SQL数据库存储设计

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/add"
            android:text="@string/add"
            android:textSize="20sp"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/delete"
            android:text="@string/delete"
            android:textSize="20sp"
            />
    </LinearLayout>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/list_show"
        android:choiceMode="singleChoice"
        android:listSelector="#fff0">

    </ListView>

<resources>
    <string name="app_name">SQLwork</string>
    <string name="name">姓名</string>
    <string name="hint">请输入你的姓名</string>
    <string name="add">增加一条记录</string>
    <string name="delete">删除第一条记录</string>

</resources>

public class MyDBHelper extends SQLiteOpenHelper {
private String sql = "create table student(_id integer primary key autoincrement," + "name text not null)";//创建表的sql语句

public MyDBHelper(Context context) {
    super(context, "studentInfo", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(sql);
}
//newVersion>oldVersion(旧版本)调用
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table if exists student");
    onCreate(db);
}

public class Name implements Serializable {
private int _id;
private String name;
public Name(){
}
public Name(String name){
    this.name=name;
}
public int get_id() {
    return _id;
}
public void set_id(int _id) {
    this._id = _id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}

public class NameDAO {
private Context context;//上下文
private MyDBHelper helper;//创建，升级，打开数据库
private SQLiteDatabase db;//对表增删改查

public NameDAO(Context context){
    helper=new MyDBHelper(context);
}
public void insert(Name name){
    //打开数据库
    db=helper.getWritableDatabase();
    //生成数据集合
    ContentValues values=new ContentValues();
    values.put("name",name.getName());
    //执行语句
    db.insert("student",null,values);
}

public Cursor selectAll() {
    db =helper.getReadableDatabase();
    Cursor cursor= db.query("student",null,null,null,null,null,null);
    return cursor;
}
public void delete(int id){
    db = helper.getWritableDatabase();
    db.delete("student","_id=?",new String[]{String.valueOf(id)});//根据数据的id号来删除数据
}
}

case R.id.delete:
            if(name!=null){            //判断记录是否为空，如果是空的话会提示记录为空
                cursor.moveToFirst();//数据的第一行
                name=new Name();
                name.set_id(cursor.getInt(cursor.getColumnIndex("_id")));获取数据第一行的id
                nameDAO.delete(name.get_id());//调用delete方法删除第一条记录
                nameDAO = new NameDAO(this);
                cursor = nameDAO.selectAll();
                adapter = new MyCursorAdapter(this, cursor);
                lvshow.setAdapter(adapter);
                Toast.makeText(this, "删除成功", Toast.LENGTH_SHORT).show();
            }
                Toast.makeText(this,"记录为空",Toast.LENGTH_SHORT).show();

            break;