NullPointerException when doing query in SQLite

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NullPointerException when doing query in SQLite

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I am having a problem that is greatly undermining the development of my application. It aims to sort out an issue (not implemented yet, I am using a fixed value for the question id) through a query in SQLite, and pass it on to the TextViews. Here is the class code:

    public class DBAdapter {
    private SQLiteDatabase banco;
    private DBHelper dbHelper;
    public DBAdapter(Context context) {
        dbHelper = new DBHelper(context);
    }
    private String[] allColumns = { DBHelper.ID, DBHelper.ALTA, DBHelper.ENUNC,
            DBHelper.ALTB, DBHelper.ALTC, DBHelper.ALTD, DBHelper.ALTE, DBHelper.ALTOK};
    public Cursor AcessarQuestao(int numquest, SQLiteDatabase bank){
        Cursor cursorquestao;

        bank = dbHelper.getWritableDatabase();

        cursorquestao= bank.query(DBHelper.TABLE_NAME, allColumns, DBHelper.ID + " = " + numquest, null, null, null, null);
        return cursorquestao;
    }


}


public class QuestActivity extends AppCompatActivity {
    Questao quest = new Questao();
private SQLiteDatabase bank;
    TextView nuncp=(TextView)findViewById(R.id.nunciado);
    TextView txt_altap=(TextView)findViewById(R.id.altea);
    TextView txt_altbp=(TextView)findViewById(R.id.alteb);
    TextView txt_altcp=(TextView)findViewById(R.id.altec);
    TextView txt_altdp=(TextView)findViewById(R.id.alted);
    TextView txt_altep=(TextView)findViewById(R.id.altee);
    DBAdapter acesso = new DBAdapter(getBaseContext());
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.questoes);
         TextView nunc=(TextView)findViewById(R.id.nunciado);
        TextView txt_alta=(TextView)findViewById(R.id.altea);
        TextView txt_altb=(TextView)findViewById(R.id.alteb);
        TextView txt_altc=(TextView)findViewById(R.id.altec);
        TextView txt_altd=(TextView)findViewById(R.id.alted);
        TextView txt_alte=(TextView)findViewById(R.id.altee);
        String password="txt";

        Cursor obterquestao = acesso.AcessarQuestao(0, bank);


        if( obterquestao != null && obterquestao.moveToFirst() ){
            quest.setEnunc(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ENUNC)));
            quest.setAlta(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTA)));
            quest.setAltb(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTB)));
            quest.setAltc(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTC)));
            quest.setAltd(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTD)));
            quest.setAlte(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTE)));
            quest.setAltok(obterquestao.getString(obterquestao.getColumnIndex(DBHelper.ALTOK)));

        }



        nuncp.setText(quest.getEnunc());
        txt_altap.setText(quest.getAlta());
        txt_altbp.setText(quest.getAltb());
        txt_altcp.setText(quest.getAltc());
        txt_altdp.setText(quest.getAltd());
        txt_altep.setText(quest.getAlte());
    }/*
    public void verificarResposta(View v) {
        switch (v.getId()) {
            case R.id.baltea:
                quest.setResp(txt_altap.getText().toString());
                if(quest.getResp().equals(quest.getAltok())){
                    Toast.makeText(getApplicationContext(), "Acertou!", Toast.LENGTH_SHORT).show();
                }

                break;
            case R.id.balteb:
                quest.setResp(txt_altbp.getText().toString());
                if(quest.getResp().equals(quest.getAltok())){
                    Toast.makeText(getApplicationContext(), "Acertou!", Toast.LENGTH_SHORT).show();
                }

                break;
            case R.id.baltec:
                quest.setResp(txt_altcp.getText().toString());
                if(quest.getResp().equals(quest.getAltok())){
                    Toast.makeText(getApplicationContext(), "Acertou!", Toast.LENGTH_SHORT).show();
                }

                break;
            case R.id.balted:
                quest.setResp(txt_altdp.getText().toString());
                if(quest.getResp().equals(quest.getAltok())){
                    Toast.makeText(getApplicationContext(), "Acertou!", Toast.LENGTH_SHORT).show();
                }

                break;
            case R.id.baltee:
                quest.setResp(txt_altep.getText().toString());
                if(quest.getResp().equals(quest.getAltok())){
                    Toast.makeText(getApplicationContext(), "Acertou!", Toast.LENGTH_SHORT).show();
                }

                break;
        }
    }*/
}
public class DBHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "bancoquestoes.db";
    public static final String TABLE_NAME = "quests";
    private static final int DATABASE_VERSION = 1;
    public static final String ID = "_id";
    public static final String ENUNC     = "enunc";
    public static final String ALTA = "alta";
    public static final String ALTB = "altb";
    public static final String ALTC = "altc";
    public static final String ALTD = "altd";
    public static final String ALTE = "alte";
    public static final String ALTOK = "altok";
    private String[] allColumns = { DBHelper.ID, DBHelper.ALTA, DBHelper.ENUNC,
            DBHelper.ALTB, DBHelper.ALTC, DBHelper.ALTD, DBHelper.ALTE, DBHelper.ALTOK};
    private static final String CRIAR_TABELA="create table " + TABLE_NAME + "(" +
            ID + " integer primary key autoincrement, " +
            ENUNC + " text not null, " +
            ALTA + " text not null, " +
            ALTB + " text not null, " +
            ALTC + " text not null, " +
            ALTD + " text not null, " +
            ALTE + " text not null, " +
            ALTOK + " text not null);";

    public DBHelper(Context context){

        super(context, DATABASE_NAME, null, DATABASE_VERSION);

    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CRIAR_TABELA);
        ContentValues values = new ContentValues();
        values.put(DBHelper.ENUNC, "Qual a resposta certa?");
        values.put(DBHelper.ALTA, "Alternativa 1");
        values.put(DBHelper.ALTB, "Alternativa 2");
        values.put(DBHelper.ALTC, "Alternativa 3(ok)");
        values.put(DBHelper.ALTD, "Alternativa 4");
        values.put(DBHelper.ALTE, "Alternativa 5");
        values.put(DBHelper.ALTOK, "Alternativa 3(ok)");
        db.insert(TABLE_NAME, null, values );
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int i, int i1) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
}

However, doing so causes the following error:

10-05 14:05:27.626 15291-15291/com.teacherfox.legendary.teacherfox
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.teacherfox.legendary.teacherfox/com.teacherfox.legendary.teacherfox.QuestActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2038)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139)
at android.app.ActivityThread.access$700(ActivityThread.java:143)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4963)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.support.v7.app.AppCompatDelegateImplBase.(AppCompatDelegateImplBase.java:68)
at android.support.v7.app.AppCompatDelegateImplV7.(AppCompatDelegateImplV7.java:146)
at android.support.v7.app.AppCompatDelegateImplV11.(AppCompatDelegateImplV11.java:28)
at android.support.v7.app.AppCompatDelegateImplV14.(AppCompatDelegateImplV14.java:41)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:190)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:172)
at
android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:512)
at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:18)
at com.teacherfox.legendary.teacherfox.QuestActivity.(QuestActivity.java:18)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1319)
at android.app.Instrumentation.newActivity(Instrumentation.java:1068)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2029)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139) 
at android.app.ActivityThread.access$700(ActivityThread.java:143) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:4963) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:511) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805) 
at dalvik.system.NativeStart.main(Native Method)

I have tried everything, but the error continues. Can anyone tell me what I'm doing wrong?

Edit: AndroidManifest

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".QuestActivity"
            android:label="@string/app_name">
        </activity>
    </application>


</manifest>

java android sqlite nullpointerexception

asked by anonymous 05.10.2016 / 19:18

1 answer

The getSelectionStart (TextView) method returns incorrect value Custom facebook share button

score 0 · Answer 1

Sorry for the late reply, but if you have not decided yet try this, change from:

public class QuestActivity extends AppCompatActivity {
Questao quest = new Questao();
private SQLiteDatabase bank;
TextView nuncp=(TextView)findViewById(R.id.nunciado);
TextView txt_altap=(TextView)findViewById(R.id.altea);
TextView txt_altbp=(TextView)findViewById(R.id.alteb);
TextView txt_altcp=(TextView)findViewById(R.id.altec);
TextView txt_altdp=(TextView)findViewById(R.id.alted);
TextView txt_altep=(TextView)findViewById(R.id.altee);
DBAdapter acesso = new DBAdapter(getBaseContext());
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.questoes);
     TextView nunc=(TextView)findViewById(R.id.nunciado);
    TextView txt_alta=(TextView)findViewById(R.id.altea);
    TextView txt_altb=(TextView)findViewById(R.id.alteb);
    TextView txt_altc=(TextView)findViewById(R.id.altec);
    TextView txt_altd=(TextView)findViewById(R.id.alted);
    TextView txt_alte=(TextView)findViewById(R.id.altee);
    String password="txt";

To:

public class QuestActivity extends AppCompatActivity {
Questao quest;
private SQLiteDatabase bank;
TextView nuncp;
TextView txt_altap;
TextView txt_altbp;
TextView txt_altcp;
TextView txt_altdp;
TextView txt_altep;
DBAdapter acesso;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.questoes);
     TextView nunc=(TextView)findViewById(R.id.nunciado);
    TextView txt_alta=(TextView)findViewById(R.id.altea);
    TextView txt_altb=(TextView)findViewById(R.id.alteb);
    TextView txt_altc=(TextView)findViewById(R.id.altec);
    TextView txt_altd=(TextView)findViewById(R.id.alted);
    TextView txt_alte=(TextView)findViewById(R.id.altee);
    String password="txt";

    nuncp=(TextView)findViewById(R.id.nunciado);
    txt_altap=(TextView)findViewById(R.id.altea);
    txt_altbp=(TextView)findViewById(R.id.alteb);
    txt_altcp=(TextView)findViewById(R.id.altec);
    txt_altdp=(TextView)findViewById(R.id.alted);
    txt_altep=(TextView)findViewById(R.id.altee);
    quest = new Questao();
    acesso = new DBAdapter(getBaseContext());