android - 单击 CursorAdapter 中的按钮时如何在 ListView 项行中执行更新和删除操作

Question

在 sqlite 数据库的帮助下，我添加了板球运动员的名字，最后它在 ListView 中显示了名字。

我在 CustomCursorAdapter.java 中添加了更新和删除按钮。下面我发布了适配器代码:

CustomCursorAdapter.java:

import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CursorAdapter;
import android.widget.TextView;

public class CustomCursorAdapter extends CursorAdapter {

    public CustomCursorAdapter(Context context, Cursor c) {
        super(context, c);
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        // when the view will be created for first time,
        // we need to tell the adapters, how each item will look
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View retView = inflater.inflate(R.layout.single_row_item, parent, false);

        return retView;
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        // here we are setting our data
        // that means, take the data from the cursor and put it in views

        TextView textViewPersonName = (TextView) view.findViewById(R.id.tv_person_name);
        textViewPersonName.setText(cursor.getString(cursor.getColumnIndex(cursor.getColumnName(1))));

      //Handle buttons and add onClickListeners
        Button deleteBtn = (Button)view.findViewById(R.id.delete_btn);
        Button updateBtn = (Button)view.findViewById(R.id.update_btn);

        deleteBtn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) { 

                notifyDataSetChanged();
            }
        });  

        updateBtn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) { 
                //do something

                notifyDataSetChanged();
            }
        });        
    }
}  

single_row_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <Button
        android:id="@+id/update_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/delete_btn"
        android:text="Update" />

    <Button
        android:id="@+id/delete_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:text="Delete" />

    <TextView
        android:id="@+id/tv_person_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/add_btn"
        android:layout_alignBottom="@+id/add_btn"
        android:layout_alignParentLeft="true"
        android:paddingBottom="5dp"
        android:text="Sample Data"
        android:textSize="15sp" />

</RelativeLayout>

PersonDatabaseHelper.java:

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

public class PersonDatabaseHelper {

    private static final String TAG = PersonDatabaseHelper.class.getSimpleName();

    // database configuration
    // if you want the onUpgrade to run then change the database_version
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "mydatabase.db";

    // table configuration
    private static final String TABLE_NAME = "person_table";         // Table name
    private static final String PERSON_TABLE_COLUMN_ID = "_id";     // a column named "_id" is required for cursor
    private static final String PERSON_TABLE_COLUMN_NAME = "person_name";
    private static final String PERSON_TABLE_COLUMN_PIN = "person_pin";

    private DatabaseOpenHelper openHelper;
    private SQLiteDatabase database;

    // this is a wrapper class. that means, from outside world, anyone will communicate with PersonDatabaseHelper,
    // but under the hood actually DatabaseOpenHelper class will perform database CRUD operations 
    public PersonDatabaseHelper(Context aContext) {

        openHelper = new DatabaseOpenHelper(aContext);
        database = openHelper.getWritableDatabase();
    }

    public void insertData (String aPersonName, String aPersonPin) {

        // we are using ContentValues to avoid sql format errors

        ContentValues contentValues = new ContentValues();

        contentValues.put(PERSON_TABLE_COLUMN_NAME, aPersonName);
        contentValues.put(PERSON_TABLE_COLUMN_PIN, aPersonPin);

        database.insert(TABLE_NAME, null, contentValues);
    }

    public Cursor getAllData () {

        String buildSQL = "SELECT * FROM " + TABLE_NAME;

        Log.d(TAG, "getAllData SQL: " + buildSQL);

        return database.rawQuery(buildSQL, null);
    }

    // this DatabaseOpenHelper class will actually be used to perform database related operation 

    private class DatabaseOpenHelper extends SQLiteOpenHelper {

        public DatabaseOpenHelper(Context aContext) {
            super(aContext, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase sqLiteDatabase) {
            // Create your tables here

            String buildSQL = "CREATE TABLE " + TABLE_NAME + "( " + PERSON_TABLE_COLUMN_ID + " INTEGER PRIMARY KEY, " +
                    PERSON_TABLE_COLUMN_NAME + " TEXT, " + PERSON_TABLE_COLUMN_PIN + " TEXT )";

            Log.d(TAG, "onCreate SQL: " + buildSQL);

            sqLiteDatabase.execSQL(buildSQL);
        }

        @Override
        public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
            // Database schema upgrade code goes here

            String buildSQL = "DROP TABLE IF EXISTS " + TABLE_NAME;

            Log.d(TAG, "onUpgrade SQL: " + buildSQL);

            sqLiteDatabase.execSQL(buildSQL);       // drop previous table

            onCreate(sqLiteDatabase);               // create the table from the beginning
        }
    }
}

输出:

在上面的截图中，它显示了更新和删除按钮。如果我点击更新按钮，它必须显示一个警告对话框并编辑指定 ListView 的名称并显示它。

然后，如果我单击“删除”按钮，它必须删除相应的 ListView 行。

任何人都可以帮我解决这个问题。谢谢。

Answer 1

最后我自己完成了。但是我没有使用 Cursor Adapter，而是使用 Base Adapter 来获取输出。

我提到了这个Tutorial .我花了更多时间找到这个教程。它对我有很大帮助。然后我对首页和我的要求进行了一些修改。

我这样更改我的首页。下面我将显示 MainActivity 中的更改:

MainActivity.java:

public class MainActivity extends Activity implements OnClickListener {

    private Button btn_add;
    ActionBar actionBar;

    private ListView listview;

    DatabaseHelper db;
    public ArrayList<ProductModel> _productlist = new ArrayList<ProductModel>();

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btn_add = (Button) findViewById(R.id.btn_add);

        btn_add.setOnClickListener(this);

        listview = (ListView) findViewById(R.id.listview);

        actionBar = getActionBar();
        ColorDrawable colorDrawable = new ColorDrawable(
                Color.parseColor("#000000"));
        actionBar.setBackgroundDrawable(colorDrawable);

    }  

    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();

        _productlist.clear();

        db = new DatabaseHelper(getApplicationContext());
        db.getWritableDatabase();
        ArrayList<ProductModel> product_list = db.getProudcts();

        for (int i = 0; i < product_list.size(); i++) {

            String tidno = product_list.get(i).getIdno();

            System.out.println("tidno>>>>>" + tidno);
            String tname = product_list.get(i).getProductname();
            String tprice = product_list.get(i).getProductprice();

            ProductModel _ProductModel = new ProductModel();

            _ProductModel.setIdno(tidno);
            _ProductModel.setProductname(tname);
            _ProductModel.setProductprice(tprice);

            _productlist.add(_ProductModel);
        }

        listview.setAdapter(new ListAdapter(this));
        db.close();

    }

    private class ListAdapter extends BaseAdapter {
        LayoutInflater inflater;
        ViewHolder viewHolder;

        public ListAdapter(Context context) {
            // TODO Auto-generated constructor stub
            inflater = LayoutInflater.from(context);
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return _productlist.size();
        }

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

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            if (convertView == null) {

                convertView = inflater.inflate(R.layout.listview_row, null);
                viewHolder = new ViewHolder();

                viewHolder.txt_pname = (TextView) convertView
                        .findViewById(R.id.txtdisplaypname);
                viewHolder.txt_pprice = (TextView) convertView
                        .findViewById(R.id.txtdisplaypprice);

                viewHolder.txtidno = (TextView) convertView
                        .findViewById(R.id.txtdisplaypid);
                convertView.setTag(viewHolder);

            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }

            viewHolder.txt_pname.setText(_productlist.get(position)
                    .getProductname().trim());
            viewHolder.txt_pprice.setText(_productlist.get(position)
                    .getProductprice().trim());

            viewHolder.txtidno.setText(_productlist.get(position).getIdno()
                    .trim());

            final int temp = position;
            (convertView.findViewById(R.id.btn_update))
                    .setOnClickListener(new OnClickListener() {

                        public void onClick(View arg0) {

                            String _productid = String.valueOf(_productlist
                                    .get(temp).getIdno());
                            String _productname = _productlist.get(temp)
                                    .getProductname();
                            String _productprice = _productlist.get(temp)
                                    .getProductprice();

                            Intent intent = new Intent(MainActivity.this,
                                    AddUpdateValues.class);

                            Bundle bundle = new Bundle();
                            bundle.putString("id", _productid);
                            bundle.putString("name", _productname);
                            bundle.putString("price", _productprice);
                            intent.putExtras(bundle);
                            startActivity(intent);

                        }
                    });

            (convertView.findViewById(R.id.btn_delete))
                    .setOnClickListener(new OnClickListener() {

                        public void onClick(View arg0) {

                            AlertDialog.Builder alertbox = new AlertDialog.Builder(
                                    MainActivity.this);
                            alertbox.setCancelable(true);
                            alertbox.setMessage("Are you sure you want to delete ?");
                            alertbox.setPositiveButton("Yes",
                                    new DialogInterface.OnClickListener() {

                                        public void onClick(
                                                DialogInterface arg0, int arg1) {

                                            Log.i(">>>TEMP>>>", temp + "");
                                            Log.i(">>>getIdno>>>>>>",
                                                    _productlist.get(temp)
                                                            .getIdno().trim()
                                                            + "");
                                            System.out
                                                    .println(">>>getIdno>>>>>>"
                                                            + _productlist
                                                                    .get(temp)
                                                                    .getIdno()
                                                                    .trim());
                                            db.removeProduct(
                                                    _productlist.get(temp)
                                                            .getIdno().trim(),
                                                    "", "");

                                            MainActivity.this.onResume();

                                            Toast.makeText(
                                                    getApplicationContext(),
                                                    "Project Deleted...",
                                                    Toast.LENGTH_SHORT).show();

                                        }  

                                    });
                            alertbox.setNegativeButton("No",
                                    new DialogInterface.OnClickListener() {
                                        public void onClick(
                                                DialogInterface arg0, int arg1) {

                                        }
                                    });
                            alertbox.show();
                        }
                    });
            return convertView;

        }
    }

    private class ViewHolder {
        TextView txt_pname;
        TextView txt_pprice;
        TextView txtidno;

    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.btn_add:
            Intent addintent = new Intent(MainActivity.this, AddRecord.class);
            startActivity(addintent);
            break;

        default:
            break;
        }

    }

}

我希望这个答案可能对某人有所帮助。