删除自定义列表视图中的多个项目 [英] delete multiple items in custom listview

问题描述

我想创建一个自定义列表视图，其中每一行都有一个文本视图和一个图像视图(我将用它来选中/取消选中列表项)，如下图所示:

I want to create a custom listview in which every single row has a textview and an imageview(which i'll use to check/uncheck the list items) as shown in the following figure:

我想从列表中删除多个项目.如何实现这一点?你能提供任何教程或参考或链接来学习这个吗??

I want to delete multiple items from the list. How to achieve this ?? Can you please provide any tutorial or reference or link to learn this ??

推荐答案

这就是我轻松创建自定义列表视图的方式:

This is how i created my custom listview with ease:

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

import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.ActivityInfo;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class DeleteData extends Activity {

    Cursor cursor;
    ListView lv_delete_data;
    static ArrayList<Integer> listOfItemsToDelete;
    SQLiteDatabase database;
    private Category[] categories;
    ArrayList<Category> categoryList;
    private ArrayAdapter<Category> listAdapter;
    ImageView iv_delete;

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

        this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

        manage_reload_list();

        listOfItemsToDelete = new ArrayList<Integer>();

        iv_delete = (ImageView) findViewById(R.id.imageViewDeleteDataDelete);
        iv_delete.setClickable(true);
        iv_delete.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listOfItemsToDelete.isEmpty()) {

                    Toast.makeText(getBaseContext(), "No items selected.",
                            Toast.LENGTH_SHORT).show();
                }

                else {
                    showDialog(
                            "Warning",
                            "Are you sure you want to delete these categories ? This will erase all records attached with it.");
                }
            }
        });

        lv_delete_data = (ListView) findViewById(R.id.listViewDeleteData);
        lv_delete_data.setAdapter(listAdapter);
        lv_delete_data.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3) {
                // TODO Auto-generated method stub
                ImageView imageView = (ImageView) arg1
                        .findViewById(R.id.imageViewSingleRowDeleteData);
                Category category = (Category) imageView.getTag();

                if (category.getChecked() == false) {
                    imageView.setImageResource(R.drawable.set_check);
                    listOfItemsToDelete.add(category.getId());
                    category.setChecked(true);
                } else {
                    imageView.setImageResource(R.drawable.set_basecircle);
                    listOfItemsToDelete.remove((Integer) category.getId());
                    category.setChecked(false);
                }
            }
        });
    }

    private void showDialog(final String title, String message) {

        AlertDialog.Builder adb = new Builder(DeleteData.this);
        adb.setTitle(title);
        adb.setMessage(message);
        adb.setIcon(R.drawable.ic_launcher);
        String btn = "Ok";
        if (title.equals("Warning")) {
            btn = "Yes";
            adb.setNegativeButton("No", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
        }

        adb.setPositiveButton(btn, new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface arg0, int arg1) {

                if (title.equals("Warning")) {

                    for (int i : listOfItemsToDelete) {

                        // -------first delete from category table-----

                        database.delete("category_fields", "cat_id=?",
                                new String[] { i + "" });

                        // --------now fetch rec_id where cat_id =
                        // i-----------------

                        cursor = database.query("records_data",
                                new String[] { "rec_id" }, "cat_id=?",
                                new String[] { i + "" }, null, null, null);
                        if (cursor.getCount() == 0)
                            cursor.close();
                        else {
                            ArrayList<Integer> al_tmp_rec_id = new ArrayList<Integer>();
                            while (cursor.moveToNext())
                                al_tmp_rec_id.add(cursor.getInt(0));
                            cursor.close();

                            for (int i1 : al_tmp_rec_id) {
                                database.delete("records_fields_data",
                                        "rec_id=?", new String[] { i1 + "" });

                                database.delete("record_tag_relation",
                                        "rec_id=?", new String[] { i1 + "" });
                            }

                            // ---------delete from records_data-------

                            database.delete("records_data", "cat_id=?",
                                    new String[] { i + "" });

                            cursor.close();
                        }
                    }

                    showDialog("Success",
                            "Categories, with their records, deleted successfully.");
                } else {
                    database.close();
                    listOfItemsToDelete.clear();
                    manage_reload_list();
                    lv_delete_data.setAdapter(listAdapter);
                }
            }
        });

        AlertDialog ad = adb.create();
        ad.show();
    }

    protected void manage_reload_list() {

        loadDatabase();

        categoryList = new ArrayList<Category>();

        // ------first fetch all categories name list-------

        cursor = database.query("category", new String[] { "cat_id",
                "cat_description" }, null, null, null, null, null);
        if (cursor.getCount() == 0) {
            Toast.makeText(getBaseContext(), "No categories found.",
                    Toast.LENGTH_SHORT).show();
            cursor.close();
        } else {

            while (cursor.moveToNext()) {

                categories = new Category[] { new Category(cursor.getInt(0),
                        cursor.getString(1)) };
                categoryList.addAll(Arrays.asList(categories));
            }
            cursor.close();
        }
        listAdapter = new CategoryArrayAdapter(this, categoryList);
    }

    static class Category {

        String cat_name = "";
        int cat_id = 0;
        Boolean checked = false;

        Category(int cat_id, String name) {
            this.cat_name = name;
            this.cat_id = cat_id;
        }

        public int getId() {
            return cat_id;
        }

        public String getCatName() {
            return cat_name;
        }

        public Boolean getChecked() {
            return checked;
        }

        public void setChecked(Boolean checked) {
            this.checked = checked;
        }

        public boolean isChecked() {
            return checked;
        }

        public void toggleChecked() {
            checked = !checked;
        }
    }

    static class CategoryViewHolder {

        ImageView imageViewCheck;
        TextView textViewCategoryName;

        public CategoryViewHolder(ImageView iv_check, TextView tv_category_name) {
            imageViewCheck = iv_check;
            textViewCategoryName = tv_category_name;
        }

        public ImageView getImageViewCheck() {
            return imageViewCheck;
        }

        public TextView getTextViewCategoryName() {
            return textViewCategoryName;
        }
    }

    static class CategoryArrayAdapter extends ArrayAdapter<Category> {

        LayoutInflater inflater;

        public CategoryArrayAdapter(Context context, List<Category> categoryList) {

            super(context, R.layout.single_row_delete_data,
                    R.id.textViewSingleRowDeleteData, categoryList);
            inflater = LayoutInflater.from(context);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            Category category = (Category) this.getItem(position);

            final ImageView imageViewCheck;
            final TextView textViewCN;

            if (convertView == null) {

                convertView = inflater.inflate(R.layout.single_row_delete_data,
                        null);

                imageViewCheck = (ImageView) convertView
                        .findViewById(R.id.imageViewSingleRowDeleteData);
                textViewCN = (TextView) convertView
                        .findViewById(R.id.textViewSingleRowDeleteData);

                convertView.setTag(new CategoryViewHolder(imageViewCheck,
                        textViewCN));
            }

            else {

                CategoryViewHolder viewHolder = (CategoryViewHolder) convertView
                        .getTag();
                imageViewCheck = viewHolder.getImageViewCheck();
                textViewCN = viewHolder.getTextViewCategoryName();
            }

            imageViewCheck.setFocusable(false);
            imageViewCheck.setFocusableInTouchMode(false);
            imageViewCheck.setClickable(true);
            imageViewCheck.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    ImageView iv = (ImageView) v;
                    Category category = (Category) iv.getTag();

                    if (category.getChecked() == false) {
                        imageViewCheck.setImageResource(R.drawable.set_check);
                        listOfItemsToDelete.add(category.getId());
                        category.setChecked(true);
                    } else {
                        imageViewCheck
                                .setImageResource(R.drawable.set_basecircle);
                        listOfItemsToDelete.remove((Integer) category.getId());
                        category.setChecked(false);
                    }
                }
            });
            imageViewCheck.setTag(category);

            if (category.getChecked() == true)
                imageViewCheck.setImageResource(R.drawable.set_check);
            else
                imageViewCheck.setImageResource(R.drawable.set_basecircle);

            textViewCN.setText(category.getCatName());

            return convertView;
        }
    }

    private void loadDatabase() {
        database = openOrCreateDatabase("WalletAppDatabase.db",
                SQLiteDatabase.OPEN_READWRITE, null);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {

            finish();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}

有疑问的可以问我...

Anyone who have doubts in this can ask me...

这篇关于删除自定义列表视图中的多个项目的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！