从LinkedList获取值到LinkedList

Question

I have a linkedlist name categories. Into this linkedlist i had values like : id, name, description, entries(linkedlist)

in the method i get a the id with a bundle. now my problem is, how can i connect/enter/get the data from entries by using the id?

(the id, name, description and entries data will be loaded from the database)

Loading from Database and add it to the LinkedList:

CRUDDatabase dbHandler = new CRUDDatabase(this);
        SQLiteDatabase db1 = dbHandler.getWritableDatabase();
        dbHandler.open();

        String[] categoryColumns = {dbHandler.ID, dbHandler.NAME, dbHandler.DESCRIPTION};
        String[] entryColumns = {dbHandler.ID, dbHandler.CATEG_ID, dbHandler.NAME, dbHandler.DESCRIPTION};

        Cursor cursorLoadCategory = db1.query(dbHandler.tableCategory, categoryColumns, null, null, null, null, null);
        cursorLoadCategory.moveToFirst();
        while(!cursorLoadCategory.isAfterLast()){

            String whereClause = dbHandler.CATEG_ID + "= ?";
            String whereArgs = String.valueOf(cursorLoadCategory.getInt(0));
            Cursor cr2 = db1.query(dbHandler.tableEntry, entryColumns,whereClause,new String[]{whereArgs},null,null,null);
            cr2.moveToFirst();
            Log.v("Get Entry Data by ID: ", "" + whereClause+" ::: " + whereArgs);

            LinkedList<Entry> entries = new LinkedList<Entry>();

                while(!cr2.isAfterLast()){
                    entries.add(new Entry(cr2.getInt(0), cr2.getInt(1), cr2.getString(2), cr2.getString(3)));

                    cr2.moveToNext();                       
                }

            System.out.println("--- CREATE CATEGORY ---");  
            Category category = new Category(cursorLoadCategory.getInt(0), cursorLoadCategory.getString(1), cursorLoadCategory.getString(2), null, null, null, entries);                


            MainActivity.categories.add(category);

From the MainActivity:

@Override
public void onClick(View v) {

    ViewGroup elements = (ViewGroup)v.getParent();
    LinearLayout lL = (LinearLayout)elements.findViewById(R.id.CatTemp_menuBoxContainer);
    int categoryId = (Integer)lL.getTag();


    Intent intentSelectedCategory = new Intent(MainActivity.this, ItemScreen.class);
    intentSelectedCategory.putExtra("catId", (int)categoryId);
    startActivity(intentSelectedCategory);
    finish();

}

From the ItemScreen.java:

public void onCreate(Bundle savedInstanceState ){
    super.onCreate(savedInstanceState);

    setContentView(R.layout.item_screen);

    Intent i = getIntent();
    Bundle extra = getIntent().getExtras();
    int categoryId = extra.getInt("catId");

    Log.v("THIS IS THE ID OF THIS CATEGORY:", ""+categoryId);

    TextView headTBox = (TextView)findViewById(R.id.HeadTextBox);
    headTBox.setText(MainActivity.categories.get(categoryId-1).getName());

...

Now here is my problem... how can i get the entries values?

Answer 1

It looks like you have to start at the beginning of the linked list and go through each node comparing the bundle ID to the categories node ID.

Good luck!