在数据库迁移期间递归调用getDatabase

Question

我已经为2个表实现了代码并且工作得很好。但是当我编写升级代码时，会出现此错误。我检查了大多数相关的帖子，甚至修复了OnUpgrade中的一些代码，其中db被递归调用。但我仍然无法弄明白。

数据库助手代码：

private static final int DATABASE_VERSION = 2;

public static final String DATABASE_NAME = "VotingUsers.db";
public static final String TABLE_IN = "in_Users";
public static final String TABLE_OUT = "out_Users";
public static final String COLUMN1 = "ID";
public static final String COLUMN2 = "NUMBER";
public static final String COLUMN3 = "FULL_NAME";
public static final String COLUMN4 = "DISPLAY_PICTURE";

public DataBaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);

}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE "+TABLE_IN+" ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );
    db.execSQL("CREATE TABLE "+TABLE_OUT+" ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );

}


@Override
public void onUpgrade(SQLiteDatabase db,int oldVersion, int newVersion) {
    Cursor cursor = db.rawQuery("select * from " + TABLE_IN,null);
        if(cursor.getCount() != 0) {
            db.execSQL("ALTER TABLE " + TABLE_IN + " ADD COLUMN FULL_NAME TEXT");
            while(cursor.moveToNext()) {
                db.execSQL("INSERT INTO " + TABLE_IN + " ("+COLUMN3+" ) Values ('"+cursor.getString(2) + " " + cursor.getString(3) +"')");
            }
            cursor.close();
        }
        db.execSQL("CREATE TABLE TEMP_TABLE ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );
        db.execSQL("INSERT INTO TEMP_TABLE (" +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) SELECT NUMBER, FULL_NAME, DISPLAY_PICTURE FROM "+TABLE_IN+");");
        db.execSQL("DROP TABLE" + TABLE_IN);
        db.execSQL("CREATE TABLE "+TABLE_IN+" ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );
        db.execSQL("INSERT INTO "+TABLE_IN+ " (" +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) SELECT " +COLUMN2+", "+COLUMN3+", "+COLUMN4+" FROM TEMP_TABLE );");
        db.execSQL("DROP TABLE TEMP_TABLE");

        cursor = db.rawQuery("select * from " + TABLE_OUT,null);
        if(cursor.getCount() != 0) {
            db.execSQL("ALTER TABLE " + TABLE_OUT + " ADD COLUMN FULL_NAME TEXT");
            while(cursor.moveToNext()) {
                db.execSQL("INSERT INTO " + TABLE_OUT + " ("+COLUMN3+" ) Values ('"+cursor.getString(2) + " " + cursor.getString(3) +"')");
            }
            cursor.close();
            db.execSQL("CREATE TABLE TEMP_TABLE ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );
            db.execSQL("INSERT INTO TEMP_TABLE (" +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) SELECT NUMBER, FULL_NAME, DISPLAY_PICTURE FROM "+TABLE_OUT+");");
            db.execSQL("DROP TABLE" + TABLE_OUT);
            db.execSQL("CREATE TABLE "+TABLE_OUT+" ( " + COLUMN1 + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN2 + " INTEGER UNIQUE, " + COLUMN3 + " TEXT, " +COLUMN4+ " TEXT );" );
            db.execSQL("INSERT INTO "+TABLE_OUT+ " (" +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) SELECT " +COLUMN2+", "+COLUMN3+", "+COLUMN4+" FROM TEMP_TABLE );");
            db.execSQL("DROP TABLE TEMP_TABLE");
        }
}

public void insertDataInUsers(Integer number, String name, String dp) {
    String ROW1 = "INSERT INTO " + TABLE_IN + " ("
            +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) Values ('"+number+"', '"+name+"', '"+dp+"')";
    getDb().execSQL(ROW1);
}

public void insertDataOutUsers(Integer number, String name, String dp) {
    String ROW2 = "INSERT INTO " + TABLE_OUT + " ("
            +COLUMN2+", "+COLUMN3+", "+COLUMN4+" ) Values ('"+number+"', '"+name+"', '"+dp+"')";
    getDb().execSQL(ROW2);
}
public SQLiteDatabase getDb() {
    SQLiteDatabase db = this.getWritableDatabase();
    return db;
}

public Cursor ShowInUserList() {
    Cursor cursor = getDb().rawQuery("select * from " + TABLE_IN,null);
    return cursor;
}

public Cursor ShowOutUserList() {
    Cursor cursor = getDb().rawQuery("select * from " + TABLE_OUT,null);
    return cursor;
}

这可能是一个小错误，但我不知道。

ERROR：

Caused by: java.lang.IllegalStateException: getDatabase called recursively
 at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:203)
 at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:163)
 at com.example.android.voteinoutexample.DataBaseHelper.createDb(DataBaseHelper.java:108)
 at com.example.android.voteinoutexample.DataBaseHelper.ShowInUserList(DataBaseHelper.java:114)
 at com.example.android.voteinoutexample.DataBaseHelper.onUpgrade(DataBaseHelper.java:42)

LINE 108

public Cursor ShowInUserList() {
    Cursor cursor = getDb().rawQuery("select * from " + TABLE_IN,null);
    return cursor;
}

在我的MainFragment OnCreate中，我有条件检查表是否存在，然后做一些事情..

    if(!InTableExists() && !OutTableExists()) {

        getUsers();
    }else {
       Cursor cursor = dbHelper.ShowInUserList();
        if(cursor.getCount() != 0) {
            data.add(new Vote(Vote.HEADER_TYPE, "IN"));
            while(cursor.moveToNext()) {


                    data.add(new Vote(Vote.ITEM_TYPE, cursor.getString(2) + " " + cursor.getString(3),cursor.getString(4)));

            }
                cursor.close();
        }

        cursor = dbHelper.ShowOutUserList();
        if(cursor.getCount() != 0) {
            data.add(new Vote(Vote.HEADER_TYPE, "OUT"));
            while(cursor.moveToNext()) {


                data.add(new Vote(Vote.ITEM_TYPE, cursor.getString(2) + " " + cursor.getString(3),cursor.getString(4)));

            }
            cursor.close();

            Toast.makeText(getActivity(),"DATA FROM DATABASE",Toast.LENGTH_LONG).show();
        }
    }

因此if条件中InTableExists（）的求值表达式也显示结果illegalStateException

CAUSE = android.database.sqlite.SQLiteException：near“）”：语法错误（代码1）:,同时编译：INSERT INTO TEMP_TABLE（NUMBER，FULL_NAME，DISPLAY_PICTURE）SELECT NUMBER，FULL_NAME，DISPLAY_PICTURE FROM in_Users）;