從LinkedList獲取值到LinkedList

Question

我有一個鏈表名稱類別。 進入此鏈表，我具有以下值：id，名稱，描述，條目（鏈表）

在方法中，我得到了一個捆綁的ID。 現在我的問題是，如何使用ID連接/輸入/獲取條目中的數據？

（ID，名稱，描述和條目數據將從數據庫中加載）

從數據庫加載並將其添加到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);

從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();

}

從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());

...

現在這是我的問題...我如何獲取條目值？

Answer 1

看來您必須從鏈表的開頭開始，然后遍歷每個節點，將包ID與類別節點ID進行比較。

祝好運！