java - Arraylist 不适用于 Android

Question

我遇到了问题，但在任何地方都找不到它。所以我正在制作这个测验应用程序。我在这里得到了我的主要 Activity :

public class MainActivity extends Activity {

    List<Vragen> quesList;
    int score=0;
    int qid=0;
    Vragen currentQ;
    TextView txtVragen;
    RadioButton rda, rdb, rdc;
    Button butVolgende;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        DBHelper db=new DBHelper(this);
        quesList=db.getAllVragen();
        currentQ=quesList.get(qid);
        txtVragen=(TextView)findViewById(R.id.txtVraag);
        rda=(RadioButton)findViewById(R.id.antwoord1);
        rdb=(RadioButton)findViewById(R.id.antwoord2);
        rdc=(RadioButton)findViewById(R.id.antwoord3);
        butVolgende=(Button)findViewById(R.id.btnVolgende);
        setVragenView();
        butVolgende.setOnClickListener(new View.OnClickListener() {     
            public void onClick(View v) {
                RadioGroup grp=(RadioGroup)findViewById(R.id.grpAntwoord);
                RadioButton antwoord=(RadioButton)findViewById(grp.getCheckedRadioButtonId());
                Log.d("yourans", currentQ.getANTWOORD()+" "+antwoord.getText());
                if(currentQ.getANTWOORD().equals(antwoord.getText()))
                {
                    score++;
                    Log.d("score", "Your score"+score);
                }
                if(qid<5){                  
                    currentQ=quesList.get(qid);
                    setVragenView();
                }else{
                    Intent intent = new Intent(MainActivity.this, ResultActivity.class);
                    Bundle b = new Bundle();
                    b.putInt("score", score); //Your score
                    intent.putExtras(b); //Put your score to your next Intent
                    startActivity(intent);
                    finish();
                }
            }
        });
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
    private void setVragenView()
    {
        txtVragen.setText(currentQ.getVRAAG());
        rda.setText(currentQ.getOPT1());
        rdb.setText(currentQ.getOPT2());
        rdc.setText(currentQ.getOPT3());
        qid++;
    }
}

这是我的 DBHelper，问题就在那里:

public class DBHelper extends SQLiteOpenHelper {
    private static final int DATABASE_VERSION = 1;
    // Database Name
    private static final String DATABASE_NAME = "DBQuiz";
    // 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_VRAAG = "vraag";
    private static final String KEY_ANTWOORD = "antwoord"; //correct option
    private static final String KEY_OPT1= "opt1"; //option 1
    private static final String KEY_OPT2= "opt2"; //option 2
    private static final String KEY_OPT3= "opt3"; //option 3
    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_VRAAG
                + " TEXT, " + KEY_ANTWOORD+ " TEXT, "+KEY_OPT1 +" TEXT, "
                +KEY_OPT2 +" TEXT, "+KEY_OPT3+" TEXT)";
        db.execSQL(sql);        
        addVragen();
        //db.close();
    }
    private void addVragen()
    {
        Vragen q1=new Vragen("Which company is the largest manufacturer" +
                " of network equipment?","HP", "IBM", "CISCO", "CISCO");
        this.addVraag(q1);
        Vragen q2=new Vragen("Which of the following is NOT " +
                "an operating system?", "SuSe", "BIOS", "DOS", "BIOS");
        this.addVraag(q2);
        Vragen q3=new Vragen("Which of the following is the fastest" +
                " writable memory?","RAM", "FLASH","Register","Register");
        this.addVraag(q3);
        Vragen q4=new Vragen("Which of the following device" +
                " regulates internet traffic?", "Router", "Bridge", "Hub","Router");
        this.addVraag(q4);
        Vragen q5=new Vragen("Which of the following is NOT an" +
                " interpreted language?","Ruby","Python","BASIC","BASIC");
        this.addVraag(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 addVraag(Vragen quest) {
        //SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(KEY_VRAAG, quest.getVRAAG()); 
        values.put(KEY_ANTWOORD, quest.getANTWOORD());
        values.put(KEY_OPT1, quest.getOPT1());
        values.put(KEY_OPT2, quest.getOPT2());
        values.put(KEY_OPT3, quest.getOPT3());
        // Inserting Row
        dbase.insert(TABLE_QUEST, null, values);        
    }
    public List<Vragen> getAllVragen() {
        List<Vragen> quesList = new ArrayList<Vragen>();
        // 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 {
                Vragen quest = new Vragen();
                quest.setID(cursor.getInt(0));
                quest.setVRAAG(cursor.getString(1));
                quest.setANTWOORD(cursor.getString(2));
                quest.setOPT1(cursor.getString(3));
                quest.setOPT2(cursor.getString(4));
                quest.setOPT3(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;
    }
}

这是我的 Logcat:

08-28 14:33:58.440: W/dalvikvm(21832): threadid=1: thread exiting with uncaught exception (group=0x416e32a0)
08-28 14:33:58.460: E/AndroidRuntime(21832): FATAL EXCEPTION: main
08-28 14:33:58.460: E/AndroidRuntime(21832): java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1
08-28 14:33:58.460: E/AndroidRuntime(21832):    at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at java.util.ArrayList.get(ArrayList.java:304)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at com.laurenswuytsjordipapen.cultural.pursuit.MainActivity$1.onClick(MainActivity.java:55)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.view.View.performClick(View.java:4262)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.view.View$PerformClick.run(View.java:17421)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.os.Handler.handleCallback(Handler.java:615)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.os.Handler.dispatchMessage(Handler.java:92)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.os.Looper.loop(Looper.java:137)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at android.app.ActivityThread.main(ActivityThread.java:4944)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at java.lang.reflect.Method.invokeNative(Native Method)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at java.lang.reflect.Method.invoke(Method.java:511)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
08-28 14:33:58.460: E/AndroidRuntime(21832):    at dalvik.system.NativeStart.main(Native Method)

有人可以帮我吗，我陷入困境，需要完成这个工作。

提前致谢!

Answer 1

java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1

表示您试图获取只有一个元素的 ArrayList 中的第二个元素。所以这意味着当你这样做时

quesList=db.getAllVragen();

您只能得到一个结果