Android 从 SQLite 数据库填充自定义 ListView

Question

我知道如何使用自定义适配器管理列表视图。 我会从 SQLite 数据库中填充我的列表视图。 这是我的 CartHandler：

public class CartHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "cartManager";

// Contacts table name
private static final String TABLE_PRODUCTS = "products";

// Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_NO = "number";
private static final String KEY_PIECES = "pieces";
private static final String KEY_PRICE = "price";
private static final String KEY_TOT_PRICE = "totprice";


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

// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
    String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_PRODUCTS + "("
            + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
            + KEY_NO + " TEXT," + KEY_PIECES + " TEXT,"+ KEY_PRICE + " TEXT," + KEY_TOT_PRICE + " TEXT" + ")";
    db.execSQL(CREATE_CONTACTS_TABLE);
}

// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_PRODUCTS);

    // Create tables again
    onCreate(db);
}


// Adding new contact
void addProduct(CartRow product) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, product.getName()); // Contact Name
    values.put(KEY_NO, product.getNumber()); // Contact Phone
    values.put(KEY_PIECES, product.getPieces());
    values.put(KEY_PRICE, product.getPrice());
    values.put(KEY_TOT_PRICE, product.getTotPrice());
    // Inserting Row
    db.insert(TABLE_PRODUCTS, null, values);
    db.close(); // Closing database connection
}

// Getting single contact
CartRow getProduct(int id) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_PRODUCTS, new String[] { KEY_ID,
                    KEY_NAME, KEY_NO, KEY_PIECES, KEY_PRICE, KEY_TOT_PRICE }, KEY_ID + "=?",
            new String[] { String.valueOf(id) }, null, null, null, null);
    if (cursor != null)
        cursor.moveToFirst();

    CartRow product = new CartRow(Integer.parseInt(cursor.getString(0)),
            cursor.getString(1), Integer.parseInt(cursor.getString(2)), Integer.parseInt(cursor.getString(3)), Integer.parseInt(cursor.getString(4)), Integer.parseInt(cursor.getString(5)));
    // return contact
    return product;
}

// Getting All Contacts
public List<CartRow> getAllProducts() {
    List<CartRow> productList = new ArrayList<CartRow>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_PRODUCTS;

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            CartRow product = new CartRow();
            product.setID(Integer.parseInt(cursor.getString(0)));
            product.setName(cursor.getString(1));
            product.setNumber(Integer.parseInt(cursor.getString(2)));
            product.setPieces(Integer.parseInt(cursor.getString(3)));
            product.setPrice(Integer.parseInt(cursor.getString(4)));
            product.setTotPrice(Integer.parseInt(cursor.getString(5)));
            // Adding contact to list
            productList.add(product);
        } while (cursor.moveToNext());
    }

    // return contact list
    return productList;
}

// Updating single contact
public int updateProduct(CartRow product) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, product.getName());
    values.put(KEY_NO, product.getNumber());
    values.put(KEY_PIECES, product.getPieces());
    values.put(KEY_PRICE, product.getPrice());
    values.put(KEY_TOT_PRICE, product.getTotPrice());

    // updating row
    return db.update(TABLE_PRODUCTS, values, KEY_ID + " = ?",
            new String[] { String.valueOf(product.getID()) });
}

// Deleting single contact
public void deleteProduct(CartRow product) {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(TABLE_PRODUCTS, KEY_ID + " = ?",
            new String[] { String.valueOf(product.getID()) });
    db.close();
}


// Getting contacts Count
public int getProductsCount() {
    String countQuery = "SELECT  * FROM " + TABLE_PRODUCTS;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    cursor.close();

    // return count
    return cursor.getCount();
}}

这是我的 CartRow 课程：

public class CartRow {

//private variables
int _id;
String _name;
int _number;
int _pieces;
int _price;
int _totprice;

// Empty constructor
public CartRow(){

}
// constructor
public CartRow(int id, String name, int number, int pieces, int price, int totprice){
    this._id = id;
    this._name = name;
    this._number = number;
    this._pieces = pieces;
    this._price = price;
    this._totprice = totprice;
}

// constructor
public CartRow(String name, int number, int pieces, int price, int totprice){
    this._name = name;
    this._number = number;
    this._pieces = pieces;
    this._price = price;
    this._totprice = totprice;
}
// getting ID
public int getID(){
    return this._id;
}

// setting id
public void setID(int id){
    this._id = id;
}

public String getName(){
    return this._name;
}

public void setName(String name){
    this._name = name;
}

public int getNumber(){
    return this._number;
}

public void setNumber(int number){
    this._number = number;
}

public int getPieces(){
    return this._pieces;
}

public void setPieces(int pieces){
    this._pieces = pieces;
}

public int getPrice(){
    return this._price;
}

public void setPrice(int price){
    this._price = price;
}

public int getTotPrice(){
    return this._totprice;
}

public void setTotPrice(int totprice){
    this._totprice = totprice;
}}

这是我想在列表视图中使用的布局。

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingLeft="20dp"
    android:paddingTop="10dp"
    android:paddingRight="10dp"
    android:background="@android:color/white"
    android:paddingBottom="10dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/number"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:textColor="@android:color/black" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/name"
        android:layout_alignBottom="@+id/number"
        android:layout_toRightOf="@+id/number"
        android:layout_toEndOf="@+id/number"
        android:layout_marginLeft="25dp"
        android:layout_marginStart="29dp"
        android:textColor="@android:color/black" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:id="@+id/pieces"
        android:layout_below="@+id/name"
        android:layout_alignLeft="@+id/name"
        android:layout_alignStart="@+id/name"
        android:layout_marginLeft="1dp"
        android:layout_marginTop="5dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:id="@+id/price"
        android:layout_below="@+id/pieces"
        android:layout_alignLeft="@+id/pieces"
        android:layout_alignStart="@+id/pieces" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/totprice"
        android:layout_alignTop="@+id/name"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:textColor="#ffe20c18" />
</RelativeLayout>

我正确地填充了数据库并读取了 LogCat 中的内容。 不知道如何填充我的列表视图。试图查看类似的问题，但发现了如何填充单个信息。 我应该已经拥有让它工作所需的大部分代码，我不会更改整个代码来遵循示例教程。 谁能帮我？ 任何建议将不胜感激。提前致谢。

Answer 1

首先在您的 Cart Class 类中创建列名列表，

public static ArrayList<String> itemIdList = new ArrayList<String>();
public static ArrayList<String> itemNameList = new ArrayList<String>();
public static ArrayList<String> itemQuantityList = new ArrayList<String>();
public static ArrayList<String> itemPriceList = new ArrayList<String>();

调用这个类从数据库中获取项目并添加到列表中。

public void getItemsFromDatabase() {

        Cursor cursor = null;

            try{
                mdb=new DBCart(getApplicationContext(), DATABASE_NAME,null, DATABASE_VERSION);
                db=mdb.getReadableDatabase();

                cursor=db.rawQuery("select * from cart", null);

                cursor.moveToFirst();

                while (cursor.moveToNext()) {                       

                        Log.e("get", cursor.getString(1)+":"+cursor.getString(2)+":"+cursor.getString(3)+":"+cursor.getString(4));
                        //Here i added data directly to lists in Custom Cart Class
                        CartClass.itemIdList.add(cursor.getString(1));
                        CartClass.itemNameList.add(cursor.getString(2));
                        CartClass.itemQuantityList.add(cursor.getString(3));
                        CartClass.itemPriceList.add(cursor.getString(4));

                }
                cursor.close();
            }catch (SQLException e){
                Log.e("DB Error", e.toString());
                e.printStackTrace();
            }           
}

首先使用此代码创建自定义购物车列表

class CustomCartList extends BaseAdapter {
    private LayoutInflater inflater;
    private SparseBooleanArray mSelectedItemsIds;

    public CustomCartList(Context context) {
        inflater = LayoutInflater.from(context);
        mSelectedItemsIds = new SparseBooleanArray();
    }

    public int getCount() {
        // TODO Auto-generated method stub
        return Cart.itemIdList.size();
    }

    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @SuppressLint("InflateParams")
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder holder;

        if(convertView == null){
            convertView = inflater.inflate(R.layout.cart_layout_row, null);
            holder = new ViewHolder();
            holder.itemName = (TextView) convertView.findViewById(R.id.itemName);
            holder.itemQuantity = (TextView) convertView.findViewById(R.id.itemQuantity);
            holder.itemPrice = (TextView) convertView.findViewById(R.id.itemPrice);

            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }


        holder.itemName.setText(Cart.itemNameList.get(position));
        holder.itemQuantity.setText(Cart.itemQuantityList.get(position));
        holder.itemPrice.setText(Cart.itemPriceList.get(position));

        return convertView;
    }

    static class ViewHolder {
        TextView itemName, itemQuantity, itemPrice;
    }

    public void toggleSelection(int position) {
        selectView(position, !mSelectedItemsIds.get(position));
    }

    public void selectView(int position, boolean value) {
        if (value)
            mSelectedItemsIds.put(position, value);
        else
            mSelectedItemsIds.delete(position);
        notifyDataSetChanged();
    }


    public int getSelectedCount() {
        return mSelectedItemsIds.size();
    }

    public SparseBooleanArray getSelectedIds() {
        return mSelectedItemsIds;
    }

    public void removeSelection() {
        mSelectedItemsIds = new SparseBooleanArray();
        notifyDataSetChanged();
    }
}

使用

创建 CustomCartList 类的适配器

CustomCartList adapter=new CustomCartList(YourActivity.this);

比设置列表适配器使用

list.setAdapter(adapter);