Android 开发Day10

这是main里面的所有代码，按版本修改过

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.hui.tally">

    <application
        android:name=".UniteApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MonthChartActivity"></activity>
        <activity android:name=".SettingActivity" />
        <activity android:name=".HistoryActivity" />
        <activity android:name=".AboutActivity" />
        <activity android:name=".SearchActivity" />
        <activity android:name=".RecordActivity" />
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;

public class AboutActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about);
    }

    public void onClick(View view) {
        finish();
    }
}

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;

import com.hui.tally.adapter.AccountAdapter;
import com.hui.tally.db.AccountBean;
import com.hui.tally.db.DBManager;
import com.hui.tally.utils.CalendarDialog;

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

public class HistoryActivity extends AppCompatActivity {
    ListView historyLv;
    TextView timeTv;

    List<AccountBean>mDatas;
    AccountAdapter adapter;
    int year,month;
    int dialogSelPos = -1;
    int dialogSelMonth = -1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_history);
        historyLv = findViewById(R.id.history_lv);
        timeTv = findViewById(R.id.history_tv_time);
        mDatas = new ArrayList<>();
        // 设置适配器
        adapter = new AccountAdapter(this,mDatas);
        historyLv.setAdapter(adapter);
        initTime();
        timeTv.setText(year+"年"+month+"月");
        loadData(year,month);
        setLVClickListener();
    }
    /*设置ListView每一个item的长按事件*/
    private void setLVClickListener() {
        historyLv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                AccountBean accountBean = mDatas.get(position);
                deleteItem(accountBean);
                return false;
            }
        });
    }

    private void deleteItem(final AccountBean accountBean) {
        final int delId = accountBean.getId();
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("提示信息").setMessage("您确定要删除这条记录么？")
                .setNegativeButton("取消",null)
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        DBManager.deleteItemFromAccounttbById(delId);
                        mDatas.remove(accountBean);   //实时刷新，从数据源删除
                        adapter.notifyDataSetChanged();
                    }
                });
        builder.create().show();
    }

    /* 获取指定年份月份收支情况的列表*/
    private void loadData(int year,int month) {
        List<AccountBean> list = DBManager.getAccountListOneMonthFromAccounttb(year, month);
        mDatas.clear();
        mDatas.addAll(list);
        adapter.notifyDataSetChanged();
    }

    private void initTime() {
        Calendar calendar = Calendar.getInstance();
        year = calendar.get(Calendar.YEAR);
        month = calendar.get(Calendar.MONTH)+1;
    }

    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.history_iv_back:
                finish();
                break;
            case R.id.history_iv_rili:
                CalendarDialog dialog = new CalendarDialog(this,dialogSelPos,dialogSelMonth);
                dialog.show();
                dialog.setDialogSize();
                dialog.setOnRefreshListener(new CalendarDialog.OnRefreshListener() {
                    @Override
                    public void onRefresh(int selPos, int year, int month) {
                        timeTv.setText(year+"年"+month+"月");
                        loadData(year,month);
                        dialogSelPos = selPos;
                        dialogSelMonth = month;
                    }
                });
                break;
        }
    }
}

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.text.method.HideReturnsTransformationMethod;
import android.text.method.PasswordTransformationMethod;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.hui.tally.adapter.AccountAdapter;
import com.hui.tally.db.AccountBean;
import com.hui.tally.db.DBManager;
import com.hui.tally.utils.BudgetDialog;
import com.hui.tally.utils.MoreDialog;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Set;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    ListView todayLv;  //展示今日收支情况的ListView
    ImageView searchIv;
    Button editBtn;
    ImageButton moreBtn;
    //声明数据源
    List<AccountBean>mDatas;
    AccountAdapter adapter;
    int year,month,day;
    //头布局相关控件
    View headerView;
    TextView topOutTv,topInTv,topbudgetTv,topConTv;
    ImageView topShowIv;
    SharedPreferences preferences;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initTime();
        initView();
        preferences = getSharedPreferences("budget", Context.MODE_PRIVATE);
        //添加ListView的头布局
        addLVHeaderView();
        mDatas = new ArrayList<>();
        //设置适配器：加载每一行数据到列表当中
        adapter = new AccountAdapter(this, mDatas);
        todayLv.setAdapter(adapter);
    }
     /** 初始化自带的View的方法*/
    private void initView() {
        todayLv = findViewById(R.id.main_lv);
        editBtn = findViewById(R.id.main_btn_edit);
        moreBtn = findViewById(R.id.main_btn_more);
        searchIv = findViewById(R.id.main_iv_search);
        editBtn.setOnClickListener(this);
        moreBtn.setOnClickListener(this);
        searchIv.setOnClickListener(this);
        setLVLongClickListener();
    }
    /** 设置ListView的长按事件*/
    private void setLVLongClickListener() {
        todayLv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                if (position == 0) {  //点击了头布局
                    return false;
                }
                int pos = position-1;
                AccountBean clickBean = mDatas.get(pos);  //获取正在被点击的这条信息

                //弹出提示用户是否删除的对话框
                showDeleteItemDialog(clickBean);
                return false;
            }
        });
    }
    /* 弹出是否删除某一条记录的对话框*/
    private void showDeleteItemDialog(final  AccountBean clickBean) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("提示信息").setMessage("您确定要删除这条记录么？")
                .setNegativeButton("取消",null)
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        int click_id = clickBean.getId();
                        //执行删除的操作
                        DBManager.deleteItemFromAccounttbById(click_id);
                        mDatas.remove(clickBean);   //实时刷新，移除集合当中的对象
                        adapter.notifyDataSetChanged();   //提示适配器更新数据
                        setTopTvShow();   //改变头布局TextView显示的内容
                    }
                });
        builder.create().show();   //显示对话框
    }

    /** 给ListView添加头布局的方法*/
    private void addLVHeaderView() {
        //将布局转换成View对象
        headerView = getLayoutInflater().inflate(R.layout.item_mainlv_top, null);
        todayLv.addHeaderView(headerView);
        //查找头布局可用控件
        topOutTv = headerView.findViewById(R.id.item_mainlv_top_tv_out);
        topInTv = headerView.findViewById(R.id.item_mainlv_top_tv_in);
        topbudgetTv = headerView.findViewById(R.id.item_mainlv_top_tv_budget);
        topConTv = headerView.findViewById(R.id.item_mainlv_top_tv_day);
        topShowIv = headerView.findViewById(R.id.item_mainlv_top_iv_hide);

        topbudgetTv.setOnClickListener(this);
        headerView.setOnClickListener(this);
        topShowIv.setOnClickListener(this);

    }
    /* 获取今日的具体时间*/
    private void initTime() {
        Calendar calendar = Calendar.getInstance();
        year = calendar.get(Calendar.YEAR);
        month = calendar.get(Calendar.MONTH)+1;
        day = calendar.get(Calendar.DAY_OF_MONTH);
    }

    // 当activity获取焦点时，会调用的方法
    @Override
    protected void onResume() {
        super.onResume();
        loadDBData();
        setTopTvShow();
    }
    /* 设置头布局当中文本内容的显示*/
    private void setTopTvShow() {
        //获取今日支出和收入总金额，显示在view当中
        float incomeOneDay = DBManager.getSumMoneyOneDay(year, month, day, 1);
        float outcomeOneDay = DBManager.getSumMoneyOneDay(year, month, day, 0);
        String infoOneDay = "今日支出 ￥"+outcomeOneDay+"  收入 ￥"+incomeOneDay;
        topConTv.setText(infoOneDay);
//        获取本月收入和支出总金额
        float incomeOneMonth = DBManager.getSumMoneyOneMonth(year, month, 1);
        float outcomeOneMonth = DBManager.getSumMoneyOneMonth(year, month, 0);
        topInTv.setText("￥"+incomeOneMonth);
        topOutTv.setText("￥"+outcomeOneMonth);

//    设置显示运算剩余
        float bmoney = preferences.getFloat("bmoney", 0);//预算
        if (bmoney == 0) {
            topbudgetTv.setText("￥ 0");
        }else{
            float syMoney = bmoney-outcomeOneMonth;
            topbudgetTv.setText("￥"+syMoney);
        }
    }

    // 加载数据库数据
    private void loadDBData() {
        List<AccountBean> list = DBManager.getAccountListOneDayFromAccounttb(year, month, day);
        mDatas.clear();
        mDatas.addAll(list);
        adapter.notifyDataSetChanged();
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.main_iv_search:
                Intent it = new Intent(this, SearchActivity.class);  //跳转界面
                startActivity(it);
                break;
            case R.id.main_btn_edit:
                Intent it1 = new Intent(this, RecordActivity.class);  //跳转界面
                startActivity(it1);
                break;
            case R.id.main_btn_more:
                MoreDialog moreDialog = new MoreDialog(this);
                moreDialog.show();
                moreDialog.setDialogSize();
                break;
            case R.id.item_mainlv_top_tv_budget:
                showBudgetDialog();
                break;
            case R.id.item_mainlv_top_iv_hide:
                // 切换TextView明文和密文
                toggleShow();
                break;
        }
        if (v == headerView) {
            //头布局被点击了
            Intent intent = new Intent();
            intent.setClass(this, MonthChartActivity.class);
            startActivity(intent);
        }
    }
    /** 显示运算设置对话框*/
    private void showBudgetDialog() {
        BudgetDialog dialog = new BudgetDialog(this);
        dialog.show();
        dialog.setDialogSize();
        dialog.setOnEnsureListener(new BudgetDialog.OnEnsureListener() {
            @Override
            public void onEnsure(float money) {
                //将预算金额写入到共享参数当中，进行存储
                SharedPreferences.Editor editor = preferences.edit();
                editor.putFloat("bmoney",money);
                editor.commit();
                //计算剩余金额
                float outcomeOneMonth = DBManager.getSumMoneyOneMonth(year, month, 0);
                float syMoney = money-outcomeOneMonth;//预算剩余 = 预算-支出
                topbudgetTv.setText("￥"+syMoney);
            }
        });
    }

    boolean isShow = true;
    /**
     * 点击头布局眼睛时，如果原来是明文，就加密，如果是密文，就显示出来
     * */
    private void toggleShow() {
        if (isShow) {   //明文====》密文
            PasswordTransformationMethod passwordMethod = PasswordTransformationMethod.getInstance();
            topInTv.setTransformationMethod(passwordMethod);   //设置隐藏
            topOutTv.setTransformationMethod(passwordMethod);   //设置隐藏
            topbudgetTv.setTransformationMethod(passwordMethod);   //设置隐藏
            topShowIv.setImageResource(R.mipmap.ih_hide);
            isShow = false;   //设置标志位为隐藏状态
        }else{  //密文---》明文
            HideReturnsTransformationMethod hideMethod = HideReturnsTransformationMethod.getInstance();
            topInTv.setTransformationMethod(hideMethod);   //设置隐藏
            topOutTv.setTransformationMethod(hideMethod);   //设置隐藏
            topbudgetTv.setTransformationMethod(hideMethod);   //设置隐藏
            topShowIv.setImageResource(R.mipmap.ih_show);
            isShow = true;   //设置标志位为隐藏状态
        }
    }
}

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.hui.tally.adapter.ChartVPAdapter;
import com.hui.tally.db.DBManager;
import com.hui.tally.frag_chart.IncomChartFragment;
import com.hui.tally.frag_chart.OutcomChartFragment;
import com.hui.tally.utils.CalendarDialog;

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

public class MonthChartActivity extends AppCompatActivity {
    Button inBtn,outBtn;
    TextView dateTv,inTv,outTv;
    ViewPager chartVp;
     int year;
     int month;
    int selectPos = -1,selectMonth =-1;
    List<Fragment>chartFragList;
    private IncomChartFragment incomChartFragment;
    private OutcomChartFragment outcomChartFragment;
    private ChartVPAdapter chartVPAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_month_chart);
        initView();
        initTime();
        initStatistics(year,month);
        initFrag();
        setVPSelectListener();
    }

    private void setVPSelectListener() {
        chartVp.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
            @Override
            public void onPageSelected(int position) {
                setButtonStyle(position);
            }
        });
    }

    private void initFrag() {
        chartFragList = new ArrayList<>();
//        添加Fragment的对象
        incomChartFragment = new IncomChartFragment();
        outcomChartFragment = new OutcomChartFragment();
//        添加数据到Fragment当中
        Bundle bundle = new Bundle();
        bundle.putInt("year",year);
        bundle.putInt("month",month);
        incomChartFragment.setArguments(bundle);
        outcomChartFragment.setArguments(bundle);
//        将Fragment添加到数据源当中
        chartFragList.add(outcomChartFragment);
        chartFragList.add(incomChartFragment);
//        使用适配器
        chartVPAdapter = new ChartVPAdapter(getSupportFragmentManager(), chartFragList);
        chartVp.setAdapter(chartVPAdapter);
//        将Fragment加载到Acitivy当中
    }

    /* 统计某年某月的收支情况数据*/
    private void initStatistics(int year, int month) {
        float inMoneyOneMonth = DBManager.getSumMoneyOneMonth(year, month, 1);  //收入总钱数
        float outMoneyOneMonth = DBManager.getSumMoneyOneMonth(year, month, 0); //支出总钱数
        int incountItemOneMonth = DBManager.getCountItemOneMonth(year, month, 1);  //收入多少笔
        int outcountItemOneMonth = DBManager.getCountItemOneMonth(year, month, 0); //支出多少笔
        dateTv.setText(year+"年"+month+"月账单");
        inTv.setText("共"+incountItemOneMonth+"笔收入, ￥ "+inMoneyOneMonth);
        outTv.setText("共"+outcountItemOneMonth+"笔支出, ￥ "+outMoneyOneMonth);

    }

    /** 初始化时间的方法*/
    private void initTime() {
        Calendar calendar = Calendar.getInstance();
        year = calendar.get(Calendar.YEAR);
        month = calendar.get(Calendar.MONTH)+1;
    }

    /** 初始化控件*/
    private void initView() {
        inBtn = findViewById(R.id.chart_btn_in);
        outBtn = findViewById(R.id.chart_btn_out);
        dateTv = findViewById(R.id.chart_tv_date);
        inTv = findViewById(R.id.chart_tv_in);
        outTv = findViewById(R.id.chart_tv_out);
        chartVp = findViewById(R.id.chart_vp);
    }

    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.chart_iv_back:
                finish();
                break;
            case R.id.chart_iv_rili:
                showCalendarDialog();
                break;
            case R.id.chart_btn_in:
                setButtonStyle(1);
                chartVp.setCurrentItem(1);
                break;
            case R.id.chart_btn_out:
                setButtonStyle(0);
                chartVp.setCurrentItem(0);
                break;
        }
    }
    /* 显示日历对话框*/
    private void showCalendarDialog() {
        CalendarDialog dialog = new CalendarDialog(this, selectPos, selectMonth);
        dialog.show();
        dialog.setDialogSize();
        dialog.setOnRefreshListener(new CalendarDialog.OnRefreshListener() {
            @Override
            public void onRefresh(int selPos, int year, int month) {
                MonthChartActivity.this.selectPos = selPos;
                MonthChartActivity.this.selectMonth = month;
                initStatistics(year,month);
                incomChartFragment.setDate(year,month);
                outcomChartFragment.setDate(year,month);
            }
        });
    }

    /* 设置按钮样式的改变  支出-0  收入-1*/
    private void setButtonStyle(int kind){
        if (kind == 0) {
            outBtn.setBackgroundResource(R.drawable.main_recordbtn_bg);
            outBtn.setTextColor(Color.WHITE);
            inBtn.setBackgroundResource(R.drawable.dialog_btn_bg);
            inBtn.setTextColor(Color.BLACK);
        }else if (kind == 1){
            inBtn.setBackgroundResource(R.drawable.main_recordbtn_bg);
            inBtn.setTextColor(Color.WHITE);
            outBtn.setBackgroundResource(R.drawable.dialog_btn_bg);
            outBtn.setTextColor(Color.BLACK);
        }
    }
}

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;

import android.os.Bundle;
import android.view.View;

import com.google.android.material.tabs.TabLayout;
import com.hui.tally.adapter.RecordPagerAdapter;
import com.hui.tally.frag_record.IncomeFragment;
import com.hui.tally.frag_record.BaseRecordFragment;
import com.hui.tally.frag_record.OutcomeFragment;

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

public class RecordActivity extends AppCompatActivity {
    TabLayout tabLayout;
    ViewPager viewPager;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_record);
        //1.查找控件
        tabLayout = findViewById(R.id.record_tabs);
        viewPager = findViewById(R.id.record_vp);
        //2.设置ViewPager加载页面
        initPager();
    }

    private void initPager() {
//        初始化ViewPager页面的集合
        List<Fragment>fragmentList = new ArrayList<>();
//        创建收入和支出页面，放置在Fragment当中
        OutcomeFragment outFrag = new OutcomeFragment(); //支出
        IncomeFragment inFrag = new IncomeFragment(); //收入
        fragmentList.add(outFrag);
        fragmentList.add(inFrag);

//        创建适配器
        RecordPagerAdapter pagerAdapter = new RecordPagerAdapter(getSupportFragmentManager(), fragmentList);
//        设置适配器
        viewPager.setAdapter(pagerAdapter);
        //将TabLayout和ViwePager进行关联
        tabLayout.setupWithViewPager(viewPager);
    }

    /* 点击事件*/
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.record_iv_back:
                finish();
                break;
        }
    }
}

package com.hui.tally;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
 
import com.hui.tally.adapter.AccountAdapter;
import com.hui.tally.db.AccountBean;
import com.hui.tally.db.DBManager;
 
import java.util.ArrayList;
import java.util.List;
 
public class SearchActivity extends AppCompatActivity {
    ListView searchLv;
    EditText searchEt;
    TextView emptyTv;
    List<AccountBean>mDatas;   //数据源
    AccountAdapter adapter;    //适配器对象
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);
        initView();
        mDatas = new ArrayList<>();
        adapter = new AccountAdapter(this,mDatas);
        searchLv.setAdapter(adapter);
        searchLv.setEmptyView(emptyTv);   //设置无数局时，显示的控件
    }
 
    private void initView() {
        searchEt = findViewById(R.id.search_et);
        searchLv = findViewById(R.id.search_lv);
        emptyTv = findViewById(R.id.search_tv_empty);
    }
 
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.search_iv_back:
                finish();
                break;
            case R.id.search_iv_sh:   //执行搜索的操作
                String msg = searchEt.getText().toString().trim();
//                判断输入内容是否为空，如果为空，就提示不能搜索
                if (TextUtils.isEmpty(msg)) {
                    Toast.makeText(this,"输入内容不能为空！",Toast.LENGTH_SHORT).show();
                    return;
                }
                //开始搜索
                List<AccountBean> list = DBManager.getAccountListByRemarkFromAccounttb(msg);
                mDatas.clear();
                mDatas.addAll(list);
                adapter.notifyDataSetChanged();
                break;
        }
    }
}

package com.hui.tally;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import com.hui.tally.db.DBManager;

public class SettingActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_setting);
    }

    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.setting_iv_back:
                finish();
                break;
            case R.id.setting_tv_clear:
                showDeleteDialog();
                break;
        }
    }

    private void showDeleteDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("删除提示")
                .setMessage("您确定要删除所有记录么？\n注意：删除后无法恢复，请慎重选择！")
                .setPositiveButton("取消",null)
                .setNegativeButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        DBManager.deleteAllAccount();
                        Toast.makeText(SettingActivity.this,"删除成功！",Toast.LENGTH_SHORT).show();
                    }
                });
        builder.create().show();
    }
}

package com.hui.tally;

import android.app.Application;

import com.hui.tally.db.DBManager;

/* 表示全局应用的类*/
public class UniteApp extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        // 初始化数据库
        DBManager.initDB(getApplicationContext());
    }
}