在RecyclerView显示SQLite的数据 [英] Display SQLite data in RecyclerView

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本文介绍了在RecyclerView显示SQLite的数据的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我搜索了很多，但我没有找到任何一步一步的指导，如何dislpay SQLite的数据RecyclerView。任何人都可以解释我怎样才能做到这一点？

我的 DataBaseAdapter： 

 公共类DataBaseAdapter {

DataBaseHelper帮手;

公共DataBaseAdapter（上下文的背景下）{
    辅助=新DataBaseHelper（上下文）;
    }

众长insertData（字符串名称，字符串卡，字符串code）{

    SQLiteDatabase DB = helper.getWritableDatabase（）;
    ContentValues​​ contentValues​​ =新ContentValues​​（）;
    contentValues​​.put（DataBaseHelper.NAME，姓名）;
    contentValues​​.put（DataBaseHelper.CARD，卡）;
    contentValues​​.put（DataBaseHelper code，code）;
    长ID = db.insert（DataBaseHelper.TABLE_NAME，空，contentValues​​）;
    返回ID;
}

公共字符串的getData（字符串名称）{
    //选择_id，姓名，卡，code
    SQLiteDatabase DB = helper.getWritableDatabase（）;
    的String []列= {DataBaseHelper.NAME，DataBaseHelper.CARD，DataBaseHelper code};
    光标光标= db.query（DataBaseHelper.TABLE_NAME，列，DataBaseHelper.NAME +=+姓名+'，NULL，NULL，NULL，NULL）;
    StringBuffer的缓冲区=新的StringBuffer（）;
    而（cursor.moveToNext（））{
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;

        字符串PersonName的= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        buffer.append（姓名++卡++ code +\ N）;

    }
    返回buffer.toString（）;
}

公共字符串getAllData（）{
    //选择_id，姓名，卡，code
    SQLiteDatabase DB = helper.getWritableDatabase（）;
    的String []列= {DataBaseHelper.UID，DataBaseHelper.NAME，DataBaseHelper.CARD，DataBaseHelper code};
    光标光标= db.query（DataBaseHelper.TABLE_NAME，列，NULL，NULL，NULL，NULL，NULL）;
    StringBuffer的缓冲区=新的StringBuffer（）;
    而（cursor.moveToNext（））{
        INT索引1 = cursor.getColumnIndex（DataBaseHelper.UID）;
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;

        INT CID = cursor.getInt（指数1）;
        字符串名称= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        buffer.append（CID ++姓名++卡++ code +\ N）;
    }
    返回buffer.toString（）;

}

静态类DataBaseHelper扩展SQLiteOpenHelper {
    私有静态最后弦乐DATABASE_NAME =cardsdatabase;
    私有静态最后弦乐TABLE_NAME =CARDSTABLE;
    私有静态最后弦乐UID =_id;
    私有静态最后字符串名称=名称;
    私有静态最后弦乐卡=一卡通;
    私有静态最后弦乐code =code;
    私有静态最终诠释DATABASE_VERSION = 1;
    私有静态最后弦乐CREATE_TABLE =创建表
            + TABLE_NAME +（+ UID
            +整数主键自动增量，+姓名
            +文本不为空，+卡+转非空，+ code
            +文字NOT NULL）;;
    私有静态最后弦乐DROP_TABLE =DROP TABLE IF EXISTS
            + TABLE_NAME;
    私人上下文的背景下;

    公共DataBaseHelper（上下文的背景下）{

        超（背景下，DataBaseHelper.DATABASE_NAME，空，DataBaseHelper.DATABASE_VERSION）;
        this.context =背景;
        吐司面包= Toast.makeText（背景下，构造被称为，Toast.LENGTH_LONG）;
        toast.show（）;
    }

    @覆盖
    公共无效的onCreate（SQLiteDatabase DB）{
        // CREATE TABLE CARDSTABLE（_id INTEGER PRIMARY KEY AUTOINCREMENT，名称VARCHAR（255））;
        尝试 {
            db.execSQL（CREATE_TABLE）;
            吐司面包= Toast.makeText（背景下，的onCreate称为，Toast.LENGTH_LONG）;
            toast.show（）;

        }赶上（的SQLException E）{
            吐司面包= Toast.makeText（背景下，+ E，Toast.LENGTH_SHORT）;
            toast.show（）;
        }


    }

    @覆盖
    公共无效onUpgrade（SQLiteDatabase分贝，INT oldVersion，诠释静态网页）{

        尝试 {
            吐司面包= Toast.makeText（背景下，onUpgrade称为，Toast.LENGTH_LONG）;
            toast.show（）;
            db.execSQL（DROP_TABLE）;
            的onCreate（DB）;
        }赶上（的SQLException E）{
            吐司面包= Toast.makeText（背景下，+ E，Toast.LENGTH_LONG）;
            toast.show（）;
        }

    }
}

您的答案将是我真的有帮助，谢谢

编辑：

类公司Databeans： 

 公共类{公司Databeans
//私有变量
INT _id;
字符串_name;
字符串_card_value;
字符串_card_ code;

//空的构造
公众公司Databeans（）{

}
//构造
公众公司Databeans（INT ID，字符串名称，字符串_card_value，字符串_card_ code）{
    this._id = ID;
    this._name =名称;
    this._card_value = _card_value;
    this._card_ code = _card_ code;
}

//构造
公众公司Databeans（字符串名称，字符串_card_value，字符串_card_ code）{
    this._name =名称;
    this._card_value = _card_value;
    this._card_ code = _card_ code;
}
//获取ID
公众诠释的getID（）{
    返回this._id;
}

//设置ID
公共无效SETID（INT ID）{
    this._id = ID;
}

//获取名称
公共字符串的getName（）{
    返回this._name;
}

//设置名称
公共无效setname可以（字符串名称）{
    this._name =名称;
}

//获取CardValue
公共字符串getCardValue（）{
    返回this._card_value;
}

//设置CardValue
公共无效setCardValue（字符串_card_value）{
    this._card_value = _card_value;
}
//获取卡code
公共字符串getCard code（）{
    返回this._card_ code;
}

//设置卡code
公共无效setCard code（字符串_card_ code）{
    this._card_ code = _card_ code;
}

}

这些行我添加到我的 DataBaseAdapter 

 公众公司Databeans getDat（字符串名称）{
        豆公司Databeans = NULL;
        SQLiteDatabase DB = this.getReadableDatabase（）;
        的String []列= {DataBaseHelper.NAME，DataBaseHelper.CARD，DataBaseHelper code};
        光标光标= db.query（DataBaseHelper.TABLE_NAME，列，DataBaseHelper.NAME +=+姓名+'，NULL，NULL，NULL，NULL）;
        如果（cursor.moveToFirst（））{
            INT指数= cursor.getColumnIndex（DataBaseHelper.UID）;
            INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
            INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
            INT index4 = cursor.getColumnIndex（DataBaseHelper code）;
            INT ID = cursor.getInt（指数）;
            字符串PersonName的= cursor.getString（索引2）;
            串卡= cursor.getString（INDEX3）;
            字符串code = cursor.getString（index4）;
            豆=新公司Databeans（ID，姓名，卡号，code）;
        }
        返回豆;
    }
    公开名单＆LT;  - 公司Databeans GT; gelAllDat（）{
        名单＆LT;  - 公司Databeans GT;名单=新的ArrayList＆LT;＆GT;（）;
        SQLiteDatabase DB = this.getReadableDatabase（）;
        的String []列= {DataBaseHelper.NAME，DataBaseHelper.CARD，DataBaseHelper code};
        光标光标= db.query（DataBaseHelper.TABLE_NAME，列，DataBaseHelper.NAME，NULL，NULL，NULL，NULL）;
        而（cursor.moveToNext（））{
            INT指数= cursor.getColumnIndex（DataBaseHelper.UID）;
            INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
            INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
            INT index4 = cursor.getColumnIndex（DataBaseHelper code）;
            INT CID = cursor.getInt（指数）;
            字符串名称= cursor.getString（索引2）;
            串卡= cursor.getString（INDEX3）;
            字符串code = cursor.getString（index4）;
            豆公司Databeans =新公司Databeans（CID，姓名，卡号，code）;
            list.add（豆）;
        }
        返回列表;

    }

和最后一个问题？我需要改变我的插入数据 DataBaseAdapter

编辑2：

我说这code我DataBaseAdapter：

 公开名单＆LT;  - 公司Databeans GT; getAllCards（）{
    名单＆LT;  - 公司Databeans GT;名单=新的ArrayList＆LT;＆GT;（）;
    查询字符串=SELECT * FROM+ DataBaseHelper.TABLE_NAME;
    SQLiteDatabase DB = helper.getReadableDatabase（）;
    光标光标= db.rawQuery（查询，NULL）;
    而（cursor.moveToNext（））{
        // INT指数= cursor.getColumnIndex（DataBaseHelper.UID）;
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;
        // INT CID = cursor.getInt（指数）;
        字符串名称= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        豆公司Databeans =新公司Databeans（姓名，卡号，code）;
        list.add（豆）;
    }

    返回列表;

}

公众公司Databeans的getData（字符串名称）{
    //选择_id，姓名，卡，code
    SQLiteDatabase DB = helper.getReadableDatabase（）;
    的String []列= {DataBaseHelper.NAME，DataBaseHelper.CARD，DataBaseHelper code};
    豆公司Databeans = NULL;
    光标光标= db.query（DataBaseHelper.TABLE_NAME，列，DataBaseHelper.NAME +=+姓名+'，NULL，NULL，NULL，NULL）;
    StringBuffer的缓冲区=新的StringBuffer（）;
    而（cursor.moveToNext（））{
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;

        字符串PersonName的= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        //buffer.append(name ++卡++ code +\ N）;
        豆=新公司Databeans（姓名，卡号，code）;

    }
    返回豆;
}

解决方案

您可以用豆开始，以遏制和型号的相关信息，并使其更容易实现。

 公共类{公司Databeans
    保护INT ID;
    受保护的字符串名称;
    保护串证;
    保护字符串code;
    //二传手，getter和构造
    ...
}

随着创建公司Databeans，你可以改变你的方法或公司Databeans的列表，返回类型，填补每一种方法里面，而不是返回一个字符串的所有领域。

 公众公司Databeans的getData（字符串名称）{
    ...
    豆公司Databeans = NULL;
    如果（cursor.moveToFirst（））{
        INT指数= cursor.getColumnIndex（DataBaseHelper.UID）;
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;
        INT ID = cursor.getInt（指数）;
        字符串PersonName的= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        豆=新公司Databeans（ID，姓名，卡号，code）;
    }
    返回豆;
}

公开名单＆LT;  - 公司Databeans GT; getAllData（）{
    名单＆LT;  - 公司Databeans GT;名单=新的ArrayList＆LT;＆GT;（）;
    ...
    而（cursor.moveToNext（））{
        INT指数= cursor.getColumnIndex（DataBaseHelper.UID）;
        INT索引2 = cursor.getColumnIndex（DataBaseHelper.NAME）;
        INT INDEX3 = cursor.getColumnIndex（DataBaseHelper.CARD）;
        INT index4 = cursor.getColumnIndex（DataBaseHelper code）;
        INT CID = cursor.getInt（指数）;
        字符串名称= cursor.getString（索引2）;
        串卡= cursor.getString（INDEX3）;
        字符串code = cursor.getString（index4）;
        豆公司Databeans =新公司Databeans（CID，姓名，卡号，code）;
        list.add（豆）;
    }
    返回列表;
}

现在，当你打电话给你的方法，你有一个目标公司Databeans（S），现在你需要写你的适配器，显示在RecyclerView的信息。

首先需要在你的活动链接，并设置RecyclerView。

  mRecyclerView =（RecyclerView）findViewById（R.id.recycler_view）;
mRecyclerView.setHasFixedSize（真正的）;
mRecyclerView.setLayoutManager（新LinearLayoutManager（本））;
mRecyclerView.setItemAnimator（新DefaultItemAnimator（））;
mRecyclerView.setAdapter（新DataBeanAdapter（dbAdapter.getAllData（），R.layout.item））;

在您需要创建DataBeanAdapter和<一href="https://developer.android.com/reference/android/support/v7/widget/RecyclerView.ViewHolder.html"相对=nofollow> ViewHolder 。

 公共类DataBeanAdapter扩展RecyclerView.Adapter＆LT; D​​ataBeanAdapter.ViewHolder＆GT; {
    私人列表＆LT;  - 公司Databeans GT;项目;
    私人诠释itemLayout;

    公共DataBeanAdapter（名单＆LT;  - 公司Databeans GT;的项目，诠释itemLayout）{
        this.items =项目;
        this.itemLayout = itemLayout;
    }

    @覆盖
    公共ViewHolder onCreateViewHolder（ViewGroup中的父母，INT viewType）{
        视图V = LayoutInflater.from（parent.getContext（））膨胀（itemLayout，父母，假）。
        返回新ViewHolder（V）;
    }

    @覆盖
    公共无效onBindViewHolder（ViewHolder持有人，INT位置）{
        项目公司Databeans = items.get（位置）;
        holder.name.setText（item.getName（））;
        holder.card.setText（item.getCard（））;
        //所有的事情你要显示的项
    }

    @覆盖
    公众诠释getItemCount（）{
        返回items.size（）;
    }

    公共静态类ViewHolder扩展RecyclerView.ViewHolder {
        公共TextView的名称;
        公众的TextView卡;

        公共ViewHolder（查看ItemView控件）{
            超（ItemView控件）;
            NAME =（TextView中）itemView.findViewById（R.id.name）;
            卡=（TextView中）itemView.findViewById（R.id.card）;
        }
    }
}

本ID的，布局和ViewHolder取决于谁，你每个项目在RecyclerView要显示的属性。

i search a lot, but i didnt find any step-by-step guide how to dislpay SQLite data in RecyclerView. Can anyone explain me how can i do this?

My DataBaseAdapter :

public class DataBaseAdapter {

DataBaseHelper helper;

public DataBaseAdapter(Context context) {
    helper = new DataBaseHelper(context);
    }

public long insertData(String name, String card, String code) {

    SQLiteDatabase db = helper.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(DataBaseHelper.NAME, name);
    contentValues.put(DataBaseHelper.CARD, card);
    contentValues.put(DataBaseHelper.CODE, code);
    long id = db.insert(DataBaseHelper.TABLE_NAME, null, contentValues);
    return id;
}

public String getData(String name){
    //select _id,Name,Card,Code
    SQLiteDatabase db = helper.getWritableDatabase();
    String[] columns = {DataBaseHelper.NAME, DataBaseHelper.CARD, DataBaseHelper.CODE};
    Cursor cursor = db.query(DataBaseHelper.TABLE_NAME, columns,DataBaseHelper.NAME+" = '"+name+"'", null, null, null, null);
    StringBuffer buffer = new StringBuffer();
    while (cursor.moveToNext()) {
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);

        String personName = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        buffer.append(name + " " + card + " " + code + "\n");

    }
    return buffer.toString();
}

public String getAllData() {
    //select _id,Name,Card,Code
    SQLiteDatabase db = helper.getWritableDatabase();
    String[] columns = {DataBaseHelper.UID, DataBaseHelper.NAME, DataBaseHelper.CARD, DataBaseHelper.CODE};
    Cursor cursor = db.query(DataBaseHelper.TABLE_NAME, columns, null, null, null, null, null);
    StringBuffer buffer = new StringBuffer();
    while (cursor.moveToNext()) {
        int index1 = cursor.getColumnIndex(DataBaseHelper.UID);
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);

        int cid = cursor.getInt(index1);
        String name = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        buffer.append(cid + " " + name + " " + card + " " + code + "\n");
    }
    return buffer.toString();

}

static class DataBaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "cardsdatabase";
    private static final String TABLE_NAME = "CARDSTABLE";
    private static final String UID = "_id";
    private static final String NAME = "Name";
    private static final String CARD = "Card";
    private static final String CODE = "Code";
    private static final int DATABASE_VERSION = 1;
    private static final String CREATE_TABLE = "create table "
            + TABLE_NAME + " (" + UID
            + " integer primary key autoincrement, " + NAME
            + " text not null, " + CARD + " ext not null, " + CODE
            + " text not null);";
    private static final String DROP_TABLE = "DROP TABLE IF EXISTS "
            + TABLE_NAME;
    private Context context;

    public DataBaseHelper(Context context) {

        super(context, DataBaseHelper.DATABASE_NAME, null, DataBaseHelper.DATABASE_VERSION);
        this.context = context;
        Toast toast = Toast.makeText(context, "constructor called", Toast.LENGTH_LONG);
        toast.show();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        //CREATE TABLE CARDSTABLE(_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(255));
        try {
            db.execSQL(CREATE_TABLE);
            Toast toast = Toast.makeText(context, "onCreate called", Toast.LENGTH_LONG);
            toast.show();

        } catch (SQLException e) {
            Toast toast = Toast.makeText(context, "" + e, Toast.LENGTH_SHORT);
            toast.show();
        }


    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        try {
            Toast toast = Toast.makeText(context, "onUpgrade called", Toast.LENGTH_LONG);
            toast.show();
            db.execSQL(DROP_TABLE);
            onCreate(db);
        } catch (SQLException e) {
            Toast toast = Toast.makeText(context, "" + e, Toast.LENGTH_LONG);
            toast.show();
        }

    }
}

Your answers will be realy helpful for me, thanks

EDIT:

DataBean class :

public class DataBean {
//private variables
int _id;
String _name;
String _card_value;
String _card_code;

// Empty constructor
public DataBean(){

}
// constructor
public DataBean(int id, String name, String _card_value, String _card_code){
    this._id = id;
    this._name = name;
    this._card_value = _card_value;
    this._card_code = _card_code;
}

// constructor
public DataBean(String name, String _card_value, String _card_code){
    this._name = name;
    this._card_value = _card_value;
    this._card_code = _card_code;
}
// getting ID
public int getID(){
    return this._id;
}

// setting id
public void setID(int id){
    this._id = id;
}

// getting name
public String getName(){
    return this._name;
}

// setting name
public void setName(String name){
    this._name = name;
}

// getting CardValue
public String getCardValue(){
    return this._card_value;
}

// setting CardValue
public void setCardValue(String _card_value){
    this._card_value = _card_value;
}
// getting CardCode
public String getCardCode(){
    return this._card_code;
}

// setting CardCode
public void setCardCode(String _card_code){
    this._card_code = _card_code;
}

}

These lines i add to my DataBaseAdapter:

public DataBean getDat(String name){
        DataBean bean=null;
        SQLiteDatabase db=this.getReadableDatabase();
        String[] columns = {DataBaseHelper.NAME, DataBaseHelper.CARD, DataBaseHelper.CODE};
        Cursor cursor = db.query(DataBaseHelper.TABLE_NAME, columns,DataBaseHelper.NAME+" = '"+name+"'", null, null, null, null);
        if (cursor.moveToFirst()) {
            int index = cursor.getColumnIndex(DataBaseHelper.UID);
            int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
            int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
            int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);
            int id = cursor.getInt(index);
            String personName = cursor.getString(index2);
            String card = cursor.getString(index3);
            String code = cursor.getString(index4);
            bean = new DataBean(id, name, card, code);
        }
        return bean;
    }
    public List<DataBean> gelAllDat(){
        List<DataBean> list = new ArrayList<>();
        SQLiteDatabase db=this.getReadableDatabase();
        String[] columns = {DataBaseHelper.NAME, DataBaseHelper.CARD, DataBaseHelper.CODE};
        Cursor cursor = db.query(DataBaseHelper.TABLE_NAME, columns,DataBaseHelper.NAME, null, null, null, null);
        while (cursor.moveToNext()) {
            int index = cursor.getColumnIndex(DataBaseHelper.UID);
            int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
            int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
            int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);
            int cid = cursor.getInt(index);
            String name = cursor.getString(index2);
            String card = cursor.getString(index3);
            String code = cursor.getString(index4);
            DataBean bean = new DataBean(cid, name, card, code);
            list.add(bean);
        }
        return list;

    }

And last question? i need to change my insert data in DataBaseAdapter?

EDIT 2:

I added this code to my DataBaseAdapter:

public List<DataBean> getAllCards(){
    List<DataBean> list=new ArrayList<>();
    String query = "SELECT  * FROM " + DataBaseHelper.TABLE_NAME;
    SQLiteDatabase db = helper.getReadableDatabase();
    Cursor cursor = db.rawQuery(query, null);
    while (cursor.moveToNext()) {
        //int index = cursor.getColumnIndex(DataBaseHelper.UID);
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);
        //int cid = cursor.getInt(index);
        String name = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        DataBean bean = new DataBean(name, card, code);
        list.add(bean);
    }

    return list;

}

public DataBean getData(String name) {
    //select _id,Name,Card,Code
    SQLiteDatabase db = helper.getReadableDatabase();
    String[] columns = {DataBaseHelper.NAME, DataBaseHelper.CARD, DataBaseHelper.CODE};
    DataBean bean=null;
    Cursor cursor = db.query(DataBaseHelper.TABLE_NAME, columns, DataBaseHelper.NAME + " = '" + name + "'", null, null, null, null);
    StringBuffer buffer = new StringBuffer();
    while (cursor.moveToNext()) {
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);

        String personName = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        //buffer.append(name + " " + card + " " + code + "\n");
        bean = new DataBean( name,card, code);

    }
    return bean;
}

解决方案

You can start with a Bean to contain and model the information and make it more easy to implement.

public class DataBean{
    protected int id;
    protected String name;
    protected String card;
    protected String code;
    //Setter, Getters and constructor
    ...
}

With the DataBean created, you can change the return types of your methods to DataBean or a List and filled inside each method instead of return a String with all the fields.

public DataBean getData(String name){
    ...
    DataBean bean = null;
    if (cursor.moveToFirst()) {
        int index = cursor.getColumnIndex(DataBaseHelper.UID);
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);
        int id = cursor.getInt(index);
        String personName = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        bean = new DataBean(id, name, card, code);    
    }
    return bean;
}

public List<DataBean> getAllData() {
    List<DataBean> list = new ArrayList<>();
    ...
    while (cursor.moveToNext()) {
        int index = cursor.getColumnIndex(DataBaseHelper.UID);
        int index2 = cursor.getColumnIndex(DataBaseHelper.NAME);
        int index3 = cursor.getColumnIndex(DataBaseHelper.CARD);
        int index4 = cursor.getColumnIndex(DataBaseHelper.CODE);
        int cid = cursor.getInt(index);
        String name = cursor.getString(index2);
        String card = cursor.getString(index3);
        String code = cursor.getString(index4);
        DataBean bean = new DataBean(cid, name, card, code);
        list.add(bean);
    }
    return list;
}

Now when you call your methods you have a DataBean object(s), now you need write your Adapter to show the information in the RecyclerView.

First need link and setup the RecyclerView in your Activity.

mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mRecyclerView.setAdapter(new DataBeanAdapter(dbAdapter.getAllData(), R.layout.item));

After you need create the DataBeanAdapter and the ViewHolder.

public class DataBeanAdapter extends RecyclerView.Adapter<DataBeanAdapter.ViewHolder>{
    private List<DataBean> items;
    private int itemLayout;

    public DataBeanAdapter(List<DataBean> items, int itemLayout){
        this.items = items;
        this.itemLayout = itemLayout;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(itemLayout, parent, false);
        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        DataBean item = items.get(position);
        holder.name.setText(item.getName());
        holder.card.setText(item.getCard());
        //All the thing you gonna show in the item
    }

    @Override
    public int getItemCount() {
        return items.size();
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public TextView name;
        public TextView card;

        public ViewHolder(View itemView) {
            super(itemView);
            name = (TextView) itemView.findViewById(R.id.name);
            card = (TextView) itemView.findViewById(R.id.card);
        }
    }
}

The id's, layout and the attributes of the ViewHolder depending who you gonna show per item in the RecyclerView.

这篇关于在RecyclerView显示SQLite的数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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