昨天对业务逻辑进行进一步的完善，遇到了大问题，今天在原有基础上添加了搜索和删除，并添加了一个数据的属性以下拉表的形式添加。遇到的问题，下拉表的信息接不到，已经解决。同时也非常感谢一篇文章的作者的分享，让我学会了下拉框的取值方法，在此附上链接：https://blog.csdn.net/S__zO/article/details/45502995

二、今天完成的源代码

package com.example.daliy;

import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;

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

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

import android.text.TextUtils;
import android.util.Log;
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 android.widget.Spinner;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {
    private static final String TAG="MainActivity";
    private List<CostBean> costBeanList;
    private DatabaseHelper helper;
    private String selectText="oo";
    CostAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        costBeanList=new ArrayList<>();
        helper=new DatabaseHelper(this);
        ListView costList=findViewById(R.id.lv_main);
        initCostData();
        mAdapter = new CostAdapter(this, costBeanList);
        costList.setAdapter(mAdapter);

        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 inflater=LayoutInflater.from(MainActivity.this);
                View viewDialog =inflater.inflate(R.layout.new_cost,null);
                final EditText cost_title=viewDialog.findViewById(R.id.et_cost_title);
                final EditText cost_money=viewDialog.findViewById(R.id.et_cost_money);
                final DatePicker cost_date=viewDialog.findViewById(R.id.dp_cost_date);
                final Spinner cost_type=viewDialog.findViewById(R.id.sp_type);
                cost_type.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        selectText=cost_type.getSelectedItem().toString();
                        Log.d(TAG, "onItemSelected: +选择运行了");
                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parent) {

                    }
                });
                builder.setTitle("新账目");
                builder.setView(viewDialog);
                builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        if(TextUtils.isEmpty(cost_title.getText())){
                            Toast.makeText(MainActivity.this,"备注为空",Toast.LENGTH_SHORT).show();
                            return;
                        }else if(TextUtils.isEmpty(cost_money.getText())){
                            Toast.makeText(MainActivity.this,"金额为空",Toast.LENGTH_SHORT).show();
                            return;
                        }
                        CostBean costBean=new CostBean();

                        costBean.costType=selectText;
                        Log.d(TAG, "onClick: "+selectText);
                        costBean.costTitle=cost_title.getText().toString();
                        costBean.costMoney=cost_money.getText().toString();
                        costBean.costDate=cost_date.getYear()+"-"+(cost_date.getMonth()+1)+"-"+cost_date.getDayOfMonth();
                        helper.insertCost(costBean);
                        costBeanList.add(costBean);
                        mAdapter.notifyDataSetChanged();
                    }
                });
                builder.setNegativeButton("Cancel",null);
                builder.create().show();
            }
        });
    }

    private void initCostData() {
//        helper.deleteAllCost();
//        for(int i=0;i<6;i++) {
//
//            CostBean cb=new CostBean();
//            cb.costDate="12-12";
//            cb.costMoney="50";
//            cb.costTitle=i+"heih";
//            helper.insertCost(cb);
//        }
        Cursor cursor = helper.getAllCost();
        if(cursor!=null){
            while (cursor.moveToNext()){
                CostBean costBean=new CostBean();
                costBean.costType=cursor.getString(cursor.getColumnIndex("cost_type"));
                costBean.costTitle=cursor.getString(cursor.getColumnIndex("cost_title"));
                costBean.costDate=cursor.getString(cursor.getColumnIndex("cost_date"));
                costBean.costMoney=cursor.getString(cursor.getColumnIndex("cost_money"));
                costBeanList.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();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_chart) {

            Intent intent = new Intent(MainActivity.this,ChartActivity.class);
            intent.putExtra("cost_list", (Serializable) costBeanList);
            startActivity(intent);
            return true;
        }
        else if(id==R.id.delete_allData){
            helper.deleteAllCost();
            costBeanList.clear();
            mAdapter.notifyDataSetChanged();
            return true;
        }
        else if(id==R.id.query){
            Intent intent = new Intent(MainActivity.this,QueryActivity.class);
            startActivity(intent);
        }
        return super.onOptionsItemSelected(item);
    }
}

MainActivity

package com.example.daliy;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import androidx.annotation.Nullable;

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

public class QueryActivity extends Activity {
    EditText queryKey;
    Button doResearch;
    DatabaseHelper helper;
    ListView listView;
    List<CostBean> list;
    //private String queryKey;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_query_layout);
        listView=findViewById(R.id.lv_query);
        queryKey = findViewById(R.id.et_queryKey);
        doResearch = findViewById(R.id.bt_do_research);
        helper=new DatabaseHelper(this);
        list=new ArrayList<>();
        initListener();
    }

    private void initListener() {
        doResearch.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(TextUtils.isEmpty(queryKey.getText())){
                    Toast.makeText(QueryActivity.this,"没有目标",Toast.LENGTH_SHORT).show();
                    return;
                }

                Cursor cursor = helper.getCost(queryKey.getText().toString());
                if(cursor!=null){
                    while (cursor.moveToNext()){
                        CostBean costBean=new CostBean();
                        costBean.costType=cursor.getString(cursor.getColumnIndex("cost_type"));
                        costBean.costTitle=cursor.getString(cursor.getColumnIndex("cost_title"));
                        costBean.costDate=cursor.getString(cursor.getColumnIndex("cost_date"));
                        costBean.costMoney=cursor.getString(cursor.getColumnIndex("cost_money"));
                        list.add(costBean);
                    }
                    cursor.close();
                }

                listView.setAdapter(new CostAdapter(QueryActivity.this,list));
            }
        });
    }
}

QueryActivity

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

    <EditText
        android:layout_width="match_parent"
        android:hint="条件"
        android:layout_margin="10dp"
        android:layout_marginTop="5dp"
        android:textSize="20sp"
        android:id="@+id/et_queryKey"
        android:layout_height="wrap_content"/>

    <Button
        android:layout_width="match_parent"
        android:text="搜索"
        android:textSize="20sp"
        android:id="@+id/bt_do_research"
        android:layout_margin="10dp"
        android:layout_height="wrap_content"/>

    <ListView
        android:layout_width="match_parent"
        android:id="@+id/lv_query"
        android:layout_margin="10dp"
        android:layout_height="wrap_content"/>

</LinearLayout>

activity_query

<?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">

    <TextView
        android:layout_width="match_parent"
        android:layout_margin="4dp"
        android:text="记账类型"
        android:textSize="20sp"
        android:layout_height="wrap_content"/>
    <Spinner
        android:layout_width="match_parent"
        android:layout_margin="4dp"
        android:entries="@array/cost_type"
        android:id="@+id/sp_type"
        android:scrollbarSize="20sp"
        android:layout_height="wrap_content"/>


    <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_gravity="center"
        android:layout_margin="4dp"
        android:calendarViewShown="false"
        android:datePickerMode="spinner" />

</LinearLayout>

new_cost

package com.example.daliy;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Spinner;
import android.widget.Toast;

import androidx.annotation.Nullable;

public class SpinnerAdapterActivity extends Activity {

    private static final String TAG="SpinnerAdapterActivity";
    public Spinner spinner;
    public String selectText;
    public SpinnerAdapterActivity(){
        spinner.findViewById(R.id.sp_type);
    }

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                selectText=parent.getItemAtPosition(position).toString();
                //Log.d(TAG, "onItemSelected: "+selectText);
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });
    }
}