Question

我添加了第二类问题，但我不知道如何使用代码，以便在列表中显示此类别。请帮帮我怎么做其他类别也可见？我在数据库中的类别：

private void addQuestion3() {

        QuestionHist q0 = new QuestionHist ("1.Historia Polski - Quiz z wiedzy ogólnej ","1", "0","0", "0", "0", "0", "0","none");
        this.addQuestion3(q0);
        QuestionHist q1 = new QuestionHist ("2.Historia Świata - Wiedza Ogólna ","1", "0","0", "0", "0", "0", "0","none");
        this.addQuestion3(q1);
}


 public void addQuestion3(QuestionHist his) {
// SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(KEY_SUBJECT, his.getSUBJECT());
        values.put(KEY_LEVEL, his.getLEVEL());
        values.put(KEY_QUES, his.getQUESTION());
        values.put(KEY_ANSWER, his.getANSWER());
        values.put(KEY_OPTA, his.getOPTA());
        values.put(KEY_OPTB, his.getOPTB());
        values.put(KEY_OPTC, his.getOPTC());
        values.put(KEY_OPTD, his.getOPTD());
        values.put(KEY_TRIAL1, "0");
        values.put(KEY_TRIAL2, "0");
        values.put(KEY_TRIAL3, "0");
        values.put(KEY_TRIAL4, "0");
        values.put(KEY_IMAGE, his.getIMAGE());
// Inserting Row
        dbase.insert(TABLE_HIS, null, values);
}


// looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                QuestionHist his = new QuestionHist();
                his.setID(cursor.getInt(0));
                his.setSUBJECT(cursor.getString(1));
                his.setLEVEL(cursor.getString(2));
                his.setQUESTION(cursor.getString(3));
                his.setANSWER(cursor.getString(4));
                his.setOPTA(cursor.getString(5));
                his.setOPTB(cursor.getString(6));
                his.setOPTC(cursor.getString(7));
                his.setOPTD(cursor.getString(8));
                his.setTRIAL1(cursor.getString(9));
                his.setTRIAL2(cursor.getString(10));
                his.setTRIAL3(cursor.getString(11));
                his.setTRIAL4(cursor.getString(12));
                his.setIMAGE(cursor.getString(13));  //13, because the trials are between OPTD and IMAGE
                quesList.add(his);
            } while (cursor.moveToNext());
        }
		return quesList;
    }


public List<QuestionHist> getQuestionsFromSubject(String subjectArg) {
        List<QuestionHist> quesList = new ArrayList<QuestionHist>();
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_HIS;
        dbase=this.getReadableDatabase();
        Cursor cursor = dbase.rawQuery(selectQuery, null);
        // looping through all rows and adding to list
        if (cursor.moveToPosition(1)) {
            do {
                if (subjectArg.equals(cursor.getString(1))) {
                    QuestionHist hist = new QuestionHist();
                    hist.setID(cursor.getInt(0));
                    hist.setSUBJECT(cursor.getString(1));
                    hist.setLEVEL(cursor.getString(2));
                    hist.setQUESTION(cursor.getString(3));
                    hist.setANSWER(cursor.getString(4));
                    hist.setOPTA(cursor.getString(5));
                    hist.setOPTB(cursor.getString(6));
                    hist.setOPTC(cursor.getString(7));
                    hist.setOPTD(cursor.getString(8));
                    hist.setTRIAL1(cursor.getString(9));
                    hist.setTRIAL2(cursor.getString(10));
                    hist.setTRIAL3(cursor.getString(11));
                    hist.setTRIAL4(cursor.getString(12));
                    hist.setIMAGE(cursor.getString(13)); //13, because the trials are between OPTD and IMAGE
                    quesList.add(hist);
                }
            } while (cursor.moveToNext());
        }
        // return quest list
        return quesList;
    }

public List<QuestionHist> getQuestionsFromSubjectAndLevel(String subjectArg, int levelArg) {
        List<QuestionHist> quesList = new ArrayList<QuestionHist>();
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_HIS;
        dbase=this.getReadableDatabase();
        Cursor cursor = dbase.rawQuery(selectQuery, null);
        // looping through all rows and adding to list
        if (cursor.moveToPosition(1)) {
            do {
                if (subjectArg.equals(cursor.getString(1)) && levelArg == Integer.parseInt(cursor.getString(2))) {
                    QuestionHist hist = new QuestionHist();
                    hist.setID(cursor.getInt(0));
                    hist.setSUBJECT(cursor.getString(1));
                    hist.setLEVEL(cursor.getString(2));
                    hist.setQUESTION(cursor.getString(3));
                    hist.setANSWER(cursor.getString(4));
                    hist.setOPTA(cursor.getString(5));
                    hist.setOPTB(cursor.getString(6));
                    hist.setOPTC(cursor.getString(7));
                    hist.setOPTD(cursor.getString(8));
                    hist.setTRIAL1(cursor.getString(9));
                    hist.setTRIAL2(cursor.getString(10));
                    hist.setTRIAL3(cursor.getString(11));
                    hist.setTRIAL4(cursor.getString(12));
                    hist.setIMAGE(cursor.getString(13)); //13, because the trials are between OPTD and IMAGE
                  quesList.add(hist);
                }
            } while (cursor.moveToNext());
        }
        // return quest list
        return quesList;
    }

public String getSubjects() {
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_HIS;
        dbase=this.getReadableDatabase();
        Cursor cursor = dbase.rawQuery(selectQuery, null);

        String dbSubjects = "";
        if (cursor.moveToPosition(0)) {
            dbSubjects = cursor.getString(1);
        }

        return dbSubjects;

和我在活动中的代码：

 btngra = (Button) findViewById(R.id.btngra);
    btnscores = (Button) findViewById(R.id.btnscores);
    btnsend = (Button) findViewById(R.id.btnsend);
    btnchangesettings = (Button) findViewById(R.id.btnchangesettings);
    listSubjects = (ListView) findViewById(R.id.listView1);
    final QuizHelper db = new QuizHelper(this);

    String subjectsRaw = db.getSubjects();
    final String[] subjects = subjectsRaw.split("/");

    // Definiowanie  adaptera
    // Pierwszy parametr - Kontekst
    // Drugi parametr - Układ rzędzie
    // Trzeci parametr - identyfikator TextView z którym są zapisywane dane
    // czwarty - tablica danych

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, android.R.id.text1, subjects) {
        @Override
        public View getView(int position, View convertView,
                            ViewGroup parent) {
            View view = super.getView(position, convertView, parent);

            TextView textView = (TextView) view.findViewById(android.R.id.text1);


                    /*YOUR CHOICE OF COLOR*/
            textView.setTextColor(Color.WHITE);
            ;

            return view;
        }
    };


    // Przypisywanie adapterow do listy
    listSubjects.setAdapter(adapter);
    listSubjects.setChoiceMode(ListView.CHOICE_MODE_SINGLE);



    // ListView Item Click Listener
    listSubjects.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long qid) {
            final String subject = (String) parent.getAdapter().getItem(position);
            // Set the item as checked to be highlighted
            for (int i = 0; i < listSubjects.getCount(); i++) {
                listSubjects.getChildAt(i).setBackgroundColor(Color.BLACK);
            }
            //listSubjects.setItemChecked(0, true);
            view.setBackgroundColor(Color.BLUE);


            //przejscie do kategorii
            btngra.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(Options.this,
                            HistQuestionActivityCategory.class);
                    Bundle bun = new Bundle();
                    bun.putString("subject", subject);
                    intent.putExtras(bun);
                    startActivity(intent);
                    resultsSent = false;
                }

            });
        }
    });

和我的屏幕：

如何添加第二类？请帮帮我

我的活动经过修改：

 btngra = (Button) findViewById(R.id.btngra);
    btnscores = (Button) findViewById(R.id.btnscores);
    btnsend = (Button) findViewById(R.id.btnsend);
    btnchangesettings = (Button) findViewById(R.id.btnchangesettings);
    listSubjects = (ListView) findViewById(R.id.listView1);
    final QuizHelper db = new QuizHelper(this);

    List<String> subjects = db.getSubjects();
    //final String[] subjects = subjectsRaw.split("/");


    // Definiowanie  adaptera
    // Pierwszy parametr - Kontekst
    // Drugi parametr - Układ rzędzie
    // Trzeci parametr - identyfikator TextView z którym są zapisywane dane
    // czwarty - tablica danych

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, android.R.id.text1,subjects) {
        @Override
        public View getView(int position, View convertView,
                            ViewGroup parent) {
            View view = super.getView(position, convertView, parent);

            TextView textView = (TextView) view.findViewById(android.R.id.text1);


                    /*YOUR CHOICE OF COLOR*/
            textView.setTextColor(Color.WHITE);
            ;

            return view;
        }
    };


    // Przypisywanie adapterow do listy
    listSubjects.setAdapter(adapter);
    listSubjects.setChoiceMode(ListView.CHOICE_MODE_SINGLE);



    // ListView Item Click Listener
    listSubjects.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long qid) {
            final String subject = (String) parent.getAdapter().getItem(position);
            // Set the item as checked to be highlighted
            for (int i = 0; i < listSubjects.getCount(); i++) {
                listSubjects.getChildAt(i).setBackgroundColor(Color.BLACK);
            }
            //listSubjects.setItemChecked(0, true);
            view.setBackgroundColor(Color.BLUE);


            //przejscie do kategorii
            btngra.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(Options.this,
                            HistQuestionActivityCategory.class);
                    Bundle bun = new Bundle();
                    bun.putString("subject", subject);
                    intent.putExtras(bun);
                    startActivity(intent);
                    resultsSent = false;
                }

            });
        }
    });

和QuizHelper：

    private void addQuestion3() {

        QuestionHist q0 = new QuestionHist ("1.Historia Polski - Quiz z wiedzy ogólnej ","1", "0","0", "0", "0", "0", "0","none");
        this.addQuestion3(q0);
        QuestionHist q1 = new QuestionHist ("2.Historia Świata - Wiedza Ogólna ","1", "0","0", "0", "0", "0", "0","none");
        this.addQuestion3(q1);
        QuestionHist q2 = new QuestionHist("1.Historia Polski - Quiz z wiedzy ogólnej ","1","Chrzest Polski miał miejsce w roku", "956", "966", "965", "978", "966","drawable/chrzestpolski");
        this.addQuestion3(q2);
        QuestionHist q3 = new QuestionHist("1.Historia Polski - Quiz z wiedzy ogólnej ","1","Którą bitwą zakończyło się tzw. 100 dni Napoleona?", "Bitwą Narodów ", "Bitwa pod Borodino", "Bitwą pod Waterloo", "Bitwa nad Berezyną", "Bitwą pod Waterloo","drawable/napoleonbonaparte");
        this.addQuestion3(q3);
        QuestionHist q4 = new QuestionHist("1.Historia Polski - Quiz z wiedzy ogólnej ","1","W którym roku powstało Księstwo Warszawskie?", "W 1807", "W 1896", "W 1900", "W 1859", "W 1807","drawable/ksiestwowarszawskie");
        this.addQuestion3(q4);
        QuestionHist q5 = new QuestionHist("1.Historia Polski - Quiz z wiedzy ogólnej ","1","Król Polski Władysław III Warneńczyk zginął w 1444 roku w bitwie pod Warną. Ile miał wówczas lat?", "20 lat ", "44 lata ", "56 lat ", "30 lat ", "20 lat ","drawable/warna");
        this.addQuestion3(q5);
        QuestionHist q6 = new QuestionHist("1.Historia Polski - Quiz z wiedzy ogólnej ","1","W którym państwie władzę sprawował Francisco Franco?", "W Hiszpanii", "W Portugalii", "We Francji", "We Włoszech", "W Hiszpanii","drawable/franco");
        this.addQuestion3(q6);


public List<String> getSubjects(){
        SQLiteDatabase db = getReadableDatabase();
        // Equivalent to the following SQLite query:
        // SELECT DISTINCT col_subject FROM table_his ORDER BY col_subject
        Cursor cursor = db.query(
                true,
                new String[]{KEY_SUBJECT},
                TABLE_HIS,
                null,null,null,
                KEY_SUBJECT + "ASC",
                null
     );
        List<String> subjects = new ArrayList<String>();
        try {
            // iterate over the cursor
            for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()){
                subjects.add(cursor.getString(0));
            }
        }finally {
            cursor.close();// release resources
        }
        return subjects;
        }



    /*public String getSubjects() {
        // Select All Query
        String selectQuery = "SELECT  * FROM " + TABLE_HIS;
        dbase=this.getReadableDatabase();
        Cursor cursor = dbase.rawQuery(selectQuery, null);

        String dbSubjects = "";
        if (cursor.moveToPosition(0)) {
            dbSubjects = cursor.getString(1);
        }

        return dbSubjects;

    }

*/

enter image description here

修改后有一个问题：真的我做错了什么？

Answer 1

您的getSubjects()方法无法执行您的操作。目前它从表中选择所有内容（这是不必要的，您只需要主题列），移动到第一行，然后返回主题。换句话说，它只会返回一个值。它完成时也不会关闭Cursor。在Activity中，final String[] subjects = subjectsRaw.split("/");行可能无法执行任何操作，因为只返回了一个主题。

这是一个应该更好的实现：

public List<String> getSubjects() {
    SQLiteDatabase db = getReadableDatabase();
    // Equivalent to the following SQLite query:
    // SELECT DISTINCT col_subject FROM table_his ORDER BY col_subject
    Cursor cursor = db.query(
            true,                      /* distinct */
            TABLE_HIS,                 /* table */
            new String[]{KEY_SUBJECT}, /* columns */
            null, null, null, null     /* where, where args, group by, having */
            KEY_SUBJECT + " ASC",      /* order by */
            null                       /* limit */
    );

    List<String> subjects = new ArrayList<>();
    try {
        // iterate over the cursor
        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
            subjects.add(cursor.getString(0));
        }
    } finally {
        cursor.close(); // release resources
    }
    return subjects;
}

使用此方法您不会需要String.split()来电，您可以立即使用List。

如何在同一个数据库Quiz Android的菜单中显示两个问题类别

1 个答案: