实验六 数据存储和访问

其他 2019-01-07 12:30:52 阅读次数: 0

实验六 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。

工程代码

项目工程结构图
在这里插入图片描述

MainActivity:

package wyx.exp_6;

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

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

public class MainActivity extends AppCompatActivity {

    EditText e1;
    EditText e2;
    EditText e3;
    EditText e4;
    Button addone;
    Button showall;
    Button clearshow;
    Button deleteall;
    Button deleteone;
    Button selectone;
    Button updateone;
    private DBAdapter db;

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

        e1=(EditText)findViewById(R.id.name);
        e2=(EditText)findViewById(R.id.age);
        e3=(EditText)findViewById(R.id.height);
        e4=(EditText)findViewById(R.id.ID);
        addone=(Button)findViewById(R.id.addone);
        showall=(Button)findViewById(R.id.showall);
        clearshow=(Button)findViewById(R.id.clearshow);
        deleteall=(Button)findViewById(R.id.deleteall);
        deleteone=(Button)findViewById(R.id.deleteone);
        selectone=(Button)findViewById(R.id.selectone);
        updateone=(Button)findViewById(R.id.updateone);

        final ListView lv1=(ListView)findViewById(R.id.lv1);
        final List<String> list=new ArrayList<String>();
        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,R.layout.list_item, list );

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

        addone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                People people=new People();
                people.Name=e1.getText().toString();
                people.Age=Integer.parseInt(e2.getText().toString());
                people.Height=Float.parseFloat(e3.getText().toString());
                db.insert(people);
                String s="添加成功！";
                list.add(s);
                lv1.setAdapter(adapter);
            }
        });

        showall.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                list.clear();
                People[] peoples=db.getAllData();
                if(peoples==null)
                {
                    String s="数据库为空！！";
                    list.add(s);
                    lv1.setAdapter(adapter);
                }
                else{
                    for(int i=0;i<peoples.length;i++)
                    {
                        People people=peoples[i];
                        list.add(people.toString());
                        lv1.setAdapter(adapter);
                    }
                }

            }
        });

        selectone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                list.clear();
                People[] peoples=db.getOneData(Long.parseLong(e4.getText().toString()));
                if(peoples==null)
                {
                    String s="没有找到相应的数据！！";
                    list.add(s);
                    lv1.setAdapter(adapter);
                }
                else{
                    list.add(peoples[0].toString());
                    lv1.setAdapter(adapter);
                }
            }
        });

        deleteone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                list.clear();
                People[] peoples=db.getOneData(Long.parseLong(e4.getText().toString()));
                if(peoples==null)
                {
                    String s="没有找到相应的数据！！";
                    list.add(s);
                    lv1.setAdapter(adapter);
                }
                else{
                    db.deleteOneData(Long.parseLong(e4.getText().toString()));
                }
            }
        });
        deleteall.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                db.deleteAllData();
                adapter.clear();
                adapter.notifyDataSetChanged() ;
            }
        });
        updateone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                list.clear();
                People[] peoples=db.getOneData(Long.parseLong(e4.getText().toString()));
                if(peoples==null)
                {
                    String s="没有找到相应的数据！！";
                    list.add(s);
                    lv1.setAdapter(adapter);
                }
                else{
                    People people=peoples[0];
                    people.Name=e1.getText().toString();
                    people.Age=Integer.parseInt(e2.getText().toString());
                    people.Height=Float.parseFloat(e3.getText().toString());
                    db.updateOneData(Long.parseLong(e4.getText().toString()),people);
                }
            }
        });
        clearshow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                adapter.clear();
                adapter.notifyDataSetChanged() ;
            }
        });
    }
}

DBAdapter

package wyx.exp_6;

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;

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

public class DBAdapter {
    private static final String DB_NAME = "people.db";
    private static final String DB_TABLE = "peopleinfo";
    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_AGE = "age";
    public static final String KEY_HEIGHT = "height";

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

    private static class DBOpenHelper extends SQLiteOpenHelper {
        public DBOpenHelper(Context context, String name, SQLiteDatabase.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_AGE+ " integer," + KEY_HEIGHT + " float);";

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

    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 void close() {
        if (db != null){
            db.close();
            db = null;
        }
    }

    public long insert(People people) {
        ContentValues newValues = new ContentValues();

        newValues.put(KEY_NAME, people.Name);
        newValues.put(KEY_AGE, people.Age);
        newValues.put(KEY_HEIGHT, people.Height);

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

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

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

    public long updateOneData(long id , People people){
        ContentValues updateValues = new ContentValues();
        updateValues.put(KEY_NAME, people.Name);
        updateValues.put(KEY_AGE, people.Age);
        updateValues.put(KEY_HEIGHT, people.Height);

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

    private People[] ConvertToPeople(Cursor cursor){
        int resultCounts = cursor.getCount();
        if (resultCounts == 0 || !cursor.moveToFirst()){
            return null;
        }
        People[] peoples = new People[resultCounts];
        for (int i = 0 ; i<resultCounts; i++){
            peoples[i] = new People();
            peoples[i].ID = cursor.getInt(0);
            peoples[i].Name = cursor.getString(cursor.getColumnIndex(KEY_NAME));
            peoples[i].Age = cursor.getInt(cursor.getColumnIndex(KEY_AGE));
            peoples[i].Height = cursor.getFloat(cursor.getColumnIndex(KEY_HEIGHT));
            cursor.moveToNext();
        }
        return peoples;
    }

    public People[] getOneData(long id) {
        Cursor results =  db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_AGE, KEY_HEIGHT}, KEY_ID + "=" + id, null, null, null, null);
        return ConvertToPeople(results);
    }

    public People[] getAllData() {
        Cursor results = db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_AGE, KEY_HEIGHT}, null, null, null, null, null);
        return ConvertToPeople(results);
    }


}

People:

package wyx.exp_6;

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

public class People {
    public int ID = -1;
    public String Name;
    public int Age;
    public float Height;

    @Override
    public String toString() {
        String result="";
        result += "ID:" + this.ID + ",";
        result += "姓名:" + this.Name + ",";
        result += "年龄:" + this.Age + ",";
        result += "身高:" + this.Height;
        return result;
    }
}

activity_main.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="wyx.exp_6.MainActivity"
    tools:layout_editor_absoluteX="0dp"
    tools:layout_editor_absoluteY="81dp">

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="370dp"
        android:layout_height="200dp"
        android:layout_marginEnd="6dp"
        android:layout_marginStart="6dp"
        android:layout_marginTop="8dp"
        android:orientation="vertical"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout_constraintLeft_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintTop_creator="1">

        <LinearLayout
            android:layout_width="370dp"
            android:layout_height="50dp"
            android:orientation="horizontal">

            <TextView
                android:layout_width="35dp"
                android:layout_height="29dp"
                android:text="姓名:" />

            <EditText
                android:id="@+id/name"
                android:layout_width="100dp"
                android:layout_height="40dp" />

        </LinearLayout>

        <LinearLayout
            android:layout_width="370dp"
            android:layout_height="50dp"
            android:orientation="horizontal">

            <TextView
                android:layout_width="35dp"
                android:layout_height="29dp"
                android:text="年龄:" />

            <EditText
                android:id="@+id/age"
                android:layout_width="100dp"
                android:layout_height="40dp" />
            <Button
                android:layout_width="80dp"
                android:layout_height="40dp"
                android:text="添加数据"
                android:id="@+id/addone" />
            <Button
                android:layout_width="80dp"
                android:layout_height="40dp"
                android:text="全部显示"
                android:id="@+id/showall" />

        </LinearLayout>

        <LinearLayout
            android:layout_width="370dp"
            android:layout_height="50dp"
            android:orientation="horizontal">

            <TextView
                android:layout_width="35dp"
                android:layout_height="29dp"
                android:text="身高:" />

            <EditText
                android:id="@+id/height"
                android:layout_width="100dp"
                android:layout_height="40dp" />
            <Button
                android:layout_width="80dp"
                android:layout_height="40dp"
                android:text="清除显示"
                android:id="@+id/clearshow" />
            <Button
                android:layout_width="80dp"
                android:layout_height="40dp"
                android:text="全部删除"
                android:id="@+id/deleteall" />

        </LinearLayout>
        <LinearLayout
        android:layout_width="370dp"
        android:layout_height="50dp"
        android:orientation="horizontal">
        <TextView
            android:layout_width="20dp"
            android:layout_height="29dp"
            android:text="ID:" />

        <EditText
            android:id="@+id/ID"
            android:layout_width="50dp"
            android:layout_height="40dp" />
        <Button
            android:id="@+id/deleteone"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:text="ID删除" />

         <Button
            android:id="@+id/selectone"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:text="ID查询" />

        <Button
            android:id="@+id/updateone"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:text="ID更新" />
        </LinearLayout>

    </LinearLayout>

    <ListView
        android:id="@+id/lv1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:longClickable="true"
        />
</LinearLayout>

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center_vertical"
        android:textColor="#0000FF"
        android:textSize="16dp" />

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="wyx.exp_6">

    <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>

实现效果

在这里插入图片描述

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