使用SQLite創建android應用程序時出錯數據庫

Question

com.example.dilshadazmat.generalknowledge, PID: 8203 
java.lang.RuntimeException: Unable to start activity ComponentInfo 
{com.example.dilshadazmat. 
generalknowledge 
/com.example.dilshadazmat.generalknowledge.Islamic_mcqs}: 
java.lang.IllegalStateException: getDatabase called recursively 
at android.app.ActivityThread.performLaunchActivity 
(ActivityThread.java:2689) 
at android.app.ActivityThread.handleLaunchActivity 
(ActivityThread.java:2756) 
at android.app.ActivityThread.access$900(ActivityThread.java:177) 
at android.app.ActivityThread$H.handleMessage 
(ActivityThread.java:1448) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:145) 
at android.app.ActivityThread.main(ActivityThread.java:5940) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run 
(ZygoteInit.java:1389) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184) 
Caused by: java.lang.IllegalStateException: getDatabase 
called recursively android.database.sqlite.SQLiteOpenHelper. 
getDatabaseLocked(SQLiteOpenHelper.java:203) 
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase 
(SQLiteOpenHelper.java:163) 
at com.example.dilshadazmat.generalknowledge.DbIslamic. 
addQuestions(DbIslamic.java:81) 
at com.example.dilshadazmat.generalknowledge.DbIslamic. 
addQuestions(DbIslamic.java:59) 
at com.example.dilshadazmat.generalknowledge. 
DbIslamic.onCreate(DbIslamic.java:49) 
at android.database.sqlite.SQLiteOpenHelper. 
getDatabaseLocked(SQLiteOpenHelper.java:251) 
at android.database.sqlite.SQLiteOpenHelper. 
getReadableDatabase(SQLiteOpenHelper.java:187) 
at com.example.dilshadazmat.generalknowledge. 
DbIslamic.getAllQuestions 
(DbIslamic.java:97) 
at com.example.dilshadazmat.generalknowledge.Islamic_mcqs.onCreate 
slamic_mcqs.java:47) 
at android.app.Activity.performCreate(Activity.java:6283) 
at android.app.Instrumentation.callActivityOnCreate 
(Instrumentation.java:1119) 
at android.app.ActivityThread.performLaunchActivity 
(ActivityThread.java:26  at 
androi 

這是我想要創建新數據庫的數據庫類。

public class DbIslamic extends SQLiteOpenHelper { 

private static final int DATABASE_VERSION = 1; 
private static final String DATABASE_NAME = "islamicMcqs"; 
private static final String TABLE_QUESTION = "questions"; 
private static final String KEY_ID = "id"; 
private static final String KEY_QUESTION = "question"; 
private static final String KEY_ANSWER = "answer"; 
private static final String KEY_OPTA = "opta"; 
private static final String KEY_OPTB = "optb"; 
private static final String KEY_OPTC = "optc"; 
private static final String KEY_OPTD = "optd"; 

private SQLiteDatabase database; 

public DbIslamic(Context context) 

{ 
    super(context, DATABASE_NAME, null, DATABASE_VERSION); 
} 

@Override 
public void onCreate(SQLiteDatabase db) 
{ 
    database = db; 

    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUESTION + 
    "(" +KEY_ID + 
"INTEGER, " 
      + KEY_QUESTION + "TEXT," + KEY_OPTA + "TEXT," + 
    KEY_OPTB +  "TEXT," + 
    KEY_OPTC + "TEXT," 
      + KEY_OPTD + "TEXT,"+ KEY_ANSWER + "TEXT)" ; 
    db.execSQL (sql); 

    addQuestions(); 

    db.close(); 
} 


private void addQuestions() 
{ 
    Islamic_mcqs q1 = new Islamic_mcqs("Who was the 
last prophet in"+" the list of prophets ?", "Hazrat Adam(A.S)", 
      "Hazrat Muhammad(S.A.W)","Hazrat Yousaf(A.S)", 
    "Hazrat Ibraheem (A.S)","B"); 
    this.addQuestions(q1); 

} 



@Override 
public void onUpgrade(SQLiteDatabase db, int oldValue, int newValue) 
{ 
    // Drop older table if existed 
    db.execSQL("DROP TABLE IF EXISTS " +TABLE_QUESTION); 
    // Create tables again 
    onCreate(db); 
} 
// Adding new question 
public void addQuestions(Islamic_mcqs questions) 
{ 
    SQLiteDatabase db = this.getWritableDatabase(); 
    ContentValues values = new ContentValues(); 
    values.put(KEY_QUESTION,questions.getQUESTION()); 
    values.put(KEY_ANSWER,questions.getANSER()); 
    values.put(KEY_OPTA,questions.getOPTA()); 
    values.put(KEY_OPTB,questions.getOPTB()); 
    values.put(KEY_OPTC,questions.getOPTC()); 
    values.put(KEY_OPTD,questions.getOPTD()); 
    // Inserting Row 
    database.insert(TABLE_QUESTION,null,values); 
} 
public List<Islamic_mcqs> getAllQuestions() 
{ 
    List<Islamic_mcqs> questionsList = new ArrayList<Islamic_mcqs>(); 
    // Select All Query 
    String selectQuery = "SELECT * FROM " + TABLE_QUESTION; 
    database=this.getReadableDatabase(); 
    Cursor cursor = database.rawQuery(selectQuery, null); 
    // looping through all rows and adding to list 
    if (cursor.moveToFirst()) { 
     do { 
      Islamic_mcqs q = new Islamic_mcqs(); 
      q.setID(cursor.getInt(0)); 
      q.setQUESTION(cursor.getString(1)); 
      q.setANSWER(cursor.getString(2)); 
      q.setOPTA(cursor.getString(3)); 
      q.setOPTAB(cursor.getString(4)); 
      q.setOPTC(cursor.getString(5)); 
      q.setOPTD(cursor.getString(6)); 
      questionsList.add(q); 
     } while (cursor.moveToNext()); 
    } 
    // return quest list 
    return questionsList; 
} 

這個類的另一個類Islamic_mcqs我想從這個數據庫中的數據庫中獲取所有數據我將保存多項選擇題。

public class Islamic_mcqs extends AppCompatActivity{ 

private int ID; 
private String QUESTION; 
private String OPTA; 
private String OPTB; 
private String OPTC; 
private String OPTD; 
private String ANSWER; 

List<Islamic_mcqs> questionList; 

int score = 0; 
int qid = 0; 


TextView tv_t,tv_num,tv_q; 
RadioButton rb_a,rb_b,rb_c,rb_d; 
Button bnext; 

Islamic_mcqs currentQ; 

@Override 
protected void onCreate(@Nullable Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.islamic_mcqs); 

    DbIslamic database = new DbIslamic(this); 
    questionList = database.getAllQuestions(); 
    Islamic_mcqs currentQ = questionList.get(qid); 

    tv_t = (TextView)findViewById(R.id.tv_title); 
    tv_q = (TextView)findViewById(R.id.tv_question); 
    tv_num = (TextView)findViewById(R.id.tvNumber); 

    rb_a = (RadioButton)findViewById(R.id.rb_A); 
    rb_b = (RadioButton)findViewById(R.id.rb_B); 
    rb_c = (RadioButton)findViewById(R.id.rb_C); 
    rb_d = (RadioButton)findViewById(R.id.rb_D); 

    bnext = (Button)findViewById(R.id.b_next); 

    setQuestionView(); 

} 
private void setQuestionView() 
{ 
    tv_q.setText(currentQ.getQUESTION()); 
    rb_a.setText(currentQ.getOPTA()); 
    rb_b.setText(currentQ.getOPTB()); 
    rb_c.setText(currentQ.getOPTC()); 
    rb_d.setText(currentQ.getOPTD()); 
    qid++; 


} 
public Islamic_mcqs() 
{ 
    ID = 0; 
    QUESTION = ""; 
    OPTA = ""; 
    OPTB = ""; 
    OPTC = ""; 
    OPTD = ""; 
    ANSWER = ""; 
} 

public Islamic_mcqs(String islQuestion, String optA, 
String optB, String optC, String optD, String answer) 
{ 
    QUESTION = islQuestion; 
    OPTA = optA; 
    OPTB = optB; 
    OPTC = optC; 
    OPTD = optD; 
    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 getOPTD() 
{ 
    return OPTD; 
} 
public String getANSER() 
{ 
    return ANSWER; 
} 
public void setID(int id) 
{ 
    ID = id; 
} 
public void setQUESTION(String islQuestion) 
{ 
    QUESTION = islQuestion; 
} 
public void setOPTA(String optA) 
{ 
    OPTA = optA; 
} 
public void setOPTAB(String optab) 
{ 
    OPTB = optab; 
} 
public void setOPTC(String optc) 
{ 
    OPTC = optc; 
} 
public void setOPTD(String optd) 
{ 
    OPTD = optd; 
} 
public void setANSWER(String answer) 
{ 
    ANSWER = answer; 
} 
} 

Answer 1

替換您的Sql。

String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUESTION + 
    "(" +KEY_ID + 
" INTEGER, " 
      + KEY_QUESTION + " TEXT," + KEY_OPTA + " TEXT," + 
    KEY_OPTB +  " TEXT," + 
    KEY_OPTC + " TEXT," 
      + KEY_OPTD + " TEXT,"+ KEY_ANSWER + " TEXT);" ; 

例如，你需要KEY_OPTC之間空間 「TEXT」，否則SQL創建將是 'optcTEXT'。

隨着空間：KEY_OPTC + 「TEXT」= 'OPTC TEXT，'

Answer 2

INTEGER PRIMARY KEY AUTOINCREMENT， 檢查你的SQLite聲明

 String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUESTION + 
    "(" +KEY_ID + 
"INTEGER, " 
      + KEY_QUESTION + "TEXT," + KEY_OPTA + "TEXT," + 
    KEY_OPTB +  "TEXT," + 
    KEY_OPTC + "TEXT," 
      + KEY_OPTD + "TEXT,"+ KEY_ANSWER + "TEXT)" ; 

與

String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUESTION + 
    "(" +KEY_ID + 
"INTEGER PRIMARY KEY AUTOINCREMENT, " 
      + KEY_QUESTION + " TEXT," + KEY_OPTA + " TEXT," + 
    KEY_OPTB +  " TEXT," + 
    KEY_OPTC + " TEXT," 
      + KEY_OPTD + " TEXT,"+ KEY_ANSWER + " TEXT)" ;