安卓开发（五）sqlite

使用listview查看：https://www.jianshu.com/p/392a7c090cae

sqlite

DbAdapter

package com.example.sqlite;

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;

public class DBAdapter {

private static final StringDB_NAME ="student.db";

    private static final StringDB_TABLE ="stuInfo";

    private static int DB_VERSION =1;

    private static final StringKEY_NAME ="name";

    private static final StringKEY_SNO ="sno";

    private static final StringKEY_CNO ="cno";

    private static final StringKEY_ID ="id";

    private static SQLiteDatabasedb;

    private Contextcontext;

    private DBopenhelperdBopenhelper;

    public DBAdapter(Context context)

{

this.context = context;

    }

public long insert(stuInfo stu)

{

ContentValues newValues =new ContentValues();

        newValues.put(KEY_SNO, stu.GetSno());

        newValues.put(KEY_CNO, stu.GetCno());

        newValues.put(KEY_NAME, stu.GetName());

        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 stuInfo[]ConvertTostuInfo(Cursor cursor)

{

int resCount = cursor.getCount();

        if(resCount==0 || !cursor.moveToFirst()){

return null;

        }

stuInfo[] stu =new stuInfo[resCount];

        for(int i=0; i

stu[i] =new stuInfo(cursor.getString(cursor.getColumnIndex(KEY_ID)) +"  " + cursor.getString(cursor.getColumnIndex(KEY_NAME)), cursor.getString(cursor.getColumnIndex(KEY_CNO)),cursor.getString(cursor.getColumnIndex(KEY_SNO)));

            cursor.moveToNext();

        }

return stu;

    }

public stuInfo[]getAllData()

{

Cursor result =db.query(DB_TABLE, new String[] {KEY_ID, KEY_SNO, KEY_CNO, KEY_NAME}, null, null, null, null, null);

        return ConvertTostuInfo(result);

    }

public void open()throws SQLiteException{

dBopenhelper =new DBopenhelper(context, DB_NAME, null, DB_VERSION);

        try{

db =dBopenhelper.getWritableDatabase();

        }catch (SQLiteException e){

db =dBopenhelper.getReadableDatabase();

        }

}

public void close()

{

if(db!=null){

db.close();

            db=null;

        }

}

private static class DBopenhelperextends SQLiteOpenHelper{

public DBopenhelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version){

super(context, name, factory, version);

        }

private final StringDB_Create="create table " +DB_TABLE +"(" +KEY_ID  +" integer primary key autoincrement,"

                +KEY_SNO +" text not null," +KEY_NAME +" text not null, " +KEY_CNO +" text not null);";

        @Override

        public void onCreate(SQLiteDatabase _db) {

_db.execSQL(DB_Create);

        }

@Override

        public void onUpgrade(SQLiteDatabase _db, int _oldViersion, int _newVersion) {

_db.execSQL("DROP TABLE IF EXISTS " +DB_TABLE);

            onCreate(_db);

        }

}

}

sqlite

package com.example.sqlite;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.AdapterView;

import android.widget.Button;

import android.widget.ListView;

import android.widget.TextView;

import java.util.ArrayList;

import java.util.List;

public class sqliteextends AppCompatActivityimplements Button.OnClickListener{

ListViewlistView;

    Listdata =new ArrayList<>();

    Buttonrefresh, insert, clear;

    TextViewname, sno, cno;

    infoAdapteradapter;

    int item_id;

    DBAdapterdbAdapter =new DBAdapter(this);

    @Override

    protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_sqlite);

        refresh = (Button) findViewById(R.id.refresh);

        insert = (Button) findViewById(R.id.insert);

        clear = (Button) findViewById(R.id.clear);

        refresh.setOnClickListener(this);

        insert.setOnClickListener(this);

        clear.setOnClickListener(this);

        name = (TextView)findViewById(R.id.name);

        sno = (TextView) findViewById(R.id.sno);

        cno = (TextView) findViewById(R.id.cno);

        adapter =new infoAdapter(this, data);

        listView = (ListView) findViewById(R.id.listView);

        listView.setAdapter(adapter);

        registerForContextMenu(listView);

    }

@Override

    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {

super.onCreateContextMenu(menu, v, menuInfo);

        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;

        item_id = info.position;

        menu.add(0, Menu.FIRST, 0, "删除");

    }

@Override

    public boolean onContextItemSelected(MenuItem item) {

dbAdapter.open();

        dbAdapter.deleteOneData((Integer.parseInt(data.get(item_id).GetName().split("  ")[0])));

        dbAdapter.close();

        data.remove(item_id);

        adapter.notifyDataSetChanged();

return true;

    }

public void Insert()

{

stuInfo stu =new stuInfo(name.getText().toString(),cno.getText().toString(), sno.getText().toString());

        dbAdapter.open();

        dbAdapter.insert(stu);

        getData();

        dbAdapter.close();

    }

public void getData()

{

dbAdapter.open();

        stuInfo stus[] =dbAdapter.getAllData();

        if(stus ==null){

data.clear();

            adapter.notifyDataSetChanged();

return;

        }

dbAdapter.close();

        data.clear();

        for(int i=0; i

{

data.add(stus[i]);

        }

adapter.notifyDataSetChanged();

    }

@Override

    public void onClick(View view) {

switch (view.getId()){

case R.id.refresh:

getData();

break;

            case R.id.insert:

Insert();

break;

            case R.id.clear:

dbAdapter.open();

                dbAdapter.deleteAllData();

                dbAdapter.close();

                getData();

break;

        }

}

}