半期考试之 SQLite操作
Posted 春招进大厂的梦想家
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了半期考试之 SQLite操作相关的知识，希望对你有一定的参考价值。
半期考试 之 SQLite操作
要求：
- 三个EditView，分别输入信息；
- 点击下方“添加”按钮，将输入的信息写入SQLite数据库中去，添加成功后，下方listview进行数据的展示；
- 点击下方“修改”按钮，可修改选定的信息（EditView显示相关信息）；
- 点击下方“删除”按钮，可删除选定的信息（listview进行同步的删除）；
xml文件
<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:orientation="vertical" >
<EditText
android:id="@+id/activity_main_etName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/activity_main_etPhone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="phone" />
<EditText
android:id="@+id/activity_main_etAge"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="number" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center" >
<Button
android:id="@+id/activity_main_btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="添加" />
<Button
android:id="@+id/activity_main_btnModi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="修改" />
<Button
android:id="@+id/activity_main_btnDel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="删除" />
</LinearLayout>
<ListView
android:id="@+id/activity_main_lstUser"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</LinearLayout>
java
public class MainActivity extends Activity implements OnClickListener, OnItemClickListener
private EditText etName, etPhone, etAge;
private Button btnAdd, btnModi, btnDel;
private ListView lstUser;
private ArrayList<HashMap<String, Object>> alUser;
private PeopleUtil pUtil;
private int SelectedId = 0;
SimpleAdapter adapter;
//UserAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etName = (EditText) this.findViewById(R.id.activity_main_etName);
etPhone = (EditText) this.findViewById(R.id.activity_main_etPhone);
etAge = (EditText) this.findViewById(R.id.activity_main_etAge);
btnAdd = (Button) this.findViewById(R.id.activity_main_btnAdd);
btnModi = (Button) this.findViewById(R.id.activity_main_btnModi);
btnDel = (Button) this.findViewById(R.id.activity_main_btnDel);
btnAdd.setOnClickListener(this);
btnModi.setOnClickListener(this);
btnDel.setOnClickListener(this);
pUtil = new PeopleUtil(this);
alUser = pUtil.getList();
lstUser = (ListView) this.findViewById(R.id.activity_main_lstUser);
adapter = new SimpleAdapter(this, alUser, R.layout.li_user, new String[]"UserName", "UserPhone", "UserAge", new int[]R.id.li_user_tvName, R.id.li_user_tvPhone, R.id.li_user_tvAge);
//adapter=new UserAdapter(this,alUser);
//为ListView添加数据
lstUser.setAdapter(adapter);
lstUser.setOnItemClickListener(this);
@Override
public void onClick(View arg0)
// TODO Auto-generated method stub
switch (arg0.getId())
case R.id.activity_main_btnAdd:
HashMap<String, String> item1 = new HashMap<String, String>();
item1.put("UserId", "0");
item1.put("UserName", etName.getText().toString());
item1.put("UserPhone", etPhone.getText().toString());
item1.put("UserAge", etAge.getText().toString());
pUtil.Save(item1);
Toast.makeText(this, "添加成功", Toast.LENGTH_LONG).show();
break;
case R.id.activity_main_btnModi:
if (SelectedId == 0)
Toast.makeText(this, "请选择要修改的用户", Toast.LENGTH_LONG).show();
return;
HashMap<String, String> item2 = new HashMap<String, String>();
item2.put("UserId", SelectedId + "");
item2.put("UserName", etName.getText().toString());
item2.put("UserPhone", etPhone.getText().toString());
item2.put("UserAge", etAge.getText().toString());
pUtil.Save(item2);
Toast.makeText(this, "修改成功", Toast.LENGTH_LONG).show();
break;
case R.id.activity_main_btnDel:
if (SelectedId == 0)
Toast.makeText(this, "请选择要删除的用户", Toast.LENGTH_LONG).show();
return;
pUtil.Delete(SelectedId);
break;
SelectedId = 0;
alUser = pUtil.getList();
adapter = new SimpleAdapter(this, alUser, R.layout.li_user, new String[]"UserName", "UserPhone", "UserAge", new int[]R.id.li_user_tvName, R.id.li_user_tvPhone, R.id.li_user_tvAge);
//adapter=new UserAdapter(this,alUser);
lstUser.setAdapter(adapter);
//adapter.notifyDataSetChanged();
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3)
HashMap<String, Object> item = alUser.get(arg2);
SelectedId = Integer.valueOf(item.get("UserId").toString());
etName.setText(item.get("UserName").toString());
etPhone.setText(item.get("UserPhone").toString());
etAge.setText(item.get("UserAge").toString());
数据库操作类:
public class DbHelper
//定义数据成员
//定义数据库的名称
private static final String DB_NAME = "people.db";
//定义当前的版本
private static final int DB_VERSION = 1;
//定义表的名称
public static final String DB_TABLE = "peopleinfo";
//定义列名
public static final String KEY_ID = "UserId";
public static final String KEY_NAME = "UserName";
public static final String KEY_PHONE = "UserTelPhone";
public static final String KEY_AGE = "UserAge";
//数据库操作相应成员的引用变量
private SQLiteDatabase db;
private final Context context;
private DBOpenHelper dbOpenHelper;
//定义一个DBOpenHelper类继承至SQLiteOpenHelper实现数据库的创建修改等操作
private static class DBOpenHelper extends SQLiteOpenHelper
//定义创建表的sql语句
private static final String DB_CREATE = "create table " + DB_TABLE
+ " (" + KEY_ID + " integer primary key autoincrement, "
+ KEY_NAME + " varchar not null, " + KEY_PHONE + " varchar,"
+ KEY_AGE + " integer);";
public DBOpenHelper(Context context, String name,
CursorFactory factory, int version)
super(context, DB_NAME, factory, version);
// TODO Auto-generated constructor stub
@Override
public void onCreate(SQLiteDatabase arg0)
// TODO Auto-generated method stub
arg0.execSQL(DB_CREATE);
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
db.execSQL("DROP TABLE IF EXISTS " + DB_TABLE);
onCreate(db);
@Override
public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion)
super.onDowngrade(db, oldVersion, newVersion);
//DbHelper构造方法需要传递一个Context参数
public DbHelper(Context _context)
context = _context;
//打开数据库
public void open() throws SQLiteException
//实例化一个DbOpenHelper对象
dbOpenHelper = new DBOpenHelper(context, DB_NAME, null, DB_VERSION);
try
db = dbOpenHelper.getWritableDatabase();
catch (SQLiteException ex)
db = dbOpenHelper.getReadableDatabase();
//关闭数据库
public void close()
if (db != null)
db.close();
db = null;
public long insert(String table, String nullColumnHack, ContentValues values)
return db.insert(table, nullColumnHack, values);
public long update(String table, ContentValues values, String whereClause,
String[] whereArgs)
return db.update(table, values, whereClause, whereArgs);
public long delete(String table, String whereClause, String[] whereArgs)
return db.delete(table, whereClause, whereArgs);
public Cursor query(String table, String[] columns, String selection,
String[] selectionArgs, String groupBy, String having,
String orderBy)
return db.query(table, columns, selection, selectionArgs, groupBy,
having, orderBy);
实体操作类：
public class PeopleUtil
private Context _Context;
private DbHelper helper;
//构造函数需要传递Context参数
public PeopleUtil(Context _Context)
this._Context=_Context;
helper = new DbHelper(_Context);
helper.open();
//保存数据
public long Save(HashMap<String,String> people)
ContentValues value=new ContentValues();
value.put(DbHelper.KEY_NAME, people.get("UserName"));
value.put(DbHelper.KEY_PHONE半期考试 之 SQLite 操作2