Java 工具栏没有显示

我需要工具栏显示在所有屏幕上，但一旦

ResultActivity，工具栏就会消失。Java启动了。有人知道如何显示工具栏吗？我尝试使用
getSupportActionBar（）.setDisplayHomeAsUpEnabled（true）并将
activity
更改为
AppCompatActivity
，但我似乎无法使用后退按钮

Java

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

import java.util.List;


public class QuizF extends Fragment {
List<Question> quesList;
int score=0;
int qid=0;
Question currentQ;
TextView txtQuestion;
RadioButton rda, rdb, rdc;
Button butNext;

View myView;

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


    DbHelper db=new DbHelper(getActivity());
    quesList=db.getAllQuestions();
    currentQ=quesList.get(qid);
    txtQuestion=(TextView)myView.findViewById(R.id.textView1);
    rda=(RadioButton)myView.findViewById(R.id.radio0);
    rdb=(RadioButton)myView.findViewById(R.id.radio1);
    rdc=(RadioButton)myView.findViewById(R.id.radio2);
    butNext=(Button)myView.findViewById(R.id.button1);
    setQuestionView();
    butNext.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RadioGroup grp = (RadioGroup) myView.findViewById(R.id.radioGroup1);
            RadioButton answer = (RadioButton) myView.findViewById(grp.getCheckedRadioButtonId());
            Log.d("yourans", currentQ.getANSWER() + " " + answer.getText());
            if (currentQ.getANSWER().equals(answer.getText())) {
                score++;
                Log.d("score", "Your score" + score);
            }
            if (qid < 5) {
                currentQ = quesList.get(qid);
                setQuestionView();
            } else {
                Intent intent = new Intent(getActivity(), ResultActivity.class);
                Bundle b = new Bundle();
                b.putInt("score", score); //Your score
                intent.putExtras(b); //Put your score to your next Intent
                startActivity(intent);
                getActivity().finish();
            }
        }
    });
    return myView;
}


public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getActivity().getMenuInflater().inflate(R.menu.activity_quiz, menu);
    return true;
}
private void setQuestionView()
{
    txtQuestion.setText(currentQ.getQUESTION());
    rda.setText(currentQ.getOPTA());
    rdb.setText(currentQ.getOPTB());
    rdc.setText(currentQ.getOPTC());
    qid++;
}
}

Java

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;
import java.util.List;

public class DbHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "triviaQuiz";
// tasks table name
private static final String TABLE_QUEST = "quest";
// tasks Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_QUES = "question";
private static final String KEY_ANSWER = "answer"; //correct option
private static final String KEY_OPTA= "opta"; //option a
private static final String KEY_OPTB= "optb"; //option b
private static final String KEY_OPTC= "optc"; //option c
private SQLiteDatabase dbase;
public DbHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
    dbase=db;
    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUEST + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_QUES
            + " TEXT, " + KEY_ANSWER+ " TEXT, "+KEY_OPTA +" TEXT, "
            +KEY_OPTB +" TEXT, "+KEY_OPTC+" TEXT)";
    db.execSQL(sql);        
    addQuestions();
    //db.close();
}
private void addQuestions()
{
    Question q1=new Question("Which company is the largest manufacturer" +
            " of network equipment?","HP", "IBM", "CISCO", "CISCO");
    this.addQuestion(q1);
    Question q2=new Question("Which of the following is NOT " +
            "an operating system?", "SuSe", "BIOS", "DOS", "BIOS");
    this.addQuestion(q2);
    Question q3=new Question("Which of the following is the fastest" +
            " writable memory?","RAM", "FLASH","Register","Register");
    this.addQuestion(q3);
    Question q4=new Question("Which of the following device" +
            " regulates internet traffic?", "Router", "Bridge", "Hub","Router");
    this.addQuestion(q4);
    Question q5=new Question("Which of the following is NOT an" +
            " interpreted language?","Ruby","Python","BASIC","BASIC");
    this.addQuestion(q5);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_QUEST);
    // Create tables again
    onCreate(db);
}
// Adding new question
public void addQuestion(Question quest) {
    //SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_QUES, quest.getQUESTION()); 
    values.put(KEY_ANSWER, quest.getANSWER());
    values.put(KEY_OPTA, quest.getOPTA());
    values.put(KEY_OPTB, quest.getOPTB());
    values.put(KEY_OPTC, quest.getOPTC());
    // Inserting Row
    dbase.insert(TABLE_QUEST, null, values);        
}
public List<Question> getAllQuestions() {
    List<Question> quesList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    dbase=this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Question quest = new Question();
            quest.setID(cursor.getInt(0));
            quest.setQUESTION(cursor.getString(1));
            quest.setANSWER(cursor.getString(2));
            quest.setOPTA(cursor.getString(3));
            quest.setOPTB(cursor.getString(4));
            quest.setOPTC(cursor.getString(5));
            quesList.add(quest);
        } while (cursor.moveToNext());
    }
    // return quest list
    return quesList;
}
public int rowcount()
{
    int row=0;
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    row=cursor.getCount();
    return row;
}
}

您需要使用“include”元素在activity:ResultActivity的布局中包括工具栏。您还可以直接在布局中添加工具栏
您需要使用“包含”元素将工具栏包括在“活动：结果活动”的布局中。您也可以直接在布局中添加工具栏
工具栏在那里，但“后退”按钮仍然不起作用工具栏在那里，但“后退”按钮仍然不起作用您必须在布局中包含工具栏，并将其设置为supportActionBar，而您在ResultActivity中没有该工具栏。如果您没有设置它，那么您对getSupportActionBar的所有调用都非常有用。您可以使用setSupportActionbar方法。您必须在布局中包含工具栏，并将其设置为supportActionBar，而您在ResultActivity中没有这样做。如果您没有设置它，那么您对getSupportActionBar的所有调用都几乎没有用处。您可以使用setSupportActionbar方法
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;
import java.util.List;

public class DbHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "triviaQuiz";
// tasks table name
private static final String TABLE_QUEST = "quest";
// tasks Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_QUES = "question";
private static final String KEY_ANSWER = "answer"; //correct option
private static final String KEY_OPTA= "opta"; //option a
private static final String KEY_OPTB= "optb"; //option b
private static final String KEY_OPTC= "optc"; //option c
private SQLiteDatabase dbase;
public DbHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
    dbase=db;
    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUEST + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_QUES
            + " TEXT, " + KEY_ANSWER+ " TEXT, "+KEY_OPTA +" TEXT, "
            +KEY_OPTB +" TEXT, "+KEY_OPTC+" TEXT)";
    db.execSQL(sql);        
    addQuestions();
    //db.close();
}
private void addQuestions()
{
    Question q1=new Question("Which company is the largest manufacturer" +
            " of network equipment?","HP", "IBM", "CISCO", "CISCO");
    this.addQuestion(q1);
    Question q2=new Question("Which of the following is NOT " +
            "an operating system?", "SuSe", "BIOS", "DOS", "BIOS");
    this.addQuestion(q2);
    Question q3=new Question("Which of the following is the fastest" +
            " writable memory?","RAM", "FLASH","Register","Register");
    this.addQuestion(q3);
    Question q4=new Question("Which of the following device" +
            " regulates internet traffic?", "Router", "Bridge", "Hub","Router");
    this.addQuestion(q4);
    Question q5=new Question("Which of the following is NOT an" +
            " interpreted language?","Ruby","Python","BASIC","BASIC");
    this.addQuestion(q5);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_QUEST);
    // Create tables again
    onCreate(db);
}
// Adding new question
public void addQuestion(Question quest) {
    //SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_QUES, quest.getQUESTION()); 
    values.put(KEY_ANSWER, quest.getANSWER());
    values.put(KEY_OPTA, quest.getOPTA());
    values.put(KEY_OPTB, quest.getOPTB());
    values.put(KEY_OPTC, quest.getOPTC());
    // Inserting Row
    dbase.insert(TABLE_QUEST, null, values);        
}
public List<Question> getAllQuestions() {
    List<Question> quesList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    dbase=this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Question quest = new Question();
            quest.setID(cursor.getInt(0));
            quest.setQUESTION(cursor.getString(1));
            quest.setANSWER(cursor.getString(2));
            quest.setOPTA(cursor.getString(3));
            quest.setOPTB(cursor.getString(4));
            quest.setOPTC(cursor.getString(5));
            quesList.add(quest);
        } while (cursor.moveToNext());
    }
    // return quest list
    return quesList;
}
public int rowcount()
{
    int row=0;
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    row=cursor.getCount();
    return row;
}
}

public class Question {
private int ID;
private String QUESTION;
private String OPTA;
private String OPTB;
private String OPTC;
private String ANSWER;
public Question()
{
    ID=0;
    QUESTION="";
    OPTA="";
    OPTB="";
    OPTC="";
    ANSWER="";
}
public Question(String qUESTION, String oPTA, String oPTB, String oPTC,
        String aNSWER) {

    QUESTION = qUESTION;
    OPTA = oPTA;
    OPTB = oPTB;
    OPTC = oPTC;
    ANSWER = aNSWER;
}
public int getID()
{
    return ID;
}
public String getQUESTION() {
    return QUESTION;
}
public String getOPTA() {
    return OPTA;
}
public String getOPTB() {
    return OPTB;
}
public String getOPTC() {
    return OPTC;
}
public String getANSWER() {
    return ANSWER;
}
public void setID(int id)
{
    ID=id;
}
public void setQUESTION(String qUESTION) {
    QUESTION = qUESTION;
}
public void setOPTA(String oPTA) {
    OPTA = oPTA;
}
public void setOPTB(String oPTB) {
    OPTB = oPTB;
}
public void setOPTC(String oPTC) {
    OPTC = oPTC;
}
public void setANSWER(String aNSWER) {
    ANSWER = aNSWER;
}

}