一、说在前面

昨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，今天增加了一个动态更改和删除的程序，从列表点击可以获取信息进入新的界面然后界面上回显出其本身的信息，下面增加了两个按钮，删除或者是更改。遇到的问题：不知道如何将date回写，并且在界面的跳转中虽然实现了对数据库的数据的更改，但是会秒退，重启之后就好了。。。

二、今天完成的代码

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);
        final ListView costList=findViewById(R.id.lv_main);
        initCostData();
        mAdapter = new CostAdapter(this, costBeanList);
        costList.setAdapter(mAdapter);
        costList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                CostBean costBean=costBeanList.get(position);
                //CostBean bean= (CostBean) mAdapter.getItem(costBean.id);
                Intent intent=new Intent(MainActivity.this,Delete_UpdateActivity.class);
                intent.putExtra("id",costBean.id);
                startActivityForResult(intent,1);

            }
        });
        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.id=cursor.getInt(cursor.getColumnIndex("id"));
                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.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.SpinnerAdapter;

import androidx.annotation.Nullable;

public class Delete_UpdateActivity extends Activity {
    private int id;
    private CostBean costBean;
    DatabaseHelper helper;
    EditText ed_title;
    EditText ed_money;
    DatePicker dp_date;
    Button bt_delete;
    Button bt_update;
    Spinner sp_type;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_delete_or_update);
        helper=new DatabaseHelper(Delete_UpdateActivity.this);
        Intent intent=getIntent();
        id=intent.getIntExtra("id",id);
        costBean=new CostBean();
        Cursor cursor=helper.getCostById(String.valueOf(id));
        if(cursor!=null){
            cursor.moveToNext();
            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"));
        }

        initData();
        initListener();
    }

    private void initData() {
        ed_title = findViewById(R.id.et_cost1_title);
        ed_money = findViewById(R.id.et_cost1_money);
        dp_date = findViewById(R.id.dp_cost1_date);
        sp_type = findViewById(R.id.sp_1type);
        bt_delete = findViewById(R.id.bt_delete);
        bt_update = findViewById(R.id.bt_update);
        ed_title.setText(costBean.costTitle);
        ed_money.setText(costBean.costMoney);
        SpinnerAdapter apsAdapter = sp_type.getAdapter();
        int size = apsAdapter.getCount();
        for (int i = 0; i < size; i++) {
            if (TextUtils.equals(costBean.costType, apsAdapter.getItem(i).toString())) {
                sp_type.setSelection(i,true);
                break;
            }
        }
    }

    private void initListener() {

        bt_delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                helper.deleteById(id);
                setResult(2);
                finish();
            }
        });
    }
}

DeleteUpdateActivity

<?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">

    <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_1type"
        android:scrollbarSize="20sp"
        android:layout_height="wrap_content"/>



    <EditText
        android:id="@+id/et_cost1_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:hint="Cost Title" />

    <EditText
        android:id="@+id/et_cost1_money"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:hint="Cost Money" />

    <DatePicker
        android:id="@+id/dp_cost1_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
        android:layout_width="match_parent"
        android:layout_height="205dp"
        android:gravity="center">

        <Button
            android:id="@+id/bt_delete"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="delete" />

        <Button
            android:id="@+id/bt_update"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:text="update" />
    </LinearLayout>


</LinearLayout>

delete_or_update

三、效果

 点击其中一条

 点击相应的键会有相应的效果然后跳转回原来的界面刷新

四、心得体会

今天感觉安卓和Javaweb好像，不过又有好多不一样且方便的东西，不过出现问题我还不怎么会处理，还需要继续加油学习。