安卓--数据存储和访问

实验目的：

分别使用sqlite3工具和Android代码的方式建立SQLite数据库。在完成建立数据库的工作后，编程实现基本的数据库操作功能，包括数据的添加、删除和更新。

实验要求：

1. 创建一个学生管理的应用，基本信息包含学生姓名，班级，学号。采用数据库存储这些信息。
2. 应用应该至少包含信息录入和删除功能。
3. 数据显示考虑采用ListView。

(1) 使用sqlite3工具建库：

使用adb前，需要先把adb加入环境变量：C:UsersFlyuzAppDataLocalAndroidSdkplatform-tools

然后在cmd或android studio命令行中进入adb shell。

出现的问题：

Android 7无法获得root权限，不能进入data/data/com.example.flyuz.sqlite6文件夹，所以不能建库，

解决方法：1 在命令行中前后使用 adb root adb remount （我不管用）

2 使用Android 6的虚拟机即可获得root权限。

 

步骤：

进入adb shell

cd data/data/com.example.flyuz.sqlite6

建数据库文件夹   mkdir databases     

建数据库  sqlite3 student.db

Create table studentinfo(num  text PRIMARY KEY,  name  text not null,  cla  text not null);

添加数据  insert into studentinfo()

查看所有表  .tables

 

package com.example.flyuz.sqlite6;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.ListView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.PopupMenu;
import android.widget.AdapterView;

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

public class MainActivity extends AppCompatActivity {
    private Button bt_add;
    private ListView lv;
    private DBAdapter dbAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt_add = (Button) findViewById(R.id.bt_add);
        lv = (ListView) findViewById(R.id.lv);
        dbAdapter = new DBAdapter(this);
        dbAdapter.open();
        init();
    }

    private void init() {
        Student[] students = dbAdapter.queryAllData();

        List<String> list = new ArrayList<String>();
        if (students != null) {
            for (Student stu : students) {
                list.add(stu.toString());
            }
        }
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
        lv.setAdapter(adapter);

        //设置事件
        bt_add.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                EditText et_class = (EditText) findViewById(R.id.et_class);
                EditText et_number = (EditText) findViewById(R.id.et_number);
                EditText et_name = (EditText) findViewById(R.id.et_name);

                String str_class = et_class.getText().toString();
                String str_number = et_number.getText().toString();
                String str_name = et_name.getText().toString();

                Student student = new Student();
                student.setNum(str_number);
                student.setName(str_name);
                student.setCla(str_class);
                long colunm = dbAdapter.insert(student);

                ArrayAdapter add_adp = (ArrayAdapter) lv.getAdapter();
                add_adp.add(student.toString());
            }
        });
        lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
                PopupMenu popup = new PopupMenu(MainActivity.this, view);
                popup.getMenuInflater().inflate(R.menu.menu, popup.getMenu());
                popup.show();
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.menu_del:
                                ArrayAdapter temp_adp = (ArrayAdapter) lv.getAdapter();
                                String delStu = (String) temp_adp.getItem(position);
                                String[] num = delStu.split("\s+");
                                String[] res = num[0].split(":");
                                long colunm = dbAdapter.deleteOneData(Integer.parseInt(res[1]));
                                temp_adp.remove(temp_adp.getItem(position));
                                return true;
                            default:
                                return false;
                        }
                    }
                });
                return true;
            }
        });
    }
}

package com.example.flyuz.sqlite6;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;

/**
 * Created by Administrator on 2018/10/29.
 */

public class DBAdapter {
    private static final String DB_NAME = "student.db";
    private static final String DB_TABLE = "studentinfo";
    private static final int DB_VERSION = 1;

    //public static final String KEY_ID = "id";
    public static final String KEY_NAME = "name";
    public static final String KEY_NUM = "num";
    public static final String KEY_CLA = "cla";

    private SQLiteDatabase db;
    private final Context context;

    public DBAdapter(Context _context) {
        context = _context;
    }

    /** Close the database */
    public void close() {
        if (db != null){
            db.close();
            db = null;
        }
    }

    /** Open the database */
    public void open() throws SQLiteException {
        DBOpenHelper dbOpenHelper = new DBOpenHelper(context, DB_NAME, null, DB_VERSION);
        try {
            db = dbOpenHelper.getWritableDatabase();
        }
        catch (SQLiteException ex) {
            db = dbOpenHelper.getReadableDatabase();
        }
    }

    private static class DBOpenHelper extends SQLiteOpenHelper {

        public DBOpenHelper(Context context, String name, CursorFactory factory, int version) {
            super(context, name, factory, version);
        }

        private static final String DB_CREATE =
                "create table " + DB_TABLE
                + "("
                + KEY_NUM + "  text PRIMARY KEY,"
                + KEY_NAME + " text not null, "
                + KEY_CLA + "  text not null"  +" );";

        @Override
        public void onCreate(SQLiteDatabase _db) {
            _db.execSQL(DB_CREATE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) {
            _db.execSQL("DROP TABLE IF EXISTS " + DB_TABLE);
            onCreate(_db);
        }
    }

    public long insert(Student student) {
        ContentValues newValues = new ContentValues();

        newValues.put(KEY_NUM, student.getNum());
        newValues.put(KEY_NAME, student.getName());
        newValues.put(KEY_CLA, student.getCla());

        return db.insert(DB_TABLE, null, newValues);
    }

    public Student[] queryAllData() {
        Cursor results =  db.query(DB_TABLE, new String[] { KEY_NUM, KEY_NAME, KEY_CLA},
                null, null, null, null, null);
        return ConvertToStudent(results);
    }
    public Student[] queryOneData(long id) {
        Cursor results =  db.query(DB_TABLE, new String[] {  KEY_NUM, KEY_NAME, KEY_CLA},
                KEY_NUM + "=" + id, null, null, null, null);
        return ConvertToStudent(results);
    }

    private Student[] ConvertToStudent(Cursor cursor){
        int resultCounts = cursor.getCount();
        if (resultCounts == 0 || !cursor.moveToFirst()){
            return null;
        }

        Student[] students = new Student[resultCounts];
        for (int i = 0 ; i<resultCounts; i++){
            students[i] = new Student();

            students[i].setNum(cursor.getString(cursor.getColumnIndex(KEY_NUM)));
            students[i].setName(cursor.getString(cursor.getColumnIndex(KEY_NAME)));
            students[i].setCla( cursor.getString(cursor.getColumnIndex(KEY_CLA)));

            cursor.moveToNext();
        }
        return students;
    }


    public long deleteAllData() {
        return db.delete(DB_TABLE, null, null);
    }

    public long deleteOneData(long id) {
        return db.delete(DB_TABLE,  KEY_NUM + "=" + id, null);
    }

    public long updateOneData(long id , Student student){
        ContentValues updateValues = new ContentValues();

        updateValues.put(KEY_NUM, student.getNum());
        updateValues.put(KEY_NAME, student.getName());
        updateValues.put(KEY_CLA, student.getCla());

        return db.update(DB_TABLE, updateValues,  KEY_NUM+ "=" + id, null);
    }
}

package com.example.flyuz.sqlite6;

/**
 * Created by Administrator on 2018/10/29.
 */

public class Student {
    private String Num;
    private String Name;
    private String Cla;

    public String toString(){
        return  "学号:" + Num +  "    姓名:" +  Name + "    班级:"  + Cla;
    }

    public String getNum() {
        return Num;
    }

    public String getName() {
        return Name;
    }

    public String getCla() {
        return Cla;
    }

    public void setNum(String num) {
        Num = num;
    }

    public void setName(String name) {
        Name = name;
    }

    public void setCla(String cla) {
        Cla = cla;
    }
}

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:gravity="center"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:gravity="center"
            android:orientation="horizontal">

            <TextView
                android:layout_width="50dp"
                android:layout_height="40dp"
                android:gravity="center"
                android:text="学号:" />

            <EditText
                android:id="@+id/et_number"
                android:layout_width="150dp"
                android:layout_height="40dp" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:gravity="center"
            android:orientation="horizontal">

            <TextView
                android:layout_width="50dp"
                android:layout_height="40dp"
                android:gravity="center"
                android:text="姓名:" />

            <EditText
                android:id="@+id/et_name"
                android:layout_width="150dp"
                android:layout_height="40dp" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:gravity="center"
            android:orientation="horizontal">

            <TextView
                android:layout_width="50dp"
                android:layout_height="40dp"
                android:gravity="center"
                android:text="班级:" />

            <EditText
                android:id="@+id/et_class"
                android:layout_width="150dp"
                android:layout_height="40dp" />
        </LinearLayout>


        <Button
            android:id="@+id/bt_add"
            android:layout_width="180dp"
            android:layout_height="40dp"
            android:text="添加" />
    </LinearLayout>

    <ListView
        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:longClickable="true" />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/menu_del"
        android:title="删除" />
</menu>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.flyuz.service5">

    <application
        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=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.flyuz.sqlite6">

    <application
        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=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>