實驗六 sqlite 之數據庫管理

實驗六 數據存儲和訪問

實驗目的：

分別使用sqlite3工具和Android代碼的方式建立SQLite數據庫。在完成建立數據庫的工作後，編程實現基本的數據庫操作功能，包括數據的添加、刪除和更新，

 

實驗要求：

1.     創建一個學生管理的應用，基本信息包含學生姓名，班級，學號。採用數據庫存儲這些信息。

2.     應用應該至少包含信息錄入和刪除功能。

3.     數據顯示考慮採用ListView。

代碼：

MainActivity.java

package com.walker.exp6;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {
    private DBAdapter db;
    private Button bt_add;
    private ListView listview;
    private SimpleAdapter simpleAdapter;
    Map<String, Object> item = new HashMap<String, Object>();
    private List<Map<String, Object>> Datas = new ArrayList<Map<String, Object>>();
    private int position;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bt_add = findViewById(R.id.btn_add);
        listview = findViewById(R.id.listview);


        bt_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //test
                Intent intent = new Intent(MainActivity.this, AddActivity.class);
                startActivity(intent);
                finish();
            }
        });

        db = new DBAdapter(MainActivity.this);
        db.open();

        display();
        //設置監聽
        listview.setOnCreateContextMenuListener(this);

    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        //添加兩個ITEM
        menu.add(0, 1, 0, "更新");
        menu.add(0, 2, 0, "刪除");
        //得到長按的position
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        position = info.position;
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {

        AdapterView.AdapterContextMenuInfo menuInfo = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
        int pos = (int) listview.getAdapter().getItemId(menuInfo.position);
        //得到對應的map對象
        Map<String, Object> stu = Datas.get(pos);
        switch (item.getItemId()) {
            case 1://更新
                Intent intent = new Intent(MainActivity.this, AddActivity.class);
                startActivity(intent);

                break;
            case 2://刪除
                //1). 刪除數據表對應的數據
                db.deleteOneData((Integer) stu.get("id"));


                //2). 刪除List對應的數據
                Datas.remove(pos);
                //3). 通知更新列表
                simpleAdapter.notifyDataSetChanged();
                Toast.makeText(MainActivity.this, "ID:" + stu.get("id") + "刪除成功", Toast.LENGTH_SHORT).show();
                break;

            default:
                break;
        }

        return super.onContextItemSelected(item);

    }

    @Override
    protected void onRestart() {
        super.onRestart();
       // display();
//       simpleAdapter.notifyDataSetChanged();
    }

    public void display() {

        String[] from = {"id", "class", "number", "name"};
        //Item佈局文件中的子view的id的數組
        int[] to = {R.id.tv_id1, R.id.tv_class1, R.id.tv_number1, R.id.tv_name1};
        // /設置適配器
        simpleAdapter = new SimpleAdapter(this, Datas, R.layout.item_view, from, to);
        listview.setAdapter(simpleAdapter);
        Student[] students = db.queryAllData();
        if (students == null) {

            return;
        }

        String cl;
        String num;
        String na;
        int id;
        for (int i = 0; i < students.length; i++) {
            cl = students[i].getClas();
            num = students[i].getNumber();
            na = students[i].getName();
            id = students[i].getID();
            //Toast.makeText(MainActivity.this,cl+num+na,Toast.LENGTH_SHORT).show();
            Map<String, Object> item = new HashMap<String, Object>();
            item.put("id", id);
            item.put("class", cl);
            item.put("number", num);
            item.put("name", na);
            Datas.add(item);
            simpleAdapter.notifyDataSetChanged();
        }


    }



}

AddActivity.java

package com.walker.exp6;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import java.util.HashMap;
import java.util.Map;

public class AddActivity extends AppCompatActivity {

    private DBAdapter db;
    private Student student;
    private Button bt_cancel;
    private Button bt_ensure;
    private EditText et_cl;
    private EditText et_num;
    private EditText et_na;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);
        bt_cancel = findViewById(R.id.bt_cancel);
        bt_ensure = findViewById(R.id.bt_ensure);
        et_cl = findViewById(R.id.et_cl);
        et_num = findViewById(R.id.et_num);
        et_na = findViewById(R.id.et_na);
        //Intent intent = getIntent();
        db = new DBAdapter(this);
        db.open();
        bt_cancel.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(AddActivity.this,MainActivity.class);
                startActivity(intent);
                finish();
            }
        });
        bt_ensure.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                String cl = et_cl.getText().toString();
                String num = et_num.getText().toString();
                String na = et_na.getText().toString();
                student = new Student(cl,num,na);
//                Toast.makeText(AddActivity.this,cl+num+na,Toast.LENGTH_SHORT).show();
                long  colunm= db.insert(student);

                //db.close();
                Intent intent = new Intent(AddActivity.this,MainActivity.class);
                startActivity(intent);
                db.close();
                finish();
            }
        });
    }

}

ADBadapter.java

package com.walker.exp6;

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;

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_CLASS = "class";
    public static final String KEY_NUMBER = "number";

    private SQLiteDatabase db;
    private final Context context;
    private DBOpenHelper dbOpenHelper;

    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 = new DBOpenHelper(context, DB_NAME, null, DB_VERSION);
        try {
            db = dbOpenHelper.getWritableDatabase();
        }
        catch (SQLiteException ex) {
            db = dbOpenHelper.getReadableDatabase();
        }
    }


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

        newValues.put(KEY_NAME, student.Name);
        newValues.put(KEY_CLASS, student.Clas);
        newValues.put(KEY_NUMBER, student.Number);

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


    public Student[] queryAllData() {
        Cursor results =  db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_CLASS, KEY_NUMBER},
                null, null, null, null, null);
        return ConvertToStudent(results);
    }

    public Student[] queryOneData(long id) {
        Cursor results =  db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_CLASS, KEY_NUMBER},
                KEY_ID + "=" + 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].ID = cursor.getInt(0);
            students[i].Name = cursor.getString(cursor.getColumnIndex(KEY_NAME));
            students[i].Clas = cursor.getString(cursor.getColumnIndex(KEY_CLASS));
            students[i].Number = cursor.getString(cursor.getColumnIndex(KEY_NUMBER));
            cursor.moveToNext();
        }
        return students;
    }

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

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

    public long updateOneData(long id , Student student){
        ContentValues updateValues = new ContentValues();
        updateValues.put(KEY_NAME, student.Name);
        updateValues.put(KEY_CLASS, student.Clas);
        updateValues.put(KEY_NUMBER, student.Number);

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

    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_ID + " integer primary key autoincrement, " +
                KEY_NAME+ " text not null, " + KEY_CLASS+ " text not null," + KEY_NUMBER + " 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);
        }
    }
}

student.java

package com.walker.exp6;

public class Student {
    public int ID = -1;
    public String Name;
    public String Number;
    public String Clas;

    public Student(String Class, String Number, String Name) {
    this.Clas = Class;
    this.Number = Number;
    this.Name = Name;
    }

    public Student() {
        super();
    }

    public String getClas() {
        return Clas;
    }

    public String getName() {
        return Name;
    }

    public String getNumber() {
        return Number;
    }

    public int getID() {
        return ID;
    }

    @Override
    public String toString() {
        String result = "";
        result += this.ID + " ";
        result += this.Clas + " ";
        result += this.Number + " ";
        result += this.Name + " ";
        return result;
    }
}

activity.xml

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


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="ID"
            android:textSize="20sp" />
        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="班級"
            android:textSize="20sp" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="學號"
            android:textSize="20sp" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="姓名"
            android:textSize="20sp" />

    </LinearLayout>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <ListView
            android:id="@+id/listview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"></ListView>

    </LinearLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/btn_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:background="@color/app_bk"
            android:text="@string/app_button"
            android:textSize="20sp" />
    </RelativeLayout>


</LinearLayout>

activity_add.xml

<?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=".AddActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#bdddc8">

        <Button
            android:id="@+id/bt_cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:text="取消"
            android:textSize="20sp"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_centerVertical="true"
            android:gravity="center_vertical|center_horizontal"
            android:text="添加名單"
            android:textSize="20sp" />

        <Button
            android:id="@+id/bt_ensure"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:text="確定"
            android:textSize="20sp"/>
    </RelativeLayout>


    <EditText
        android:id="@+id/et_num"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="學號"
        android:inputType="text"
        android:textSize="20sp" />


    <EditText
        android:id="@+id/et_na"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="姓名"
        android:textSize="20sp" />


    <EditText
        android:id="@+id/et_cl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="班級"
        android:textSize="20sp" />

</LinearLayout>

item_view.xml

<?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">
    <TextView
        android:id="@+id/tv_id1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textSize="20sp"/>
    <TextView
        android:id="@+id/tv_class1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textSize="20sp"/>
    <TextView
        android:id="@+id/tv_number1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textSize="20sp"/>
    <TextView
        android:id="@+id/tv_name1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textSize="20sp"/>
</LinearLayout>