我想通过点击删除一行

Question

在此应用程序中，用户将产品添加到他们的购物中 list.Then 他可以通过切换到 class below.Now 查看他添加到购物清单中的产品我希望用户拥有通过单击存储产品的行来删除产品的选项，我想知道这怎么可能？谢谢。

DataListActivity

 package ie.example.artur.projectrepeat;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class DataListActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {

    ListView listView;
    SQLiteDatabase sqLiteDatabase;
    DatabaseClass  database;
    Cursor cursor;
    ListDataAdapter listDataAdapter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.data_list_layout);


        listView = (ListView) findViewById(R.id.list_view);
        listDataAdapter = new ListDataAdapter(getApplicationContext(), R.layout.row_layout);
        listView.setAdapter(listDataAdapter);
        listView.setOnItemClickListener(this);
        database = new DatabaseClass(getApplicationContext());

        sqLiteDatabase = database.getReadableDatabase();

        Cursor cursor=database.getInformation(sqLiteDatabase);

        if (cursor.moveToFirst()) {
            do {

                String id, product_name, category;
                id = cursor.getString(0);
                product_name = cursor.getString(1);
                category = cursor.getString(2);
                DataProvider dataProvider = new DataProvider(id, product_name, category);
                listDataAdapter.add(dataProvider);
            } while (cursor.moveToNext()


                    );

        }
    }

   @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        TextView tv = (TextView) view.findViewById(R.id.product_id);
        sqLiteDatabase = database.getReadableDatabase();
        DatabaseClass.DeleteInformation(tv.getText().toString(), sqLiteDatabase);


        listDataAdapter.notifyDataSetChanged();


    }


    }

这是我的数据库

  package ie.example.artur.projectrepeat;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;

/**
 * Created by family on 06/07/2016.
 */
public class DatabaseClass extends SQLiteOpenHelper {
    public static final String DATABASE_Name = "Product.db2";
    public static final String Table_Name = "product_table2";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "Name";
    public static final String COL_3 = "Quantity";
    public static final String COL_4 = "Category";
    public static final String COL_5 = "Importance";
    public DatabaseClass(Context context) {
        super(context, DATABASE_Name, null, 1);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + Table_Name + " (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,Quantity TEXT,Category INTEGER,Importance TEXT);");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("Drop Table If Exists" + Table_Name);
        onCreate(db);
    }

    public boolean insertData(String name, String quantity, String category,String importance) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2, name);
        contentValues.put(COL_3, quantity);
        contentValues.put(COL_4, category);
        contentValues.put(COL_5, importance);

        long result = db.insert(Table_Name, null, contentValues);

            if (result == -1)
                return false;
            else
                return true;
        }

    public Cursor getAllData() {
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor res = db.rawQuery("select * from " + Table_Name, null);
        return res;
    }

    public boolean updateData(String id,String name,String quantity,String category,String importance ) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_1, id);
        contentValues.put(COL_2, name);
        contentValues.put(COL_3, quantity);
        contentValues.put(COL_4, category);
        contentValues.put(COL_5, importance);
        db.update(Table_Name,contentValues,"id =?",new String[]{id});
                return true;
    }

   /* public Cursor getCursor(){
        SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();

        queryBuilder.setR
    }
*/
   public Integer DeleteData (String id) {
       SQLiteDatabase db = this.getWritableDatabase();
       return db.delete(Table_Name,"ID = ?",new String[]{id});
   }
    public static void DeleteInformation(String item_name, SQLiteDatabase sqLiteDatabase){

        String selection = COL_1+" LIKE ?";
        String [] selection_args = {item_name};
        sqLiteDatabase.delete(Table_Name,selection,selection_args);

    }

    public Cursor getInformation(SQLiteDatabase sqLiteDatabase)
    {
        Cursor cursor;
        String [] Projections = {COL_1,COL_2,COL_4};

        cursor  = sqLiteDatabase.query(Table_Name,Projections,null,null,null,null,null);
        return cursor;

    }

    public Cursor getItem(String item_name ,SQLiteDatabase sqLiteDatabase){
        String [] Projections = {COL_1,COL_2,COL_3,COL_4,COL_5};
        String selection = COL_1+" LIKE ?";
        String [] selection_args = {item_name};
        Cursor cursor = sqLiteDatabase.query(Table_Name,Projections,selection,selection_args,null,null,null);
        return cursor;

    }


}

数据提供者

package ie.example.artur.projectrepeat;

/**
 * Created by family on 10/08/2016.
 */
public class DataProvider {

    private String id;
    private String product_name;
    private String category;

    public DataProvider(String id,String product_name,String category)
    {
    this.id = id;
    this.product_name=product_name;
    this.category=category;




    }


    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }


    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getProduct_name() {
        return product_name;
    }

    public void setProduct_name(String product_name) {
        this.product_name = product_name;
    }
}

ListDataActivity

package ie.example.artur.projectrepeat;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by family on 10/08/2016.
 */
public class ListDataAdapter extends ArrayAdapter  {
   List list = new ArrayList ();

    public ListDataAdapter(Context context, int resource) {
        super(context, resource);
    }





    static class LayoutHandler
    {
        TextView id,product_name,category;

    }
    @Override
    public void add(Object object) {
        super.add(object);
        list.add(object);
    }

    @Override
    public int getCount() {
        return list.size();

    }



    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
       LayoutHandler layoutHandler;
        View row = convertView;
        if(row == null)
        {
            LayoutInflater layoutInflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = layoutInflater.inflate(R.layout.row_layout,parent,false);
            layoutHandler = new LayoutHandler();
            layoutHandler.id = (TextView) row.findViewById(R.id.product_id);
            layoutHandler.product_name = (TextView) row.findViewById(R.id.product_name);
            layoutHandler.category = (TextView) row.findViewById(R.id.product_category);
            row.setTag(layoutHandler);
        }
        else {
            layoutHandler = (LayoutHandler) row.getTag();

        }
        DataProvider dataProvider = (DataProvider) this.getItem(position);
        layoutHandler.id.setText(dataProvider.getId());
        layoutHandler.product_name.setText(dataProvider.getProduct_name());
        layoutHandler.category.setText(dataProvider.getCategory());



        return row;




    }


    }

Answer 1

为此，您需要在该行中设置一个 OnClickListener 或在具有附加侦听器的单元格中创建一个按钮。然后在侦听器内部从项目数组和数据库中删除该项目。我不会为您编写代码，而是给您一个 OnClickListener 的示例：

final Button button = (Button) findViewById(R.id.button_id);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // Perform action on click 
                // delete this item from the database
                (new DatabaseClass()).DeleteData(list.get(position).id);  
                // delete this item from the list array
                list.remove(position);

                // reload the listview
                adapter.notifyDataSetChanged();
            }
        });

在适配器的 getView() 方法中，您可能希望在设置布局处理程序值后立即添加此 onclick 侦听器。希望这至少能让您知道该怎么做。您可以采用多种不同的方法，但我强烈建议您不要让整行都可点击，而是使用带有 "remove" 的按钮。并考虑在执行删除数据的操作之前先显示确认模式。

Answer 2

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        TextView tv=view.findViewBtId(R.id.product_id);
        databaseObject.DeleteData(tv.getText().toString());
        listAdapter.removeItemAt(position);
         // to close the current activity
         finish();

    }
});

按照上面的代码在您的 ListView 上设置 setOnItemClickListener。

我正在您的适配器中添加 removeItemAt 方法 class

    package ie.example.artur.projectrepeat;

    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.TextView;

    import java.util.ArrayList;
    import java.util.List;

    /**
     * Created by family on 10/08/2016.
     */
    public class ListDataAdapter extends ArrayAdapter  {
       List list = new ArrayList ();

        public ListDataAdapter(Context context, int resource) {
            super(context, resource);
        }





        static class LayoutHandler
        {
            TextView id,product_name,category;

        }
        @Override
        public void add(Object object) {
            super.add(object);
            list.add(object);
        }

        @Override
        public int getCount() {
            return list.size();

        }



        @Override
        public Object getItem(int position) {
            return list.get(position);
        }
        // pass you item position which you want to remove
        public void removeItemAt(int position){
        list.remove(position);
        this.notifyDataStateChange();
        }    

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
           LayoutHandler layoutHandler;
            View row = convertView;
            if(row == null)
            {
                LayoutInflater layoutInflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = layoutInflater.inflate(R.layout.row_layout,parent,false);
                layoutHandler = new LayoutHandler();
                layoutHandler.id = (TextView) row.findViewById(R.id.product_id);
                layoutHandler.product_name = (TextView) row.findViewById(R.id.product_name);
                layoutHandler.category = (TextView) row.findViewById(R.id.product_category);
                row.setTag(layoutHandler);
            }
            else {
                layoutHandler = (LayoutHandler) row.getTag();

            }
            DataProvider dataProvider = (DataProvider) this.getItem(position);
            layoutHandler.id.setText(dataProvider.getId());
            layoutHandler.product_name.setText(dataProvider.getProduct_name());
            layoutHandler.category.setText(dataProvider.getCategory());



            return row;




        }


        }

我想通过点击删除一行

I would like to delete a row by clicking on it

android

android-sqlite