實驗六 資料儲存和訪問
阿新 • • 發佈：2019-01-07
實驗六 資料儲存和訪問
實驗目的
分別使用sqlite3工具和Android程式碼的方式建立SQLite資料庫。在完成建立資料庫的工作後，程式設計實現基本的資料庫操作功能，包括資料的新增、刪除和更新。
實驗要求
- 建立一個學生管理的應用，基本資訊包含學生姓名，班級，學號。採用資料庫儲存這些資訊。
- 應用應該至少包含資訊錄入和刪除功能。
- 資料顯示考慮採用ListView。
工程程式碼
專案工程結構圖
MainActivity:
package 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 += "年齡:" + 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"