尝试添加第二张表时应用崩溃

Question

好吧，我现在真的很困惑。 我正在尝试向程序中添加新表，但是每当执行此操作时，我都会崩溃，尤其是onCreate方法。 我无法为我的爱找出原因。 有什么建议么？

这也是我得到的错误，但是我在任何地方都找不到category.db

引起原因：android.database.sqlite.SQLiteException：否这样的表：category.db（代码1）：，而编译时：SELECT * FROM Categories.db

private final static int DB_VERSION = 2;

public static String TABLE_NAME = "players";
public static String DB_NAME = "playerslist.db";
public static String SCORE = "score";
public static String ID = "_id";
public static String PLAYER_NAME = "name";

public static String CATEGORY_TABLE_NAME = "categories";
public static String CATEGORY_NAME = "category_name";
public static String CATEGORY_VALUE = "category_value";
public static String CATEGORY_ID = "category_id";
public static String CATEGORY_PLAYER_ID = "category_player_id";

public static String CREATE_PLAYER_TABLE = "CREATE TABLE "+TABLE_NAME+" ("+ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+PLAYER_NAME+" TEXT, "+
        SCORE+" TEXT)";
public static String CREATE_CATEGORY_TABLE = "CREATE TABLE "+CATEGORY_TABLE_NAME+"("+CATEGORY_ID+" INTEGER" +
        "PRIMARY KEY AUTOINCREMENT, "+CATEGORY_NAME+" TEXT, "+CATEGORY_VALUE+" INTEGER, "
        +CATEGORY_PLAYER_ID+" INTEGER)";

public SQLHelp(Context context) {
    super(context, DB_NAME, null, 2);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_PLAYER_TABLE);
    db.execSQL(CREATE_CATEGORY_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    for(int i = oldVersion; i < newVersion; i++){
        switch(i){
            case 1:
                db.execSQL(CREATE_CATEGORY_TABLE);
            break;
        }
    }
}

Answer 1

更改您的CREATE TABLE字符串以将IF NOT EXISTS包括在内，
CREATE TABLE IF NOT EXISTS Table_name(Columns)

Answer 2

从设备或仿真器中删除您的应用程序，然后再次安装/运行，它应该可以工作。

我遇到了同样的问题，然后我简单地从设备中删除了该应用程序，它开始工作了。

Answer 3

尝试这个..

创建第二个表时，您具有“ INTEGER” +“ PRIMARY KEY AUTOINCREMENT”。

我做到了这一点。

public static String CREATE_CATEGORY_TABLE = "CREATE TABLE "+CATEGORY_TABLE_NAME+"("+CATEGORY_ID+ " INTEGER PRIMARY KEY AUTOINCREMENT, "+CATEGORY_NAME+" TEXT, "+CATEGORY_VALUE+" INTEGER, "
    +CATEGORY_PLAYER_ID+" INTEGER)";

您应该致电SQLiteOpenHelper

private static class DatabaseHelper extends SQLiteOpenHelper{
    DatabaseHelper(Context context){
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    public void onCreate(SQLiteDatabase db){
          db.execSQL(CREATE_PLAYER_TABLE);
          db.execSQL(CREATE_CATEGORY_TABLE);
    }
    public void onUpgrade(SQLiteDatabase db, int arg1, int arg2{
          db.execSQL("DROP TABLE IF EXISTS " + CREATE_PLAYER_TABLE);
          db.execSQL("DROP TABLE IF EXISTS " + CREATE_CATEGORY_TABLE);
          onCreate(db);
    }