send arguments
 FragmentManager fragmentManager = getSupportFragmentManager();        // for transaction, call fragment manager
 fragmentManager.beginTransaction().replace(R.id.main_frame, f).addToBackStack(null).commit();
  // addToBackStack = optional if ypu want to add the fragment to stack
  // commit = end the transaction

如果要发送参数：

 Bundle bundle = new Bundle();
 bundle.putInt("position", groups.get(position));
 bundle.putString("anyText", groups.getText());

无法从其他片段加载片段

2 个答案: