我试着找了一个教程来学习如何使用sqlite制作recycleview,但是我对他的步骤了解得不太清楚。有没有人能够帮助我解决以下问题:如何创建一个从sqlite获取数据并适配到recycleview上的适配器。
RecyclerViewHolder.java
package com.my.app;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
public class RecyclerViewHolder extends RecyclerView.ViewHolder {
TextView tv1;
ImageView imageView;
public RecyclerViewHolder(View itemView) {
super(itemView);
tv1 =(TextView)itemView.findViewById(R.id.data_kategori);
imageView=(ImageView)itemView.findViewById(R.id.list_kategori);
}
}
RecycleAdapter.java
package com.my.app;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
public class RecycleAdapter extends RecyclerView.Adapter<RecycleAdapter.myViewHolder> {
public ArrayList<String> myValues;
public RecycleAdapter (ArrayList<String> myValues){
this.myValues = myValues;
}
@Override
public RecycleAdapter.myViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View listitem =LayoutInflater.from(parent.getContext()).inflate(R.layout.list_kategori, parent, false);
return new myViewHolder(listitem);
}
@Override
public void onBindViewHolder(RecycleAdapter.myViewHolder holder, int position) {
holder.data_nm.setText(myValues.get(position));
}
@Override
public int getItemCount() {
return myValues.size();
}
public static class myViewHolder extends RecyclerView.ViewHolder {
private TextView data_nm;
public myViewHolder (View itemView) {
super(itemView);
data_nm =(TextView)itemView.findViewById(R.id.data_kategori);
}
}
}
DbHelper.java
package com.my.app;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DbHelper extends SQLiteOpenHelper {
// Database Information
static final String DB_NAME = "SavePassword";
// database version
static final int DB_VERSION = 1;
// Table Name
public static final String kategori_tb = "tb_kategori";
// Table columns
public static final String kategori_id = "_id";
public static final String kategori_nm = "nm";
// Creating table query
private static final String data_kategori = "create table " + kategori_tb + "(" + kategori_id
+ " INTEGER PRIMARY KEY AUTOINCREMENT, " + kategori_nm + " TEXT NOT NULL);";
public DbHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(data_kategori);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + data_kategori);
onCreate(db);
}
}
**DbManager.java**
package com.my.app;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class DbManager {
private DbHelper dbHelper;
private Context context;
private SQLiteDatabase database;
public DbManager(Context c) {
context = c;
}
public DbManager open() throws SQLException {
dbHelper = new DbHelper(context);
database = dbHelper.getWritableDatabase();
return this;
}
public void close() {
dbHelper.close();
}
public Cursor fetch_data() {
String[] columns = new String[] { DbHelper.kategori_id, DbHelper.kategori_nm };
Cursor cursor = database.query(DbHelper.kategori_tb, columns, null, null, null, null, null);
if (cursor != null) {
cursor.moveToFirst();
}
return cursor;
}
public void insert_data(String nm_kategori) {
ContentValues value = new ContentValues();
value.put(DbHelper.kategori_nm, nm_kategori);
database.insert(DbHelper.kategori_tb, null, value);
}
}
MainActivity.java
package com.savepassword.app;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.res.Resources;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.AppCompatEditText;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.util.ArrayList;
import static com.savepassword.app.R.id.nama_kategori;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, View.OnClickListener {
RecyclerView recyclerView;
private DbManager dbManager;
private Button crk;
private Context context = this;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<String> myValues = new ArrayList<>();
//adapter = new SimpleCursorAdapter(this, R.layout.view_akun, cursor, from, to, 0);
myValues.add("kitkat");
myValues.add("lolipop");
myValues.add("nougat");
RecycleAdapter adapter = new RecycleAdapter(myValues);
RecyclerView myView = (RecyclerView)findViewById(R.id.rc_kategori);
myView.setHasFixedSize(true);
myView.setAdapter(adapter);
myView.setLayoutManager(new GridLayoutManager(this, 2));
myView.addItemDecoration(new GridSpacingItemDecoration(2, dpToPx(10), true));
myView.setItemAnimator(new DefaultItemAnimator());
}
}