Android开发之记账本开发第六天

古之立大事者，不惟有超世之才，亦必有坚忍不拔之志。这篇文章主要讲述Android开发之记账本开发第六天相关的知识，希望能为你提供帮助。
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

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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

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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

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< ?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