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问题描述
我试图找到一个如何使用sqlite进行recycleview的教程，但我对他的步骤知之甚少.有谁可以帮助我解决以下问题.创建sqlite的数据适配器recycleview.
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()); } }解决方案
没有可用于直接将CursorAdapter或Cursor与Recyclerview.Adapter<>一起使用的东西.
相反，您可以做的是使用Cursor从sqlite获取数据，将数据填充到ArrayList中并将其传递给Recyclerview.Adapter.
这是使用加载器
I've tried to find a tutorial how to make recycleview with sqlite but I am a little less understood his steps. is there who can help me to solve the following problem. create a data adapter recycleview of sqlite.
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()); } }解决方案
There is no such things available to use CursorAdapter or a Cursor directly with Recyclerview.Adapter<>.
Instead what you can do is Fetch data from sqlite using Cursor, populate data into an ArrayList and pass it to the Recyclerview.Adapter.
Here is another approach of using Loaders
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如何从sqlite数据库附加RecyclerView适配器
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