Android平台开发demo-通讯录增删查

【实例简介】

设计一个应用程序，工程名为userMS，实现数据库中用户的读取、添加、删除、查询及群发短信。

【实例截图】

【核心代码】

详见附件

package com.example.userms;

import android.content.ContentValues;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.database.DataSetObserver;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;


import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

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


public class MainActivity extends AppCompatActivity {
    private DataBaseHelper dataBaseHelper;
    final List<User> list = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        dataBaseHelper = new DataBaseHelper(this, "user.db", null, 1);
        Button createDatabase = findViewById(R.id.create_database);
        createDatabase.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dataBaseHelper.getWritableDatabase();//创建数据库
            }
        });
        final ListAdapter adapter=new BaseAdapter() {
            @Override
            public int getCount() {
                return list.size();
            }

            @Override
            public Object getItem(int position) {
                return null;
            }

            @Override
            public long getItemId(int position) {
                return 0;
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                View view;
                if(convertView == null )
                {
                    LayoutInflater inflater = MainActivity.this.getLayoutInflater();
                    view = inflater.inflate(R.layout.user_item,null);
                    //view = View.inflate(getBaseContext(),R.layout.item,null);
                }
                else
                {
                    view = convertView;
                }
                //从studentlist中取出一行数据，position相当于数组下标,可以实现逐行取数据
                User user1 = list.get(position);
                //TextView name = (TextView) LayoutInflater.from(MainActivity.this).inflate(R.layout.item, null).findViewById(R.id.stu_name);
                //TextView xuehao = (TextView) LayoutInflater.from(MainActivity.this).inflate(R.layout.item, null).findViewById(R.id.stu_number);
                //TextView Class = (TextView) LayoutInflater.from(MainActivity.this).inflate(R.layout.item, null).findViewById(R.id.stu_age);
                TextView name = (TextView)view.findViewById(R.id.user_name);
                TextView phone  = (TextView)view.findViewById(R.id.telnumber);
                TextView id = view.findViewById(R.id.id);
                phone.setText(user1.getPhone());
                name.setText(user1.getName());
                id.setText(String.valueOf(user1.getId()));
                return view;
            }
        };

        Button add = findViewById(R.id.add_data);
        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
//                final EditText inputServer = new EditText(MainActivity.this);
//                final EditText inputPhone = new EditText(MainActivity.this);
//                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
//                builder.setTitle("新增用户").setIcon(android.R.drawable.ic_dialog_info).setView(inputServer).setNegativeButton("取消", new DialogInterface.OnClickListener() {
//                    @Override
//                    public void onClick(DialogInterface dialog, int which) {
//                        dialog.dismiss();
//                    }
//                });
//                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
//                    @Override
//                    public void onClick(DialogInterface dialog, int which) {
//                        String name = inputServer.getText().toString();
//                        String phone = inputPhone.getText().toString();
//                        Log.d("MainActivity",name   phone);
//                    }
//                });
//                builder.show();
                Intent intent = new Intent(MainActivity.this,Add.class);
                startActivity(intent);
            }
        });

        Button query = findViewById(R.id.query);
        query.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final SQLiteDatabase db = dataBaseHelper.getWritableDatabase();
                Cursor cursor = db.query("users", null, null, null, null, null, null);
                User user = null;
                if (cursor.moveToFirst()) {
                    do {
                        String name = cursor.getString(cursor.getColumnIndex("name"));
                        String phone = cursor.getString(cursor.getColumnIndex("phone"));
                        int id = cursor.getInt(cursor.getColumnIndex("id"));
                        user = new User(name, phone);
                        user.setId(id);
                        list.add(user);
//                        Log.d("MainActivity", name);
//                        Log.d("MainActivity", author);
//                        Log.d("MainActivity", "pages"   pages);
//                        Log.d("MainActivity", "price" price);
                    } while (cursor.moveToNext());
                    cursor.close();
                }
                final ListView listView = (ListView)findViewById(R.id.listview);
                listView.setAdapter(adapter);
                listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
                    @Override
                    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                        SQLiteDatabase db = dataBaseHelper.getWritableDatabase();
                        int delid = list.get(position).getId();
                        list.remove(position);
                        db.delete("users", "id=?",new String[]{String.valueOf(delid)});
                        Toast.makeText(MainActivity.this, delid   "已删除", Toast.LENGTH_SHORT).show();
                        listView.setAdapter(adapter);
                        return false;
                    }
                });
            }
        });
    }

}