初识Android(安卓)制作一个简单的记账本
16lz
2021-01-24
初识Android 制作一个简单的记账本
- 主要功能
- 实现一个记账本页面
- 可以添加数据并更新到页面中
- 主要步骤
- 运行截图
- 主页面
- 点击红色按钮弹出添加页面
- 完成后自动更新到目录下
主要功能
实现一个记账本页面
可以添加数据并更新到页面中
主要步骤
- 创建一个新项目，选择Basic Activity
- 修改content_main.xml，将TextView修改成ListView
<ListView android:id="@+id/lv_main" android:layout_width="match_parent" android:layout_height="match_parent" />- 创建一个layout,取名为list_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="80dp"> <TextView android:id="@+id/tv_title" android:layout_width="150dp" android:layout_height="80dp" android:layout_marginLeft="10dp" android:layout_alignParentLeft="true" android:gravity="center" android:singleLine="true" android:textSize="30sp" android:ellipsize="marquee" android:text="costTitle" /> <TextView android:id="@+id/tv_date" android:layout_width="wrap_content" android:layout_height="80dp" android:gravity="center" android:textSize="20sp" android:layout_marginLeft="15dp" android:layout_toRightOf="@+id/tv_title" android:text="costDate"/> <TextView android:id="@+id/tv_cost" android:layout_width="wrap_content" android:layout_height="80dp" android:gravity="center" android:layout_alignParentRight="true" android:layout_marginRight="20dp" android:textSize="25sp" android:text="25"/>RelativeLayout>效果如图：
- 创建一个CostBean.java
public class CostBean { public String costTitle; public String costDate; public String costMoney;}- 创建一个CostListAdapter.java,继承BaseAdapter
public class CostListAdapter extends BaseAdapter { private List<CostBean> mList; private Context mContext; private LayoutInflater mLayoutInflater; public CostListAdapter(Context context, List<CostBean> list) { mContext = context; mList = list; mLayoutInflater = LayoutInflater.from(context); } @Override public int getCount() { return mList.size(); } @Override public Object getItem(int position) { return mList.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; if(convertView == null){ viewHolder = new ViewHolder(); convertView = mLayoutInflater.inflate(R.layout.list_item, null); viewHolder.mTvCostTitle = (TextView) convertView.findViewById(R.id.tv_title); viewHolder.mTvCostDate = (TextView)convertView.findViewById(R.id.tv_date); viewHolder.mTvCostMoney =(TextView) convertView.findViewById(R.id.tv_cost); convertView.setTag(viewHolder); }else{ viewHolder = (ViewHolder) convertView.getTag(); } CostBean bean = mList.get(position); viewHolder.mTvCostTitle.setText(bean.costTitle); viewHolder.mTvCostDate.setText(bean.costDate); viewHolder.mTvCostMoney.setText(bean.costMoney); return convertView; } private static class ViewHolder{ public TextView mTvCostTitle; public TextView mTvCostDate; public TextView mTvCostMoney; }}- 在MainActivity中设置
mDatabaseHelper = new DatabaseHelper(this);mCostBeanList = new ArrayList<>();ListView costList = findViewById(R.id.lv_main);initCostData();costList.setAdapter(mAdapter);定义的全局变量
private List<CostBean> mCostBeanList;private DatabaseHelper mDatabaseHelper;private CostListAdapter mAdapter;调用之前，创建一个initCostData()方法，使得调用它时，我们可以从数据库中查出所有的数据并显示到ListView上
private void initCostData() { 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(); } }- 数据库的创建，创建一个DatabaseHelper.java,用以保存记账的数据
创建一个数据库取名为account_daily;在onCreate方法中创建一张表account_cost,在其中增加相应的字段
public class DatabaseHelper extends SQLiteOpenHelper { public DatabaseHelper(Context context) { super(context,"account_daily", null, 1); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("create table if not exists account_cost(" + "id integer primary key, " + "cost_title varchar, " + "cost_date varchar, " + "cost_money varchar)"); }调用insertCost(),将一个插入的对象传递进数据库中:
public void insertCost(CostBean costBean){ SQLiteDatabase database = getWritableDatabase(); ContentValues cv = new ContentValues(); cv.put("cost_title", costBean.costTitle); cv.put("cost_date", costBean.costDate); cv.put("cost_money", costBean.costMoney); database.insert("account_cost",null,cv); }查询数据库中Cursor所有结果:
public Cursor getAllCostData(){ SQLiteDatabase database =getWritableDatabase(); return database.query("account_cost",null,null, null,null,null, "cost_date ASC"); } public void deleteAllData(){ SQLiteDatabase database = getWritableDatabase(); database.delete("account_cost",null,null); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }}- 修改fab按钮，使得当我们点击时弹出一个新的窗口，可以创建一条新纪录，并且能保存并更新数据,在MainActivity中修改
fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); LayoutInflater inflater = LayoutInflater.from(MainActivity.this); View viewDialog = inflater.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 date = (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 = date.getYear() + "-" +(date.getMonth() + 1) + "-" + date.getDayOfMonth(); mDatabaseHelper.insertCost(costBean); mCostBeanList.add(costBean); mAdapter.notifyDataSetChanged(); } }); builder.setNegativeButton("Cancel",null); builder.create().show(); } });}其中还要给创建的Dialog创建一个新的布局，我们取名为new_cost_data.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:gravity="center"> <EditText android:id="@+id/et_cost_title" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="4dp" android:hint="Cost Title" /> <EditText android:id="@+id/et_cost_money" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="4dp" android:hint="Cost Money" /> <DatePicker android:id="@+id/dp_cost_date" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" android:datePickerMode="spinner" android:calendarViewShown="false" />LinearLayout>效果大致如下：
至此程序大致编辑完毕，我们可以来运行测试一下！
运行截图
主页面
点击红色按钮弹出添加页面
完成后自动更新到目录下
作者：杨坤萍
链接: link.
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