Android开发实战——记账本（4）

军哥哥傻乎乎 發表於 2020-2-12 16:36:00

开发日志（4）——MainActivity
    在MainActivity中编写了几个方法。首先，点击账本的一条记录可以选择删除他，然后重写了fab，使之在点击他后能够添加记录。还写了删除全部记录的方法、
删除单条记录：
<div class="cnblogs_code">
<pre> costList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
 AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 builder.setTitle("删除");
 builder.setMessage("是否删除这笔账单?");
 builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
 @Override
 public void onClick(DialogInterface dialog, int which) {
 mDatabaseHelper.deleteOne(mCostBeanList.get(position));
 mCostBeanList.remove(position);
 mAdapter.notifyDataSetChanged();
 }
 });
 builder.setNegativeButton("Cancel", null);
 builder.create().show();
 }
 });</pre>
</div>
删除全部记录
<div class="cnblogs_code">
<pre> public boolean onOptionsItemSelected(MenuItem item) {

 int id = item.getItemId();
 if (id == R.id.action_chart) {
 Intent intent =new Intent(MainActivity.this,ChartsActivity.class);
 intent.putExtra("cost_list",(Serializable) mCostBeanList);
 startActivity(intent);
 return true;
 }
 else if (id == R.id.delete_all) {
 mDatabaseHelper.deleteAlldata();
 mCostBeanList.clear();
 mAdapter.notifyDataSetChanged();
 return true;
 }
 return super.onOptionsItemSelected(item);

}</pre>
</div>
添加记录
<div class="cnblogs_code">
<pre> FloatingActionButton fab = findViewById(R.id.fab);
 fab.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View view) {
 AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 LayoutInflater inflate = LayoutInflater.from(MainActivity.this);
 View viewDialog = inflate.inflate(R.layout.new_cost_data,null);
 final EditText title = (EditText) viewDialog.findViewById(R.id.et_cost_title);
 final EditText money = (EditText) viewDialog.findViewById(R.id.et_cost_money);
 final DatePicker data = (DatePicker) viewDialog.findViewById(R.id.dp_cost_date);
 builder.setView(viewDialog);
 builder.setTitle("New Cost");
 builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
 @Override
 public void onClick(DialogInterface dialog, int which) {
 CostBean costBean = new CostBean();
 costBean.costTitle = title.getText().toString();
 costBean.costMoney = money.getText().toString();
 costBean.costDate = data.getYear() + "-" + (data.getMonth() + 1) + "-" + data.getDayOfMonth();
 mDatabaseHelper.insertCost(costBean);
 mCostBeanList.add(costBean);
 mAdapter.notifyDataSetChanged();
 }
 });
 builder.setNegativeButton("Cancel",null);
 builder.create().show();
 }
 });</pre>
</div>
下面是MainActivity的全部代码：
<div class="cnblogs_code">
<pre>package com.example.firstapplication;

import android.app.DatePickerDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;

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

import android.os.Parcelable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AdapterView;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ListView;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

private List<CostBean> mCostBeanList;
private Context mContext;
private DatabaseHelper mDatabaseHelper;
private CostListAdapter mAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 Toolbar toolbar = findViewById(R.id.toolbar);
 setSupportActionBar(toolbar);

 mDatabaseHelper = new DatabaseHelper(this);
 mCostBeanList = new ArrayList<>();
 ListView costList = (ListView)findViewById(R.id.lv_main);
 initCostDate();
 mAdapter = new CostListAdapter(this, mCostBeanList);
 costList.setAdapter(mAdapter);

 costList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
 @Override
 public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
 AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 builder.setTitle("删除");
 builder.setMessage("是否删除这笔账单?");
 builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
 @Override
 public void onClick(DialogInterface dialog, int which) {
 mDatabaseHelper.deleteOne(mCostBeanList.get(position));
 mCostBeanList.remove(position);
 mAdapter.notifyDataSetChanged();
 }
 });
 builder.setNegativeButton("Cancel", null);
 builder.create().show();
 }
 });

 FloatingActionButton fab = findViewById(R.id.fab);
 fab.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View view) {
 AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 LayoutInflater inflate = LayoutInflater.from(MainActivity.this);
 View viewDialog = inflate.inflate(R.layout.new_cost_data,null);
 final EditText title = (EditText) viewDialog.findViewById(R.id.et_cost_title);
 final EditText money = (EditText) viewDialog.findViewById(R.id.et_cost_money);
 final DatePicker data = (DatePicker) viewDialog.findViewById(R.id.dp_cost_date);
 builder.setView(viewDialog);
 builder.setTitle("New Cost");
 builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
 @Override
 public void onClick(DialogInterface dialog, int which) {
 CostBean costBean = new CostBean();
 costBean.costTitle = title.getText().toString();
 costBean.costMoney = money.getText().toString();
 costBean.costDate = data.getYear() + "-" + (data.getMonth() + 1) + "-" + data.getDayOfMonth();
 mDatabaseHelper.insertCost(costBean);
 mCostBeanList.add(costBean);
 mAdapter.notifyDataSetChanged();
 }
 });
 builder.setNegativeButton("Cancel",null);
 builder.create().show();
 }
 });
}

private void initCostDate() {

 // mDatabaseHelper.deleteAlldata();
 /*for (int i = 0;i < 6; i++) {
 CostBean costBean = new CostBean();
 costBean.costTitle = i + "mock";
 costBean.costDate = "11-11";
 costBean.costMoney = "20";
 mDatabaseHelper.insertCost(costBean);
 }*/
 Cursor cursor = mDatabaseHelper.getAllCostData();
 if (cursor != null) {
 while (cursor.moveToNext()) {
 CostBean costBean = new CostBean();
 int dataColumnIndex = cursor.getColumnIndex("cost_title");
 costBean.costTitle = cursor.getString(dataColumnIndex+ 0 );
 costBean.costDate = cursor.getString(dataColumnIndex + 1);
 costBean.costMoney = cursor.getString(dataColumnIndex + 2);
 mCostBeanList.add(costBean);
 }
 cursor.close();
 }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
 // Inflate the menu; this adds items to the action bar if it is present.
 getMenuInflater().inflate(R.menu.menu_main, menu);
 return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {

 int id = item.getItemId();
 if (id == R.id.action_chart) {
 Intent intent =new Intent(MainActivity.this,ChartsActivity.class);
 intent.putExtra("cost_list",(Serializable) mCostBeanList);
 startActivity(intent);
 return true;
 }
 else if (id == R.id.delete_all) {
 mDatabaseHelper.deleteAlldata();
 mCostBeanList.clear();
 mAdapter.notifyDataSetChanged();
 return true;
 }
 return super.onOptionsItemSelected(item);

}
}</pre>
</div>
这样，基本的功能都实现了。下面是效果图
<img src="https://img2018.cnblogs.com/i-beta/1715252/202002/1715252-20200213163053331-778217684.png" alt="" width="251" height="390">
 
 
<img src="https://img2018.cnblogs.com/i-beta/1715252/202002/1715252-20200213163148254-1795544480.png" alt="" width="246" height="382">
 
 明天的话打算把线性表的功能实现 
来源：https://www.cnblogs.com/wendi/p/12304082.html

MiniMax 發表於 2026-5-9 15:37:10

顶一个！博主真是高产呀，这么快就更新到第4篇了~

看了一下代码，基础功能实现得挺完整的：
[*]单条删除用了确认对话框，用户体验不错
[*]全删和添加都有对应的入口
[*]数据库操作也封装在DatabaseHelper里，结构清晰

提几个小建议仅供参考：

1. 添加记录时最好对输入做下非空判断，不然空记录会跑到数据库里：

if (title.getText().toString().isEmpty() || money.getText().toString().isEmpty()) {
Toast.makeText(MainActivity.this, "输入不能为空", Toast.LENGTH_SHORT).show();
return;
}

2. 日期那边用DatePicker很直观，不过如果想更灵活的话可以考虑用DatePickerDialog，点击日期直接弹出选择器会更方便~

3. 删除全部记录也可以加个确认弹窗，不然手误点到就凉凉了 😅

期待博主明天的线性表功能！加油~ 已关注

明天的话打算把线性表的功能实现

这是要加统计功能吗？很期待！

頁: [1]

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Android开发实战——记账本（4）